Preparation of Chromium-iron Metal Powder from Chromium Slag by Reduction Roasting and Magnetic Separation

Chromium slag (CS) has become one of the most hazardous solid waste containing chromium and iron. Based on its characteristics, the technology of reduction roasting and magnetic separation was employed to treat CS. The major impurity element of CS is magnesium and it exists in magnesium ferrite phase, which is hard to recover iron in the absence of additives. During reduction roasting, additives (Al2O3 and CaF2) could destroy the structure of magnesium ferrite and improve the iron grade and recovery. The final product, i. e. chromium-iron powder, contains 72.54% Fe and 13.56% Cr, with the iron recovery of 80.34% and chromium recovery of 80.70%.