Studies on recovery of copper, nickel, cobalt and molybdenum values from abulk sulphide concentrate of an Indian uranium ore

Laboratory studies were carried out on the roasting of the bulk sulfide flo at, produced from the uranium mill at Jaduguda in India, assaying 11% Cu, 7 % Ni, 0.4% Co and 3% Mo, adopting a factorial design scheme varying the roa sting temperature in the range of 773-923 K, residence time between 4-6 h, addition of percentage quartz from 0 to 14, and addition of percent alkali sulfate between 0 and 6. Fisher's test indicated that the temperature, perc ent alkali addition and their interaction effects are effective for recover ing Ni and Co in that order, whereas temperature alone was significant for recovering Cu. While leaching the roasted mass with water, an in situ solut ion pH of 3 was attained. Mo was partially recovered in these leach liquors since MoO3, formed while roasting, is not easily soluble under mild acidic conditions. Further roasting experiments at increased residence times for improving the recovery of Ni, and alkaline leaching experiments for recover ing remaining Mo values from the initial leach residue indicated the possib ility of recovering Cu, Ni, Co and Mo with corresponding overall yields of 98%, 65%, 93% and 93%, respectively by roasting at a temperature of 823 K, for 4 h residence time by adding 12% by wt. Li2SO4 before roasting. (C) 200 1 Elsevier Science B.V. All rights reserved.