Improvements in or relating to method of lowering the carbon content of high carbon ferrochromium

摘要

The carbon content of high carbon ferrochromium is lowered by establishing a fluidized bed of the comminuted material by blowing upwardly through a body thereof a stream of oxidising gas, maintaining said fluidized bed at a temperature of 900 DEG -1400 DEG C. for a time sufficient to oxidise a substantial portion of the carbon and metal of the ferrochromium and to remove said carbon from said ferrochromium as carbon monoxide or carbon dioxide, and thereafter treating said partially oxidized ferrochromium at an elevated temperature in a reducing gas atmosphere for a time sufficient to reduce a substantial portion of the metal oxide content of the ferrochromium back to metal. The reduction step is preferably performed in a fluid bed reactor which may be the same reactor used for the oxidation step, and is preferably carried out at a temperature of 1000 DEG -1400 DEG C. The preferred oxidising gas is air, but oxygen or carbon dioxide may also be used as well as other oxygen-containing gases having constituents other than nitrogen, and mixtures of such gases. The preferred reducing gas is hydrogen although other reducing gases such as carbon monoxide, water gas, methane, or mixtures thereof may be used.