Preparation of High-Purity Tin by Zone Melting

Abstract

High-purity tin is widely used in advanced technologies such as aerospace, electronic information, and nuclear industry. It has become a key material supporting the development of human science and technology innovation. However, there are few studies on the preparation methods of high purity tin. A novel technique was developed to purify 99.99682% tin by zone refining in an argon atmosphere. The impacts of zone melting conditions, such as the segregation coefficient, zone melting rate, and the number of zone melting passes, on the purity of refined tin were experimentally studied. The results showed that the segregation coefficients of Ag, Al, As, Bi, Ca, Cu, Fe, Ni, Pb, Au, Co, and Zn were less than 1, and the segregation coefficient of Sb was greater than but close to 1. Zone melting rates had an obvious effect on zone refining, while the number of passes had little effect. The 99.99682% purity tin was refined into 99.99906% purity tin under the optimized conditions at a zone melting rate of 0.6 mm/min and after 10 cycles of zone melting and cooling.