Separation and Recovery of Chromium from Solution After Vanadium Precipitation

The separation and recovery of chromium from solution after vanadium precipitation were investigated by deep removal of vanadium, hydrolysis precipitation of chromium, and preparation of chromium oxide. Hydrous oxide of trivalent iron is an effective deep vanadium remover and can be recycled. Under the most suitable conditions including hydrous oxide of trivalent iron addition with a Fe/V molar ratio of 4, reaction temperature of 60 degrees C, reaction time of 10 min, as well as the solution pH value of 3.0, the removal of vanadium reached 97.4%. Cr3+ and Mn2+ in solution can be separated through precipitation method. Under the conditions including solution pH value of 6.0, reaction temperature of 35 degrees C, and reaction time of 2 h, the precipitation of chromium was 96.6%. After deep remove manganese using sodium thiosulfate as the reducing agent, the well-crystallized Cr2O3 product with a purity of 99.1% was prepared. The manganese in the solution after chromium recovery can be recycled as an oxidant by hydrolysis precipitation and hydrogen peroxide oxidation.