Effect of a novel depressant on surface modification mechanism of arsenopyrite and improvement of S–As flotation separation performance

Arsenopyrite is commonly found in pyrite concentrates. High-temperature pyrometallurgy produces highly toxic arsenic vapor, while hydrometallurgy generates arsenic-containing wastewater. Flotation is an effective pretreatment method for arsenic removal. This study investigated the selective depression behavior and mechanism of D-penicillamine (DP) on arsenopyrite flotation. Single-mineral and artificial mixed-mineral tests revealed that at a DP concentration of 7 × 10 –4 mol/L, the mixed concentrate had As grade and recovery of 7.34 % and 17.40 %, respectively. This indicates the selective depressive effect of DP on arsenopyrite, enabling effective flotation separation from pyrite. DP adsorption significantly reduced the hydrophobicity of the arsenopyrite surface, with minimal impact on pyrite. Columnar adsorption peaks were observed on the arsenopyrite surface. This suggests coordination between the N and S atoms of DP molecules and the As sites on the arsenopyrite surface, forming N–As and S–As complexes. A hydrophilic film approximately 11.03 Å thick formed on the arsenopyrite (001) surface, which hindered further collector adsorption. This study provides a green and pollution-free approach for the flotation separation of S–As.