Chrome Alloys (Ferrochrome)

Chromium alloys, the collective name for the various categories of ferrochrome - are processed from chromite ore, and their main application is in metallurgy where they are an essential ingredient in stainless steel manufacturing. Stainless steel production accounts for 90 percent of ferrochrome consumption. There are three main categories of ferrochrome, namely, high, medium and low carbon ferrochrome.
High carbon ferrochrome or charge chrome (3 to 8 percent carbon), is used to produce steels in which both chromium and carbon must be present. It is made by reducing chromite with coke in a submerged arc furnace with the charge being introduced from an open top. The latest trend in charge chrome production entails the adoption of plasma furnace technology, which involves the injection of pulverized chrome ore into a shaft furnace containing generators that produce high temperature ionized gases. Plasma furnaces allow friable chromite fines to be used as the raw materials, which result in lower material loss thereby increasing the ferroalloy recovery rate. Ferrochrome containing less than 3 percent medium; carbon ferrochrome, is produced by adding chromite, lime, silicon and fluorspar to molten high carbon ferrochrome in a two-stage process. Ferrochrome with an even lower content of carbon (maximum of 0,1 percent) is produced by heating high carbon ferrochrome with ground quartzite in a high vacuum with the removal of carbon as carbon monoxide. Low carbon ferrochrome is used for producing chromium steels in which the presence of carbon is detrimental.