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A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. Blast refers to the combustion air being supplied above atmospheric pressure.^[1]

In a blast furnace, fuel (coke), ores, and flux (limestone) are continuously supplied through the top of the furnace, while a hot blast of air (sometimes with oxygen enrichment) is blown into the lower section of the furnace through a series of pipes called tuyeres, so that the chemical reactions take place throughout the furnace as the material falls downward. The end products are usually molten metal and slag phases tapped from the bottom, and waste gases (flue gas) exiting from the top of the furnace.^[2] The downward flow of the ore along with the flux in contact with an upflow of hot, carbon monoxide-rich combustion gases is a countercurrent exchange and chemical reaction process.^[3]

In contrast, air furnaces (such as reverberatory furnaces) are naturally aspirated, usually by the convection of hot gases in a chimney flue. According to this broad definition, bloomeries for iron, blowing houses for tin, and smelt mills for lead would be classified as blast furnaces. However, the term has usually been limited to those used for smelting iron ore to produce pig iron, an intermediate material used in the production of commercial iron and steel, and the shaft furnaces used in combination with sinter plants in base metals smelting.^[4]^[5]

Blast furnaces are estimated to have been responsible for over 4% of global greenhouse gas emissions between 1900 and 2015, but are difficult to decarbonize.^[6]

Process engineering and chemistry

Blast furnaces of Třinec Iron and Steel Works in Czech Republic

Blast furnaces operate on the principle of chemical reduction whereby carbon monoxide converts iron oxides to elemental iron.

Blast furnaces differ from bloomeries and reverberatory furnaces in that in a blast furnace, flue gas is in direct contact with the ore and iron, allowing carbon monoxide to diffuse into the ore and reduce the iron oxide. The blast furnace operates as a countercurrent exchange process whereas a bloomery does not. Another difference is that bloomeries operate as a batch process whereas blast furnaces operate continuously for long periods. Continuous operation is also preferred because blast furnaces are difficult to start and stop. Also, the carbon in pig iron lowers the melting point below that of steel or pure iron; in contrast, iron does not melt in a bloomery.

Silica has to be removed from the pig iron. It reacts with calcium oxide (burned limestone) and forms silicates, which float to the surface of the molten pig iron as slag. Historically, to prevent contamination from sulfur, the best quality iron^{[according to whom?]} was produced with charcoal.^{[citation needed]}

In a blast furnace, a downward-moving column of ore, flux, coke (or charcoal^{[citation needed]}) and their reaction products must be sufficiently porous for the flue gas to pass through, upwards. To ensure this permeability the particle size of the coke or charcoal is of great relevance. Therefore, the coke must be strong enough so it will not be crushed by the weight of the material above it. Besides the physical strength of its particles, the coke must also be low in sulfur, phosphorus, and ash.^[7]

The main chemical reaction producing the molten iron is:

Fe₂O₃ + 3CO → 2Fe + 3CO₂^[8]

This reaction might be divided into multiple steps, with the first being that preheated air blown into the furnace reacts with the carbon in the form of coke to produce carbon monoxide and heat:

2 C_(s) + O_2(g) → 2 CO_(g)^[9]

Hot carbon monoxide is the reducing agent for the iron ore and reacts with the iron oxide to produce molten iron and carbon dioxide. Depending on the temperature in the different parts of the furnace (warmest at the bottom) the iron is reduced in several steps. At the top, where the temperature usually is in the range between 200 °C and 700 °C, the iron oxide is partially reduced to iron(II,III) oxide, Fe₃O₄.

3 Fe₂O_3(s) + CO_(g) → 2 Fe₃O_4(s) + CO_2(g)^[9]

The temperatures 850 °C, further down in the furnace, the iron(II,III) is reduced further to iron(II) oxide:

Fe₃O_4(s) + CO_(g) → 3 FeO_(s) + CO_2(g)^[9]

Hot carbon dioxide, unreacted carbon monoxide, and nitrogen from the air pass up through the furnace as fresh feed material travels down into the reaction zone. As the material travels downward, the counter-current gases both preheat the feed charge and decompose the limestone to calcium oxide and carbon dioxide:

CaCO_3(s) → CaO_(s) + CO_2(g)^[9]

The calcium oxide formed by decomposition reacts with various acidic impurities in the iron (notably silica), to form a fayalitic slag which is essentially calcium silicate, Ca Si O
₃:^[8]

SiO₂ + CaO → CaSiO₃^[10]^[11]

As the iron(II) oxide moves down to the area with higher temperatures, ranging up to 1200 °C degrees, it is reduced further to iron metal:

FeO_(s) + CO_(g) → Fe_(s) + CO_2(g)^[9]

The carbon dioxide formed in this process is re-reduced to carbon monoxide by the coke:

C_(s) + CO_2(g) → 2 CO_(g)^[9]

The temperature-dependent equilibrium controlling the gas atmosphere in the furnace is called the Boudouard reaction:

2CO ⇌ CO₂ + C

The pig iron produced by the blast furnace has a relatively high carbon content of around 4–5% and usually contains too much sulphur, making it very brittle, and of limited immediate commercial use. Some pig iron is used to make cast iron. The majority of pig iron produced by blast furnaces undergoes further processing to reduce the carbon and sulphur content and produce various grades of steel used for construction materials, automobiles, ships and machinery. Desulphurisation usually takes place during the transport of the liquid steel to the steelworks. This is done by adding calcium oxide, which reacts with the iron sulfide contained in the pig iron to form calcium sulfide (called lime desulfurization).^[12] In a further process step, the so-called basic oxygen steelmaking, the carbon is oxidized by blowing oxygen onto the liquid pig iron to form crude steel.

History

Cast iron has been found in China dating to the 5th century BC, but the earliest extant blast furnaces in China date to the 1st century AD and in the West from the High Middle Ages.^[13] They spread from the region around Namur in Wallonia (Belgium) in the late 15th century, being introduced to England in 1491. The fuel used in these was invariably charcoal. The successful substitution of coke for charcoal is widely attributed to English inventor Abraham Darby in 1709. The efficiency of the process was further enhanced by the practice of preheating the combustion air (hot blast), patented by Scottish inventor James Beaumont Neilson in 1828.^[14]

China

Archaeological evidence shows that bloomeries appeared in China around 800 BC. Originally it was thought that the Chinese started casting iron right from the beginning, but this theory has since been debunked^{[clarification needed]} by the discovery of 'more than ten' iron digging implements found in the tomb of Duke Jing of Qin (d. 537 BC), whose tomb is located in Fengxiang County, Shaanxi (a museum exists on the site today).^[15] There is however no evidence of the bloomery in China after the appearance of the blast furnace and cast iron. In China, blast furnaces produced cast iron, which was then either converted into finished implements in a cupola furnace, or turned into wrought iron in a fining hearth.^[16]

Although cast iron farm tools and weapons were widespread in China by the 5th century BC^{[citation needed]}, employing workforces of over 200 men in iron smelters from the 3rd century onward, the earliest blast furnaces constructed were attributed to the Han dynasty in the 1st century AD.^[17] These early furnaces had clay walls and used phosphorus-containing minerals as a flux.^[18] Chinese blast furnaces ranged from around two to ten meters in height, depending on the region. The largest ones were found in modern Sichuan and Guangdong, while the 'dwarf" blast furnaces were found in Dabieshan. In construction, they are both around the same level of technological sophistication.^[19]

The effectiveness of the Chinese human and horse powered blast furnaces was enhanced during this period by the engineer Du Shi (c. AD 31), who applied the power of waterwheels to piston-bellows in forging cast iron.^[20] Early water-driven reciprocators for operating blast furnaces were built according to the structure of horse powered reciprocators that already existed. That is, the circular motion of the wheel, be it horse driven or water driven, was transferred by the combination of a belt drive, a crank-and-connecting-rod, other connecting rods, and various shafts, into the reciprocal motion necessary to operate a push bellow.^[21]^[22] Donald Wagner suggests that early blast furnace and cast iron production evolved from furnaces used to melt bronze. Certainly, though, iron was essential to military success by the time the State of Qin had unified China (221 BC). Usage of the blast and cupola furnace remained widespread during the Song and Tang dynasties.^[23] By the 11th century, the Song dynasty Chinese iron industry made a switch of resources from charcoal to coke in casting iron and steel, sparing thousands of acres of woodland from felling. This may have happened as early as the 4th century AD.^[24]^[25]

The primary advantage of the early blast furnace was in large scale production and making iron implements more readily available to peasants.^[26] Cast iron is more brittle than wrought iron or steel, which required additional fining and then cementation or co-fusion to produce, but for menial activities such as farming it sufficed. By using the blast furnace, it was possible to produce larger quantities of tools such as ploughshares more efficiently than the bloomery. In areas where quality was important, such as warfare, wrought iron and steel were preferred. Nearly all Han period weapons are made of wrought iron or steel, with the exception of axe-heads, of which many are made of cast iron.^[27]

Blast furnaces were also later used to produce gunpowder weapons such as cast iron bomb shells and cast iron cannons during the Song dynasty.^[28]

Medieval Europe

The simplest forge, known as the Corsican, was used prior to the advent of Christianity. Examples of improved bloomeries are the Stuckofen,^[29] sometimes called wolf-furnace,^[30] which remained until the beginning of the 19th century. Instead of using natural draught, air was pumped in by a trompe, resulting in better quality iron and an increased capacity. This pumping of air in with bellows is known as cold blast, and it increases the fuel efficiency of the bloomery and improves yield. They can also be built bigger than natural draught bloomeries.

Oldest European blast furnaces

The oldest known blast furnaces in the West were built in Durstel in Switzerland, the Märkische Sauerland in Germany, and at Lapphyttan in Sweden, where the complex was active between 1205 and 1300.^[31] At Noraskog in the Swedish parish of Järnboås, traces of even earlier blast furnaces have been found, possibly from around 1100.^[32] These early blast furnaces, like the Chinese examples, were very inefficient compared to those used today. The iron from the Lapphyttan complex was used to produce balls of wrought iron known as osmonds, and these were traded internationally – a possible reference occurs in a treaty with Novgorod from 1203 and several certain references in accounts of English customs from the 1250s and 1320s. Other furnaces of the 13th to 15th centuries have been identified in Westphalia.^[33]

The technology required for blast furnaces may have either been transferred from China, or may have been an indigenous innovation. Al-Qazvini in the 13th century and other travellers subsequently noted an iron industry in the Alburz Mountains to the south of the Caspian Sea. This is close to the silk route, so that the use of technology derived from China is conceivable. Much later descriptions record blast furnaces about three metres high.^[34] As the Varangian Rus' people from Scandinavia traded with the Caspian (using their Volga trade route), it is possible that the technology reached Sweden by this means.^[35] The Vikings are known to have used double bellows, which greatly increases the volumetric flow of the blast.^[36]

The Caspian region may also have been the source for the design of the furnace at Ferriere, described by Filarete,^[37] involving a water-powered bellows at Semogo in Valdidentro in northern Italy in 1226. In a two-stage process the molten iron was tapped twice a day into water, thereby granulating it.^[38]

Cistercian contributions

The General Chapter of the Cistercian monks spread some technological advances across Europe. This may have included the blast furnace, as the Cistercians are known to have been skilled metallurgists.^[39] According to Jean Gimpel, their high level of industrial technology facilitated the diffusion of new techniques: "Every monastery had a model factory, often as large as the church and only several feet away, and waterpower drove the machinery of the various industries located on its floor." Iron ore deposits were often donated to the monks along with forges to extract the iron, and after a time surpluses were offered for sale. The Cistercians became the leading iron producers in Champagne, France, from the mid-13th century to the 17th century,^[40] also using the phosphate-rich slag from their furnaces as an agricultural fertilizer.^[41]

Archaeologists are still discovering the extent of Cistercian technology.^[42] At Laskill, an outstation of Rievaulx Abbey and the only medieval blast furnace so far identified in Britain, the slag produced was low in iron content.^[43] Slag from other furnaces of the time contained a substantial concentration of iron, whereas Laskill is believed to have produced cast iron quite efficiently.^[43]^[44]^[45] Its date is not yet clear, but it probably did not survive until Henry VIII's Dissolution of the Monasteries in the late 1530s, as an agreement (immediately after that) concerning the "smythes" with the Earl of Rutland in 1541 refers to blooms.^[46] Nevertheless, the means by which the blast furnace spread in medieval Europe has not finally been determined.

Origin and spread of early modern blast furnaces

Early modern blast furnace pictured in the former coat of arms of Lohtaja

Due to the increased demand for iron for casting cannons, the blast furnace came into widespread use in France in the mid 15th century.^[47]^[48]

The direct ancestor of those used in France and England was in the Namur region, in what is now Wallonia (Belgium). From there, they spread first to the Pays de Bray on the eastern boundary of Normandy and from there to the Weald of Sussex, where the first furnace (called Queenstock) in Buxted was built in about 1491, followed by one at Newbridge in Ashdown Forest in 1496. They remained few in number until about 1530 but many were built in the following decades in the Weald, where the iron industry perhaps reached its peak about 1590. Most of the pig iron from these furnaces was taken to finery forges for the production of bar iron.^[49]

The first British furnaces outside the Weald appeared during the 1550s, and many were built in the remainder of that century and the following ones. The output of the industry probably peaked about 1620, and was followed by a slow decline until the early 18th century. This was apparently because it was more economic to import iron from Sweden and elsewhere than to make it in some more remote British locations. Charcoal that was economically available to the industry was probably being consumed as fast as the wood to make it grew.^[50]

The first blast furnace in Russia opened in 1637 near Tula and was called the Gorodishche Works. The blast furnace spread from there to central Russia and then finally to the Urals.^[51]

Coke blast furnaces

In 1709, at Coalbrookdale in Shropshire, England, Abraham Darby began to fuel a blast furnace with coke instead of charcoal. Coke's initial advantage was its lower cost, mainly because making coke required much less labor than cutting trees and making charcoal, but using coke also overcame localized shortages of wood, especially in Britain and eleswhere in Europe. Metallurgical grade coke will bear heavier weight than charcoal, allowing larger furnaces.^[52]^[53] A disadvantage is that coke contains more impurities than charcoal, with sulfur being especially detrimental to the iron's quality. Coke's impurities were more of a problem before hot blast reduced the amount of coke required and before furnace temperatures were hot enough to make slag from limestone free flowing. (Limestone ties up^{[further explanation needed]} sulphur. Manganese may also be added to tie up^{[clarification needed]} sulphur.)^[54]^{: 123–125}^[55]^[56]^[47]^{: 122–123}

Coke iron was initially only used for foundry work, making pots and other cast iron goods. Foundry work was a minor branch of the industry, but Darby's son built a new furnace at nearby Horsehay, and began to supply the owners of finery forges with coke pig iron for the production of bar iron. Coke pig iron was by this time cheaper to produce than charcoal pig iron. The use of a coal-derived fuel in the iron industry was a key factor in the British Industrial Revolution.^[57]^[58]^[59] However, in many areas of the world charcoal was cheaper while coke was more expensive even after the Industrial Revolution: e. g., in the US charcoal-fueled iron production fell in share to about a half ca. 1850^[60] but still continued to increase in absolute terms until ca. 1890,^[61] while in João Monlevade in the Brazilian Highlands charcoal-fired blast furnaces were built as late as the 1930s and only phased out in 2000.^[62]

Darby's original blast furnace has been archaeologically excavated and can be seen in situ at Coalbrookdale, part of the Ironbridge Gorge Museums. Cast iron from the furnace was used to make girders for the world's first cast iron bridge in 1779. The Iron Bridge crosses the River Severn at Coalbrookdale and remains in use for pedestrians.

