Blast furnace

Last updated

Former AHM blast furnace in Port of Sagunt, Valencia, Spain Alto Horno, Puerto de Sagunto, Espana, 2015-01-04, DD 91.JPG
Former 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. [1]

Contents

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 Trinec Iron and Steel Works in Czech Republic VysokePece1.jpg
Blast furnaces of Třinec Iron and Steel Works in Czech Republic
Charcoal burning iron blast furnace in Jackson County, Ohio, 1923 Geography of Ohio - DPLA - aaba7b3295ff6973b6fd1e23e33cde14 (page 111) (cropped2).jpg
Charcoal burning iron blast furnace in Jackson County, Ohio, 1923
Rising carbon monoxide reduces iron oxides to pure iron through a series of reactions that occur at different areas within a blast furnace. Blast Furnace Reactions.jpg
Rising carbon monoxide reduces iron oxides to pure iron through a series of reactions that occur at different areas within a blast furnace.

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 was produced with charcoal.

The downward moving column of ore, flux, 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. [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) + O2(g) → 2 CO(g) [9]

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 °C and 700 °C, the iron oxide is partially reduced to iron(II,III) oxide, Fe3O4.

3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(g) [9]

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

Fe3O4(s) + CO(g) → 3 FeO(s) + CO2(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:

CaCO3(s) → CaO(s) + CO2(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) + CO2(g) [9]

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

C(s) + CO2(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.

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 CO2 emissions in the world (see greenhouse gases). [13] Several alternatives are being investigated such as plastic waste, biomass or hydrogen as reducing agent, which can substantially reduce the carbon emissions. [14] The injection of, for example, hydrogen into blast furnaces can reduce carbon emissions by 20 percent. [15]

The challenge set by the greenhouse gas emissions of the blast furnace is being addressed in an ongoing[ when? ] European Program called ULCOS (Ultra Low CO2 Steelmaking). [16] 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. [17] 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.[ needs update ]

History

An illustration of furnace bellows operated by waterwheels from the Nong Shu, by Wang Zhen in 1313 during China's Yuan dynasty Yuan Dynasty - waterwheels and smelting.png
An illustration of furnace bellows operated by waterwheels from the Nong Shu, by Wang Zhen in 1313 during China's Yuan dynasty
A Chinese fining and blast furnace in Tiangong Kaiwu, 1637 Chinese Fining and Blast Furnace.jpg
A Chinese fining and blast furnace in Tiangong Kaiwu , 1637

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. [18] 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. [19]

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). [20] 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. [21]

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. [22] These early furnaces had clay walls and used phosphorus-containing minerals as a flux. [23] 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. [24]

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. [25] 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. [26] [27] 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. [28] 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. [29] [30]

The primary advantage of the early blast furnace was in large scale production and making iron implements more readily available to peasants. [31] 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. [32]

Blast furnaces were also later used to produce gunpowder weapons such as cast iron bomb shells and cast iron cannons during the Song dynasty. [33]

Medieval Europe

The simplest forge, known as the Corsican, was used prior to the advent of Christianity. Examples of improved bloomeries are the Stuckofen, [34] sometimes called wolf-furnace, [35] ) 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. [36] At Noraskog in the Swedish parish of Järnboås, traces of even earlier blast furnaces have been found, possibly from around 1100. [37] 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. [38]

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. [39] 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. [40] The Vikings are known to have used double bellows, which greatly increases the volumetric flow of the blast. [41]

The Caspian region may also have been the source for the design of the furnace at Ferriere, described by Filarete, [42] 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. [43]

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. [44] 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, [45] also using the phosphate-rich slag from their furnaces as an agricultural fertilizer. [46]

Archaeologists are still discovering the extent of Cistercian technology. [47] 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. [48] Slag from other furnaces of the time contained a substantial concentration of iron, whereas Laskill is believed to have produced cast iron quite efficiently. [48] [49] [50] 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. [51] 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

Drawing of an 18th-century blast furnace HautfourneauXVIII 1nb.jpg
Drawing of an 18th-century blast furnace
Early modern blast furnace pictured in the former coat of arms of Lohtaja Lohtaja.vaakuna.svg
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. [52] [53]

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. [54]

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. [55]

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. [56]

