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

Abstract

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 Fe-rich 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 Fe–Sn 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.