Abstract:The arsenic sulfide residue generated during the pyrometallurgical treatment of non-ferrous metal smelting wastewater acid and the blast furnace gas ash produced during steel smelting are both classified as hazardous waste. Existing treatment methods suffer from issues such as lengthy processes and low resource recovery efficiency. To address these challenges, this study proposes a co-treatment method for arsenic sulfide residue and blast furnace gas ash using a sulfur fixation roasting-beneficiation combined process. This method involves low-temperature reduction and sulfur fixation roasting of arsenic sulfide residue (containing As2S3 and blast furnace gas ash (primarily containing ZnO), enabling the one-step production of metallic arsenic and zinc sulfide. Subsequent gravity separation and flotation yield metallic arsenic and zinc sulfide concentrate. The feasibility of the process was first analyzed thermodynamically. Single-factor experiments were conducted to investigate the effects of roasting temperature, time, and theoretical dosage of blast furnace gas ash on arsenic generation and sulfur fixation efficiency. The main conclusions are as follows. The optimized conditions for the co-treatment of arsenic sulfide residue and blast furnace gas ash via sulfur fixation roasting-beneficiation are: roasting temperature of 600℃, reaction time of 2h, and ZnO dosage in blast furnace gas ash at 1.4 times the theoretical requirement for sulfur fixation. Under these conditions, the sulfur fixation rate reaches 93.64%, and the metallic arsenic generation rate reaches 90.25%. This process achieves short-flow, efficient co-treatment of arsenic sulfide residue and blast furnace gas ash, enabling comprehensive recovery of metallic arsenic and zinc. Additionally, most of the sulfur in the raw materials is fixed, making this an environmentally friendly process for the clean utilization and disposal of secondary resources. It holds potential for application in the reduction and safe disposal of arsenic sulfide hazardous waste.
