Sustainable Mining and Metallurgy

Arsenic sulfide residue produced from sulfidization of As-containing acidic wastewater contains a high As content, categorized as typical hazardous waste. In this paper, the hydrogen peroxide oxidation process was adopted to treat arsenic sulfide residue and produce sulfur residue and As-rich solution that is reduced by sulfur dioxide to generate the arsenic trioxide product. Optimal reaction conditions were obtained through tests on oxidation leaching process. The dosages of sulfuric acid, industrial grade hydrogen peroxide and catalyst should be 10%, 30% and 0.1% of the amount of arsenic sulfide residue respectively. The liquid-solid ratio should be 1∶1, temperature should be at 85℃ and reaction duration should be 2h. Under such conditions, the As removal rate can exceed 93%, and the arsenic trioxide product obtained from reduction of As-rich solution is up to the As₂O₃-1 requirements stipulated in GB 26721—2011.