METHOD FOR ALUMINOTHERMIC PRODUCTION OF METALLIC CHROME (VARIANTS) Russian patent published in 2005 - IPC

FIELD: metallurgy.

SUBSTANCE: method comprises steps of melting charge and discharging melt products. Charge contains chrome oxide, aluminum, lime, oxidizing agent such as sodium nitrate according to variant 1 and sodium (potassium) anhydride and dichromate according to variants 2,3; in addition according to variants 2, 3 - calcium hydroxide and sodium chloride and according to variant 2 - fluorspar concentrate. In variant 2 chrome containing nitrogen up to 0.05 mass % is produced. In variant 3 chrome containing nitrogen up to 0.01 mass % is produced. Variants have different features, namely: preset relation of lime (and calcium hydroxide in variants 2,3) to aluminum; limited content of carbon in lime; addition of large part of lime with minimum content of carbon directly to charge and remaining part of lime with more content of carbon - to charging bed; predetermined relations of charge components; loading and melting charge by one stage at high speed 310 - 450kg/m² min; feeding fluorspar concentrate onto liquid slag remained after draining to lining slag (variant 2).

EFFECT: optimization of thermodynamic and kinetic conditions of reducing process, increased content of chrome, lowered content of impurities such as aluminum, carbon, nitrogen, improved yield of higher kinds of aluminothermic chrome.

3 cl, 1 tbl, 7 ex