College of Life Sciences, Northwest Normal University, Lanzhou 730070, China.
Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
J Hazard Mater. 2024 May 15;470:134193. doi: 10.1016/j.jhazmat.2024.134193. Epub 2024 Apr 2.
Arsenopyrite and pyrite often coexist in metal deposits and tailings, thus simultaneous bioleaching of both sulfides has economic (as well as environmental) significance. Important targets in bio-oxidation operations are high solubilization rates and minimized accumulation of Fe(III)/As-bearing secondary products. This study investigated the role of pyrite bioleaching in the enhancement of arsenopyrite dissolution. At a pyrite to arsenopyrite mass ratio of 1:1, 93.6% of As and 93.0% of Fe were solubilized. The results show that pyrite bio-oxidation can promote arsenopyrite dissolution, enhance S bio-oxidation, and inhibit the formation of jarosites, tooeleite, and amorphous ferric arsenate. The dry weight of the pyrite & arsenopyrite residue was reduced by 95.1% after bioleaching, compared to the initial load, while only 5% weight loss was observed when pyrite was absent. A biofilm was formed on the arsenopyrite surface in the presence of pyrite, while a dense passivation layer was observed in the absence of pyrite. As(III) (as AsO) was a dominant As species in the pyrite & arsenopyrite residue. Novel and detailed findings are presented on arsenopyrite bio-dissolution in the presence of pyrite, and the presented approach could contribute to the development of novel cost-effective extractive bioprocesses. ENVIRONMENTAL IMPLICATION: The oxidation of arsenopyrite presents significant environmental hazards, as it can contribute to acid mine drainage generation and arsenic mobilization from sulfidic mine wastes. Bioleaching is a proven cost-effective and environmentally friendly extractive technology, which has been applied for decades in metal recovery from minerals or tailings. In this work, efficient extraction of arsenic from arsenopyrite bioleaching was presented through coupling the process with bio-oxidation of pyrite, resulting in lowered accumulation of hazardous and metastable Fe(III)/As-bearing secondary phases. The results could help improve current biomining operations and/or contribute to the development of novel cost-effective bioprocesses for metal extraction.
黄铁矿和毒砂经常共存于金属矿床和尾矿中，因此同时浸出这两种硫化物具有经济（以及环境）意义。生物氧化作业的重要目标是高溶解率和最小化 Fe(III)/含砷次生产物的积累。本研究调查了黄铁矿生物浸出在促进毒砂溶解中的作用。在黄铁矿与毒砂的质量比为 1:1 时，93.6%的 As 和 93.0%的 Fe 被溶解。结果表明，黄铁矿生物氧化可以促进毒砂溶解，增强 S 生物氧化，并抑制铁砷矾、水砷铁矾和无定形铁砷酸盐的形成。与初始负载相比，生物浸出后黄铁矿和毒砂残渣的干重减少了 95.1%，而在不存在黄铁矿的情况下，仅观察到 5%的重量损失。在存在黄铁矿的情况下，在毒砂表面形成了生物膜，而在不存在黄铁矿的情况下观察到致密的钝化层。在黄铁矿和毒砂残渣中，As(III)（以 AsO 形式存在）是主要的 As 物种。本研究提出了在黄铁矿存在下毒砂生物溶解的新的详细发现，所提出的方法可能有助于开发新型经济高效的提取生物技术。环境意义：毒砂的氧化会带来重大的环境危害，因为它会导致酸性矿山排水的产生和硫化矿废物中砷的迁移。生物浸出是一种经过验证的具有成本效益和环境友好的提取技术，已在从矿物或尾矿中回收金属方面应用了几十年。在这项工作中，通过将该工艺与黄铁矿的生物氧化相结合，从毒砂生物浸出中高效提取砷，降低了危险和亚稳定的 Fe(III)/含砷次生相的积累。研究结果有助于改进当前的生物采矿作业，或有助于开发新型经济高效的金属提取生物技术。
