Separation of copper-lead using 2,5-dimercapto-1,3,4-thiadiazole as chalcopyrite depressant: Adsorption and hydrophilicity studies

Abstract

Galena separation from chalcopyrite poses a notable challenge in mineral processing, owing to the involvement of high dosages of traditional process reagents and substantial environmental impact. This study addresses this challenge by introducing 2,5-dimethoxy-1,3,4-thiadiazole (DMTD) as a chalcopyrite depressant using sodium ethyl xanthate (NaEX) as a collector. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) analyses showed that DMTD can be adsorbed on the surfaces of chalcopyrite and galena, but the adsorption on chalcopyrite is stronger than that on galena. UV–vis, zeta potential and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses revealed that DMTD impeded the adsorption of NaEX on chalcopyrite; moreover, NaEX could desorb the DMTD adsorbed on galena and re-adsorb it on galena. Surface hydrophilicity tests revealed that DMTD significantly enhanced the hydrophilicity of chalcopyrite in the presence of NaEX, and galena was selectively separated from chalcopyrite using 1×10− 4 mol/L DMTD at pH exceeding 5. The recovery of galena remained >90 %, while that of chalcopyrite drastically decreased to <5 %. Furthermore, artificial-mixing experiments confirmed the separation effect of DMTD as a chalcopyrite depressant. Notably, this study avoids environmental pollution caused by traditional depressants, offering a potential green approach to achieve effective flotation separation of copper–lead sulfide ore.