Steam-powered blast

The steam engine was applied to power blast air, overcoming a shortage of water power in areas where coal and iron ore were located. This was first done at Coalbrookdale where a steam engine replaced a horse-powered pump in 1742.^[63] Such engines were used to pump water to a reservoir above the furnace. The first engines used to blow cylinders directly was supplied by Boulton and Watt to John Wilkinson's New Willey Furnace.^[64] This powered a cast iron blowing cylinder, which had been invented by his father Isaac Wilkinson. He patented such cylinders in 1736,^[65] to replace the leather bellows, which wore out quickly. Isaac was granted a second patent, also for blowing cylinders, in 1757.^[66] The steam engine and cast iron blowing cylinder led to a large increase in British iron production in the late 18th century.^[47]

Hot blast

Hot blast was the single most important advance in fuel efficiency of the blast furnace and was one of the most important technologies developed during the Industrial Revolution.^[67]^[68] Hot blast was patented by James Beaumont Neilson at Wilsontown Ironworks in Scotland in 1828. Within a few years of the introduction, hot blast was developed to the point where fuel consumption was cut by one-third using coke or two-thirds using coal, while furnace capacity was also significantly increased. Within a few decades, the practice was to have a "stove" as large as the furnace next to it into which the waste gas (containing CO) from the furnace was directed and burnt. The resultant heat was used to preheat the air blown into the furnace.^[69]

Hot blast enabled the use of raw anthracite coal, which was difficult to light, in the blast furnace. Anthracite was first tried successfully by George Crane at Ynyscedwyn Ironworks in south Wales in 1837.^[70] It was taken up in America by the Lehigh Crane Iron Company at Catasauqua, Pennsylvania, in 1839. Anthracite use declined when very high capacity blast furnaces requiring coke were built in the 1870s.

Modern applications of the blast furnace

Iron blast furnaces

The blast furnace remains an important part of modern iron production. Modern furnaces are highly efficient, including Cowper stoves to pre-heat the blast air and employ recovery systems to extract the heat from the hot gases exiting the furnace. Competition in industry drives higher production rates. The largest blast furnace in the world is in South Korea, with a volume around 6,000 m³ (210,000 cu ft). It can produce around 5,650,000 tonnes (5,560,000 LT) of iron per year.^[71]

This is a great increase from the typical 18th-century furnaces, which averaged about 360 tonnes (350 long tons; 400 short tons) per year. Variations of the blast furnace, such as the Swedish electric blast furnace, have been developed in countries which have no native coal resources.

According to Global Energy Monitor, the blast furnace is likely to become obsolete to meet climate change objectives of reducing carbon dioxide emission,^[72] but BHP disagrees.^[73] An alternative process involving direct reduced iron (DRI) is likely to succeed it,^{[citation needed]} but this also needs to use a blast furnace to melt the iron and remove the gangue (impurities) unless the ore is very high quality.^[73]

Oxygen blast furnace

The oxygen blast furnace (OBF) process has been extensively studied theoretically because of the potentials of promising energy conservation and CO₂ emission reduction.^[74] This type may be the most suitable for use with CCS.^[73] The main blast furnace has of three levels; the reduction zone (523–973 K (250–700 °C; 482–1,292 °F)), slag formation zone (1,073–1,273 K (800–1,000 °C; 1,472–1,832 °F)), and the combustion zone (1,773–1,873 K (1,500–1,600 °C; 2,732–2,912 °F)).

Blast furnaces are currently rarely used in copper smelting, but modern lead smelting blast furnaces are much shorter than iron blast furnaces and are rectangular in shape.^[75] Modern lead blast furnaces are constructed using water-cooled steel or copper jackets for the walls, and have no refractory linings in the side walls.^[76] The base of the furnace is a hearth of refractory material (bricks or castable refractory).^[76] Lead blast furnaces are often open-topped rather than having the charging bell used in iron blast furnaces.^[77]

The blast furnace used at the Nyrstar Port Pirie lead smelter differs from most other lead blast furnaces in that it has a double row of tuyeres rather than the single row normally used.^[75] The lower shaft of the furnace has a chair shape with the lower part of the shaft being narrower than the upper.^[75] The lower row of tuyeres being located in the narrow part of the shaft.^[75] This allows the upper part of the shaft to be wider than the standard.^[75]

Zinc blast furnaces

The blast furnaces used in the Imperial Smelting Process ("ISP") were developed from the standard lead blast furnace, but are fully sealed.^[78] This is because the zinc produced by these furnaces is recovered as metal from the vapor phase, and the presence of oxygen in the off-gas would result in the formation of zinc oxide.^[78]

Blast furnaces used in the ISP have a more intense operation than standard lead blast furnaces, with higher air blast rates per m² of hearth area and a higher coke consumption.^[78]

Zinc production with the ISP is more expensive than with electrolytic zinc plants, so several smelters operating this technology have closed in recent years.^[79] However, ISP furnaces have the advantage of being able to treat zinc concentrates containing higher levels of lead than can electrolytic zinc plants.^[78]

Manufacture of stone wool

Stone wool or rock wool is a spun mineral fibre used as an insulation product and in hydroponics. It is manufactured in a blast furnace fed with diabase rock which contains very low levels of metal oxides. The resultant slag is drawn off and spun to form the rock wool product.^[80] Very small amounts of metals are also produced which are an unwanted by-product.

Modern iron process

**Blast furnace diagram**
Hot blast from Cowper stoves
Melting zone (*bosh*)
Reduction zone of ferrous oxide (*barrel*)
Reduction zone of ferric oxide (*stack*)
Pre-heating zone (*throat*)
Feed of ore, limestone, and coke
Exhaust gases
Column of ore, coke and limestone
Removal of slag
Tapping of molten pig iron
Collection of waste gases

Modern furnaces are equipped with an array of supporting facilities to increase efficiency, such as ore storage yards where barges are unloaded. The raw materials are transferred to the stockhouse complex by ore bridges, or rail hoppers and ore transfer cars. Rail-mounted scale cars or computer controlled weight hoppers weigh out the various raw materials to yield the desired hot metal and slag chemistry. The raw materials are brought to the top of the blast furnace via a skip car powered by winches or conveyor belts.^[81]

There are different ways in which the raw materials are charged into the blast furnace. Some blast furnaces use a "double bell" system where two "bells" are used to control the entry of raw material into the blast furnace. The purpose of the two bells is to minimize the loss of hot gases in the blast furnace. First, the raw materials are emptied into the upper or small bell which then opens to empty the charge into the large bell. The small bell then closes, to seal the blast furnace, while the large bell rotates to provide specific distribution of materials before dispensing the charge into the blast furnace.^[82]^[83] A more recent design is to use a "bell-less" system. These systems use multiple hoppers to contain each raw material, which is then discharged into the blast furnace through valves.^[82] These valves are more accurate at controlling how much of each constituent is added, as compared to the skip or conveyor system, thereby increasing the efficiency of the furnace. Some of these bell-less systems also implement a discharge chute in the throat of the furnace (as with the Paul Wurth top) in order to precisely control where the charge is placed.^[84]

The iron making blast furnace itself is built in the form of a tall structure, lined with refractory brick, and profiled to allow for expansion of the charged materials as they heat during their descent, and subsequent reduction in size as melting starts to occur. Coke, limestone flux, and iron ore (iron oxide) are charged into the top of the furnace in a precise filling order which helps control gas flow and the chemical reactions inside the furnace. Four "uptakes" allow the hot, dirty gas high in carbon monoxide content to exit the furnace throat, while "bleeder valves" protect the top of the furnace from sudden gas pressure surges. The coarse particles in the exhaust gas settle in the "dust catcher" and are dumped into a railroad car or truck for disposal, while the gas itself flows through a venturi scrubber and/or electrostatic precipitators and a gas cooler to reduce the temperature of the cleaned gas.^[81]

The "casthouse" at the bottom half of the furnace contains the bustle^{[clarification needed]} pipe, water cooled copper tuyeres and the equipment for casting the liquid iron and slag. Once a "taphole" is drilled through the refractory clay plug, liquid iron and slag flow down a trough through a "skimmer" opening, separating the iron and slag. Modern, larger blast furnaces may have as many as four tapholes and two casthouses.^[81] Once the pig iron and slag has been tapped, the taphole is again plugged with refractory clay.

The tuyeres are used to implement a hot blast, which is used to increase the efficiency of the blast furnace. The hot blast is directed into the furnace through water-cooled copper nozzles called tuyeres near the base. The hot blast temperature can be from 900 to 1,300 °C (1,650 to 2,370 °F) depending on the stove design and condition. The temperatures they deal with may be 2,000 to 2,300 °C (3,630 to 4,170 °F). Oil, tar, natural gas, powdered coal and oxygen can also be injected into the furnace at tuyere level to combine with the coke to release additional energy and increase the percentage of reducing gases present which is necessary to increase productivity.^[81]

The exhaust gasses of a blast furnace are generally cleaned in the dust collector – such as an inertial separator, a baghouse, or an electrostatic precipitator. Each type of dust collector has strengths and weaknesses – some collect fine particles, some coarse particles, some collect electrically charged particles. Effective exhaust clearing relies on multiple stages of treatment.^[85] Waste heat is usually collected from the exhaust gases, for example by the use of a Cowper stove, a variety of heat exchanger.

Environmental impact

Fossil fuel (coke, natural gas) use in blast furnaces is a source of greenhouse gas emissions and the blast furnace is the most emission intensive stage of the steel making process.^[86]^[87] Fuels and reductants such as plastic waste,^[88] biomass^[89] and hydrogen^[90] are being used by steelmakers^[91] as possible alternatives to fossil fuels, although cost and availability remain a challenge^{[citation needed]} and deployment is limited.

Electric arc furnaces (EAF) are cited as an alternative steel production path which avoids the use of blast furnaces, however, depending on the characteristics of the steel product required the two furnace types are not always interchangeable. Furthermore, EAFs utilize steel scrap as a feedstock but estimates suggest that there will not be enough scrap available to meet future steel demand.^[92] Using hydrogen gas as a reductant to produce DRI (so called H2-DRI) from iron ore, which is then used as a feedstock for an EAF provides a technologically feasible, low emission alternative to blast furnaces.^[90] The H2-DRI EAF production route is in a fledgling state, with just one plant in operation.^[93]

A 2000 report from the International Energy Agency Greenhouse Gas Technical Collaboration Programme (IEAGHG)^[94] shows that 70% of the CO₂ emissions from integrated steel plants arise directly from the blast furnace gas (BFG). By treating BFG with carbon capture technology prior to use for heat exchange and energy recovery within the plant, a portion of these emissions can be abated. The report estimates that chemical CO₂ absorption would cost $35/t of CO₂, plus $8–20/t CO₂ for transportation and storage.^[94] At the time, this would have increased steel production costs by 15–20%,^[87] ^{[citation needed]} presenting a barrier to decarbonisation for steelmakers which typically operate with margins of 8-10%.^[95] As of 2024 no blast furnaces have been equipped with carbon capture technology.

ULCOS (Ultra Low CO₂ Steelmaking)^[96] was a European programme exploring processes to reduce blast furnace emissions by at least 50%. Technologies identified include carbon capture and storage (CCS) and alternative energy sources and reductants such as hydrogen, electricity and biomass.^[97]

Preserved historic blast furnaces

Historically it was normal procedure for a decommissioned blast furnace to be demolished and either replaced with a newer, improved one, or to have the entire site demolished and treated for follow-up use of the area. In recent decades, several countries have realized the historic value of blast furnaces and have transformed them into museums. Examples can be found in the Czech Republic, France, Germany, Japan, Luxembourg, Poland, Romania, Mexico, Russia, Spain, United Kingdom, and United States.

Gallery

Abandoned blast furnace in Sestao, Spain. The furnace itself is inside the central girderwork.
Part of the gas cleaning system of a blast furnace in Monclova, Mexico. This one is about to be de-commissioned and replaced.