Coke blast furnaces

The original blast furnaces at Blists Hill in Madeley, England Blast Furnaces at Blists Hill.jpg
The original blast furnaces at Blists Hill in Madeley, England
Charging the experimental blast furnace, a photo from the Fixed Nitrogen Research Laboratory in Washington D.C., 1930 THC 2003.902.116 Charging the Experimental Blast Furnace.tif
Charging the experimental blast furnace, a photo from the Fixed Nitrogen Research Laboratory in Washington D.C., 1930
Remnants of a blast furnace in Russia first commissioned in 1715 by order of Peter the Great with the help of Holland masters. Domennaia pech', Ist'e.JPG
Remnants of a blast furnace in Russia first commissioned in 1715 by order of Peter the Great with the help of Holland masters.

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 on the Continent. Metallurgical grade coke will bear heavier weight than charcoal, allowing larger furnaces. [57] [58] 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.) [59] :123–125 [60] [61] [52] :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. [62] [63] [64] 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.

The first coke blast furnace in Germany (1794-), depicted in a miniature in the Deutsches Museum Germany First Coke Blast Furnace Miniature DM.jpg
The first coke blast furnace in Germany (1794-), depicted in a miniature in the Deutsches Museum

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. [65] 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. [66] This powered a cast iron blowing cylinder, which had been invented by his father Isaac Wilkinson. He patented such cylinders in 1736, [67] to replace the leather bellows, which wore out quickly. Isaac was granted a second patent, also for blowing cylinders, in 1757. [68] The steam engine and cast iron blowing cylinder led to a large increase in British iron production in the late 18th century. [52]

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. [69] [70] 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. [71]

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. [72] 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. [73]

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, [74] but BHP disagrees. [75] An alternative process involving direct reduced iron 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. [75]

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. [76] This type may be the most suitable for use with CCS. [75] 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. [77] 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. [78] The base of the furnace is a hearth of refractory material (bricks or castable refractory). [78] Lead blast furnaces are often open-topped rather than having the charging bell used in iron blast furnaces. [79]

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. [77] The lower shaft of the furnace has a chair shape with the lower part of the shaft being narrower than the upper. [77] The lower row of tuyeres being located in the narrow part of the shaft. [77] This allows the upper part of the shaft to be wider than the standard. [77]

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. [80] 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. [80]

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. [80]

Zinc production with the ISP is more expensive than with electrolytic zinc plants, so several smelters operating this technology have closed in recent years. [81] However, ISP furnaces have the advantage of being able to treat zinc concentrates containing higher levels of lead than can electrolytic zinc plants. [80]

Manufacture of stone wool

Tuyeres of a blast furnace in Gerdau, Brazil Blast furnace tuyeres.jpg
Tuyeres of a blast furnace in Gerdau, Brazil

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. [82] Very small amounts of metals are also produced which are an unwanted by-product.

Modern iron process

Blast furnace placed in an installation
Iron ore + limestone sinter
Coke
Elevator
Feedstock inlet
Layer of coke
Layer of sinter pellets of ore and limestone
Hot blast (around 1200 degC)
Removal of slag
Tapping of molten pig iron
Slag pot
Torpedo car for pig iron
Dust cyclone for separation of solid particles
Cowper stoves for hot blast
Smoke stack
Feed air for Cowper stoves (air pre-heaters)
Powdered coal
Coke oven
Coke
Blast furnace gas downcomer Blast furnace NT.PNG
Blast furnace placed in an installation
  1. Iron ore + limestone sinter
  2. Coke
  3. Elevator
  4. Feedstock inlet
  5. Layer of coke
  6. Layer of sinter pellets of ore and limestone
  7. Hot blast (around 1200 °C)
  8. Removal of slag
  9. Tapping of molten pig iron
  10. Slag pot
  11. Torpedo car for pig iron
  12. Dust cyclone for separation of solid particles
  13. Cowper stoves for hot blast
  14. Smoke stack
  15. Feed air for Cowper stoves (air pre-heaters)
  16. Powdered coal
  17. Coke oven
  18. Coke
  19. Blast furnace gas downcomer
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 VysokaPec.jpg
Blast furnace diagram
  1. Hot blast from Cowper stoves
  2. Melting zone (bosh)
  3. Reduction zone of ferrous oxide (barrel)
  4. Reduction zone of ferric oxide (stack)
  5. Pre-heating zone (throat)
  6. Feed of ore, limestone, and coke
  7. Exhaust gases
  8. Column of ore, coke and limestone
  9. Removal of slag
  10. Tapping of molten pig iron
  11. 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. [83]

