Water leaching of arsenic trioxide from metallurgical dust with emphasis on its kinetics

从冶金烟尘中水浸提取As2O3的动力学研究（英文）

Water leaching of As2O3 from metallurgical dust containing various metals was investigated,serving the purpose of dearsenization and simultaneous metal enrichment especially for indium.Effects of leaching temperature,liquid/solid ratio(LSR)and leaching time were studied.It was found that the initial dissolution was very fast but was then so inhibited by the increasingly dissolved As2O3,which makes it difficult to saturate enough arsenic in the leaching solution or in leaching out all the soluble arsenic with excess dosage of water within acceptable time(120 min).Only about 73%of As2O3 was extracted under the optimal conditions investigated.Two-step leaching showed similar trends and was thus unnecessary for improving As2O3 extraction.These observations could reasonably be accounted for the reversibility of the dissolution reaction.Kinetically,the leaching was described satisfactorily by the semi-empirical Avrami model with the apparent activation energy of 36.08 kJ/mol.The purity of the obtained product As2O3 could reach 98.7%,while the indium could be enriched in the leaching residue without loss.

本文采用了水浸方法从含有多种金属的冶金烟尘中提取As2O3,目的在于脱砷的同时使其中有价金属特别是铟得以富集。主要研究了浸出温度、浸出液固比(LSR)和浸出时间对脱砷过程的影响。结果显示,在浸出初期砷溶解极快,但随着浸出液中砷浓度的提高,砷的浸出受到抑制。这使得浸出液难以达到饱和,即使使用过量的水也难以在可接受的时间范围内(120 min)将砷全部浸出。在最佳实验条件下,As2O3的浸出率仅为73%。采用两步浸出法,对于脱砷效果并无根本性的改善。这些现象可由As2O3溶解反应的可逆性得以解释。动力学上,浸出过程可用半经验的Avrami模型进行描述,经计算,反应活化能为36.08 kJ/mol。实验所得As2O3纯度可达98.7%,且水浸过程中铟并未发生损失。