Passivation Evaluation of Tin Anode Containing Sb and Bi Assuming Tin Electrorefining

Abstract

The recycling of solder materials, including those used for electronics mounting, will be increasingly desirable considering the demands of SDGs. There will also be greater diversification of anode composition in electrorefining. These tendencies will reduce the purity of anode materials. The electrorefining process is a key technology for recovering Sn from used materials. It has been reported that anode electrodes containing various impurity metals tend to be passivated easily. Anode passivation reduces refining purity. In this study, we evaluated the effect of Sn anode composition on passivation time in a sulfate bath under an electrorefining process. Some of the tin anode impurities considered are Bismuth and Antimony, though there are others. In this report we clarify that specific amounts of Bi in Sn-Sb material led to anti-passivation.