New information on the pyrite bioleaching mechanism at low and high temperature
New information on the pyrite bioleaching mechanism at low and high temperature
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DOI：
10.1016/s0304-386x(03)00172-5
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发表时间：
2003-10-01
期刊：
影响因子：
4.7
通讯作者：
Muñoz, JA
中科院分区：
文献类型：
--
作者：
Rodriguez, Y;Ballester, A;Muñoz, JA
通过细菌对浸出剂（Fe ~（3+））的间接作用和微生物细胞对矿物表面的直接攻击，研究了黄铁矿的细菌浸出机理。研究表明，黄铁矿生物浸出过程受溶出铁氧化态的显著影响。亚铁/三价铁的比例控制了该过程中涉及的氧化反应的相对速率。黄铁矿的溶解受矿物表面Fe ~（2+）和Fe ~（3+）的竞争吸附控制。亚铁离子在表面上的积累导致对三价铁侵蚀的扩散屏障，产生本体溶液中三价铁离子浓度的增加，其抑制浓度高于16 g/L的微生物氧化能力。细胞附着到矿物表面的速率与矿物溶解速率之间存在关系，因为初始附着占生物浸出过程期间溶解速率的大部分。这是由接触生物浸出释放的矿物攻击和附着的微生物的表面上积累的Fe 2+的快速氧化的Fe 2+解释。结果表明，黄铁矿溶解的合作生物浸出策略，接触生物浸出和间接生物浸出的矿物可能同时发生通过硫代硫酸盐机制。(C)2003 Elsevier B. V.保留所有权利。
The mechanism of pyrite bioleaching has been studied through both the indirect action of bacteria by recycling the leaching agent (Fe3+) and the direct attack of microbial cells attached to the mineral surface. Causes of the decrease of the dissolution rate and the ultimate levelling off of the process are also identified.The study shows that pyrite bioleaching is markedly affected by the oxidation state of the dissolved iron. The ferrous/ferric ratio controls the relative rate of the oxidation reactions involved in the process. Additionally, the pyrite dissolution is controlled by the competitive chemisorption between Fe2+ and Fe3+ on the mineral surface. The accumulation of ferrous ions on the surface results in a diffusion barrier to the ferric attack, producing an increase of the ferric ion concentration in the bulk solution that inhibits the microbial oxidation capacity for concentrations higher than 16 g/L. There is a relationship between the rate of cell attachment to mineral surfaces and the mineral dissolution rate, since the initial attachment accounts for much of the dissolution rate during the bioleaching process. This is explained by the release of Fe2+ from the mineral attack by contact bioleaching and the rapid oxidation of Fe2+ accumulated on the surface by attached microorganisms. The results point to a cooperative bioleaching strategy for pyrite dissolution, whereby contact bioleaching and indirect bioleaching of the mineral possibly occur simultaneously via a thiosulphate mechanism. (C) 2003 Elsevier B.V. All rights reserved.