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^ tec-science (21 June 2018). "From pig iron to crude steel". tec-science. Retrieved 2 November 2019.
^ Peter J. Golas (1999). Science and Civilisation in China: Volume 5, Chemistry and Chemical Technology, Part 13, Mining. Cambridge University Press. p. 152. ISBN 978-0-521-58000-7. ...earliest blast furnace discovered in China from about the first century AD
^ Simcoe, Charles R. "The Age of Steel: Part II." Advanced Materials & Processes 172.4 (2014): 32–33. Academic Search Premier.
^ "The Earliest Use of Iron in China" by Donald B. Wagner in Metals in Antiquity, by Suzanne M. M. Young, A. Mark Pollard, Paul Budd and Robert A. Ixer (BAR International Series, 792), Oxford: Archaeopress, 1999, pp. 1–9.
^ Wagner 2008, p. 230.
^ Ebrey, p. 30.
^ Early iron in China, Korea, and Japan Archived 5 February 2007 at the Wayback Machine, Donald B. Wagner, March 1993
^ Wagner 2008, p. 6.
^ Needham, Joseph (1986), Science and Civilisation in China, Volume 4: Physics and Physical Technology, Part 2, Mechanical Engineering, Taipei: Cambridge University Press, p. 370, ISBN 0-521-05803-1
^ Hong-Sen Yan, Marco Ceccarelli (2009). International Symposium on History of Machines and Mechanisms. Springer Science and Business Media. pp. 235–249. ISBN 978-1-4020-9484-2.
^ Needham 1986, pp. 118–119.
^ The Coming of the Ages of Steel. Brill Archive. 1961. p. 54. GGKEY:DN6SZTCNQ3G.
^ Donald B. Wagner, 'Chinese blast furnaces from the 10th to the 14th century' Historical Metallurgy 37(1) (2003), 25–37; originally published in West Asian Science, Technology, and Medicine 18 (2001), 41–74.
^ Ebrey, p. 158.
^ Wagner 2008, p. 169.
^ Wagner 2008, p. 1.
^ Liang 2006.
^ Strassburger, Julius H. (1969). Blast Furnace-theory and Practice. Gordon and Breach Science Publishers. p. 4. ISBN 978-0-677-10420-1.
^ Douglas Alan Fisher, Excerpt from The Epic of Steel Archived 25 February 2007 at the Wayback Machine, Davis Town Museum & Harper & Row, NY 1963.
^ Jockenhövel, Albrecht et al. (1997) "Archaeological Investigations on the Beginning of Blast Furnace-Technology in Central Europe" Archived 24 February 2013 at the Wayback Machine Abteilung für Ur- und Frühgeschichtliche Archäologie, Westfälische Wilhelms-Universität Münster; abstract published as: Jockenhövel, A. (1997) "Archaeological Investigations on the Beginning of Blast Furnace-Technology in Central Europe" pp. 56–58 In Crew, Peter and Crew, Susan (editors) (1997) Early Ironworking in Europe: Archaeology and Experiment: Abstracts of the International Conference at Plas Tan y Bwlch 19–25 September 1997 (Plas Tan y Bwlch Occasional Papers No 3) Snowdonia National Park Study Centre, Gwynedd, Wales, OCLC 470699473; archived here [1] by WebCite on 11 March 2012
^ A. Wetterholm, 'Blast furnace studies in Nora bergslag' (Örebro universitet 1999, Järn och Samhälle) ISBN 91-7668-204-8
^ N. Bjökenstam, 'The Blast Furnace in Europe during the Middle Ages: part of a new system for producing wrought iron' in G. Magnusson, The Importance of Ironmaking: Technological Innovation and Social Change I (Jernkontoret, Stockholm 1995), 143–153 and other papers in the same volume.
^ Wagner 2008, 349–351.
^ Wagner 2008, 354.
^ Markewitz, Darrell (25 March 2006). "Adventures in Early Iron Production – An overview of experimental iron smelts, 2001–2005". www.warehamforge.ca. Archived from the original on 22 September 2015.
^ Wagner 2008, 355.
^ Awty, B. G. (January 1989). "The Blast Furnace in the Renaissance Period: Haut Fourneau or Fonderie?". Transactions of the Newcomen Society. 61 (1): 65–78. doi:10.1179/tns.1989.005.
^ Woods, p. 34.
^ Gimpel, p. 67.
^ Woods, p. 35.
^ Woods, p. 36.
^ ^a ^b Woods, p. 37.
^ R. W. Vernon, G. McDonnell and A. Schmidt (1998). "An integrated geophysical and analytical appraisal of early iron-working: three case studies". Historical Metallurgy. 32 (2): 72–75, 79.
^ David Derbyshire, 'Henry "Stamped Out Industrial Revolution"' Archived 13 June 2014 at the Wayback Machine, The Daily Telegraph (21 June 2002); cited by Woods.
^ Schubert, H. R. (1957), History of the British iron and steel industry from c. 450 BC to AD 1775, Routledge & Kegan Paul, pp. 395–397
^ ^a ^b ^c Tylecote, R. F. (1992). A History of Metallurgy, Second Edition. London: Maney Publishing, for the Institute of Materials. ISBN 978-0901462886.
^ Merson, John (1990). The Genius That Was China: East and West in the Making of the Modern World. Woodstock, New York: The Overlook Press. p. 69. ISBN 0-87951-397-7A companion to the PBS Series "The Genius That Was China"{{cite book}}: CS1 maint: postscript (link)
^ Awty, Brian; Whittick, Christopher (2002). "The Lordship of Canterbury, iron-founding at Buxted, and the continental antecedents of cannon-founding in the Weald". Sussex Archaeological Collections. 140: 71–81. doi:10.5284/1085896.
^ P. W. King, 'The production and consumption of iron in early modern England and Wales' Economic History Review LVIII(1), 1–33; G. Hammersley, 'The charcoal iron industry and its fuel 1540–1750' Economic History Review Ser. II, XXVI (1973), pp. 593–613.
^ Yakovlev, V. B. (1957), "Development of Wrought Iron Production", Metallurgist, 1 (8), New York: Springer: 545, doi:10.1007/BF00732452, S2CID 137551466
^ Landes, David. S. (1969). The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present. Cambridge; New York: Press Syndicate of the University of Cambridge. pp. 90–93. ISBN 0-521-09418-6.
^ Rosen, William (2012). The Most Powerful Idea in the World: A Story of Steam, Industry and Invention. University of Chicago Press. p. 149. ISBN 978-0226726342.
^ Tylecote, R. F. (1992). A History of Metallurgy, Second Edition. London: Maney Publishing, for the Institute of Materials. ISBN 978-0901462886.
^ McNeil, Ian (1990). An Encyclopedia of the History of Technology. London: Routledge. ISBN 0415147921.
^ "Coke for Blast Furnace Ironmaking". steel.org. Archived from the original on 8 February 2017.
^ Raistrick, Arthur (1953), Dynasty of Iron Founders: The Darbys and Coalbrookedale, York: Longmans, Green
^ Hyde
^ Trinder, Barrie Stuart; Trinder, Barrie (2000), The Industrial Revolution in Shropshire, Chichester: Phillimore, ISBN 1-86077-133-5
^ http://web.archive.org/web/20150522202649/https://www.fpl.fs.fed.us/documnts/pdf1985/baker85a.pdf
^ Schallenberg, Richard H. (July 1975). "Evolution, adaptation and survival: the very slow death of the American charcoal iron industry". Annals of Science. 32 (4): 341–358. doi:10.1080/00033797500200331. ISSN 0003-3790.
^ https://thebeautyofsteel.com/steel-plants-archive/arcelormittal-monlevadea
^ A. Raistrick, Dynasty of ironmasters (Sessions, York, 1989), 138–139.
^ H.W. Dickinson and Rhys Jenkins, James Watt and the steam engine (Moorland, Ashbourne 1981 edn), 111–112.
^ English patent, no.553.
^ English patent, no.713.
^ Landes, David. S. (1969). The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present. Cambridge; New York: Press Syndicate of the University of Cambridge. p. 92. ISBN 0-521-09418-6.
^ Ayres, Robert (1989). "Technological Transformations and Long Waves" (PDF). p. 21. Archived from the original (PDF) on 1 March 2012. Retrieved 17 October 2013. Fig. 7 shows C/Fe ratio time series.
^ Birch, pp. 181–189.
^ Hyde, p. 159.
^ "POSCO Gwangyang blast furnace emerges as world largest", The Dong-a Ilbo, 10 June 2013
^ "Steel sector may be saddled with up to $70 bln stranded assets -report". Reuters. 29 June 2021. Retrieved 10 July 2021.
^ ^a ^b ^c "Pathways to decarbonisation episode two: steelmaking technology". Archived from the original on 5 November 2020.
^ Zhang, Wei; Dai, Jing; Li, Chengzhi; Yu, Xiaobing; Xue, Zhengliang; Saxén, Henrik (January 2021). "A Review on Explorations of the Oxygen Blast Furnace Process". Steel Research International. 92 (1). doi:10.1002/srin.202000326. S2CID 224952826.
^ ^a ^b ^c ^d ^e R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 77.
^ ^a ^b R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 75.
^ R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 76.
^ ^a ^b ^c ^d R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 89.
^ R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 90.
^ "What is stone wool?". rockwool.co.uk. Archived from the original on 10 February 2010.
^ ^a ^b ^c ^d American Iron and Steel Institute (2005). How a Blast Furnace Works. steel.org.
^ ^a ^b McNeil, Ian (2002). An Encyclopedia of the History of Technology. Taylor & Francis. p. 163. ISBN 978-0-203-19211-5.
^ Strassburger, Julius H. (1969). Blast Furnace-theory and Practice. Gordon and Breach Science Publishers. p. 564. ISBN 978-0-677-10420-1.
^ Whitfield, Peter, Design and Operation of a Gimbal Top Charging System (PDF), archived from the original (PDF) on 5 March 2009, retrieved 22 June 2008
^ "Comparison of techniques employed at Scunthorpe Integrated Steelworks with those in the BAT Conclusions for Iron and Steel Production published in the Official Journal of the European Union" (PDF). HM Government UK. 8 March 2012. Retrieved 19 January 2021.
^ Liang, Wang; Wang, Guangwei; Xu, Runsheng; Ning, Xiaojun; Zhang, Jianliang; Guo, Xingmin; Jiang, Chunhe; Wang, Chuan (August 2023). "Life cycle assessment of blast furnace ironmaking processes: A comparison of fossil fuels and biomass hydrochar applications". Fuel. 345: 128138. Bibcode:2023Fuel..34528138L. doi:10.1016/j.fuel.2023.128138.
^ ^a ^b IEA-GHG, 2000. Greenhouse Gas Emissions from Major Industrial Sources – Iron and Steel Production. Report no. PH3/30. Cheltenham, UK, IEA Greenhouse Gas R&D Programme. https://ieaghg.org/docs/General_Docs/Reports/PH3-30%20iron-steel.pdf Accessed July 30, 2021.
^ Knepper, M.; Babich, A.; Senk, D.; Bürgler, Thomas; Feilmayr, Christoph; Kieberger, N. (22 October 2012). "Waste Plastics Injection: Reaktion Kinetics and Effect on the Blast Furnace Process". ResearchGate. Retrieved 31 July 2024.
^ Wang, Chuan; Mellin, Pelle; Lövgren, Jonas; Nilsson, Leif; Yang, Weihong; Salman, Hassan; Hultgren, Anders; Larsson, Mikael (September 2015). "Biomass as blast furnace injectant – Considering availability, pretreatment and deployment in the Swedish steel industry". Energy Conversion and Management. 102: 217–226. Bibcode:2015ECM...102..217W. doi:10.1016/j.enconman.2015.04.013.
^ ^a ^b Pei, Martin; Petäjäniemi, Markus; Regnell, Andreas; Wijk, Olle (18 July 2020). "Toward a Fossil Free Future with HYBRIT: Development of Iron and Steelmaking Technology in Sweden and Finland". Metals. 10 (7): 972. doi:10.3390/met10070972.
^ De Ras, Kevin; Van de Vijver, Ruben; Galvita, Vladimir V; Marin, Guy B; Van Geem, Kevin M (December 2019). "Carbon capture and utilization in the steel industry: challenges and opportunities for chemical engineering". Current Opinion in Chemical Engineering. 26: 81–87. Bibcode:2019COCE...26...81D. doi:10.1016/j.coche.2019.09.001. hdl:1854/LU-8635595.
^ IEA (2020). "Iron and Steel Technology Roadmap". International Energy Agency. Retrieved 6 August 2024.
^ "Hybrit". Hybrit. Retrieved 7 August 2024.
^ ^a ^b "IEAGHG - Facilitating technology advancements, addressing barriers, and enabling deployment". IEAGHG. Retrieved 7 August 2024.
^ "SteelLens | Metals & Mining | McKinsey & Company". www.mckinsey.com. Retrieved 7 August 2024.
^ http://www.ulcos.org Archived 21 November 2008 at the Wayback Machine
^ ICIT-Revue de Métallurgie, September and October issues, 2009

Bibliography

Birch, Alan (2005), The Economic History of the British Iron and Steel Industry, 1784–1879, Routledge, ISBN 0-415-38248-3
Ebrey, Patricia Buckley; Walthall, Anne; Palais, James B. (2005), East Asia: A Cultural, Social, and Political History, Boston: Houghton Mifflin, ISBN 0-618-13384-4
Gimpel, Jean (1976), The Medieval Machine: The Industrial Revolution of the Middle Ages, New York: Holt, Rinehart and Winston, ISBN 0-03-014636-4
Hyde, Charles K. (1977), Technological Change and the British iron industry, 1700–1870, Princeton: Princeton University Press, ISBN 0-691-05246-8
Liang, Jieming (2006), Chinese Siege Warfare: Mechanical Artillery & Siege Weapons of Antiquity, Singapore, Republic of Singapore: Leong Kit Meng, ISBN 981-05-5380-3
Wagner, Donald B. (2008), Science and Civilization in China Volume 5–11: Ferrous Metallurgy, Cambridge University Press^{[ISBN missing]}
Woods, Thomas (2005), How the Catholic Church Built Western Civilization, Washington, D.C.: Regnery Publ., ISBN 0-89526-038-7

External links

[1] "Blast furnace | Definition, Temperature, Diagrams, & Facts | Britannica". www.britannica.com. 11 October 2024. Retrieved 8 November 2024.

[2] Schmult, Brian (2016). "Evolution of the Hopewell Furnace Blast Machinery". IA. The Journal of the Society for Industrial Archeology. 42 (2): 5–22.

[3] Spirin, N A; Yaroshenko, Yu G; Lavrov, V V (September 2016). "Development of heat-transfer circuits in the blast furnace". IOP Conference Series: Materials Science and Engineering. 150 (1): 012022. Bibcode:2016MS&E..150a2022S. doi:10.1088/1757-899X/150/1/012022.

[4] P J Wand, "Copper smelting at Electrolytic Refining and Smelting Company of Australia Ltd., Port Kembla, N.S.W.", in: Mining and Metallurgical Practices in Australasia: The Sir Maurice Mawby Memorial Volume, Ed J T Woodcock (The Australasian Institute of Mining and Metallurgy: Melbourne, 1980) 335–340.

[5] R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 9–12.

[:0-6] Pooler, Michael (January 2019). "Cleaning up steel is key to tackling climate change". Financial Times. Archived from the original on 10 December 2022. Retrieved 7 July 2021.

[7] Oeters, Franz; Ottow, Manfred; Meiler, Heinrich; Lüngen, Hans Bodo; Koltermann, Manfred; Buhr, Andreas; Yagi, Jun-Ichiro; Formanek, Lothar; Rose, Fritz; Flickenschild, Jürgen; Hauk, Rolf; Steffen, Rolf; Skroch, Reiner; Mayer-Schwinning, Gernot; Bünnagel, Heinz-Lothar; Hoff, Hans-Georg (2006). "Iron". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a14_461.pub2. ISBN 978-3527306732.

[Formulae-8] "Blast Furnace". Science Aid. Archived from the original on 17 December 2007. Retrieved 30 December 2007.

[InorganicChemistry-9] ^ ^a ^b ^c ^d ^e ^f Rayner-Canham & Overton (2006), Descriptive Inorganic Chemistry, Fourth Edition, New York: W. H. Freeman and Company, pp. 534–535, ISBN 978-0-7167-7695-6

[form2sci-10] Dr. K. E. Lee, Form Two Science (Biology Chemistry Physics)

[openstax-11] Flowers, Paul; Robinson, William R.; Langley, Richard; Theopold, Klaus (2015). "Occurrence, Preparation, and Properties of Transition Metals and Their Compounds". Chemistry. OpenStax. ISBN 978-1938168390.

[12] tec-science (21 June 2018). "From pig iron to crude steel". tec-science. Retrieved 2 November 2019.

