Enhanced chalcopyrite dissolution in stirred tank reactors by temperature increase during bioleaching

作者：Sabrina Hedrich, Catherine Joulian, Torsten Graupner, Axel Schippers, Anne-Gwénaëlle Guezennec · 发表于：Hydrometallurgy · 年份：2018 · DOI：10.1016/j.hydromet.2018.05.018 · 被引用次数：71 · 研究领域：Metal Extraction and Bioleaching、Minerals Flotation and Separation Techniques、Extraction and Separation Processes

Primary copper sulfides, such as chalcopyrite, represent the most important copper resource and are currently mainly exploited by pyrometallurgy. Bioleaching is considered as environmental-friendly and economic alternative, and the technical feasibility of stirred tank reactor (STR) bioleaching of copper ore concentrates using acidophilic, iron- /sulfur-oxidizing microorganisms was proven. In case of copper concentrates from Kupferschiefer-type ore the copper recovery at temperatures suitable for moderately thermophilic acidophiles was, however, incomplete due to inefficient chalcopyrite dissolution. The presented study therefore aimed to enhance chalcopyrite dissolution by decoupling of growth and bioleaching activity of the acidophiles. This was achieved by a controlled temperature increase in laboratory bioreactor experiments with copper concentrate from Kupferschiefer-type ore. Total cell number and microbial activity monitoring allowed to define three stages of the bioleaching process: (i) growth phase, (ii) bioleaching phase and (iii) resting phase. The total residence time was close to seven days, according to copper recovery and iron oxidation activity. Experiments at constant temperatures (42 °C, 48 °C, 50 °C) and a controlled temperature increase at the end of the growth phase of 42/46 °C, 44/48 °C and 46/50 °C, showed that metal recovery was enhanced by incremental temperature increase and resulted in a lower redox potential. Copper recovery was improved from origi...