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104-541: Its history is traced to 1873, when it was decided to build two blast furnaces at the location. The town of Hagfors used to play host to the Swedish Rally , a car rally , every February, which provided a significant annual economic windfall for the region. Hagfors was one of the last places in Sweden to receive the formal title of a city , when it was detached from Norra Råda in 1950. The designated coat of arms

208-408: A steam engine replaced a horse-powered pump in 1742. 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. This powered a cast iron blowing cylinder , which had been invented by his father Isaac Wilkinson . He patented such cylinders in 1736, to replace

312-528: A 33% to 40% recovery of magnetite by weight, to produce a concentrate grading in excess of 64% iron by weight. The typical magnetite iron ore concentrate has less than 0.1% phosphorus , 3–7% silica , and less than 3% aluminium . As of 2019, magnetite iron ore is mined in Minnesota and Michigan in the United States , eastern Canada , and northern Sweden . Magnetite-bearing banded iron formation

416-696: A benchmark to be followed by the rest of the industry. Singapore Mercantile Exchange (SMX) has launched the world's first global iron ore futures contract, based on the Metal Bulletin Iron Ore Index (MBIOI) which uses daily price data from a broad spectrum of industry participants and independent Chinese steel consultancy and data provider Shanghai Steelhome's widespread contact base of steel producers and iron ore traders across China. The futures contract has seen monthly volumes over 1,500,000 t (1,500,000 long tons; 1,700,000 short tons) after eight months of trading. This move follows

520-542: A blast furnace to melt the iron and remove the gangue (impurities) unless the ore is very high quality. The oxygen blast furnace (OBF) process has been extensively studied theoretically because of the potentials of promising energy conservation and CO 2 emission reduction. This type may be the most suitable for use with CCS. 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

624-425: A blast furnace, a downward-moving column of ore, flux, coke (or charcoal ) 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,

728-470: 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,

832-572: A fining hearth. 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. These early furnaces had clay walls and used phosphorus -containing minerals as a flux . Chinese blast furnaces ranged from around two to ten meters in height, depending on

936-484: 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 . However, in many areas of

1040-455: 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

1144-424: A premium price. Due to the high density of hematite relative to associated silicate gangue, hematite beneficiation usually involves a combination of beneficiation techniques. One method relies on passing the finely-crushed ore over a slurry containing magnetite or other agent such as ferrosilicon which increases its density. When the density of the slurry is properly calibrated, the hematite will sink and

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1248-463: 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

1352-453: A relatively low-grade ore, they are also inexpensive to collect, as they do not have to be mined. Because of this, companies such as Magnetation have started reclamation projects where they use iron ore tailings as a source of metallic iron. The two main methods of recycling iron from iron ore tailings are magnetizing roasting and direct reduction. Magnetizing roasting uses temperatures between 700 and 900 °C (1,292 and 1,652 °F) for

1456-616: A source of iron ore. Prior to the industrial revolution, most iron was obtained from widely-available goethite or bog ore , for example, during the American Revolution and the Napoleonic Wars . Historically, much of the iron ore utilized by industrialized societies has been mined from predominantly hematite deposits with grades of around 70% Fe. These deposits are commonly referred to as "direct shipping ores" or "natural ores". Increasing iron ore demand, coupled with

1560-606: A switch to index-based quarterly pricing by the world's three largest iron ore miners— Vale , Rio Tinto , and BHP —in early 2010, breaking a 40-year tradition of benchmark annual pricing. Iron is the most abundant element on earth but not in the crust. The extent of the accessible iron ore reserves is not known, though Lester Brown of the Worldwatch Institute suggested in 2006 that iron ore could run out within 64 years (that is, by 2070), based on 2% growth in demand per year. Geoscience Australia calculates that

1664-418: A time of under 1 hour to produce an iron concentrate (Fe 3 O 4 ) to be used for iron smelting. For magnetizing roasting, it is important to have a reducing atmosphere to prevent oxidization and the formation of Fe 2 O 3 because it is harder to separate as it is less magnetic. Direct reduction uses hotter temperatures of over 1,000 °C (1,830 °F) and longer times of 2–5 hours. Direct reduction

