ABSTRACT

Arsenic, one of the most toxic elements, is a byproduct generated from metallurgical processes of arsenic-containing ores. Arsenic can be formed into an arsenic trioxide as a byproduct during the decopperization in electro-refining process when processing high arsenic-bearing copper minerals. However, arsenic trioxide has a very high arsenic mobility, so it requires to be re-dissolved and immobilized into scorodite (FeAsO₄▪2H₂O). In this study, methanesulfonic acid (MSA) was tested for both arsenic trioxide leaching and scorodite precipitation. Arsenic trioxide leaching tests showed the arsenic extraction of 80% at 21°C in MSA with H₂O₂ as an oxidant within 6 hours. Meanwhile, arsenic precipitation tests were conducted to achieve above 95% arsenic removal within 6 hours by the formation of scorodite at an initial pH of 0.5 and temperature of 80°C. In addition, coarser scorodite particles were formed in higher temperature and lower solution pH. The optimum condition for scorodite crystallization in MSA medium can be suggested to be at 80°C with the initial pH of 0.5.

摘要

砷是毒性最强的元素之一，是含砷矿石冶金过程中产生的副产品。在加工高砷铜矿物时，在电解精炼过程中的脱铜过程中，砷会形成副产物三氧化二砷。但是，三氧化二砷具有很高的砷迁移率，因此需要重新溶解并固定在臭葱石（FeAsO ₄ ▪2H ₂ O）中。在这项研究中，测试了甲磺酸 (MSA) 的三氧化二砷浸出和臭葱石沉淀。三氧化二砷浸出试验表明，在 21°C 的 MSA 中，H ₂ O _{2的砷提取率为 80%}6 小时内作为氧化剂。同时，进行砷沉淀试验，以在初始 pH 为 0.5 和温度为 80°C 下形成臭葱石，在 6 小时内实现 95% 以上的砷去除率。此外，在较高的温度和较低的溶液 pH 值下会形成较粗的臭葱石颗粒。MSA 介质中臭葱石结晶的最佳条件可建议为 80°C，初始 pH 值为 0.5。