EFFECT OF ROASTING WITH AMMONIUM-SULFATE AND SULFURIC-ACID ON THE EXTRACTION OF COPPER AND COBALT FROM COPPER CONVERTER SLAG

Copper converter slag, provided by Ergani Copper Co. of Etibank and containing 2.56% copper and 0.22% cobalt, was roasted with ammonium sulfate. The effects of such parameters as temperature (200-600-degrees-C), duration of roasting (15-120 min), and amount of ammonium sulfate (0.5-2.5 times stoichiometric) have been studied. Under optimum conditions (slag size, -100 mesh; stoichiometric requirement of ammonium sulfate; roasting temperature of 400-degrees-C for 60 min), we obtained 88% Cu and 67% Co by extraction. Similar studies were carried out with concentrated sulfuric acid. The influence of experimental variables such as roasting temperature (25-300-degrees-C), roasting period (30-120 min), and amount of sulfuric acid (0.5-2 times stoichiometric) has been studied. Under atmospheric conditions, i.e., at 200-degrees-C and a roasting period of 60 min with 1.5 times the stoichiometric amount of sulfuric acid, recoveries of copper and cobalt were 82 and 96%, respectively.