China Nonferrous Metallurgy

HCl leaching-SO2 reduction is a new process for the production of tellurium. Because of the short process, the simple equipment configuration, the high recovery rate, it has a good application prospect. In this paper, the effects of leaching temperature, leaching time, leaching liquid-solid ratio, pre-reduction time, reduction time, reduction temperature and other parameters on tellurium recovery rate were investigated. In order to improve the tellurium reduction rate and recovery rate, the measures of deep reduction of by iron powder were innovatively proposed. The main conclusions are as follows, under the conditions of leaching temperature 65℃, leaching time 60min, leaching liquid-solid ratio 3∶1, pre-reduction time 5min, reduction time 6h and reduction temperature 70℃, the leaching rate of tellurium is 95.5%, and the reduction rate is 91.5%. After washing and casting, the tellurium powder can be obtained to meet the Te9995 standard. The reduction rate of tellurium can be further increased to 96% by deep reduction of tellurium-containing solution with iron powder, and the recovery rate of tellurium in the process is 91.68%. Compared with the electrowinning process, the new process can shorten the production cycle by 95%, and realize the efficient output of tellurium products and the improvement of economic benefits.