[Golas1999-13] Peter J. Golas (1999). Science and Civilisation in China: Volume 5, Chemistry and Chemical Technology, Part 13, Mining. Cambridge University Press. p. 152. ISBN 978-0-521-58000-7. ...earliest blast furnace discovered in China from about the first century AD

[14] Simcoe, Charles R. "The Age of Steel: Part II." Advanced Materials & Processes 172.4 (2014): 32–33. Academic Search Premier.

[15] "The Earliest Use of Iron in China" by Donald B. Wagner in Metals in Antiquity, by Suzanne M. M. Young, A. Mark Pollard, Paul Budd and Robert A. Ixer (BAR International Series, 792), Oxford: Archaeopress, 1999, pp. 1–9.

[FOOTNOTEWagner2008230-16] Wagner 2008, p. 230.

[ebrey_30-17] Ebrey, p. 30.

[18] Early iron in China, Korea, and Japan Archived 5 February 2007 at the Wayback Machine, Donald B. Wagner, March 1993

[FOOTNOTEWagner20086-19] Wagner 2008, p. 6.

[20] Needham, Joseph (1986), Science and Civilisation in China, Volume 4: Physics and Physical Technology, Part 2, Mechanical Engineering, Taipei: Cambridge University Press, p. 370, ISBN 0-521-05803-1

[21] Hong-Sen Yan, Marco Ceccarelli (2009). International Symposium on History of Machines and Mechanisms. Springer Science and Business Media. pp. 235–249. ISBN 978-1-4020-9484-2.

[needham_volume_4_part_2_118-22] Needham 1986, pp. 118–119.

[The_Coming_of_the_Ages_of_Steel-23] The Coming of the Ages of Steel. Brill Archive. 1961. p. 54. GGKEY:DN6SZTCNQ3G.

[24] Donald B. Wagner, 'Chinese blast furnaces from the 10th to the 14th century' Historical Metallurgy 37(1) (2003), 25–37; originally published in West Asian Science, Technology, and Medicine 18 (2001), 41–74.

[25] Ebrey, p. 158.

[FOOTNOTEWagner2008169-26] Wagner 2008, p. 169.

[FOOTNOTEWagner20081-27] Wagner 2008, p. 1.

[FOOTNOTELiang2006-28] Liang 2006.

[29] Strassburger, Julius H. (1969). Blast Furnace-theory and Practice. Gordon and Breach Science Publishers. p. 4. ISBN 978-0-677-10420-1.

[30] Douglas Alan Fisher, Excerpt from The Epic of Steel Archived 25 February 2007 at the Wayback Machine, Davis Town Museum & Harper & Row, NY 1963.

[31] Jockenhövel, Albrecht et al. (1997) "Archaeological Investigations on the Beginning of Blast Furnace-Technology in Central Europe" Archived 24 February 2013 at the Wayback Machine Abteilung für Ur- und Frühgeschichtliche Archäologie, Westfälische Wilhelms-Universität Münster; abstract published as: Jockenhövel, A. (1997) "Archaeological Investigations on the Beginning of Blast Furnace-Technology in Central Europe" pp. 56–58 In Crew, Peter and Crew, Susan (editors) (1997) Early Ironworking in Europe: Archaeology and Experiment: Abstracts of the International Conference at Plas Tan y Bwlch 19–25 September 1997 (Plas Tan y Bwlch Occasional Papers No 3) Snowdonia National Park Study Centre, Gwynedd, Wales, OCLC 470699473; archived here [1] by WebCite on 11 March 2012

[32] A. Wetterholm, 'Blast furnace studies in Nora bergslag' (Örebro universitet 1999, Järn och Samhälle) ISBN 91-7668-204-8

[33] N. Bjökenstam, 'The Blast Furnace in Europe during the Middle Ages: part of a new system for producing wrought iron' in G. Magnusson, The Importance of Ironmaking: Technological Innovation and Social Change I (Jernkontoret, Stockholm 1995), 143–153 and other papers in the same volume.

[34] Wagner 2008, 349–351.

[35] Wagner 2008, 354.

[36] Markewitz, Darrell (25 March 2006). "Adventures in Early Iron Production – An overview of experimental iron smelts, 2001–2005". www.warehamforge.ca. Archived from the original on 22 September 2015.

[37] Wagner 2008, 355.

[38] Awty, B. G. (January 1989). "The Blast Furnace in the Renaissance Period: Haut Fourneau or Fonderie?". Transactions of the Newcomen Society. 61 (1): 65–78. doi:10.1179/tns.1989.005.

[Woods_34-39] Woods, p. 34.

[Gimpel-40] Gimpel, p. 67.

[41] Woods, p. 35.

[Woods36-42] Woods, p. 36.

[Woods37-43] Woods, p. 37.

[44] R. W. Vernon, G. McDonnell and A. Schmidt (1998). "An integrated geophysical and analytical appraisal of early iron-working: three case studies". Historical Metallurgy. 32 (2): 72–75, 79.

[Woods-45] David Derbyshire, 'Henry "Stamped Out Industrial Revolution"' Archived 13 June 2014 at the Wayback Machine, The Daily Telegraph (21 June 2002); cited by Woods.

[46] Schubert, H. R. (1957), History of the British iron and steel industry from c. 450 BC to AD 1775, Routledge & Kegan Paul, pp. 395–397

[Tylecote_1992-47] Tylecote, R. F. (1992). A History of Metallurgy, Second Edition. London: Maney Publishing, for the Institute of Materials. ISBN 978-0901462886.

[48] Merson, John (1990). The Genius That Was China: East and West in the Making of the Modern World. Woodstock, New York: The Overlook Press. p. 69. ISBN 0-87951-397-7A companion to the PBS Series "The Genius That Was China"{{cite book}}: CS1 maint: postscript (link)

[Queenstock-49] Awty, Brian; Whittick, Christopher (2002). "The Lordship of Canterbury, iron-founding at Buxted, and the continental antecedents of cannon-founding in the Weald". Sussex Archaeological Collections. 140: 71–81. doi:10.5284/1085896.

[50] P. W. King, 'The production and consumption of iron in early modern England and Wales' Economic History Review LVIII(1), 1–33; G. Hammersley, 'The charcoal iron industry and its fuel 1540–1750' Economic History Review Ser. II, XXVI (1973), pp. 593–613.

[dwip-51] Yakovlev, V. B. (1957), "Development of Wrought Iron Production", Metallurgist, 1 (8), New York: Springer: 545, doi:10.1007/BF00732452, S2CID 137551466

[Landes_1969-52] Landes, David. S. (1969). The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present. Cambridge; New York: Press Syndicate of the University of Cambridge. pp. 90–93. ISBN 0-521-09418-6.

[53] Rosen, William (2012). The Most Powerful Idea in the World: A Story of Steam, Industry and Invention. University of Chicago Press. p. 149. ISBN 978-0226726342.

[54] Tylecote, R. F. (1992). A History of Metallurgy, Second Edition. London: Maney Publishing, for the Institute of Materials. ISBN 978-0901462886.

[McNeil1990-55] McNeil, Ian (1990). An Encyclopedia of the History of Technology. London: Routledge. ISBN 0415147921.

[56] "Coke for Blast Furnace Ironmaking". steel.org. Archived from the original on 8 February 2017.

[57] Raistrick, Arthur (1953), Dynasty of Iron Founders: The Darbys and Coalbrookedale, York: Longmans, Green

[58] Hyde

[59] Trinder, Barrie Stuart; Trinder, Barrie (2000), The Industrial Revolution in Shropshire, Chichester: Phillimore, ISBN 1-86077-133-5

[60] ttp://web.archive.org/web/20150522202649/https://www.fpl.fs.fed.us/documnts/pdf1985/baker85a.pdf

[61] Schallenberg, Richard H. (July 1975). "Evolution, adaptation and survival: the very slow death of the American charcoal iron industry". Annals of Science. 32 (4): 341–358. doi:10.1080/00033797500200331. ISSN 0003-3790.

[62] ttps://thebeautyofsteel.com/steel-plants-archive/arcelormittal-monlevadea

[63] A. Raistrick, Dynasty of ironmasters (Sessions, York, 1989), 138–139.

[64] H.W. Dickinson and Rhys Jenkins, James Watt and the steam engine (Moorland, Ashbourne 1981 edn), 111–112.

[65] English patent, no.553.

[66] English patent, no.713.

[67] Landes, David. S. (1969). The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present. Cambridge; New York: Press Syndicate of the University of Cambridge. p. 92. ISBN 0-521-09418-6.

[68] Ayres, Robert (1989). "Technological Transformations and Long Waves" (PDF). p. 21. Archived from the original (PDF) on 1 March 2012. Retrieved 17 October 2013. Fig. 7 shows C/Fe ratio time series.

[Neilson-69] Birch, pp. 181–189.

[70] Hyde, p. 159.

[71] "POSCO Gwangyang blast furnace emerges as world largest", The Dong-a Ilbo, 10 June 2013

[72] "Steel sector may be saddled with up to $70 bln stranded assets -report". Reuters. 29 June 2021. Retrieved 10 July 2021.

[:1-73] "Pathways to decarbonisation episode two: steelmaking technology". Archived from the original on 5 November 2020.

[74] Zhang, Wei; Dai, Jing; Li, Chengzhi; Yu, Xiaobing; Xue, Zhengliang; Saxén, Henrik (January 2021). "A Review on Explorations of the Oxygen Blast Furnace Process". Steel Research International. 92 (1). doi:10.1002/srin.202000326. S2CID 224952826.

[Sinclair77-75] R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 77.

[Sinclair75-76] R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 75.

[77] R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 76.

[Sinclair89-78] R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 89.

[79] R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 90.

[80] "What is stone wool?". rockwool.co.uk. Archived from the original on 10 February 2010.

[AISI-81] American Iron and Steel Institute (2005). How a Blast Furnace Works. steel.org.

[et-82] McNeil, Ian (2002). An Encyclopedia of the History of Technology. Taylor & Francis. p. 163. ISBN 978-0-203-19211-5.

[83] Strassburger, Julius H. (1969). Blast Furnace-theory and Practice. Gordon and Breach Science Publishers. p. 564. ISBN 978-0-677-10420-1.

[84] Whitfield, Peter, Design and Operation of a Gimbal Top Charging System (PDF), archived from the original (PDF) on 5 March 2009, retrieved 22 June 2008

[85] "Comparison of techniques employed at Scunthorpe Integrated Steelworks with those in the BAT Conclusions for Iron and Steel Production published in the Official Journal of the European Union" (PDF). HM Government UK. 8 March 2012. Retrieved 19 January 2021.

[86] Liang, Wang; Wang, Guangwei; Xu, Runsheng; Ning, Xiaojun; Zhang, Jianliang; Guo, Xingmin; Jiang, Chunhe; Wang, Chuan (August 2023). "Life cycle assessment of blast furnace ironmaking processes: A comparison of fossil fuels and biomass hydrochar applications". Fuel. 345: 128138. Bibcode:2023Fuel..34528138L. doi:10.1016/j.fuel.2023.128138.

[:2-87] IEA-GHG, 2000. Greenhouse Gas Emissions from Major Industrial Sources – Iron and Steel Production. Report no. PH3/30. Cheltenham, UK, IEA Greenhouse Gas R&D Programme. https://ieaghg.org/docs/General_Docs/Reports/PH3-30%20iron-steel.pdf Accessed July 30, 2021.

