China Nonferrous Metallurgy

Antimony is a common impurity in tin metallurgy. Sn and Sb separation is one of the key difficulties encountered in tin production. In this paper, the process of NaOH leaching → antimony oxide precipitation → purification and impurity removal → cathode antimony production by electrodeposition is used to separate tin and antinomy in tin anode slime. The test results show that with the initial concentration of NaOH of 167 g/L, a liquid-solid ratio of 5〖DK〗∶1, leaching temperature of 150 ℃ and leaching time of 60 min, the tin leaching efficiency is 89.68% and the antimony leaching efficiency is 75.57%. Oxidative precipitation of antimony is conducted for the leachate, with an antimony precipitation rate of above 99%, and the produced sodium antimonate is up to the quality standard of chemical products. The liquid after antimony precipitation is added with sodium sulfide for lead removal and then electrodeposition is conducted. The quality of the cathode tin produced by electrodeposition is up to the quality standard of tin fine product. The technology can separate most of tin and antimony from the high Sb-Sn anode slime, which are recovered in the forms of tin fine product and sodium antimonate, the recovered products are of high value.