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. [84] [85] 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. [84] 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. [86]

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. [83]

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. [83] 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 °C to 1300 °C (1600 °F to 2300 °F) depending on the stove design and condition. The temperatures they deal with may be 2000 °C to 2300 °C (3600 °F to 4200 °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. [83]

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. [87] 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. [88]

Environmental impact

A drawing of a blast furnace dust catcher Dust catcher drawing.png
A drawing of a blast furnace dust catcher

The results showed that global warming potential and acidification potential were the most significant environmental impacts. On average producing a tonne of steel emits 1.8 tonnes of CO2. [6] [89] 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. [90]

Decommissioned blast furnaces as museum sites

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 United States.

See also

Related Research Articles

<span class="mw-page-title-main">Smelting</span> Use of heat and a reducing agent to extract metal from ore

Smelting is a process of applying heat and a chemical reducing agent to an ore to extract a desired base metal product. It is a form of extractive metallurgy that is used to obtain many metals such as iron, copper, silver, tin, lead and zinc. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal behind. The reducing agent is commonly a fossil fuel source of carbon, such as carbon monoxide from incomplete combustion of coke—or, in earlier times, of charcoal. The oxygen in the ore binds to carbon at high temperatures as the chemical potential energy of the bonds in carbon dioxide is lower than that of the bonds in the ore.

<span class="mw-page-title-main">Pig iron</span> Iron alloy

Pig iron, also known as crude iron, is an intermediate good used by the iron industry in the production of steel. It is developed by smelting iron ore in a blast furnace. Pig iron has a high carbon content, typically 3.8–4.7%, along with silica and other constituents of dross, which makes it brittle and not useful directly as a material except for limited applications.

<span class="mw-page-title-main">Wrought iron</span> Iron alloy with a very low carbon content

Wrought iron is an iron alloy with a very low carbon content in contrast to that of cast iron. It is a semi-fused mass of iron with fibrous slag inclusions, which give it a wood-like "grain" that is visible when it is etched, rusted, or bent to failure. Wrought iron is tough, malleable, ductile, corrosion resistant, and easily forge welded, but is more difficult to weld electrically.

<span class="mw-page-title-main">Steelmaking</span> Process for producing steel from iron ore and scrap

Steelmaking is the process of producing steel from iron ore and/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel.

<span class="mw-page-title-main">Industrial processes</span> Process of producing goods

Industrial processes are procedures involving chemical, physical, electrical, or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry.

<span class="mw-page-title-main">Bloomery</span> Type of furnace once used widely for smelting iron from its oxides

A bloomery is a type of metallurgical furnace once used widely for smelting iron from its oxides. The bloomery was the earliest form of smelter capable of smelting iron. Bloomeries produce a porous mass of iron and slag called a bloom. The mix of slag and iron in the bloom, termed sponge iron, is usually consolidated and further forged into wrought iron. Blast furnaces, which produce pig iron, have largely superseded bloomeries.

Pyrometallurgy is a branch of extractive metallurgy. It consists of the thermal treatment of minerals and metallurgical ores and concentrates to bring about physical and chemical transformations in the materials to enable recovery of valuable metals. Pyrometallurgical treatment may produce products able to be sold such as pure metals, or intermediate compounds or alloys, suitable as feed for further processing. Examples of elements extracted by pyrometallurgical processes include the oxides of less reactive elements like iron, copper, zinc, chromium, tin, and manganese.

<span class="mw-page-title-main">Puddling (metallurgy)</span> Step in the manufacture of iron

Puddling is the process of converting pig iron to bar (wrought) iron in a coal fired reverberatory furnace. It was developed in England during the 1780s. The molten pig iron was stirred in a reverberatory furnace, in an oxidizing environment to burn the carbon, resulting in wrought iron. It was one of the most important processes for making the first appreciable volumes of valuable and useful bar iron without the use of charcoal. Eventually, the furnace would be used to make small quantities of specialty steels.

<span class="mw-page-title-main">Direct reduced iron</span> Newly mined and refined type of metal

Direct reduced iron (DRI), also called sponge iron, is produced from the direct reduction of iron ore into iron by a reducing gas which either contains elemental carbon or hydrogen. When hydrogen is used as the reducing gas there are no greenhouse gases produced. Many ores are suitable for direct reduction.