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@@ Line 1: / Line 1: @@
 {{Short description|Type of furnace used for smelting to produce industrial metals}}
 {{Use dmy dates|date=June 2020}}
-[[File:Alto Horno, Puerto de Sagunto, España, 2015-01-04, DD 91.JPG|thumb|upright=1.1|Former [[Altos Hornos del Mediterráneo|AHM]] blast furnace in Port of Sagunt, [[Valencia]], Spain]]
+[[File:Alto Horno, Puerto de Sagunto, España, 2015-01-04, DD 91.JPG|thumb|upright=1.1|Former [[Altos Hornos del Mediterráneo|AHM]] blast furnace in Port of Sagunt, [[Valencia]], Spain]]A '''blast furnace''' is a type of [[metallurgical furnace]] used for [[smelting]] to produce industrial metals, generally [[pig iron]], but also others such as [[lead]] or [[copper]].  ''Blast'' refers to the combustion air being supplied above [[atmospheric pressure]].<ref>{{Cite web |date=2024-10-11 |title=Blast furnace {{!}} Definition, Temperature, Diagrams, & Facts {{!}} Britannica |url=https://www.britannica.com/technology/blast-furnace |access-date=2024-11-08 |website=www.britannica.com |language=en}}</ref>
+In a blast furnace, fuel ([[coke (fuel)|coke]]), [[ores]], and [[Flux (metallurgy)|flux]] ([[limestone]]) are continuously supplied through the top of the furnace, while a hot blast of [[air]] (sometimes with [[oxygen]] enrichment) is blown into the lower section of the furnace through a series of pipes called [[tuyeres]], so that the [[#Process engineering and chemistry|chemical reactions]] take place throughout the furnace as the material falls downward. The end products are usually molten metal and [[slag]] phases tapped from the bottom, and waste gases ([[flue gas]]) exiting from the top of the furnace.<ref>{{cite journal |last1=Schmult |first1=Brian |title=Evolution of the Hopewell Furnace Blast Machinery |journal=IA. The Journal of the Society for Industrial Archeology |date=2016 |volume=42 |issue=2 |pages=5–22}}</ref> The downward flow of the ore along with the flux in contact with an upflow of hot, [[carbon monoxide]]-rich combustion gases is a [[countercurrent exchange]] and chemical reaction process.<ref>{{cite journal |last1=Spirin |first1=N A |last2=Yaroshenko |first2=Yu G |last3=Lavrov |first3=V V |title=Development of heat-transfer circuits in the blast furnace |journal=IOP Conference Series: Materials Science and Engineering |date=September 2016 |volume=150 |issue=1 |pages=012022 |doi=10.1088/1757-899X/150/1/012022 |bibcode=2016MS&E..150a2022S |doi-access=free }}</ref>
-A '''blast furnace''' is a type of [[metallurgical furnace]] used for [[smelting]] to produce industrial metals, generally [[pig iron]], but also others such as [[lead]] or [[copper]].  ''Blast'' refers to the combustion air being supplied above [[atmospheric pressure]].<ref>See: [[Draft (boiler)]]</ref>
-In a blast furnace, fuel ([[coke (fuel)|coke]]), [[ores]], and [[Flux (metallurgy)|flux]] ([[limestone]]) are continuously supplied through the top of the furnace, while a hot blast of [[air]] (sometimes with [[oxygen]] enrichment) is blown into the lower section of the furnace through a series of pipes called [[tuyeres]], so that the [[#Process engineering and chemistry|chemical reactions]] take place throughout the furnace as the material falls downward. The end products are usually molten metal and [[slag]] phases tapped from the bottom, and waste gases ([[flue gas]]) exiting from the top of the furnace.<ref>{{cite journal |last1=Schmult |first1=Brian |title=Evolution of the Hopewell Furnace Blast Machinery |journal=IA. The Journal of the Society for Industrial Archeology |date=2016 |volume=42 |issue=2 |pages=5–22}}</ref> The downward flow of the ore along with the flux in contact with an upflow of hot, [[carbon monoxide]]-rich combustion gases is a [[countercurrent exchange]] and chemical reaction process.<ref>[http://iopscience.iop.org/article/10.1088/1757-899X/150/1/012022/pdf ''Development of heat transfer circuits in the blast furnace, IOP Conference Series: Materials Science and Engineering'']</ref>
 In contrast, air furnaces (such as [[reverberatory furnace]]s) are naturally aspirated, usually by the [[convection]] of hot gases in a [[Chimney-flue|chimney flue]]. According to this broad definition, [[bloomery|bloomeries]] for iron, [[blowing house]]s for [[tin]], and [[smelt mill]]s for [[lead]] would be classified as blast furnaces. However, the term has usually been limited to those used for smelting [[iron ore]] to produce [[pig iron]], an intermediate material used in the production of commercial iron and [[steel]], and the shaft furnaces used in combination with [[sinter plant]]s in [[base metals]] smelting.<ref>P J Wand, "Copper smelting at Electrolytic Refining and Smelting Company of Australia Ltd., Port Kembla, N.S.W.", in: '' Mining and Metallurgical Practices in Australasia: The Sir Maurice Mawby Memorial Volume'', Ed J T Woodcock (The Australasian Institute of Mining and Metallurgy: Melbourne, 1980) 335–340.</ref><ref>R J Sinclair, ''The Extractive Metallurgy of Lead'' (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 9–12.</ref>
-Blast furnaces are estimated to have been responsible for over 4% of global [[greenhouse gas emissions]] between 1900 and 2015, but are difficult to decarbonize.<ref name=":0" />
+Blast furnaces are estimated to have been responsible for over 4% of global [[greenhouse gas emissions]] between 1900 and 2015, but are difficult to decarbonize.<ref name=":0">{{Cite news |last1=Pooler |first1=Michael |date=January 2019 |title=Cleaning up steel is key to tackling climate change |url=https://www.ft.com/content/3bcbcb60-037f-11e9-99df-6183d3002ee1 |url-access=subscription |url-status=live |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/3bcbcb60-037f-11e9-99df-6183d3002ee1 |archive-date=10 December 2022 |access-date=2021-07-07 |website=[[Financial Times]]}}</ref>
 ==Process engineering and chemistry==
@@ Line 15: / Line 13: @@
 [[File:Geography of Ohio - DPLA - aaba7b3295ff6973b6fd1e23e33cde14 (page 111) (cropped2).jpg|thumb|upright=1.1|Charcoal burning iron blast furnace in [[Jackson County, Ohio]], 1923]]
 [[File:Blast Furnace Reactions.jpg|thumb|upright=1.1|Rising [[carbon monoxide]] reduces [[iron oxide]]s to pure [[iron]] through a series of reactions that occur at different areas within a blast furnace.]]
-Blast furnaces operate on the principle of [[redox|chemical reduction]] whereby carbon monoxide converts iron oxides to elemental iron. Blast furnaces differ from [[bloomery|bloomeries]] and [[reverberatory furnace]]s in that in a blast furnace, flue gas is in direct contact with the ore and iron, allowing carbon monoxide to diffuse into the ore and reduce the iron oxide. The blast furnace operates as a [[countercurrent exchange]] process whereas a bloomery does not. Another difference is that bloomeries operate as a batch process whereas blast furnaces [[Continuous production|operate continuously]] for long periods. Continuous operation is also preferred because blast furnaces are difficult to start and stop. Also, the carbon in pig iron lowers the melting point below that of steel or pure iron; in contrast, iron does not melt in a bloomery.
+Blast furnaces operate on the principle of [[redox|chemical reduction]] whereby carbon monoxide converts iron oxides to elemental iron.
+Blast furnaces differ from [[bloomery|bloomeries]] and [[reverberatory furnace]]s in that in a blast furnace, flue gas is in direct contact with the ore and iron, allowing carbon monoxide to diffuse into the ore and reduce the iron oxide. The blast furnace operates as a [[countercurrent exchange]] process whereas a bloomery does not. Another difference is that bloomeries operate as a batch process whereas blast furnaces [[Continuous production|operate continuously]] for long periods. Continuous operation is also preferred because blast furnaces are difficult to start and stop. Also, the carbon in pig iron lowers the melting point below that of steel or pure iron; in contrast, iron does not melt in a bloomery.
-[[Silica]] has to be removed from the pig iron. It reacts with [[calcium oxide]] (burned limestone) and forms silicates, which float to the surface of the molten pig iron as slag. Historically, to prevent contamination from sulfur, the best quality iron was produced with charcoal.
+[[Silica]] has to be removed from the pig iron. It reacts with [[calcium oxide]] (burned limestone) and forms silicates, which float to the surface of the molten pig iron as slag. Historically, to prevent contamination from sulfur, the best quality iron{{according to whom|date=September 2024}} was produced with charcoal.{{cn|date=September 2024}}
-The downward moving column of ore, flux, [[coke (fuel)|coke]] or charcoal and reaction products must be sufficiently porous for the flue gas to pass through. To ensure this permeability the particle size of the coke or charcoal is of great relevance.   Therefore, the coke must be strong enough so it will not be crushed by the weight of the material above it. Besides the physical strength of its particles, the coke must also be low in sulfur, [[phosphorus]], and ash.<ref>{{Ullmann |doi=10.1002/14356007.a14_461.pub2|title=Iron|year=2006|last1=Oeters|first1=Franz|last2=Ottow|first2=Manfred|last3=Meiler|first3=Heinrich|last4=Lüngen|first4=Hans Bodo|last5=Koltermann|first5=Manfred|last6=Buhr|first6=Andreas|last7=Yagi|first7=Jun-Ichiro|last8=Formanek|first8=Lothar|last9=Rose|first9=Fritz|last10=Flickenschild|first10=Jürgen|last11=Hauk|first11=Rolf|last12=Steffen|first12=Rolf|last13=Skroch|first13=Reiner|last14=Mayer-Schwinning|first14=Gernot|last15=Bünnagel|first15=Heinz-Lothar|last16=Hoff|first16=Hans-Georg}}</ref>
+In a blast furnace, a downward-moving column of ore, flux, [[coke (fuel)|coke]] (or charcoal{{cn|date=September 2024}}) and their reaction products must be sufficiently porous for the flue gas to pass through, upwards. To ensure this permeability the particle size of the coke or charcoal is of great relevance. Therefore, the coke must be strong enough so it will not be crushed by the weight of the material above it. Besides the physical strength of its particles, the coke must also be low in sulfur, [[phosphorus]], and ash.<ref>{{Ullmann |doi=10.1002/14356007.a14_461.pub2|title=Iron|year=2006|last1=Oeters|first1=Franz|last2=Ottow|first2=Manfred|last3=Meiler|first3=Heinrich|last4=Lüngen|first4=Hans Bodo|last5=Koltermann|first5=Manfred|last6=Buhr|first6=Andreas|last7=Yagi|first7=Jun-Ichiro|last8=Formanek|first8=Lothar|last9=Rose|first9=Fritz|last10=Flickenschild|first10=Jürgen|last11=Hauk|first11=Rolf|last12=Steffen|first12=Rolf|last13=Skroch|first13=Reiner|last14=Mayer-Schwinning|first14=Gernot|last15=Bünnagel|first15=Heinz-Lothar|last16=Hoff|first16=Hans-Georg}}</ref>
 The main chemical reaction producing the molten iron is:
@@ Line 28: / Line 28: @@
 :2 C<sub>(s)</sub> + O<sub>2(g)</sub> → 2 CO<sub>(g)</sub><ref name="InorganicChemistry">{{Citation | last = Rayner-Canham & Overton | title = Descriptive Inorganic Chemistry, Fourth Edition | place = New York | publisher = W. H. Freeman and Company | pages = 534–535 | year = 2006 | isbn = 978-0-7167-7695-6 }}</ref>
-The hot carbon monoxide is the reducing agent for the iron ore and reacts with the [[iron oxide]] to produce molten iron and [[carbon dioxide]]. Depending on the temperature in the different parts of the furnace (warmest at the bottom) the iron is reduced in several steps. At the top, where the temperature usually is in the range between 200&nbsp;°C and 700&nbsp;°C, the iron oxide is partially reduced to iron(II,III) oxide, Fe<sub>3</sub>O<sub>4</sub>.
+Hot carbon monoxide is the reducing agent for the iron ore and reacts with the [[iron oxide]] to produce molten iron and [[carbon dioxide]]. Depending on the temperature in the different parts of the furnace (warmest at the bottom) the iron is reduced in several steps. At the top, where the temperature usually is in the range between 200&nbsp;°C and 700&nbsp;°C, the iron oxide is partially reduced to iron(II,III) oxide, Fe<sub>3</sub>O<sub>4</sub>.
 :3 Fe<sub>2</sub>O<sub>3(s)</sub> + CO<sub>(g)</sub> → 2 Fe<sub>3</sub>O<sub>4(s)</sub> + CO<sub>2(g)</sub><ref name="InorganicChemistry"/>
@@ Line 56: / Line 56: @@
 The [[pig iron]] produced by the blast furnace has a relatively high carbon content of around 4–5% and usually contains too much sulphur, making it very brittle, and of limited immediate commercial use. Some pig iron is used to make [[cast iron]]. The majority of pig iron produced by blast furnaces undergoes further processing to reduce the carbon and sulphur content and produce various grades of steel used for construction materials, automobiles, ships and machinery. Desulphurisation usually takes place during the transport of the liquid steel to the steelworks. This is done by adding ''calcium oxide'', which reacts with the [[iron sulfide]] contained in the pig iron to form [[calcium sulfide]] (called ''lime desulfurization'').<ref>{{Cite web|url=https://www.tec-science.com/material-science/steel-making/from-pig-iron-to-crude-steel/|title=From pig iron to crude steel|last=tec-science|date=2018-06-21|website=tec-science|language=en-US|access-date=2019-11-02}}</ref> In a further process step, the so-called [[Basic oxygen furnace|basic oxygen steelmaking]], the carbon is oxidized by blowing oxygen onto the liquid pig iron to form ''crude steel''.
-Although the efficiency of blast furnaces is constantly evolving, the chemical process inside the blast furnace remains the same. One of the biggest drawbacks of the blast furnaces is the inevitable carbon dioxide production as iron is reduced from iron oxides by carbon and as of 2016, there is no economical substitute – steelmaking is one of the largest industrial contributors of the CO<sub>2</sub> emissions in the world (see [[greenhouse gases]]).<ref>{{Cite journal|last1=Wang|first1=Peng|last2=Ryberg|first2=Morten|last3=Yang|first3=Yi|last4=Feng|first4=Kuishuang|last5=Kara|first5=Sami|last6=Hauschild|first6=Michael|last7=Chen|first7=Wei-Qiang|date=2021-04-06|title=Efficiency stagnation in global steel production urges joint supply- and demand-side mitigation efforts|journal=Nature Communications|language=en|volume=12|issue=1|pages=2066|doi=10.1038/s41467-021-22245-6|pmid=33824307|issn=2041-1723|pmc=8024266|bibcode=2021NatCo..12.2066W}}</ref> Several alternatives are being investigated such as [[plastic waste]], biomass or hydrogen as reducing agent, which can substantially reduce the carbon emissions.<ref>{{Cite journal|date=2019-12-01|title=Carbon capture and utilization in the steel industry: challenges and opportunities for chemical engineering|url=https://www.sciencedirect.com/science/article/abs/pii/S221133981930036X|journal=Current Opinion in Chemical Engineering|language=en|volume=26|pages=81–87|doi=10.1016/j.coche.2019.09.001|issn=2211-3398|last1=De Ras|first1=Kevin|last2=Van De Vijver|first2=Ruben|last3=Galvita|first3=Vladimir V.|last4=Marin|first4=Guy B.|last5=Van Geem|first5=Kevin M.|bibcode=2019COCE...26...81D |s2cid=210619173|hdl=1854/LU-8635595|hdl-access=free}}</ref> The injection of, for example, hydrogen into blast furnaces can reduce carbon emissions by 20 percent.<ref>{{Cite web |last1=Hoffmann |first1=Christian |last2=Van Hoey |first2=Michel |last3=Zeumer |first3=Benedikt |date=April 2020 |title=Decarbonization challenge for steel: Hydrogen as a solution in Europe |url=https://www.mckinsey.com/~/media/McKinsey/Industries/Metals%20and%20Mining/Our%20Insights/Decarbonization%20challenge%20for%20steel/Decarbonization-challenge-for-steel.pdf |publisher=McKinsey & Company |page=6}}</ref>
