Electrolytic Refining of a Pb–Sn Crude Alloy

Abstract—The mechanism of electrode processes for preparing a refined lead–tin alloy via electrolysis is presented. Rather close potentials of lead and tin allow the metals to deposit and precipitate from solutions of simple salts without forming new compounds and solid solutions. A lead–tin alloy is deposited on the cathode when passing electric current through the following solution (g/L): 94 SnSiF6, 65 PbSiF6, and 86 H2SiF6. Such metals as Zn, Cd, Fe, Ni, and Sn precipitate to the solution. Impurities of As, Sb, Bi, Cu, and Ag precipitate to a slime. The content of each metal in the solution does not exceed 0.004%. The process is carried out at a current efficiency of 95% and an electric energy consumption of 174 kW h t–1. The purity of the electrolyte alloy is 99.992%.