Separation of Fe and Sn-Cu Phases in an Fe-Sn-Cu-B System

Scrap metal often includes a large amount of copper and tin. It is important to recover copper and tin from this scrap metal for recycling. Separation into two liquid phases, namely Fe and Sn(-Cu) phases, has been investigated at 1523 K in Fe-Sn-B and Fe-Sn-Cu-B systems. In the Fe-Sn-B system, the tin content of the Ferich phase and the iron content of the Sn-rich phase are 13.7 and 11.7 mass%, respectively, when [mass%B](in Fe)=3.62. Boron widens the miscibility gap of the FeSn binary system. The isothermal section diagram of the Fe-Sn-Cu-2.66 mass%B quaternary system at 1523 K is described. In the Fe-Sn-Cu-B system, separation into two liquid phases, Fe-rich and [Sn-Cu]-rich, is found over all ratios of [mass%Sn]/[mass%Cu]. The separation region is enlarged as the [mass%Sn]/ [mass%Cu] ratio is decreased. By using the separation into two liquid phases, iron can be enriched in the Fe-rich phase and copper and tin can be enriched in the [Sn-Cu]-rich phase. It is possible to recover copper and tin effectively from Fe-Sn-Cu alloy.