There are numerous valuable metals and the hazardous element arsenic in the iron slag produced in the zinc hydrometallurgy. The arsenic must be removed for comprehensive recovery of valuable elements. Generally, the alkaline arsenic removal produces large amounts of iron hydroxide colloids and iron slag agglomeration. Here, ultrasonic enhancement of NaOH–NaS system is proposed to selectively remove arsenic from iron slag. Ultrasound destroys the agglomeration and encapsulation of zinc-containing iron slag and promotes the liquid-solid interfacial reaction. The arsenic removal percentage is 92.24% under ultrasonic power of 400 W, which is 12.14% higher than the conventional alkaline arsenic removal. The apparent activation energy of ultrasonic-enhanced alkali leaching for arsenic removal is calculated to be only 8.84 kJ/mol by kinetic experiments. Diffusion is proved to be the limiting link in the ultrasonic-enhanced leaching process for arsenic removal. This study proves that ultrasonic-enhanced NaS–NaOH system has a good prospect for selective removal of arsenic from iron slag.

中文翻译：

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超声波强化铁渣选择性除砷和硫化物转化

湿法炼锌产生的铁渣中含有大量有价金属和有害元素砷。必须除去砷以全面回收有价元素。一般碱除砷会产生大量的氢氧化铁胶体和铁渣团聚。在此，提出了超声强化 NaOH-NaS 系统来选择性地去除铁渣中的砷。超声波破坏含锌铁渣的团聚和包裹性，促进液固界面反应。超声波功率为400 W时，除砷率为92.24%，比常规碱除砷提高了12.14%。通过动力学实验计算出超声波强化碱浸除砷的表观活化能仅为8.84 kJ/mol。扩散被证明是超声强化浸出除砷过程中的限制环节。本研究证明超声强化NaS-NaOH体系在铁渣中选择性脱砷方面具有良好的前景。