Ferro Alloys
Ferroalloy refers to various alloys of iron with a high proportion of one or more other elements such as manganese, aluminium, or silicon. They are used in the production of steels and alloys. The alloy impart distinctive qualities to steel and cast iron or serve important functions during production and are, therefore, closely associated with the iron and steel industry, the leading consumer of ferroalloys. The leading ferroalloy-producing countries in 2008 were Ukraine, China, South Africa and Russia, which accounted for 77% of the world production. World production of bulk chromium, manganese and silicon ferroalloys was estimated as 29.1 million tonnes (Mt) in 2008, a 3% decrease compared with 2007.
Ferroalloys are produced generally by two methods : in a blast furnace or in an electric arc furnace. Blast furnace production continuously decreased during the 20th century, whereas the electric arc production is still increasing. Today, feromanganese can be still efficiently produced in a blast furnace, but, even in this case, electric arc furnace are spreading. More commonly, ferroalloys are produced by carbothermic reactions, involving reduction of oxides with carbon (as coke) in the presence of iron. Some ferroalloys are produced by the addition of elements into molten iron.
It is also possible to produce somme ferroalloys by direct reduction[fr] processes. For example, the Krupp-Renn process[fr] is used in Japan to produce ferronickel.