1768-655: A typically titanium -bearing magnetite, often with vanadium . These ores form a niche market, with specialty smelters used to recover the iron, titanium, and vanadium. These ores are beneficiated essentially similarly to banded iron formation ores, but usually are more easily upgraded via crushing and screening . The typical titanomagnetite concentrate grades 57% Fe, 12% Ti, and 0.5% V 2 O 5 . For every one ton of iron ore concentrate produced, approximately 2.5–3.0 tons of iron ore tailings will be discharged. Statistics show that there are 130 million tons of iron ore tailings discharged every year. If, for example,

1872-659: A value of $ 2.3 billion. 46% of Canada's iron ore comes from the Iron Ore Company of Canada mine, in Labrador City , Newfoundland , with secondary sources including the Mary River Mine in Nunavut . According to the U.S. Geological Survey's 2021 Report on iron ore, India is estimated to produce 59,000,000 t (58,000,000 long tons; 65,000,000 short tons) of iron ore in 2020, placing it as

1976-504: Is a countercurrent exchange and chemical reaction process. 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

2080-511: Is a high-volume, low-margin business, as the value of iron is significantly lower than base metals. It is highly capital intensive, and requires significant investment in infrastructure such as rail in order to transport the ore from the mine to a freight ship. For these reasons, iron ore production is concentrated in the hands of a few major players. World production averages 2,000,000,000 t (2.0 × 10 long tons; 2.2 × 10 short tons) of raw ore annually. The world's largest producer of iron ore

2184-428: 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 . 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)

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2288-541: Is believed to have produced cast iron quite efficiently. 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. Nevertheless, the means by which the blast furnace spread in medieval Europe has not finally been determined. Due to

2392-463: 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. The downward flow of the ore along with the flux in contact with an upflow of hot, carbon monoxide -rich combustion gases

2496-428: Is expected to rise by a CAGR of 2% between 2023 and 2027, and industry analyst Fitch Solutions forecasted in 2021 that Brazil's annual production will reach 592,000,000 t (583,000,000 long tons; 653,000,000 short tons) by 2030. In 2017, Canadian iron ore mines produced 49,000,000 t (48,000,000 long tons; 54,000,000 short tons) of iron ore in concentrate pellets and 13.6 million tons of crude steel. Of

2600-510: Is followed by Japan and Korea, which consume a significant amount of raw iron ore and metallurgical coal . In 2006, China produced 588,000,000 t (579,000,000 long tons; 648,000,000 short tons) of iron ore, with an annual growth of 38%. Over the last 40 years, iron ore prices have been decided in closed-door negotiations between the small handful of miners and steelmakers which dominate both spot and contract markets. Until 2006, prices were determined in annual benchmark negotiations between

2704-603: Is in the iron ranges around Lake Superior . These iron ranges occur in Minnesota and Michigan, which combined accounted for 93% of the usable iron ore produced in the United States in 2014. Seven of the nine operational open pit mines in the United States are located in Minnesota as well as two of the three tailings reclamation operations. The other two active open pit mines were located in Michigan . In 2016, one of

2808-709: Is mined extensively in Brazil as of 2019, which exports significant quantities to Asia , and there is a nascent and large magnetite iron ore industry in Australia . Direct-shipping iron ore (DSO) deposits (typically composed of hematite ) are currently exploited on all continents except Antarctica , with the largest intensity in South America , Australia, and Asia. Most large hematite iron ore deposits are sourced from altered banded iron formations and (rarely) igneous accumulations. DSO deposits are typically rarer than

2912-464: Is possible that the technology reached Sweden by this means. The Vikings are known to have used double bellows, which greatly increases the volumetric flow of the blast. The Caspian region may also have been the source for the design of the furnace at Ferriere , described by Filarete , involving a water-powered bellows at Semogo in Valdidentro in northern Italy in 1226. In a two-stage process

3016-463: Is the raw material used to make pig iron , which is one of the main raw materials to make steel —98% of the mined iron ore is used to make steel. In 2011 the Financial Times quoted Christopher LaFemina, mining analyst at Barclays Capital, saying that iron ore is "more integral to the global economy than any other commodity, except perhaps oil ". Metallic iron is virtually unknown on

