Patent ID: 7220394
Filing Date: 2007-05-22
Classification: C22B,Y02P

Abstract:
1. A process for simultaneous recovery of chromium and iron from chromite ore processing residue (COPR), said process comprising the steps of: i) treating the COPR with not less than 20% w/w, of a metal hydroxide at a temperature not less than 350° C. for a time period not less than 10 minutes under atmospheric condition to form a grog; ii) subjecting the grog of step (i) to aqueous leaching at a temperature in the range of from 30–100° C. to form a suspension; iii) separating the suspension of step (ii) to obtain a chromate solution and an iron rich residue; iv) drying the chromate solution of step (iii) to obtain chromate salt in powder form; v) dissolving the iron rich residue of step (iii), with not less than 20% w/w, of a mineral acid at a temperature in the range of from 30–120° C. for a period of not less than 5 minutes; vi) treating the mineral acid of step (v) with sodium sulfate to obtain a suspension; vii) separating the suspension of step (vi) to obtain an iron solution and a solid residue; viii) discarding the solid residue and adjusting the pH of the iron solution of step (vii) to 2-4, and ix) drying the iron solution of step (viii), to obtain iron salt in powder form.