Mineralization and productization of valuable metals in copper telluride slag by sulfurization selectivity and vacuum distillation

Abstract

Copper telluride slag is a sparsely distributed precious metal slag that is produced during copper smelting. In addition to recovering tellurium from copper telluride slag, it is necessary to maximize the recovery of other valuable metals, but the sulfurization-vacuum treatment process of copper telluride slag lacks fundamental research to guide all-metal recovery. This paper experimentally studies the comprehensive sulfidation selectivity and vacuum distillation of valuable metals (Cu, Te, Se, Ag, Sb, and As) in copper telluride slag. The results demonstrate that sulfidation broke the chemical bonds between Cu-Te and Cu-Se, which removed oxygen from Cu, Sb, and As without reacting with Ag. Under a vacuum, the volatility of Sb2S3, As2S3, Se, and Te was significantly greater than that of Ag2Te, Ag2Se, Ag2S, and Cu2S. The experimental results showed that 95.91% of Te, 43.50% of Se, 94.59% of As, and 68.77% of Sb entered the volatiles, while more than 99% of Cu and Ag remained in the residue. The economic potential indicated that processing 1 ton of copper telluride slag can save $200 in chemical costs, and the residue can be directly used as a mineral raw material for copper smelting. This study offers a practical reference for recovering valuable metals from copper telluride slag via selective sulfuration and vacuum distillation.