3120-481: Is the Brazilian mining corporation Vale , followed by Australian companies Rio Tinto Group and BHP . A further Australian supplier, Fortescue Metals Group Ltd, has helped bring Australia's production to first in the world. The seaborne trade in iron ore—that is, iron ore to be shipped to other countries—was 849,000,000 t (836,000,000 long tons; 936,000,000 short tons) in 2004. Australia and Brazil dominate

3224-425: Is used to produce sponge iron (Fe) to be used for steel-making. Direct reduction requires more energy, as the temperatures are higher and the time is longer and it requires more reducing agent than magnetizing roasting. Lower-grade sources of iron ore generally require beneficiation , using techniques like crushing, milling , gravity or heavy media separation , screening, and silica froth flotation to improve

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3328-402: Is very unusual for subarctic climate since summer days are warm in combination with winter average highs being just below freezing with lows only being around −10 °C (14 °F). Cold extremes are frequent for such a southerly area, with an all-time low of −42 °C (−44 °F) being unique for a Swedish area just north of 60 degrees latitude . It being a subarctic climate is a result of

3432-905: The Chichester Range , the Hamersley Range and Koolyanobbing , Western Australia . Other types of ore are coming to the fore recently, such as oxidised ferruginous hardcaps, for instance laterite iron ore deposits near Lake Argyle in Western Australia. The total recoverable reserves of iron ore in India are about 9,602,000,000 t (9.450 × 10 long tons; 1.0584 × 10 short tons) of hematite and 3,408,000,000 t (3.354 × 10 long tons; 3.757 × 10 short tons) of magnetite . Chhattisgarh , Madhya Pradesh , Karnataka , Jharkhand , Odisha , Goa , Maharashtra , Andhra Pradesh , Kerala , Rajasthan , and Tamil Nadu are

3536-774: 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 . The technology required for blast furnaces may have either been transferred from China, or may have been an indigenous innovation. Al-Qazvini in

3640-602: The Earth 's surface except as iron-nickel alloys from meteorites and very rare forms of deep mantle xenoliths . Although iron is the fourth-most abundant element in the Earth's crust , composing about 5%, the vast majority is bound in silicate or, more rarely, carbonate minerals, and smelting pure iron from these minerals would require a prohibitive amount of energy. Therefore, all sources of iron used by human industry exploit comparatively rarer iron oxide minerals, primarily hematite . Prehistoric societies used laterite as

3744-540: The Industrial Revolution . 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

3848-545: 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 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

3952-492: 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. 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

4056-564: The Pilbara region of Western Australia is approximately 844,000,000 t (831,000,000 long tons; 930,000,000 short tons) per year and rising. Gavin Mudd ( RMIT University ) and Jonathon Law ( CSIRO ) expect it to be gone within 30–50 years and 56 years, respectively. These 2010 estimates require ongoing review to take into account shifting demand for lower-grade iron ore and improving mining and recovery techniques (allowing deeper mining below

4160-893: The fuel efficiency of the bloomery and improves yield. They can also be built bigger than natural draught bloomeries. 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. At Noraskog in the Swedish parish of Järnboås, traces of even earlier blast furnaces have been found, possibly from around 1100. These early blast furnaces, like

4264-407: The silicate mineral fragments will float and can be removed. Iron is the world's most commonly used metal—steel, of which iron ore is the key ingredient, represents almost 95% of all metal used per year. It is used primarily in structures, ships, automobiles, and machinery. Iron-rich rocks are common worldwide, but ore-grade commercial mining operations are dominated by the countries listed in

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4368-420: The 13,600,000 t (13,400,000 long tons; 15,000,000 short tons) of steel 7,000,000 t (6,900,000 long tons; 7,700,000 short tons) was exported, and 43,100,000 t (42,400,000 long tons; 47,500,000 short tons) of iron ore was exported at a value of $ 4.6 billion. Of the iron ore exported, 38.5% of the volume was iron ore pellets with a value of $ 2.3 billion, and 61.5% was iron ore concentrates with