<span class="mw-page-title-main">Electrometallurgy</span>

Electrometallurgy is a method in metallurgy that uses electrical energy to produce metals by electrolysis. It is usually the last stage in metal production and is therefore preceded by pyrometallurgical or hydrometallurgical operations. The electrolysis can be done on a molten metal oxide which is used for example to produce aluminium from aluminium oxide via the Hall-Hérault process. Electrolysis can be used as a final refining stage in pyrometallurgical metal production (electrorefining) and it is also used for reduction of a metal from an aqueous metal salt solution produced by hydrometallurgy (electrowinning).

<span class="mw-page-title-main">Finery forge</span>

A finery forge is a forge used to produce wrought iron from pig iron by decarburization in a process called "fining" which involved liquifying cast iron in a fining hearth and removing carbon from the molten cast iron through oxidation. Finery forges were used as early as the 3rd century BC in China. The finery forge process was replaced by the puddling process and the roller mill, both developed by Henry Cort in 1783–4, but not becoming widespread until after 1800.

<span class="mw-page-title-main">Hot blast</span> Metallurgical preheating of air

Hot blast refers to the preheating of air blown into a blast furnace or other metallurgical process. As this considerably reduced the fuel consumed, hot blast was one of the most important technologies developed during the Industrial Revolution. Hot blast also allowed higher furnace temperatures, which increased the capacity of furnaces.

<span class="mw-page-title-main">Ironsand</span> A type of sand with heavy concentrations of iron

Ironsand, also known as iron-sand or iron sand, is a type of sand with heavy concentrations of iron. It is typically dark grey or blackish in colour.

<span class="mw-page-title-main">Walloon forge</span>

A Walloon forge is a type of finery forge that decarbonizes pig iron into wrought iron.

<span class="mw-page-title-main">Ferrous metallurgy</span> Metallurgy of iron and its alloys

Ferrous metallurgy is the metallurgy of iron and its alloys. The earliest surviving prehistoric iron artifacts, from the 4th millennium BC in Egypt, were made from meteoritic iron-nickel. It is not known when or where the smelting of iron from ores began, but by the end of the 2nd millennium BC iron was being produced from iron ores in the region from Greece to India, and sub-Saharan Africa. The use of wrought iron was known by the 1st millennium BC, and its spread defined the Iron Age. During the medieval period, smiths in Europe found a way of producing wrought iron from cast iron, in this context known as pig iron, using finery forges. All these processes required charcoal as fuel.

<span class="mw-page-title-main">Cornwall Iron Furnace</span> Historic district in Pennsylvania, United States

Cornwall Iron Furnace is a designated National Historic Landmark that is administered by the Pennsylvania Historical and Museum Commission in Cornwall, Lebanon County, Pennsylvania in the United States. The furnace was a leading Pennsylvania iron producer from 1742 until it was shut down in 1883. The furnaces, support buildings and surrounding community have been preserved as a historical site and museum, providing a glimpse into Lebanon County's industrial past. The site is the only intact charcoal-burning iron blast furnace in its original plantation in the western hemisphere. Established by Peter Grubb in 1742, Cornwall Furnace was operated during the Revolution by his sons Curtis and Peter Jr. who were major arms providers to George Washington. Robert Coleman acquired Cornwall Furnace after the Revolution and became Pennsylvania's first millionaire. Ownership of the furnace and its surroundings was transferred to the Commonwealth of Pennsylvania in 1932.

<span class="mw-page-title-main">Cupola furnace</span> Small blast furnace for melting scrap iron without reduction reactions

A cupola or cupola furnace is a melting device used in foundries that can be used to melt cast iron, Ni-resist iron and some bronzes. The cupola can be made almost any practical size. The size of a cupola is expressed in diameters and can range from 1.5 to 13 feet. The overall shape is cylindrical and the equipment is arranged vertically, usually supported by four legs. The overall look is similar to a large smokestack.

<span class="mw-page-title-main">Archaeometallurgical slag</span> Artefact of ancient iron production

Archaeometallurgical slag is slag discovered and studied in the context of archaeology. Slag, the byproduct of iron-working processes such as smelting or smithing, is left at the iron-working site rather than being moved away with the product. As it weathers well, it is readily available for study. The size, shape, chemical composition and microstructure of slag are determined by features of the iron-working processes used at the time of its formation.

