Influence of Sulfur Morphology on Arsenic Removal from Zinc Dust

Selectively removing arsenic from zinc dust is crucial for environmental protection and resource recycling. This research systematically investigates the arsenic (As) removal behavior from zinc dust under alkaline conditions with various sulfur species (Na₂S, NaHS, thiourea, and elemental sulfur), and, through thermodynamic and kinetic analysis, we have elucidated the reaction mechanisms. The experimental results demonstrate that the Na₂S and thiourea systems achieve the highest arsenic leaching efficiency, with the thiourea system displaying good selectivity and effectively inhibiting zinc and lead dissolution. Although the Na₂S system has a high arsenic leaching rate, it is accompanied by significant dissolution of zinc and lead. In contrast, the leaching efficiencies of elemental sulfur and NaHS systems are relatively low. Kinetic analysis reveals that, under high-temperature conditions, the thiourea system is diffusion-controlled and exhibits low activation energy (5.15 kJ/mol), indicating that it is an efficient and selective leaching system. This research provides a solid theoretical foundation and practical support for the environmentally friendly treatment and efficient resource utilization of arsenic-laden waste.