Abstract:
In order to achieve clean utilization and harmless disposal of antimony smelting arsenic-alkali residue, a new process for cleaning arsenic-alkali residue of "ball mill leaching-recovery of antimony by gravity-waste alkali spray-arsenic precipitation by oxidation-stable solidified arsenic" was proposed. The results showed that the efficient separation of Sb, As and alkali with the As leaching rate of 96.78% and alkali leaching rate of 97.35% could be realized under the arsenic-alkali residue with the liquid-solid ratio of 4:1 grounded in a ball mill for 20 minutes and then leached for 40 minutes at room temperature. In order to extract the antimony from the recovered leaching slag, the shaking table was used to recover Sb with the recovery of 40%~50%, and the As content in the concentrate was less than 1%, and the Sb content was greater than or equal to 10%, which could be recycled through the smelting system. Based on the principle of acid-base neutralization, the leachate (high-arsenic waste alkali) entered the flue gas desulfurization spray system in the smelting process and reacted with SO
2 in the flue gas. Therefore, the content of SO
2 and As in the flue gas could reach the discharge standard and the purpose of synergistic treatment of leaching lye and flue gas SO
2 was achieved. After high-arsenic wastewater was added to H
2O
2 to oxidize arsenic, and then arsenic removal agent (biological agent) was added to precipitate with arsenic, the As content in the wastewater was reduced to 150 mg/m
3, and the two stages of the arsenic removal efficiency could reach 88.4% and 92.5%, respectively. The resulting arsenic removal slag was treated with an Fe-contained stabilizer. When the mass ratio of addition was 9%, the toxicity leaching concentration of the solidified As was reduced from 348.67 mg/L to 0.65 mg/L, which reached the entry criteria for hazardous waste landfills. The results of the industrial expansion test showed that the new process could achieve the purpose of waste treatment and clean utilization of arsenic-alkali slag.