-The challenge set by the greenhouse gas emissions of the blast furnace is being addressed in an ongoing{{When|date=July 2021}} European Program called ULCOS (Ultra Low [[Carbon Dioxide|CO<sub>2</sub>]] [[Steelmaking]]).<ref>http://www.ulcos.org {{webarchive|url=https://web.archive.org/web/20081121182534/http://www.ulcos.org/ |date=21 November 2008 }}</ref> Several new process routes have been proposed and investigated in depth to cut specific emissions ({{CO2}} per ton of steel) by at least 50%. Some rely on the capture and further storage (CCS) of {{CO2}}, while others choose decarbonizing iron and steel production, by turning to hydrogen, electricity and biomass.<ref>ICIT-Revue de Métallurgie, September and October issues, 2009</ref> In the nearer term, a technology that incorporates CCS into the blast furnace process itself and is called the Top-Gas Recycling Blast Furnace is under development, with a scale-up to a commercial size blast furnace under way.{{Update inline|date=July 2021}}
 ==History==
@@ Line 71: / Line 67: @@
 Archaeological evidence shows that bloomeries appeared in China around 800 BC. Originally it was thought that the Chinese started casting iron right from the beginning, but this theory has since been debunked{{Clarify|reason=how does the discovery debunk the hypothesis?|date=July 2021}} by the discovery of 'more than ten' iron digging implements found in the tomb of [[Duke Jing of Qin]] (d. 537 BC), whose tomb is located in [[Fengxiang County]], [[Shaanxi]] (a museum exists on the site today).<ref>"The Earliest Use of Iron in China" by Donald B. Wagner in ''Metals in Antiquity'', by Suzanne M. M. Young, A. Mark Pollard, Paul Budd and Robert A. Ixer (BAR International Series, 792), Oxford: [[Archaeopress]], 1999, pp. 1–9.</ref> There is however no evidence of the bloomery in China after the appearance of the blast furnace and cast iron. In China, blast furnaces produced cast iron, which was then either converted into finished implements in a cupola furnace, or turned into wrought iron in a fining hearth.{{sfn|Wagner|2008|p=230}}
-Although [[cast iron]] farm tools and weapons were widespread in China by the 5th century BC, employing workforces of over 200 men in iron smelters from the 3rd century onward, the earliest blast furnaces constructed were attributed to the [[Han dynasty]] in the 1st century AD.<ref name="ebrey 30">Ebrey, p.&nbsp;30.</ref> These early furnaces had clay walls and used [[phosphorus]]-containing minerals as a [[flux (metallurgy)|flux]].<ref>[http://www.staff.hum.ku.dk/dbwagner/KoreanFe/KoreanFe.html Early iron in China, Korea, and Japan] {{webarchive|url=https://web.archive.org/web/20070205063947/http://www.staff.hum.ku.dk/dbwagner/KoreanFe/KoreanFe.html |date=5 February 2007 }}, Donald B. Wagner, March 1993</ref> Chinese blast furnaces ranged from around two to ten meters in height, depending on the region. The largest ones were found in modern [[Sichuan]] and [[Guangdong]], while the 'dwarf" blast furnaces were found in [[Dabieshan]]. In construction, they are both around the same level of technological sophistication.{{sfn|Wagner|2008|p=6}}
+Although [[cast iron]] farm tools and weapons were widespread in China by the 5th century BC{{Citation needed|reason=according to whom and what scientific evidence? It seemed far fetched that cast iron tools we're widely spread when labor requirements in ancient China remained higher than many other cultures|date=October 2024}}, employing workforces of over 200 men in iron smelters from the 3rd century onward, the earliest blast furnaces constructed were attributed to the [[Han dynasty]] in the 1st century AD.<ref name="ebrey 30">Ebrey, p.&nbsp;30.</ref> These early furnaces had clay walls and used [[phosphorus]]-containing minerals as a [[flux (metallurgy)|flux]].<ref>[http://www.staff.hum.ku.dk/dbwagner/KoreanFe/KoreanFe.html Early iron in China, Korea, and Japan] {{webarchive|url=https://web.archive.org/web/20070205063947/http://www.staff.hum.ku.dk/dbwagner/KoreanFe/KoreanFe.html |date=5 February 2007 }}, Donald B. Wagner, March 1993</ref> Chinese blast furnaces ranged from around two to ten meters in height, depending on the region. The largest ones were found in modern [[Sichuan]] and [[Guangdong]], while the 'dwarf" blast furnaces were found in [[Dabieshan]]. In construction, they are both around the same level of technological sophistication.{{sfn|Wagner|2008|p=6}}
 The effectiveness of the Chinese human and horse powered blast furnaces was enhanced during this period by the engineer [[Du Shi]] (c.&nbsp;AD&nbsp;31), who applied the power of [[waterwheel]]s to [[piston]]-[[bellows]] in forging cast iron.<ref>{{Citation | last = Needham | first = Joseph | title = Science and Civilisation in China, Volume 4: Physics and Physical Technology, Part 2, Mechanical Engineering | place = Taipei | publisher = Cambridge University Press | page = 370 | year = 1986 | isbn = 0-521-05803-1 }}</ref> Early water-driven reciprocators for operating blast furnaces were built according to the structure of horse powered reciprocators that already existed. That is, the circular motion of the wheel, be it horse driven or water driven, was transferred by the combination of a [[belt drive]], a crank-and-connecting-rod, other [[connecting rods]], and various shafts, into the reciprocal motion necessary to operate a push bellow.<ref>{{cite book |author=Hong-Sen Yan, Marco Ceccarelli |title=International Symposium on History of Machines and Mechanisms |url=https://books.google.com/books?id=Dkq6_mdW43IC&q=han+dynasty+crank+and+connecting+rod&pg=PA249 |publisher=Springer Science and Business Media|isbn=978-1-4020-9484-2|pages=235–249|year=2009 }}</ref><ref name="needham volume 4 part 2 118">{{harvnb|Needham|1986|pp=118&ndash;119}}.</ref> Donald Wagner suggests that early blast furnace and cast iron production evolved from furnaces used to melt [[bronze]]. Certainly, though, iron was essential to military success by the time the [[State of Qin]] had unified China (221&nbsp;BC). Usage of the blast and cupola furnace remained widespread during the [[Song dynasty|Song]] and [[Tang dynasty|Tang dynasties]].<ref name="The Coming of the Ages of Steel">{{cite book|title=The Coming of the Ages of Steel|url=https://books.google.com/books?id=uMwUAAAAIAAJ&pg=PA54|publisher=Brill Archive|page=54|id=GGKEY:DN6SZTCNQ3G|year = 1961}}</ref> By the 11th century, the [[Song dynasty]] Chinese iron industry made a switch of resources from [[charcoal]] to [[Coke (fuel)|coke]] in casting iron and steel, sparing thousands of acres of woodland from felling. This may have happened as early as the 4th century AD.<ref>Donald B. Wagner, 'Chinese blast furnaces from the 10th to the 14th century' ''Historical Metallurgy'' 37(1) (2003), 25–37; originally published in ''West Asian Science, Technology, and Medicine'' 18 (2001), 41–74.</ref><ref>Ebrey, p.&nbsp;158.</ref>
@@ Line 80: / Line 76: @@
 === Medieval Europe ===
-The simplest [[forge]], known as the Corsican, was used prior to the advent of [[Christianity]]. Examples of improved bloomeries are the Stuckofen,<ref>{{cite book|author=Julius H. Strassburger |title=Blast Furnace-theory and Practice |url=https://books.google.com/books?id=n7oOAAAAQAAJ |access-date=12 July 2012 |year=1969 |publisher=Gordon and Breach Science Publishers |isbn=978-0-677-10420-1 |page=4}}</ref> sometimes called wolf-furnace,<ref>Douglas Alan Fisher, [http://www.davistownmuseum.org/toolPreBlastFurnace.html Excerpt from The Epic of Steel] {{webarchive|url=https://web.archive.org/web/20070225050049/http://www.davistownmuseum.org/toolPreBlastFurnace.html |date=25 February 2007 }}, Davis Town Museum & Harper & Row, NY 1963.</ref> which remained until the beginning of the 19th century. Instead of using natural draught, air was pumped in by a ''[[trompe]]'', resulting in better quality iron and an increased capacity. This pumping of air in with bellows is known as ''cold blast'', and it increases the [[fuel efficiency]] of the bloomery and improves yield. They can also be built bigger than natural draught bloomeries.
+The simplest [[forge]], known as the Corsican, was used prior to the advent of [[Christianity]]. Examples of improved bloomeries are the Stuckofen,<ref>{{cite book |last1=Strassburger |first1=Julius H. |title=Blast Furnace-theory and Practice |date=1969 |publisher=Gordon and Breach Science Publishers |isbn=978-0-677-10420-1 |page=4 }}</ref> sometimes called wolf-furnace,<ref>Douglas Alan Fisher, [http://www.davistownmuseum.org/toolPreBlastFurnace.html Excerpt from The Epic of Steel] {{webarchive|url=https://web.archive.org/web/20070225050049/http://www.davistownmuseum.org/toolPreBlastFurnace.html |date=25 February 2007 }}, Davis Town Museum & Harper & Row, NY 1963.</ref> which remained until the beginning of the 19th century. Instead of using natural draught, air was pumped in by a ''[[trompe]]'', resulting in better quality iron and an increased capacity. This pumping of air in with bellows is known as ''cold blast'', and it increases the [[fuel efficiency]] of the bloomery and improves yield. They can also be built bigger than natural draught bloomeries.
 ====Oldest European blast furnaces====
 The oldest known blast furnaces in the West were built in [[Durstel]] in [[Switzerland]], the Märkische [[Sauerland]] in [[Germany]], and at [[Lapphyttan]] in [[Sweden]], where the complex was active between 1205 and 1300.<ref>Jockenhövel, Albrecht ''et al.'' (1997) [https://www.uni-muenster.de/UrFruehGeschichte/forschen/maerkischessauerland_engl.html "Archaeological Investigations on the Beginning of Blast Furnace-Technology in Central Europe"] {{webarchive|url=https://web.archive.org/web/20130224111115/http://www.uni-muenster.de/UrFruehGeschichte/forschen/maerkischessauerland_engl.html|date=24 February 2013}} Abteilung für Ur- und Frühgeschichtliche Archäologie, Westfälische Wilhelms-Universität Münster; abstract published as: Jockenhövel, A. (1997) "Archaeological Investigations on the Beginning of Blast Furnace-Technology in Central Europe" pp.&nbsp;56–58 ''In'' Crew, Peter and Crew, Susan (editors) (1997) ''Early Ironworking in Europe: Archaeology and Experiment: Abstracts of the International Conference at Plas Tan y Bwlch 19–25 September 1997'' (Plas Tan y Bwlch Occasional Papers No 3) Snowdonia National Park Study Centre, Gwynedd, Wales, {{OCLC|470699473}}; archived here [https://web.archive.org/web/20130224111115/http://www.uni-muenster.de/UrFruehGeschichte/forschen/maerkischessauerland_engl.html] by [[WebCite]] on 11 March 2012</ref> At Noraskog in the Swedish parish of Järnboås, traces of even earlier blast furnaces have been found, possibly from around 1100.<ref>A. Wetterholm, 'Blast furnace studies in Nora bergslag' (Örebro universitet 1999, Järn och Samhälle) {{ISBN|91-7668-204-8}}</ref> These early blast furnaces, like the [[Chinese history|Chinese]] examples, were very inefficient compared to those used today. The iron from the Lapphyttan complex was used to produce balls of [[wrought iron]] known as [[Osmond iron|osmond]]s, and these were traded internationally – a possible reference occurs in a treaty with [[Novgorod]] from 1203 and several certain references in accounts of English customs from the 1250s and 1320s. Other furnaces of the 13th to 15th centuries have been identified in [[Westphalia]].<ref>N. Bjökenstam, 'The Blast Furnace in Europe during the Middle Ages: part of a new system for producing wrought iron' in G. Magnusson, ''The Importance of Ironmaking: Technological Innovation and Social Change'' I (Jernkontoret, Stockholm 1995), 143–153 and other papers in the same volume.</ref>
-The technology required for blast furnaces may have either been transferred from China, or may have been an indigenous innovation. [[Al-Qazvini]] in the 13th century and other travellers subsequently noted an iron industry in the [[Alborz|Alburz]] Mountains to the south of the [[Caspian Sea]]. This is close to the [[silk route]], so that the use of technology derived from China is conceivable.
+The technology required for blast furnaces may have either been transferred from China, or may have been an indigenous innovation. [[Al-Qazvini]] in the 13th century and other travellers subsequently noted an iron industry in the [[Alborz|Alburz]] Mountains to the south of the [[Caspian Sea]]. This is close to the [[silk route]], so that the use of technology derived from China is conceivable. Much later descriptions record blast furnaces about three metres high.<ref>Wagner 2008, 349–351.</ref> As the [[Varangian]] [[Rus' people]] from [[Scandinavia]] traded with the Caspian (using their [[Volga trade route]]), it is possible that the technology reached Sweden by this means.<ref>Wagner 2008, 354.</ref> The Vikings are known to have used double bellows, which greatly increases the volumetric flow of the blast.<ref>{{cite web|url=http://www.warehamforge.ca/ROMiron/index.html|title=Adventures in Early Iron Production – An overview of experimental iron smelts, 2001–2005|first= Darrell|last = Markewitz |website=www.warehamforge.ca |url-status=live|date = 25 March 2006|archive-url=https://web.archive.org/web/20150922082031/http://www.warehamforge.ca/ROMiron/index.html |archive-date=22 September 2015}}</ref>
-In a two-stage process the molten iron was tapped twice a day into water, thereby granulating it.<ref>{{cite journal |last1=Awty |first1=B. G. |title=The Blast Furnace in the Renaissance Period: ''Haut Fourneau'' or ''Fonderie''? |journal=Transactions of the Newcomen Society |date=January 1989 |volume=61 |issue=1 |pages=65–78 |doi=10.1179/tns.1989.005}}</ref>
+The Caspian region may also have been the source for the design of the furnace at [[Ferriere]], described by [[Filarete]],<ref>Wagner 2008, 355.</ref> involving a water-powered bellows at Semogo in [[Valdidentro]] in northern Italy in 1226. In a two-stage process the molten iron was tapped twice a day into water, thereby granulating it.<ref>{{cite journal |last1=Awty |first1=B. G. |title=The Blast Furnace in the Renaissance Period: ''Haut Fourneau'' or ''Fonderie''? |journal=Transactions of the Newcomen Society |date=January 1989 |volume=61 |issue=1 |pages=65–78 |doi=10.1179/tns.1989.005}}</ref>
 ====Cistercian contributions====
@@ Line 109: / Line 105: @@
 [[File:THC 2003.902.116 Charging the Experimental Blast Furnace.tif|thumb|upright=1.1|Charging the experimental blast furnace, a photo from the Fixed Nitrogen Research Laboratory in [[Washington D.C.]], 1930]]
 [[File:Доменная печь, Истье.JPG|thumb|upright=1.1|Remnants of a blast furnace in [[Russia]] first commissioned in 1715 by order of [[Peter the Great]] with the help of Holland masters.{{citation needed|date=January 2023}}]]