The HIsarna ironmaking process is a direct reduced iron process for iron making in which iron ore is processed almost directly into liquid iron (pig iron). The process combines two process units, the Cyclone Converter Furnace (CCF) for ore melting and pre-reduction and a Smelting Reduction Vessel (SRV) where the final reduction stage to liquid iron takes place. The process does not require the manufacturing of iron ore agglomerates such as pellets and sinter, nor the production of coke, which are necessary for the blast furnace process. Without these steps, the HIsarna process is more energy-efficient and has a lower carbon footprint than traditional ironmaking processes. In 2018 Tata Steel announced it has demonstrated that more than 50% CO2 emission reduction is possible with HIsarna technology, without the need for carbon capture technology.

<span class="mw-page-title-main">Metallurgical furnace</span> Device used to heat, melt, or otherwise process metals

A metallurgical furnace, often simply referred to as a furnace when the context is known, is an industrial furnace used to heat, melt, or otherwise process metals. Furnaces have been a central piece of equipment throughout the history of metallurgy; processing metals with heat is even its own engineering specialty known as pyrometallurgy.

References

  1. See: Draft (boiler)
  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. Development of heat transfer circuits in the blast furnace, IOP Conference Series: Materials Science and Engineering
  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.
  6. 1 2 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 (2006). "Iron". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a14_461.pub2. ISBN   978-3527306732.
  8. 1 2 "Blast Furnace". Science Aid. Archived from the original on 17 December 2007. Retrieved 30 December 2007.
  9. 1 2 3 4 5 6 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
  10. Dr. K. E. Lee, Form Two Science (Biology Chemistry Physics)
  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.
  13. Wang, Peng; Ryberg, Morten; Yang, Yi; Feng, Kuishuang; Kara, Sami; Hauschild, Michael; Chen, Wei-Qiang (6 April 2021). "Efficiency stagnation in global steel production urges joint supply- and demand-side mitigation efforts". Nature Communications. 12 (1): 2066. Bibcode:2021NatCo..12.2066W. doi:10.1038/s41467-021-22245-6. ISSN   2041-1723. PMC   8024266 . PMID   33824307.
  14. De Ras, Kevin; Van De Vijver, Ruben; Galvita, Vladimir V.; Marin, Guy B.; Van Geem, Kevin M. (1 December 2019). "Carbon capture and utilization in the steel industry: challenges and opportunities for chemical engineering". Current Opinion in Chemical Engineering. 26: 81–87. doi:10.1016/j.coche.2019.09.001. ISSN   2211-3398. S2CID   210619173.
  15. Hoffmann, Christian; Van Hoey, Michel; Zeumer, Benedikt (April 2020). "Decarbonization challenge for steel: Hydrogen as a solution in Europe" (PDF). McKinsey & Company. p. 6.
  16. http://www.ulcos.org Archived 21 November 2008 at the Wayback Machine
  17. ICIT-Revue de Métallurgie, September and October issues, 2009
  18. 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
  19. Simcoe, Charles R. "The Age of Steel: Part II." Advanced Materials & Processes 172.4 (2014): 32–33. Academic Search Premier.
  20. "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.
  21. Wagner 2008, p. 230.
  22. Ebrey, p. 30.
  23. Early iron in China, Korea, and Japan Archived 5 February 2007 at the Wayback Machine , Donald B. Wagner, March 1993
  24. Wagner 2008, p. 6.
  25. 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
  26. 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.
  27. Needham 1986 , pp. 118–119.
  28. The Coming of the Ages of Steel. Brill Archive. 1961. p. 54. GGKEY:DN6SZTCNQ3G.
  29. 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.
  30. Ebrey, p. 158.
  31. Wagner 2008, p. 169.
  32. Wagner 2008, p. 1.
  33. Liang 2006.
  34. Julius H. Strassburger (1969). Blast Furnace-theory and Practice. Gordon and Breach Science Publishers. p. 4. ISBN   978-0-677-10420-1 . Retrieved 12 July 2012.
  35. Douglas Alan Fisher, Excerpt from The Epic of Steel Archived 25 February 2007 at the Wayback Machine , Davis Town Museum & Harper & Row, NY 1963.
  36. 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 by WebCite on 11 March 2012
