Recovery of tellurium from decopperizing leach solution of copper refinery slimes by a fixed bed reactor

Abstract

A process is proposed for the recovery of tellurium from the decopperizing leach solution of copper refinery slimes. At present, in the Naoshima Smelter and Refinery, tellurium is recovered as copper telluride from the decopperizing leach solution by precipitation with metallic copper. The leach solution is stirred in a tank with copper choppings for 48 h at 85°C. The resulting copper telluride is settled at the bottom of the tank and recovered by filtration. A drawback of this process is the long reaction time; thus not all the leach solution can be treated with the existing facility. Therefore, the application of a fixed bed reactor packed with copper choppings was studied to improve the tellurium recovery. In this process, tellurium pregnant leach solution was heated and pumped upwards through the reactor. The copper telluride product was carried over with the solution and settled in a tank. Optimum reaction conditions, such as temperature and linear velocity, were determined by laboratory tests so as to achieve a carryover of copper telluride without a problem of blockage. The rate of reaction of metallic copper with tellurium is first order with respect to the tellurium concentration. Pilot plant tests were also conducted to determine design parameters of the commercial plant.