-In 1709, at [[Coalbrookdale]] in Shropshire, England, [[Abraham Darby I|Abraham Darby]] began to fuel a blast furnace with [[coke (fuel)|coke]] instead of [[charcoal]]. Coke's initial advantage was its lower cost, mainly because making coke required much less labor than cutting trees and making charcoal, but using coke also overcame localized shortages of wood, especially in Britain and on the Continent. Metallurgical grade coke will bear heavier weight than charcoal, allowing larger furnaces.<ref name="Landes_1969">
+In 1709, at [[Coalbrookdale]] in Shropshire, England, [[Abraham Darby I|Abraham Darby]] began to fuel a blast furnace with [[coke (fuel)|coke]] instead of [[charcoal]]. Coke's initial advantage was its lower cost, mainly because making coke required much less labor than cutting trees and making charcoal, but using coke also overcame localized shortages of wood, especially in Britain and eleswhere in Europe. Metallurgical grade coke will bear heavier weight than charcoal, allowing larger furnaces.<ref name="Landes_1969">
 {{cite book
 |title=The Unbound Prometheus: Technological Change and Industrial Development in Western Europe from 1750 to the Present
@@ Line 128: / Line 124: @@
 |isbn= 978-0226726342 |page=149
 }}
-</ref> A disadvantage is that coke contains more impurities than charcoal, with sulfur being especially detrimental to the iron's quality. Coke's impurities were more of a problem before hot blast reduced the amount of coke required and before furnace temperatures were hot enough to make slag from limestone free flowing.  (Limestone ties up sulfur. Manganese may also be added to tie up sulfur.)<ref>{{cite book|title=A History of Metallurgy, Second Edition |last=Tylecote |first=R. F. |year= 1992|publisher =Maney Publishing, for the Institute of Materials |location= London|isbn=978-0901462886}}</ref>{{rp|123–125}}<ref name ="McNeil1990">{{cite book |title=An Encyclopedia of the History of Technology |last=McNeil |first=Ian |year=1990 |publisher=Routledge |location=London |isbn=0415147921 |url=https://archive.org/details/isbn_9780415147927 }}</ref><ref>{{cite web|url=http://www.steel.org/making-steel/how-its-made/processes/processes-info/coke-production-for-blast-furnace-ironmaking.aspx|title=Coke for Blast Furnace Ironmaking|website=steel.org|url-status=dead|archive-url=https://web.archive.org/web/20170208204105/https://www.steel.org/making-steel/how-its-made/processes/processes-info/coke-production-for-blast-furnace-ironmaking.aspx|archive-date=8 February 2017}}</ref><ref name="Tylecote_1992">{{cite book|title=A History of Metallurgy, Second Edition |last=Tylecote |first=R. F.|year= 1992|publisher =Maney Publishing, for the Institute of Materials |location= London|isbn=978-0901462886}}</ref>{{rp|122–123}}
+</ref> A disadvantage is that coke contains more impurities than charcoal, with sulfur being especially detrimental to the iron's quality. Coke's impurities were more of a problem before hot blast reduced the amount of coke required and before furnace temperatures were hot enough to make slag from limestone free flowing.  (Limestone ties up{{explain|date=November 2024}} sulphur. Manganese may also be added to tie up{{clarify|date=November 2024}} sulphur.)<ref>{{cite book|title=A History of Metallurgy, Second Edition |last=Tylecote |first=R. F. |year= 1992|publisher =Maney Publishing, for the Institute of Materials |location= London|isbn=978-0901462886}}</ref>{{rp|123–125}}<ref name ="McNeil1990">{{cite book |title=An Encyclopedia of the History of Technology |last=McNeil |first=Ian |year=1990 |publisher=Routledge |location=London |isbn=0415147921 |url=https://archive.org/details/isbn_9780415147927 }}</ref><ref>{{cite web|url=http://www.steel.org/making-steel/how-its-made/processes/processes-info/coke-production-for-blast-furnace-ironmaking.aspx|title=Coke for Blast Furnace Ironmaking|website=steel.org|url-status=dead|archive-url=https://web.archive.org/web/20170208204105/https://www.steel.org/making-steel/how-its-made/processes/processes-info/coke-production-for-blast-furnace-ironmaking.aspx|archive-date=8 February 2017}}</ref><ref name="Tylecote_1992">{{cite book|title=A History of Metallurgy, Second Edition |last=Tylecote |first=R. F.|year= 1992|publisher =Maney Publishing, for the Institute of Materials |location= London|isbn=978-0901462886}}</ref>{{rp|122–123}}
-Coke iron was initially only used for [[foundry]] work, making pots and other cast iron goods. Foundry work was a minor branch of the industry, but Darby's son built a new furnace at nearby Horsehay, and began to supply the owners of [[finery forge]]s with coke pig iron for the production of bar iron. Coke pig iron was by this time cheaper to produce than charcoal pig iron. The use of a coal-derived fuel in the iron industry was a key factor in the British [[Industrial Revolution]].<ref>{{Citation | last = Raistrick | first = Arthur | title = Dynasty of Iron Founders: The Darbys and Coalbrookedale | place = York | publisher = Longmans, Green | year = 1953}}</ref><ref>Hyde</ref><ref>{{Citation | last1 = Trinder | first1 = Barrie Stuart | last2 = Trinder | first2 = Barrie | title = The Industrial Revolution in Shropshire | place = Chichester | publisher = Phillimore | year = 2000 | isbn = 1-86077-133-5}}</ref> Darby's original blast furnace has been archaeologically excavated and can be seen in situ at Coalbrookdale, part of the [[Ironbridge Gorge]] Museums. Cast iron from the furnace was used to make [[girder]]s for the world's first cast iron bridge in 1779. [[The Iron Bridge]] crosses the [[River Severn]] at Coalbrookdale and remains in use for pedestrians.
+Coke iron was initially only used for [[foundry]] work, making pots and other cast iron goods. Foundry work was a minor branch of the industry, but Darby's son built a new furnace at nearby Horsehay, and began to supply the owners of [[finery forge]]s with coke pig iron for the production of bar iron. Coke pig iron was by this time cheaper to produce than charcoal pig iron. The use of a coal-derived fuel in the iron industry was a key factor in the British [[Industrial Revolution]].<ref>{{Citation | last = Raistrick | first = Arthur | title = Dynasty of Iron Founders: The Darbys and Coalbrookedale | place = York | publisher = Longmans, Green | year = 1953}}</ref><ref>Hyde</ref><ref>{{Citation | last1 = Trinder | first1 = Barrie Stuart | last2 = Trinder | first2 = Barrie | title = The Industrial Revolution in Shropshire | place = Chichester | publisher = Phillimore | year = 2000 | isbn = 1-86077-133-5}}</ref> However, in many areas of the world charcoal was cheaper while coke was more expensive even after the Industrial Revolution: e. g., in the US charcoal-fueled iron production fell in share to about a half ca. 1850<ref>http://web.archive.org/web/20150522202649/https://www.fpl.fs.fed.us/documnts/pdf1985/baker85a.pdf</ref> but still continued to increase in absolute terms until ca. 1890,<ref>{{Cite journal |last=Schallenberg |first=Richard H. |date=July 1975 |title=Evolution, adaptation and survival: the very slow death of the American charcoal iron industry |url=https://www.tandfonline.com/doi/full/10.1080/00033797500200331 |journal=Annals of Science |language=en |volume=32 |issue=4 |pages=341–358 |doi=10.1080/00033797500200331 |issn=0003-3790}}</ref> while in [[João Monlevade]] in the [[Brazilian Highlands]] charcoal-fired blast furnaces were built as late as the 1930s and only phased out in 2000.<ref>https://thebeautyofsteel.com/steel-plants-archive/arcelormittal-monlevadea</ref>
+Darby's original blast furnace has been archaeologically excavated and can be seen in situ at Coalbrookdale, part of the [[Ironbridge Gorge]] Museums. Cast iron from the furnace was used to make [[girder]]s for the world's first cast iron bridge in 1779. [[The Iron Bridge]] crosses the [[River Severn]] at Coalbrookdale and remains in use for pedestrians.
 [[File:Germany First Coke Blast Furnace Miniature DM.jpg|thumb|upright=1.1|The first coke blast furnace in [[Germany]] (1794-), depicted in a miniature in the [[Deutsches Museum]]]]
@@ Line 170: / Line 168: @@
 This is a great increase from the typical 18th-century furnaces, which averaged about {{convert|360|t}} per year. Variations of the blast furnace, such as the Swedish electric blast furnace, have been developed in countries which have no native coal resources.
-According to ''[[Global Energy Monitor]]'', the blast furnace is likely to become obsolete to meet [[climate change]] objectives of reducing carbon dioxide emission,<ref>{{Cite web|date=2021-06-29|title=Steel sector may be saddled with up to $70 bln stranded assets -report|url=https://www.reuters.com/business/energy/steel-sector-may-be-saddled-with-up-70-bln-stranded-assets-report-2021-06-29/|access-date=2021-07-10|website=Reuters}}</ref> but [[BHP]] disagrees.<ref name=":1" />  An alternative process involving [[direct reduced iron]] is likely to succeed it,{{Citation needed|date=July 2021}} but this also needs to use a blast furnace to melt the iron and remove the [[gangue]] (impurities) unless the ore is very high quality.<ref name=":1">{{Cite web|title=Pathways to decarbonisation episode two: steelmaking technology|url=https://www.bhp.com/media-and-insights/prospects/2020/11/pathways-to-decarbonisation-episode-two-steelmaking-technology/|url-status=live|archive-url=https://web.archive.org/web/20201105063202/https://www.bhp.com/media-and-insights/prospects/2020/11/pathways-to-decarbonisation-episode-two-steelmaking-technology/ |archive-date=5 November 2020 }}</ref>
+According to ''[[Global Energy Monitor]]'', the blast furnace is likely to become obsolete to meet [[climate change]] objectives of reducing carbon dioxide emission,<ref>{{Cite web|date=2021-06-29|title=Steel sector may be saddled with up to $70 bln stranded assets -report|url=https://www.reuters.com/business/energy/steel-sector-may-be-saddled-with-up-70-bln-stranded-assets-report-2021-06-29/|access-date=2021-07-10|website=Reuters}}</ref> but [[BHP]] disagrees.<ref name=":1" />  An alternative process involving [[direct reduced iron]] (DRI) is likely to succeed it,{{Citation needed|date=July 2021}} but this also needs to use a blast furnace to melt the iron and remove the [[gangue]] (impurities) unless the ore is very high quality.<ref name=":1">{{Cite web|title=Pathways to decarbonisation episode two: steelmaking technology|url=https://www.bhp.com/media-and-insights/prospects/2020/11/pathways-to-decarbonisation-episode-two-steelmaking-technology/|url-status=live|archive-url=https://web.archive.org/web/20201105063202/https://www.bhp.com/media-and-insights/prospects/2020/11/pathways-to-decarbonisation-episode-two-steelmaking-technology/ |archive-date=5 November 2020 }}</ref>
 ==== Oxygen blast furnace ====
 {{Expand section|date=July 2021}}
-The oxygen blast furnace (OBF) process has been extensively studied theoretically because of the potentials of promising energy conservation and {{CO2}} emission reduction.<ref>{{Cite journal |last1=Zhang |first1=Wei |last2=Dai |first2=Jing |last3=Li |first3=Chengzhi |last4=Yu |first4=Xiaobing |last5=Xue |first5=Zhengliang |last6=Saxén |first6=Henrik |date=January 2021 |title=A Review on Explorations of the Oxygen Blast Furnace Process |url=https://onlinelibrary.wiley.com/doi/10.1002/srin.202000326 |journal=Steel Research International |language=en |volume=92 |issue=1 |pages=2000326 |doi=10.1002/srin.202000326 |s2cid=224952826 |issn=1611-3683}}</ref> This type may be the most suitable for use with CCS.<ref name=":1" /> The main blast furnace has of three levels; the reduction zone ({{convert|523–973|K|C F|abbr=on}}), slag formation zone ({{convert|1073–1273|K|C F|abbr=on}}), and the combustion zone ({{convert|1773–1873|K|C F|abbr=on}}).
+The oxygen blast furnace (OBF) process has been extensively studied theoretically because of the potentials of promising energy conservation and {{CO2}} emission reduction.<ref>{{cite journal |last1=Zhang |first1=Wei |last2=Dai |first2=Jing |last3=Li |first3=Chengzhi |last4=Yu |first4=Xiaobing |last5=Xue |first5=Zhengliang |last6=Saxén |first6=Henrik |title=A Review on Explorations of the Oxygen Blast Furnace Process |journal=Steel Research International |date=January 2021 |volume=92 |issue=1 |doi=10.1002/srin.202000326 |s2cid=224952826 |url=https://urn.fi/URN:NBN:fi-fe2022012811123 }}</ref> This type may be the most suitable for use with CCS.<ref name=":1" /> The main blast furnace has of three levels; the reduction zone ({{convert|523–973|K|C F|abbr=on}}), slag formation zone ({{convert|1073–1273|K|C F|abbr=on}}), and the combustion zone ({{convert|1773–1873|K|C F|abbr=on}}).
 Blast furnaces are currently rarely used in copper smelting, but modern lead smelting blast furnaces are much shorter than iron blast furnaces and are rectangular in shape.<ref name = "Sinclair77">R J Sinclair, ''The Extractive Metallurgy of Lead'' (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 77.</ref> Modern lead blast furnaces are constructed using water-cooled steel or copper jackets for the walls, and have no refractory linings in the side walls.<ref name = "Sinclair75">R J Sinclair, ''The Extractive Metallurgy of Lead'' (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 75.</ref> The base of the furnace is a hearth of [[Fire brick|refractory material]] (bricks or castable refractory).<ref name = "Sinclair75"/> Lead blast furnaces are often open-topped rather than having the charging bell used in iron blast furnaces.<ref>R J Sinclair, ''The Extractive Metallurgy of Lead'' (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 76.</ref>
@@ Line 229: / Line 227: @@
 Modern furnaces are equipped with an array of supporting facilities to increase efficiency, such as ore storage yards where barges are unloaded. The raw materials are transferred to the stockhouse complex by ore bridges, or [[Hopper car|rail hopper]]s and [[Railcar|ore transfer cars]]. Rail-mounted scale cars or computer controlled weight hoppers weigh out the various raw materials to yield the desired hot metal and slag chemistry. The raw materials are brought to the top of the blast furnace via a [[skip (container)|skip]] car powered by winches or conveyor belts.<ref name="AISI">American Iron and Steel Institute (2005). [https://web.archive.org/web/20070510164459/http://www.steel.org/AM/Template.cfm?Section=Home&template=%2FCM%2FHTMLDisplay.cfm&ContentID=5433 How a Blast Furnace Works]. steel.org.</ref>
