Ferrochrome or ferrochromium (FeCr) is a type of ferroalloy , that is, an alloy of chromium and iron , generally containing 50 to 70% chromium by weight.
16-488: Ferrochrome is produced by electric arc carbothermic reduction of chromite . Most of the global output is produced in South Africa , Kazakhstan and India , which have large domestic chromite resources. Increasing amounts are coming from Russia and China. Production of steel, especially that of stainless steel with chromium content of 10 to 20%, is the largest consumer and the main application of ferrochrome. Over 80% of
32-404: A commodity chemical . Recently, development of the 'MagSonic' carbothermic magnesium process has restarted interest in its chemistry: The reaction is readily reversible from its product vapors , and requires rapid cooling to prevent back-reaction . Metallurgical grade silicon may also be obtained by carbothermic reaction. The overall reaction is following: The actual reaction given
48-607: A family of materials and minerals containing calcium ions (Ca ) together with inorganic phosphate anions. Some so-called calcium phosphates contain oxide and hydroxide as well. Calcium phosphates are white solids of nutritional value and are found in many living organisms, e.g., bone mineral and tooth enamel . In milk, it exists in a colloidal form in micelles bound to casein protein with magnesium , zinc , and citrate –collectively referred to as colloidal calcium phosphate (CCP). Various calcium phosphate minerals, which often are not white owing to impurities, are used in
64-543: A low carbon content, is most commonly used in stainless steel production. Alternatively, high carbon FeCr produced from high-grade ore found in Kazakhstan (among other places) is more commonly used in specialist applications such as engineering steels where a high Cr/Fe ratio and minimum levels of other elements ( sulfur , phosphorus , titanium etc.) are important and production of finished metals takes place in small electric arc furnaces compared to large scale blast furnaces. In
80-478: Is attributable to the entropy of reaction: two solids, the metal oxide (and flux) and carbon, are converted to a new solid (metal) and a gas (CO x ), the latter having high entropy. A prominent example is that of iron ore smelting . Many reactions are involved, but the simplified equation is usually shown as: On a more modest scale, about 1 million tons of elemental phosphorus is produced annually by carbothermic reactions. Calcium phosphate (phosphate rock)
96-489: Is heated to 1,200–1,500 °C with sand, which is mostly SiO 2 , and coke (impure carbon) to produce P 4 . The chemical equation for this process when starting with fluoroapatite , a common phosphate mineral, is: Of historic interest is the Leblanc process . A key step in this process is the reduction of sodium sulfate with coal: The Na 2 S is then treated with calcium carbonate to give sodium carbonate ,
112-434: Is more complex than it seems and includes several steps. Sometimes carbothermic reactions are coupled to other conversions. One example is the chloride process for separating titanium from ilmenite , the main ore of titanium. In this process, a mixture of carbon and the crushed ore is heated at 1000 °C under flowing chlorine gas, giving titanium tetrachloride : For some metals, carbothermic reactions do not afford
128-419: The polyphosphates , such as P 2 O 7 and triphosphate P 3 O 10 : These materials contain other anions in addition to phosphate: Calcium phosphate stones account for approximately 15% of kidney stone disease . Calcium phosphate stones tend to grow in alkaline urine, especially when Proteus bacteria are present. It is the most common type in pregnant women. Calcium phosphate
144-404: The furnace hearth, the tap hole is drilled open and a stream of molten metal and slag rushes down a trough into a chill or ladle. Ferrochrome solidifies in large castings which are crushed for sale or further processed. Ferrochrome is generally classified by the amount of carbon and chrome it contains. The vast majority of FeCr produced is "charge chrome" from South Africa, with high carbon being
160-448: The metal, but instead give the metal carbide . This behavior is observed for titanium, hence the use of the chloride process . Carbides also form upon high temperature treatment of Cr 2 O 3 with carbon. For this reason, aluminium is employed as the reducing agent. This chemical reaction article is a stub . You can help Misplaced Pages by expanding it . Calcium phosphate The term calcium phosphate refers to
176-405: The past, Ferrochrome alloys were used in the formulation of Type III Compact Cassettes . Ferrochrome production is essentially a carbothermic reduction operation taking place at high temperatures. Chromite (an oxide of Cr and Fe) is reduced by coal and coke to form the iron-chromium alloy. The heat for this reaction can come from several forms, but typically from the electric arc formed between
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#1732891639968192-488: The production of phosphoric acid and fertilizers . Overuse of certain forms of calcium phosphate can lead to nutrient -containing surface runoff and subsequent adverse effects upon receiving waters such as algal blooms and eutrophication (over-enrichment with nutrients and minerals). These materials contain Ca combined with PO 4 , HPO 4 , or H 2 PO 4 : These materials contain Ca combined with
208-643: The reduction of substances, often metal oxides (O ), using carbon (C) as the reducing agent . The reduction is usually conducted in the electric arc furnace or reverberatory furnace , depending on the metal ore. These chemical reactions are usually conducted at temperatures of several hundred degrees Celsius. Such processes are applied for production of the elemental forms of many elements. The ability of metals to participate in carbothermic reactions can be predicted from Ellingham diagrams . Carbothermal reactions produce carbon monoxide (CO) and sometimes carbon dioxide (CO 2 ). The facility of these conversions
224-493: The second largest segment followed by the smaller sectors of low carbon and intermediate carbon material. In March 2021, the Shanghai Futures Exchange decided that it would list ferrochrome futures at some unknown date. At the time, ferrochrome spot 6–8% C, basis 50% Cr, ddp China was trading at $ 1,336–1,382. In January 2021 the spot price had been 25% lower. Carbothermic Carbothermic reactions involve
240-411: The tips of electrodes in the bottom of the furnace and the furnace hearth. This arc creates temperatures of about 2,800 °C (5,070 °F). In the process of smelting, huge amounts of electricity are consumed, making production very expensive in countries where power costs are high. Tapping of the material from the furnace takes place intermittently. When enough smelted ferrochrome has accumulated in
256-417: The world's ferrochrome is utilised in the production of stainless steel. In 2006, 28,000,000 tons of stainless steel were produced. Stainless steel depends on chromium for its appearance and resistance to corrosion. Average chrome content in stainless steel is approx. 18%. It is also used to add chromium to carbon steel . FeCr from South Africa, known as "charge chrome" and produced from a Cr containing ore with
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