A novel trithiocarbonate collector featuring high-temperature resistance for copper slag flotation

Abstract

The nature of copper slag flotation is unique due to the high temperature in the flotation pulp and high metallic copper content in the feed. Despite its great potential for valorizing slag, copper slag flotation remains challenging due to the deactivation of traditional dithiocarbonate (DTC) collectors (e.g., butyl xanthate) under high temperatures. DTC collectors also respond poorly to the metallic copper due to the difficulty in forming stable chemical adsorption. In this work, possible deactivation mechanisms of DTC collectors are proposed, i.e., decomposition, oxidation and thermal desorption. A novel furfuryl trithiocarbonate (FTTC) collector was designed and synthesized. Spectral characterization using FT-IR, H-NMR and ion trap MS confirmed the molecular structure of the synthesized collector and its decomposition, oxidation and polymerization products at 55 °C. The novel collector features high-temperature resistance and high metallic copper recovery, as revealed by the single mineral flotation experiments of chalcopyrite, pyrite and metallic copper at both 25 °C and 55 °C. The high collecting ability and selectivity of our collector were explained by EHOMO and ELUMO values using first-principles calculations. Our work provides guidance for the design of collectors exhibiting high-temperature resistance for copper slag flotation, aims at constituting a meaningful contribution for unlocking potential copper resources in copper slag.