4472-662: 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. As the Varangian Rus' people from Scandinavia traded with the Caspian (using their Volga trade route ), it

4576-411: 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

4680-500: The 17th century, also using the phosphate -rich slag from their furnaces as an agricultural fertilizer . Archaeologists are still discovering the extent of Cistercian technology. 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. Slag from other furnaces of the time contained a substantial concentration of iron, whereas Laskill

4784-479: The 4th century AD. The primary advantage of the early blast furnace was in large scale production and making iron implements more readily available to peasants. 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

4888-572: 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 . 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

4992-691: The 62–64% Fe range. Granite and ultrapotassic igneous rocks were sometimes used to segregate magnetite crystals and form masses of magnetite suitable for economic concentration. A few iron ore deposits, notably in Chile , are formed from volcanic flows containing significant accumulations of magnetite phenocrysts . Chilean magnetite iron ore deposits within the Atacama Desert have also formed alluvial accumulations of magnetite in streams leading from these volcanic formations. Some magnetite skarn and hydrothermal deposits have been worked in

5096-522: The Corsican, was used prior to the advent of Christianity . Examples of improved bloomeries are the Stuckofen, sometimes called wolf-furnace, 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

5200-429: The United States is estimated to have accounted for 2% of the world's iron ore output. In the United States there are twelve iron ore mines, with nine being open pit mines and three being reclamation operations. There were also ten pelletizing plants, nine concentration plants, two direct-reduced iron (DRI) plants, and one iron nugget plant that were operating in 2014. In the United States the majority of iron ore mining

5304-846: The advantage of being able to treat zinc concentrates containing higher levels of lead than can electrolytic zinc plants. Iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite ( Fe 3 O 4 , 72.4% Fe), hematite ( Fe 2 O 3 , 69.9% Fe), goethite ( FeO(OH) , 62.9% Fe), limonite ( FeO(OH)·n(H 2 O) , 55% Fe), or siderite ( FeCO 3 , 48.2% Fe). Ores containing very high quantities of hematite or magnetite, typically greater than about 60% iron, are known as natural ore or direct shipping ore , and can be fed directly into iron-making blast furnaces . Iron ore

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5408-463: 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: 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 : As

5512-432: 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, but BHP disagrees. An alternative process involving direct reduced iron (DRI) is likely to succeed it, but this also needs to use

5616-479: 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. Blast furnaces were also later used to produce gunpowder weapons such as cast iron bomb shells and cast iron cannons during the Song dynasty . The simplest forge , known as

5720-415: 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. In

5824-470: The coke must also be low in sulfur, phosphorus , and ash. The main chemical reaction producing the molten iron is: 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: 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

5928-424: 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. 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. The base of

6032-411: The concentration of the ore and remove impurities. The results, high-quality fine ore powders, are known as fines. Magnetite is magnetic , and hence easily separated from the gangue minerals and capable of producing a high-grade concentrate with very low levels of impurities. The grain size of the magnetite and its degree of commingling with the silica groundmass determine the grind size to which

6136-533: The country's " economic demonstrated resources " of iron currently amount to 24 gigatonnes , or 24,000,000,000 t (2.4 × 10 long tons; 2.6 × 10 short tons). Another estimate places Australia's reserves of iron ore at 52,000,000,000 t (5.1 × 10 long tons; 5.7 × 10 short tons), or 30% of the world's estimated 170,000,000,000 t (1.7 × 10 long tons; 1.9 × 10 short tons), of which Western Australia accounts for 28,000,000,000 t (2.8 × 10 long tons; 3.1 × 10 short tons). The current production rate from

6240-584: The depletion of high-grade hematite ores in the United States, led after World War II to the development of lower-grade iron ore sources, principally the use of magnetite and taconite . Iron ore mining methods vary by the type of ore being mined. There are four main types of iron ore deposits worked currently, depending on the mineralogy and geology of the ore deposits. These are magnetite, titanomagnetite , massive hematite, and pisolitic ironstone deposits. The origin of iron can be ultimately traced to its formation through nuclear fusion in stars, and most of

