Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany.
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Leipzig, Germany.
Chemosphere. 2018 Apr;196:368-376. doi: 10.1016/j.chemosphere.2017.12.138. Epub 2017 Dec 28.
For Kupferschiefer mining established pyrometallurgical and acidic bioleaching methods face numerous problems. This is due to the finely grained and dispersed distribution of the copper minerals, the complex mineralogy, comparably low copper content, and the possibly high carbonate and organic content in this ore. Leaching at neutral pH seemed worth a try: At neutral pH the abundant carbonates do not need to be dissolved and therewith would not consume excessive amounts of provided acids. Certainly, copper solubility at neutral pH is reduced compared to an acidic environment; however, if copper complexing ligands would be supplied abundantly, copper contents in the mobile phase could easily reach the required economic level. We set up a model system to study the effect of parameters such as pH, microorganisms, microbial metabolites, and organic ligands on covellite leaching to get a better understanding of the processes in copper leaching at pH ≥ 6. With this model system we could show that glutamic acid and the microbial siderophore desferrioxamine B promote covellite dissolution. Both experimental and modeling data showed that pH is an important parameter in covellite dissolution. An increase of pH from 6 to 9 could elevate copper extraction in the presence of glutamic acid by a factor of five. These results have implications for both development of a biotechnological process regarding metal extraction from Kupferschiefer, and for the interaction of bacterial metabolites with the lithosphere and potential mobilization of heavy metals in alkaline environments.
对于钾盐矿开采，现有的火法冶金和酸性生物浸出方法面临着许多问题。这是由于铜矿物的细粒和分散分布、复杂的矿物学、相对较低的铜含量以及该矿石中可能较高的碳酸盐和有机物含量。尝试中性 pH 值浸出似乎值得一试：在中性 pH 值下，丰富的碳酸盐不需要溶解，从而不会消耗过多提供的酸。当然，与酸性环境相比，中性 pH 值下铜的溶解度降低；但是，如果提供大量的铜络合剂，可移动相中的铜含量很容易达到所需的经济水平。我们建立了一个模型系统来研究 pH 值、微生物、微生物代谢物和有机配体等参数对铜蓝浸出的影响，以更好地了解 pH 值≥6 时铜浸出的过程。通过该模型系统，我们可以证明谷氨酸和微生物铁载体去铁胺 B 促进了铜蓝的溶解。实验和模拟数据均表明，pH 值是铜蓝溶解的重要参数。在存在谷氨酸的情况下，pH 值从 6 增加到 9 可以将铜的提取率提高五倍。这些结果对于从钾盐矿开发生物技术金属提取过程以及细菌代谢物与岩石圈的相互作用和碱性环境中重金属的潜在迁移都具有重要意义。
