高砷烟尘碱性浸出液氧化结晶制备砷酸钠

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 mL/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(Na₃AsO₄·10H₂O)产品, 纯度为95.85%。

Preparation of Sodium Arsenate from Alkaline Leach Solution of High-Arsenic Dust by Oxidization-crystallization

Recovering arsenic in the form of sodium arsenate from alkaline leach solution of high-arsenic dust, respectively by direct crystallization and oxidization-crystallization has been explored. Results showed the oxidization-crystallization process with hydrogen peroxide led to a better crystallization effect than the direct method. It was found that the experiment with the temperature for both oxidization and crystallization at 30 ℃, H₂O₂/As mole ratio at 0.8, 2 h for the process of crystallization and the hydrogen peroxide added at the speed of 0.4 mL/min, could lead to the crystallization rate of 90% and over 98%, respectively for As and Sb. The obtained product was then purified by recystallization technique including dissolving and filtration, resulted in the final product sodium arsenate(Na₃AsO₄·10H₂O) with purity up to 95.85%.