6344-478: The furnace has a chair shape with the lower part of the shaft being narrower than the upper. The lower row of tuyeres being located in the narrow part of the shaft. This allows the upper part of the shaft to be wider than the standard. The blast furnaces used in the Imperial Smelting Process ("ISP") were developed from the standard lead blast furnace, but are fully sealed. This is because

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6448-472: The furnace is a hearth of refractory material (bricks or castable refractory). Lead blast furnaces are often open-topped rather than having the charging bell used in iron blast furnaces. 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. The lower shaft of

6552-474: 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. 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. It was taken up in America by

6656-481: 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 m (210,000 cu ft). It can produce around 5,650,000 tonnes (5,560,000 LT) of iron per year. 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

6760-442: The gangue is separated during the beneficiation process and is removed as tailings . Taconite tailings are mostly the mineral quartz , which is chemically inert. This material is stored in large, regulated water settling ponds. The key parameters for magnetite ore being economic are the crystallinity of the magnetite, the grade of the iron within the banded iron formation host rock, and the contaminant elements which exist within

6864-800: The groundwater table). Brazil is the second-largest producer of iron ore after Australia, accounting for 16% of the world's iron ore production. After a somewhat sluggish production volume 2010-2020, partly due to the Mariana dam disaster in 2015 and the Brumadinho dam disaster in 2019, which halted the production at the two involved mines, production has increased steadily since 2021, when Brazil produced 431,000,000 t (424,000,000 long tons; 475,000,000 short tons). In 2022 it increased to 435,000,000 t (428,000,000 long tons; 480,000,000 short tons) and in 2023 to 440,000,000 t (430,000,000 long tons; 490,000,000 short tons). The Brazilian production

6968-694: The increased demand for iron for casting cannons, the blast furnace came into widespread use in France in the mid 15th century. 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

7072-450: The iron and carbon smelting must be kept in an oxygen-deficient (reducing) state to promote the burning of carbon to produce CO and not CO 2 . The inclusion of even small amounts of some elements can have profound effects on the behavioral characteristics of a batch of iron or the operation of a smelter. These effects can be both good and bad, some catastrophically bad. Some chemicals are deliberately added, such as flux, which makes

7176-413: The iron from the oxygen, a stronger elemental bond must be presented to attach to the oxygen. Carbon is used because the strength of a carbon-oxygen bond is greater than that of the iron-oxygen bond at high temperatures. Thus, the iron ore must be powdered and mixed with coke , to be burnt in the smelting process. Carbon monoxide is the primary ingredient of chemically stripping oxygen from iron. Thus,

7280-895: The iron is thought to have originated in dying stars that are large enough to explode as supernovae . The Earth's core is thought to consist mainly of iron, but this is inaccessible from the surface. Some iron meteorites are thought to have originated from asteroids 1,000 km (620 mi) in diameter or larger. Banded iron formations (BIFs) are sedimentary rocks containing more than 15% iron composed predominantly of thinly-bedded iron minerals and silica (as quartz ). Banded iron formations occur exclusively in Precambrian rocks, and are commonly weakly-to-intensely metamorphosed . Banded iron formations may contain iron in carbonates ( siderite or ankerite ) or silicates ( minnesotaite , greenalite , or grunerite ), but in those mined as iron ores, oxides ( magnetite or hematite ) are

7384-400: 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 sulphur. Manganese may also be added to tie up sulphur.) Coke iron was initially only used for foundry work, making pots and other cast iron goods. Foundry work was

7488-461: 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: The carbon dioxide formed in this process is re-reduced to carbon monoxide by the coke : The temperature-dependent equilibrium controlling the gas atmosphere in the furnace is called the Boudouard reaction : The pig iron produced by the blast furnace has

7592-454: The leather bellows, which wore out quickly. Isaac was granted a second patent, also for blowing cylinders, in 1757. The steam engine and cast iron blowing cylinder led to a large increase in British iron production in the late 18th century. 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