-There are different ways in which the raw materials are charged into the blast furnace. Some blast furnaces use a "double bell" system where two "bells" are used to control the entry of raw material into the blast furnace. The purpose of the two bells is to minimize the loss of hot gases in the blast furnace. First, the raw materials are emptied into the upper or small bell which then opens to empty the charge into the large bell. The small bell then closes, to seal the blast furnace, while the large bell rotates to provide specific distribution of materials before dispensing the charge into the blast furnace.<ref name=et>{{Citation | last = McNeil | first = Ian | title = An encyclopaedia of the history of technology | publisher = Taylor & Francis | page = 163 | year = 1990 | url = https://books.google.com/books?id=WW4Q-vMA6IMC | isbn = 0-415-01306-2}}</ref><ref>{{Citation | last = Strassburger | first = Julius H. | title = Blast furnace: Theory and Practice | publisher = Taylor & Francis | page = 564 | year = 1969 | url = https://books.google.com/books?id=xLsOAAAAQAAJ | isbn = 0-677-10420-0}}</ref> A more recent design is to use a "bell-less" system. These systems use multiple hoppers to contain each raw material, which is then discharged into the blast furnace through valves.<ref name=et/> These valves are more accurate at controlling how much of each constituent is added, as compared to the skip or conveyor system, thereby increasing the efficiency of the furnace. Some of these bell-less systems also implement a discharge chute in the throat of the furnace (as with the Paul Wurth top) in order to precisely control where the charge is placed.<ref>{{Citation|last=Whitfield |first=Peter |title=Design and Operation of a Gimbal Top Charging System |url=http://www2.sea.siemens.com/NR/rdonlyres/FFA8AF1C-1791-46E8-AA09-917BB28D8701/0/038.pdf |access-date=2008-06-22 |url-status=dead |archive-url=https://web.archive.org/web/20090305185028/http://www2.sea.siemens.com/NR/rdonlyres/FFA8AF1C-1791-46E8-AA09-917BB28D8701/0/038.pdf |archive-date=5 March 2009 }}</ref>
+There are different ways in which the raw materials are charged into the blast furnace. Some blast furnaces use a "double bell" system where two "bells" are used to control the entry of raw material into the blast furnace. The purpose of the two bells is to minimize the loss of hot gases in the blast furnace. First, the raw materials are emptied into the upper or small bell which then opens to empty the charge into the large bell. The small bell then closes, to seal the blast furnace, while the large bell rotates to provide specific distribution of materials before dispensing the charge into the blast furnace.<ref name=et>{{cite book |last1=McNeil |first1=Ian |title=An Encyclopedia of the History of Technology |date=2002 |publisher=Taylor & Francis |isbn=978-0-203-19211-5 |page=163 }}</ref><ref>{{cite book |last1=Strassburger |first1=Julius H. |title=Blast Furnace-theory and Practice |date=1969 |publisher=Gordon and Breach Science Publishers |isbn=978-0-677-10420-1 |page=564 }}</ref> A more recent design is to use a "bell-less" system. These systems use multiple hoppers to contain each raw material, which is then discharged into the blast furnace through valves.<ref name=et/> These valves are more accurate at controlling how much of each constituent is added, as compared to the skip or conveyor system, thereby increasing the efficiency of the furnace. Some of these bell-less systems also implement a discharge chute in the throat of the furnace (as with the Paul Wurth top) in order to precisely control where the charge is placed.<ref>{{Citation|last=Whitfield |first=Peter |title=Design and Operation of a Gimbal Top Charging System |url=http://www2.sea.siemens.com/NR/rdonlyres/FFA8AF1C-1791-46E8-AA09-917BB28D8701/0/038.pdf |access-date=2008-06-22 |url-status=dead |archive-url=https://web.archive.org/web/20090305185028/http://www2.sea.siemens.com/NR/rdonlyres/FFA8AF1C-1791-46E8-AA09-917BB28D8701/0/038.pdf |archive-date=5 March 2009 }}</ref>
 The iron making blast furnace itself is built in the form of a tall structure, lined with [[refractory]] brick, and profiled to allow for expansion of the charged materials as they heat during their descent, and subsequent reduction in size as melting starts to occur. Coke, [[limestone]] flux, and iron ore (iron oxide) are charged into the top of the furnace in a precise filling order which helps control gas flow and the chemical reactions inside the furnace. Four "uptakes" allow the hot, dirty gas high in carbon monoxide content to exit the furnace throat, while "bleeder valves" protect the top of the furnace from sudden gas pressure surges. The coarse particles in the exhaust gas settle in the "dust catcher" and are dumped into a railroad car or truck for disposal, while the gas itself flows through a [[venturi scrubber]] and/or electrostatic precipitators and a gas cooler to reduce the temperature of the cleaned gas.<ref name="AISI"/>
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 The exhaust gasses of a blast furnace are generally cleaned in the [[dust collector]] –  such as an [[inertia]]l separator, a [[baghouse]], or an [[electrostatic precipitator]]. Each type of dust collector has strengths and weaknesses – some collect fine particles, some coarse particles, some collect electrically charged particles. Effective exhaust clearing relies on multiple stages of treatment.<ref>{{cite web|url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/488404/Reg_60_response_dated_02-09-13.pdf|title=Comparison of techniques employed at Scunthorpe Integrated Steelworks with those in the BAT Conclusions for Iron and Steel Production published in the Official Journal of the European Union|date=8 March 2012|access-date=19 January 2021|publisher= HM Government UK}}</ref>  Waste heat is usually collected from the exhaust gases, for example by the use of a [[Cowper stove]], a variety of [[heat exchanger]].
-The IEA Green House Gas R&D Programme (IEAGHG) has shown that in an integrated steel plant, 70% of the {{CO2}} is directly from the blast furnace gas (BFG). It is possible to use carbon capture technology on the BFG before the BFG goes on to be used for heat exchange processes within the plant. In 2000, the IEAGHG estimated using that chemical absorption to capture BFG would cost $35/t of {{CO2}} (an additional $8–20/t of {{CO2}} would be required for {{CO2}} transportation and storage). This would make the entire steel production process in a plant 15–20% more expensive.<ref>IEA-GHG, 2000. Greenhouse Gas Emissions from Major Industrial Sources – Iron and Steel Production. Report no. PH3/30. Cheltenham, UK, IEA Greenhouse Gas R&D Programme. https://ieaghg.org/docs/General_Docs/Reports/PH3-30%20iron-steel.pdf Accessed July 30, 2021.</ref>
 ==Environmental impact==
 {{expand section|date=July 2021}}
-[[File:Dust catcher drawing.png|thumb|upright=1.1|A drawing of a blast furnace dust catcher]]
-The results showed that [[Climate change|global warming]] potential and [[Ocean acidification|acidification]] potential were the most significant environmental impacts. On average producing a tonne of steel emits 1.8 tonnes of {{CO2}}.<ref name=":0">{{Cite news|title=Cleaning up steel is key to tackling climate change|url=https://www.ft.com/content/3bcbcb60-037f-11e9-99df-6183d3002ee1 |archive-url=https://ghostarchive.org/archive/20221210/https://www.ft.com/content/3bcbcb60-037f-11e9-99df-6183d3002ee1 |archive-date=10 December 2022 |url-access=subscription|url-status=live|access-date=2021-07-07|website=[[Financial Times]]|date=January 2019|last1=Pooler|first1=Michael}}</ref><ref>{{Cite web|url=https://www.iea.org/data-and-statistics/charts/direct-co2-intensity-of-the-iron-and-steel-sector-in-the-net-zero-scenario-2010-2030|title=Direct CO2 intensity of the iron and steel sector in the Net Zero Scenario, 2010-2030 – Charts – Data & Statistics|website=IEA}}</ref> However, a steel mill using a top gas recycling blast furnace (TGRBF) producing a tonne of steel will emit 0.8 to 1.3 tonnes of {{CO2}} depending upon the recycle rate of the TGRBF.<ref>{{Cite journal|last1=Ho|first1=Minh T.|last2=Bustamante|first2=Andrea|last3=Wiley|first3=Dianne E.|date=November 2013|title=Comparison of {{CO2}} capture economics for iron and steel mills|url=https://linkinghub.elsevier.com/retrieve/pii/S1750583613003010|journal=International Journal of Greenhouse Gas Control|language=en|volume=19|pages=145–159|doi=10.1016/j.ijggc.2013.08.003|bibcode=2013IJGGC..19..145H }}</ref>
+[[Fossil fuel]] (coke, natural gas) use in blast furnaces is a source of [[greenhouse gas emissions]] and the blast furnace is the most emission intensive stage of the steel making process.<ref>{{cite journal |last1=Liang |first1=Wang |last2=Wang |first2=Guangwei |last3=Xu |first3=Runsheng |last4=Ning |first4=Xiaojun |last5=Zhang |first5=Jianliang |last6=Guo |first6=Xingmin |last7=Jiang |first7=Chunhe |last8=Wang |first8=Chuan |date=August 2023 |title=Life cycle assessment of blast furnace ironmaking processes: A comparison of fossil fuels and biomass hydrochar applications |journal=Fuel |volume=345 |pages=128138 |bibcode=2023Fuel..34528138L |doi=10.1016/j.fuel.2023.128138}}</ref><ref name=":2">IEA-GHG, 2000. Greenhouse Gas Emissions from Major Industrial Sources – Iron and Steel Production. Report no. PH3/30. Cheltenham, UK, IEA Greenhouse Gas R&D Programme. https://ieaghg.org/docs/General_Docs/Reports/PH3-30%20iron-steel.pdf Accessed July 30, 2021.</ref> Fuels and reductants such as [[plastic waste]],<ref>{{Cite web |last1=Knepper |first1=M. |last2=Babich |first2=A. |last3=Senk |first3=D. |last4=Bürgler |first4=Thomas |last5=Feilmayr |first5=Christoph |last6=Kieberger |first6=N. |date=22 October 2012 |title=Waste Plastics Injection: Reaktion Kinetics and Effect on the Blast Furnace Process |url=https://www.researchgate.net/publication/347574211 |access-date=31 July 2024 |website=ResearchGate}}</ref> biomass<ref>{{cite journal |last1=Wang |first1=Chuan |last2=Mellin |first2=Pelle |last3=Lövgren |first3=Jonas |last4=Nilsson |first4=Leif |last5=Yang |first5=Weihong |last6=Salman |first6=Hassan |last7=Hultgren |first7=Anders |last8=Larsson |first8=Mikael |date=September 2015 |title=Biomass as blast furnace injectant – Considering availability, pretreatment and deployment in the Swedish steel industry |url=http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-165060 |journal=Energy Conversion and Management |volume=102 |pages=217–226 |bibcode=2015ECM...102..217W |doi=10.1016/j.enconman.2015.04.013}}</ref> and hydrogen<ref name=":3">{{cite journal |last1=Pei |first1=Martin |last2=Petäjäniemi |first2=Markus |last3=Regnell |first3=Andreas |last4=Wijk |first4=Olle |date=18 July 2020 |title=Toward a Fossil Free Future with HYBRIT: Development of Iron and Steelmaking Technology in Sweden and Finland |journal=Metals |volume=10 |issue=7 |pages=972 |doi=10.3390/met10070972 |doi-access=free}}</ref> are being used by steelmakers<ref>{{cite journal |last1=De Ras |first1=Kevin |last2=Van de Vijver |first2=Ruben |last3=Galvita |first3=Vladimir V |last4=Marin |first4=Guy B |last5=Van Geem |first5=Kevin M |date=December 2019 |title=Carbon capture and utilization in the steel industry: challenges and opportunities for chemical engineering |journal=Current Opinion in Chemical Engineering |volume=26 |pages=81–87 |bibcode=2019COCE...26...81D |doi=10.1016/j.coche.2019.09.001 |hdl=1854/LU-8635595|hdl-access=free }}</ref> as possible alternatives to fossil fuels, although cost and availability remain a challenge{{Citation needed|date=August 2024}} and deployment is limited.
-==Decommissioned blast furnaces as museum sites==
+[[Electric arc furnace|Electric arc furnaces (EAF)]] are cited as an alternative steel production path which avoids the use of blast furnaces, however, depending on the characteristics of the steel product required the two furnace types are not always interchangeable. Furthermore, EAFs utilize steel scrap as a feedstock but estimates suggest that there will not be enough scrap available to meet future steel demand.<ref>{{Cite web |last=IEA |date=2020 |title=Iron and Steel Technology Roadmap |url=https://www.iea.org/reports/iron-and-steel-technology-roadmap |access-date=6 August 2024 |website=[[International Energy Agency]]}}</ref> Using hydrogen gas as a reductant to produce DRI (so called H2-DRI) from iron ore, which is then used as a feedstock for an EAF provides a technologically feasible, low emission alternative to blast furnaces.<ref name=":3" /> The H2-DRI EAF production route is in a fledgling state, with just one plant in operation.<ref>{{Cite web |title=Hybrit |url=https://www.hybritdevelopment.se/en/ |access-date=2024-08-07 |website=Hybrit |language=en-US}}</ref>
+A 2000 report from the [[International Energy Agency]] Greenhouse Gas Technical Collaboration Programme (IEAGHG)<ref name=":4">{{Cite web |title=IEAGHG - Facilitating technology advancements, addressing barriers, and enabling deployment |url=https://ieaghg.org/ |access-date=2024-08-07 |website=IEAGHG |language=en-GB}}</ref> shows that 70% of the {{CO2}} emissions from integrated steel plants arise directly from the blast furnace gas (BFG). By treating BFG with [[Carbon capture and storage|carbon capture]] technology prior to use for heat exchange and energy recovery within the plant, a portion of these emissions can be abated. The report estimates that chemical {{CO2}} absorption would cost $35/t of {{CO2}}, plus $8–20/t {{CO2}} for transportation and storage.<ref name=":4" /> At the time, this would have increased steel production costs by 15–20%,<ref name=":2" /> {{Citation needed|date=August 2024|reason=More recent citation required}} presenting a barrier to decarbonisation for steelmakers which typically operate with margins of 8-10%.<ref>{{Cite web |title=SteelLens {{!}} Metals & Mining {{!}} McKinsey & Company |url=https://www.mckinsey.com/industries/metals-and-mining/how-we-help-clients/steel-lens |access-date=2024-08-07 |website=www.mckinsey.com}}</ref> As of 2024 no blast furnaces have been equipped with carbon capture technology.
+ULCOS (Ultra Low [[Carbon Dioxide|CO<sub>2</sub>]] [[Steelmaking]])<ref>http://www.ulcos.org {{webarchive|url=https://web.archive.org/web/20081121182534/http://www.ulcos.org/|date=21 November 2008}}</ref> was a European programme exploring processes to reduce blast furnace emissions by at least 50%. Technologies identified include carbon capture and storage (CCS) and alternative energy sources and reductants such as hydrogen, electricity and biomass.<ref>ICIT-Revue de Métallurgie, September and October issues, 2009</ref>[[File:Dust catcher drawing.png|thumb|upright=1.1|A drawing of a blast furnace dust catcher]]
+==Preserved historic blast furnaces==
 {{Main|List of preserved historic blast furnaces}}
-For a long time, it was normal procedure for a decommissioned blast furnace to be demolished and either be replaced with a newer, improved one, or to have the entire site demolished to make room for follow-up use of the area. In recent decades, several countries have realized the value of blast furnaces as a part of their industrial history. Rather than being demolished, abandoned steel mills were turned into museums or integrated into multi-purpose parks. The largest number of preserved historic blast furnaces exists in Germany; other such sites exist in Spain, France, the [[Czech Republic]], [[Great Britain]]. Japan, [[Luxembourg]], [[Poland]], [[Romania]], [[Mexico]], [[Russia]] and the [[List of preserved historic blast furnaces#United States|United States]].
+Historically it was normal procedure for a decommissioned blast furnace to be demolished and either replaced with a newer, improved one, or to have the entire site demolished and treated for follow-up use of the area. In recent decades, several countries have realized the historic value of blast furnaces and have transformed them into museums. Examples can be found in the [[Czech Republic]], France, Germany, Japan, [[Luxembourg]], [[Poland]], [[Romania]], [[Mexico]], [[Russia]], Spain, [[United Kingdom]], and [[United States]].
 ==Gallery==