(中南大學(xué) 冶金與環(huán)境工程學(xué)院，長沙 410083)
摘 要: 以含砷污酸為原料，通過中和除雜—沉砷—洗滌—浸出—蒸發(fā)結(jié)晶—溶解制取三氧化二砷，實(shí)現(xiàn)含砷污酸的資源化。結(jié)果表明：將污酸中和至pH為2，使污酸的酸度降低；在中和液中加入硫酸銅，控制Cu和As的摩爾比為1.5:1，調(diào)節(jié)體系pH為8沉淀As，得到亞砷酸銅，As的沉淀率達(dá)到97.81%；通過洗滌除雜提高亞砷酸銅中As和Cu的含量；采用10%硫酸溶液，在液固比為5:1條件下浸出亞砷酸銅，所得溶液蒸發(fā)結(jié)晶得到三氧化二砷與硫酸銅的混合物；用水溶解該混合物后過濾得到硫酸銅溶液及符合YS/T-99-1997As2O3-3號產(chǎn)品標(biāo)準(zhǔn)的三氧化二砷。
關(guān)鍵字: 污酸；浸出；回收；三氧化二砷；硫酸銅
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:A novel technique for recovery of copper and arsenic from arsenic-containing waste acid discharged from copper smelter was proposed, and the process was composed of neutralization and purification—precipitation of arsenic—washing—leaching—evaporative crystallization—dissolution. Arsenic trioxide and cupric sulfate were obtained and resource of waste acid was accomplished. The results show that the acidity of the waste acid decreases and a certain amount of impurities is removed when the pH value of the system is neutralized to 2 by lime milk. Copper arsenite precipitates with arsenic precipitation efficiency of 97.81% when cupric sulfate is added into the neutralized solution. At the same time, the molar ratio of Cu and As is controlled at 1.5:1 and pH value of system is adjusted to 8 by sodium hydroxide. The contents of copper and arsenic in the precipitate of copper arsenite are increased by washing. 10% sulfuric acid was adopted to treat copper arsenite by leaching at liquid-solid ratio of 5:1, and then, a mixture of arsenic trioxide and cupric sulfate is obtained after the leachate is evaporated and crystallized. Finally, through dissolution and filtration of the solid mixture, cupric sulfate remains in the residual solution while arsenic trioxide meeting the product standard of YS/T-99-1997As2O3-3 is collected in the filter cake.
Key words: waste acid; leaching; recovery; arsenic trioxide; cupric sulfate