7696-409: The low September night temperatures. Given that Gustavsfors is located somewhat north and Hagfors being a little bit more urban, it is quite possible that the locality just reaches the continental threshold that would require 10 °C (50 °F) September mean temperatures. In terms of the official reference period of 1961-1990 however, the area is firmly subarctic. Hagfors airport is located at

7800-423: The magnetite concentrate. The size and strip ratio of most magnetite resources is irrelevant, as a banded iron formation can be hundreds of meters thick, extend hundreds of kilometers along strike , and can easily come to more than three billion or more tonnes of contained ore. The typical grade of iron at which a magnetite-bearing banded iron formation becomes economic is roughly 25% iron, which can generally yield

7904-476: The magnetite-bearing BIF or other rocks which form its main source, or protolith rock, but are considerably cheaper to mine and process as they require less beneficiation due to the higher iron content. However, DSO ores can contain significantly higher concentrations of penalty elements, typically being higher in phosphorus, water content (especially pisolite sedimentary accumulations), and aluminium ( clays within pisolites). Export-grade DSO ores are generally in

8008-399: The main iron ore producers ( BHP Billiton , Rio Tinto , and Vale S.A. ) and Japanese importers. In 2006, Chinese company Baosteel began handling negotiations for the importer side. The Chinese government replaced Baosteel with China Iron and Steel Association as lead negotiator in 2009. Traditionally, the first deal reached between these the major producers and the major importers sets

8112-410: The mine tailings contain an average of approximately 11% iron, there would be approximately 1.41 million tons of iron wasted annually. These tailings are also high in other useful metals such as copper , nickel , and cobalt , and they can be used for road-building materials like pavement and filler and building materials such as cement, low-grade glass, and wall materials. While tailings are

8216-535: The molten iron was tapped twice a day into water, thereby granulating it. 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 . According to Jean Gimpel, their high level of industrial technology facilitated the diffusion of new techniques: "Every monastery had

8320-509: The past as high-grade iron ore deposits requiring little beneficiation . There are several granite-associated deposits of this nature in Malaysia and Indonesia . Other sources of magnetite iron ore include metamorphic accumulations of massive magnetite ore such as at Savage River , Tasmania , formed by shearing of ophiolite ultramafics . Another, minor, source of iron ores are magmatic accumulations in layered intrusions which contain

8424-480: The principal Indian producers of iron ore. World consumption of iron ore grows 10% per year on average with the main consumers being China, Japan, Korea, the United States, and the European Union. China is currently the largest consumer of iron ore, which translates to be the world's largest steel producing country. It is also the largest importer, buying 52% of the seaborne trade in iron ore in 2004. China

8528-481: The principal iron mineral. Banded iron formations are known as taconite within North America. The mining involves moving tremendous amounts of ore and waste. The waste comes in two forms: non-ore bedrock in the mine ( overburden or interburden locally known as mullock), and unwanted minerals, which are an intrinsic part of the ore rock itself ( gangue ). The mullock is mined and piled in waste dumps , and

8632-497: The process was further enhanced by the practice of preheating the combustion air ( hot blast ), patented by Scottish inventor James Beaumont Neilson in 1828. 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 by the discovery of 'more than ten' iron digging implements found in

8736-515: The production of commercial iron and steel , and the shaft furnaces used in combination with sinter plants in base metals smelting. 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. 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

8840-429: The quartz is left behind when the resultant powder is passed under a magnetic separator. Generally, most magnetite banded iron formation deposits must be ground to between 32 and 45 μm (0.0013 and 0.0018 in) in order to produce a low-silica magnetite concentrate. Magnetite concentrate grades are generally in excess of 70% iron by weight and usually are low in phosphorus, aluminium, titanium, and silica and demand

8944-602: 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. 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. Early water-driven reciprocators for operating blast furnaces were built according to

9048-407: The rock must be comminuted to enable efficient magnetic separation to provide a high-purity magnetite concentrate. This determines the energy inputs required to run a milling operation. Mining of banded iron formations involves coarse crushing and screening, followed by rough crushing and fine grinding to comminute the ore to the point where the crystallized magnetite and quartz are fine enough that

