Amorphous ferric arsenate is an important arsenic-containing compound in the mining-impacted environment and hydrometallurgical tailings, especially in the disposal of smelting wastewater in nonferrous smelting industries. It acts as an intermediate for arsenic removal and immobilization in the disposal of arsenic-containing wastewater. However, amorphous ferric arsenate suffers from poor stability with a high arsenic leachability in the aqueous environment. In this study, we develop a new strategy to remove and immobilize arsenic from copper smelting wastewater using copper slag through an in situ encapsulation of ferric arsenate with silica gel. The strategy provides an inherent arsenic disposal solution for copper smelting processes, allowing the removal of arsenic in the form of environmentally friendly precipitates. The results show copper slag mainly composed of Fe₂SiO₄ and Fe₃O₄ can be dissolved in copper smelting wastewater containing high sulfuric acid and arsenic, providing abundant Fe³⁺ ions and silicates for the following arsenic precipitation. In the room-temperature solid-liquid reaction between copper slag and wastewater, the Fe-As co-precipitation and the in situ encapsulation results in an environmentally stable and core-shell structured precipitate consisting of an amorphous ferric arsenate core and a silica gel shell. Copper slag achieves an arsenic removal efficiency of 98.85% and an arsenic removal capacity of 66.86 mg/g in the disposal of smelting wastewater with an initial arsenic concentration of 8458 mg/L. The findings and proposed strategy demonstrates the potential for the efficient and affordable disposal of arsenic-containing wastewater.

在采矿影响的环境和湿法冶金尾矿中，非晶态砷酸铁是一种重要的含砷化合物，尤其是在有色冶炼行业中处理冶炼废水时。它作为含砷废水处理中砷去除和固定化的中间体。但是，无定形砷酸铁在水环境中稳定性差，砷的浸出性高。在这项研究中，我们开发了一种新策略，该方法通过使用原位铜渣从铜冶炼废水中去除和固定砷用硅胶包封砷酸铁。该策略为铜冶炼过程提供了一种固有的砷处理解决方案，可以以环境友好的沉淀物的形式去除砷。结果表明，以Fe ₂ SiO ₄和Fe ₃ O ₄为主要成分的铜渣可溶于高硫酸和高砷的铜冶炼废水中，为随后的砷沉淀提供丰富的Fe ³⁺离子和硅酸盐。在铜渣与废水的室温固液反应中，Fe-As共沉淀和原位包封导致环境稳定且核壳结构的沉淀物，该沉淀物由无定形砷酸铁核和硅胶壳组成。铜渣在初始砷浓度为8458 mg / L的冶炼废水处理中实现了98.85％的除砷效率和66.86 mg / g的除砷能力。研究结果和拟议的策略证明了有效和负担得起的处理含砷废水的潜力。