Recovery of Chromium from Stainless Steel dust

Abstract

This investigation deals with the recovery of chromium as sodium chromate of 99.5% purity from stainless steel dust containing 7.72% chromium obtained from stainless steel processing plants. The stainless steel dust mostly contained iron in oxide form along with chromium, nickel (1.7 1%) and manganese (3.5 5%). The steel dust was roas-ted with soda ash followed by water leaching to recover the major constituent chromium. It was found that the roasting at 1073 K in 90 minutes resulted in maximum (95%) chromium recovery. Kinetics of sodium chromate formation followed topochemical model involving chemical reactions at the surface with activation energy of 22 kJmol" 1 . TG/DTA, XRD phase identification and SEM-EDX confirmed the exper-imental observation and the mode of reaction.