Rapid removal of copper impurity from bismuth–copper alloy melts via super-gravity separation

A green method of super-gravity separation, which can enhance the filtration process of bismuth and copper phases, was investigated and discussed for the rapid removal of copper impurity from bismuth–copper alloy melts. After separation by the super-gravity field, the bismuth-rich liquid phases were mainly filtered from the alloy melt along the super-gravity direction, whereas most of the fine copper phases were retained in the opposite direction. With optimized conditions of separation temperature at 280°C, gravity coefficient at 450, and separation time at 200 s, the mass proportion of the separated bismuth from the Bi–2wt%Cu and Bi–10wt%Cu alloys respectively reached 96% and 85% , which indicated the minimal loss of bismuth in the residual. Simultaneously, the removal ratio of impurity copper from the Bi–2wt%Cu and Bi–10wt%Cu alloys reached 88% and 98%, respectively. Furthermore, the separation process could be completed rapidly and is environmentally friendly and efficient.