Research on Separation of Chromium and Iron in Waste Ferrochromium Alloy

Recycling of chromium from waste ferrochromium alloy has been researched.Ferrochromium alloy is leached using sulfuric acid,iron is removed from the leaching solution by Mohr's salt crystallization method.The main effects of technological conditions on ferrochromium alloy leaching and chromium and iron separation are examined.The research results indicat that when sulfuric acid concentration is of 500 g/L,solid-liquid ratio is of 1∶6,temperature is of 95 ℃,alloy granularity is of 61~44 μm,leaching time is of 4 h,the chromium leaching rate reaches 93.85%.Under the conditions of solution pH of 0.5,ammonium sulfate excess coefficient of 3.0,[Cr3+] of 70 g/L,[Fe2+] of 15~20 g/L,temperature of 70 ℃,reaction time of 6 h,rapid cooling,crystallization of 24 h,96.52% of iron is removed and only 1.85% of chromium is lost,very good chromium and iron separation effect can be obtained.