Recovery of crown zinc and metallic copper from copper smelter dust by evaporation, condensation and super-gravity separation

Abstract

Copper smelter dust is an ultrafine hazardous waste containing various heavy metallic elements. This manuscript proposed a novel method for efficient recovery of crown zinc and metallic copper from copper smelter dust, including evaporation and condensation of zinc vapor, and super-gravity separation of copper droplets. Firstly, the fine zinc oxide powders mixed in the dust were efficiently transformed into zinc vapor and escaped from the dust through carbothermal reduction at 1373–1573 K, which was effectively condensed into the metallic zinc named as “crown zinc” above its melting point. Subsequently, the dispersed fine copper droplets were evidently separated from the residue above the melting point of Cu as driven by super-gravity. Accordingly, crown zinc and metallic copper, with high purity of 98.57 wt% and 99.99 wt%, were efficiently recovered from the copper smelter dust with the high recovery ratios of 99.94% and 98.86%, respectively.