9152-446: The seaborne trade, with 72% of the market. BHP, Rio and Vale control 66% of this market between them. In Australia , iron ore is won from three main sources: pisolite " channel iron deposit " ore derived by mechanical erosion of primary banded-iron formations and accumulated in alluvial channels such as at Pannawonica, Western Australia ; and the dominant metasomatically altered banded iron formation -related ores such as at Newman ,

9256-464: The seventh largest global center of iron ore production, behind Australia, Brazil, China, India, Russia, and South Africa. Producers of iron ore in Ukraine include Ferrexpo , Metinvest , and ArcelorMittal Kryvyi Rih . In 2014, mines in the United States produced 57,500,000 t (56,600,000 long tons; 63,400,000 short tons) of iron ore with an estimated value of $ 5.1 billion. Iron mining in

9360-451: The seventh-largest global center of iron ore production, behind Australia, Brazil, China, Russia, South Africa, and Ukraine. India's iron ore production in 2023 was 285,000,000 metric tonnes and was the fourth largest producer in the world. According to the U.S. Geological Survey's 2021 Report on iron ore, Ukraine is estimated to have produced 62,000,000 t (61,000,000 long tons; 68,000,000 short tons) of iron ore in 2020, placing it as

9464-479: 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. Donald Wagner suggests that early blast furnace and cast iron production evolved from furnaces used to melt bronze . Certainly, though, iron

9568-401: The table aside. The major constraint to economics for iron ore deposits is not necessarily the grade or size of the deposits, because it is not particularly hard to geologically prove enough tonnage of the rocks exist. The main constraint is the position of the iron ore relative to market, the cost of rail infrastructure to get it to market, and the energy cost required to do so. Mining iron ore

9672-469: 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, Fe 3 O 4 . The temperatures 850 °C, further down in the furnace, the iron(II,III) is reduced further to iron(II) oxide: Hot carbon dioxide, unreacted carbon monoxide, and nitrogen from

9776-467: 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). 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

9880-645: The town's border. There are flights with Amapola Flyg to Stockholm Arlanda and Torsby airports. Valsarna are a motorcycle speedway club from Tallhult, who compete in the Swedish Speedway Team Championship . Their home track is at the Tallhult Motorstadion which is located to the North of Hagfors on the road to Geijersholm . They are twice league champions of Sweden. Blast furnace A blast furnace

9984-472: 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 ). 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 . Cast iron has been found in China dating to

10088-602: The two mines shut down. There have also been iron ore mines in Utah and Alabama ; however, the last iron ore mine in Utah shut down in 2014 and the last iron ore mine in Alabama shut down in 1975. Iron ores consist of oxygen and iron atoms bonded together into molecules. To convert it to metallic iron, it must be smelted or sent through a direct reduction process to remove the oxygen. Oxygen-iron bonds are strong, and to remove

10192-774: 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 but still continued to increase in absolute terms until ca. 1890, 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. Darby's original blast furnace has been archaeologically excavated and can be seen in situ at Coalbrookdale, part of

10296-586: 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. Blast furnaces used in the ISP have a more intense operation than standard lead blast furnaces, with higher air blast rates per m of hearth area and a higher coke consumption. Zinc production with the ISP is more expensive than with electrolytic zinc plants, so several smelters operating this technology have closed in recent years. However, ISP furnaces have

10400-477: Was a tribute to the furnaces. At that time the town had 6,501 inhabitants. Today it is the seat of the much larger Hagfors Municipality , but is not an administrative entity of its own. The Hagfors area has a subarctic climate due to the area's cool nights. The official weather station is located in Gustavsfors, a rural locality 13 kilometres (8.1 mi) to the north at a similar altitude. The climate type

10504-532: 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 . The first British furnaces outside the Weald appeared during

10608-477: 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 . 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

10712-529: 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. A disadvantage is that coke contains more impurities than charcoal, with sulfur being especially detrimental to

10816-646: Was probably being consumed as fast as the wood to make it grew. 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 . In 1709, at Coalbrookdale in Shropshire, England, Abraham Darby began to fuel a blast furnace with coke instead of charcoal . Coke's initial advantage

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