  37. A. Wetterholm, 'Blast furnace studies in Nora bergslag' (Örebro universitet 1999, Järn och Samhälle) ISBN   91-7668-204-8
  38. 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.
  39. Wagner 2008, 349–351.
  40. Wagner 2008, 354.
  41. 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.
  42. Wagner 2008, 355.
  43. 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.
  44. Woods, p. 34.
  45. Gimpel, p. 67.
  46. Woods, p. 35.
  47. Woods, p. 36.
  48. 1 2 Woods, p. 37.
  49. 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.
  50. David Derbyshire, 'Henry "Stamped Out Industrial Revolution"' Archived 13 June 2014 at the Wayback Machine , The Daily Telegraph (21 June 2002); cited by Woods.
  51. 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
  52. 1 2 3 Tylecote, R. F. (1992). A History of Metallurgy, Second Edition. London: Maney Publishing, for the Institute of Materials. ISBN   978-0901462886.
  53. 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)
  54. 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 .
  55. 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.
  56. Yakovlev, V. B. (1957), "Development of Wrought Iron Production", Metallurgist, New York: Springer, 1 (8): 545, doi:10.1007/BF00732452, S2CID   137551466
  57. 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.
  58. 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.
  59. Tylecote, R. F. (1992). A History of Metallurgy, Second Edition. London: Maney Publishing, for the Institute of Materials. ISBN   978-0901462886.
  60. McNeil, Ian (1990). An Encyclopedia of the History of Technology. London: Routledge. ISBN   0415147921.
  61. "Coke for Blast Furnace Ironmaking". steel.org. Archived from the original on 8 February 2017.
  62. Raistrick, Arthur (1953), Dynasty of Iron Founders: The Darbys and Coalbrookedale, York: Longmans, Green
  63. Hyde
  64. Trinder, Barrie Stuart; Trinder, Barrie (2000), The Industrial Revolution in Shropshire, Chichester: Phillimore, ISBN   1-86077-133-5
  65. A. Raistrick, Dynasty of ironmasters (Sessions, York, 1989), 138–139.
  66. H.W. Dickinson and Rhys Jenkins, James Watt and the steam engine (Moorland, Ashbourne 1981 edn), 111–112.
  67. English patent, no.553.
  68. English patent, no.713.
  69. 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.
  70. 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.
  71. Birch, pp. 181–189.
  72. Hyde, p. 159.
  73. "POSCO Gwangyang blast furnace emerges as world largest", The Dong-a Ilbo, 10 June 2013
  74. "Steel sector may be saddled with up to $70 bln stranded assets -report". Reuters. 29 June 2021. Retrieved 10 July 2021.
  75. 1 2 3 "Pathways to decarbonisation episode two: steelmaking technology". Archived from the original on 5 November 2020.
  76. 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): 2000326. doi:10.1002/srin.202000326. ISSN   1611-3683. S2CID   224952826.
  77. 1 2 3 4 5 R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 77.
  78. 1 2 R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 75.
  79. R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 76.
  80. 1 2 3 4 R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 89.
  81. R J Sinclair, The Extractive Metallurgy of Lead (The Australasian Institute of Mining and Metallurgy: Melbourne, 2009), 90.
  82. "What is stone wool?". rockwool.co.uk. Archived from the original on 10 February 2010.
  83. 1 2 3 4 American Iron and Steel Institute (2005). How a Blast Furnace Works. steel.org.
  84. 1 2 McNeil, Ian (1990), An encyclopaedia of the history of technology, Taylor & Francis, p. 163, ISBN   0-415-01306-2
  85. Strassburger, Julius H. (1969), Blast furnace: Theory and Practice, Taylor & Francis, p. 564, ISBN   0-677-10420-0
  86. 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
  87. "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.
  88. 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.
  89. "Direct CO2 intensity of the iron and steel sector in the Net Zero Scenario, 2010-2030 – Charts – Data & Statistics". IEA.
  90. Ho, Minh T.; Bustamante, Andrea; Wiley, Dianne E. (November 2013). "Comparison of CO2 capture economics for iron and steel mills". International Journal of Greenhouse Gas Control. 19: 145–159. Bibcode:2013IJGGC..19..145H. doi:10.1016/j.ijggc.2013.08.003.

Bibliography