Ferrochrome is a ferroalloy composed of chromium and iron and it is classified according to its carbon content mainly.If ferrochorme has less than 0.5 % C it is named as low carbon ferrochrome and if it has 5-8 % C it is named as high carbon ferrochrome. Standard high carbon ferrochrome contains 65 % Cr and if it contains 55-58 % Cr it is named as charge chrome.

High carbon ferrochrome is produced in a submerged electric arc furnace using chromite ore, metallurgical coke and fluxes. 4-4.5 Mwh electric energy is required to produce one ton of this alloy. It is mainly used in stainless steel industry and alloying steel.

Low carbon ferrochrome is exactly the same alloy but it contains very less amount of carbon.  To lower carbon content a completely different process is used to produce it. Instead of carbothermic reduction, oxides are reduced with silicothermic reduction. The most popular process is the Perrin process to produce low carbon ferrochrome. In a seperate submerged electric arc furnace a silicon rich alloy is produced and then this liquid silicon alloy which is named as silicoferrochrome is reacted in the reaction laddles with molten chromite which is already melted in a seperate electric arc furnace. It is an energy depended process and in total 10-12 Mwh electric energy is required to produce one ton of low carbon ferrochrome. Low carbon ferrochrome is mainly used for high quality steel alloy production.

There is a newly developed low carbon ferrochrome production process in which, molten or solid silicoferrochrome produced is reacted inside a DC furnace to react with the molten chromite that is also melted inside the same furnace. By this new process a significant amount of energy is saved. Also this process requires less lime consumption. The main advantage of this process is the further decreased carbon contents. The generated slag contains less than 1% chrome exide and it is granulated to be used as filling and construction material.

• [Editor:Yueleilei]