探索了以砷酸钠形式回收高砷烟尘碱性浸出液中砷的新工艺,分别进行了直接结晶与氧化结晶实验研究。结果表明,采用双氧水氧化结晶效果明显优于直接结晶效果,在氧化温度30℃、结晶温度30℃、H2O2/As摩尔比0.8、结晶时间2 h、双氧水加入速度0.4 m L/min的优化工艺条件下,砷锑结晶率分别达90%和98%以上。结晶粗产品经溶解、过滤不溶物、蒸发结晶,得到纯化后的砷酸钠(Na3As O4·10H2O)产品,纯度为95.85%。
Arsenic is selectively extracted from high-arsenic dust by NaOH-Na2S alkaline leaching process. In the leaching arsenic process, the effects of alkali-to-dust ratio, sodium sulfide addition, leaching temperature, leaching time and liquid-to-solid ratio on metals leaching efficiencies were investigated. The results show that the arsenic can be effectively separated from other metals under the optimum conditions of alkali/dust mass ratio of 0.5, sodium sulfide addition of 0.25 g/g, leaching temperature of 90 ℃, leaching time of 2 h, and liquid-to-solid ratio of 5：1 （mL/g）. Under these conditions, the average leaching efficiencies of arsenic, antimony, lead, tin and zinc are 92.75%, 11.68%, 0.31%, 29.75% and 36.85%, respectively. The NaOH-Na2S alkaline leaching process provides a simple and highly efficient way to remove arsenic from high-arsenic dust, leaving residue as a suitable lead resource.
