Winogradsky Institute of Microbiology, Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences, Leninsky Ave., 33, bld. 2, 119071, Moscow, Russia.
Winogradsky Institute of Microbiology, Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences, Leninsky Ave., 33, bld. 2, 119071, Moscow, Russia.
J Environ Manage. 2022 Sep 15;318:115587. doi: 10.1016/j.jenvman.2022.115587. Epub 2022 Jun 24.
The development of cost-effective environmentally friendly technologies is of current importance for the intensification of metal recovery. Here, we propose a new direction in the use of a two-step process for the treatment of complex sulfidic ores. In the first step, ore flotation allows the obtainment of a bulk copper-zinc concentrate and low-toxicity waste. In the second step, zinc is selectively extracted by chemical leaching with a biogenic ferric iron solution, while copper is accumulated in the leach residue. Importantly, the efficiency of this step depends on the chemical and mineralogical composition of polymetallic concentrates. Four samples of the copper-zinc sulfide concentrate with various contents of copper and zinc have been leached in multiple cycles at 80 °C, 10% of pulp density, and pH 1.3-1.5. The leaching of the concentrate that contained 14.7% of copper and 5.0% of zinc for three leaching cycles (total duration, 5.75 h) allowed the obtainment of a leach residue containing 15.3 and 0.14% of copper and zinc, respectively. At the same time, the leaching of another concentrate that contained 19.2% of copper and 2.64% of zinc after one leaching cycle (total duration, 0.67 h) led to copper and zinc contents of 19.1 and 0.72%, respectively, in the leach residue. Therefore, the treatment of only two concentrates allowed the obtainment of high-grade copper concentrates containing low amounts of zinc. Ferric iron, the oxidant of sulfide minerals, was fully regenerated in leachate within 30-35 h at 40 °C using an acidophilic microbial community dominated by Leptospirillum ferriphilum, Sulfobacillus spp., and Ferroplasma acidiphilum. The loss of copper and zinc in solid waste of the bioregeneration did not exceed 1.0% and 1.8%, respectively. The proposed flowsheet of bulk concentrate processing has several important advantages over conventional technologies, including short duration of leaching, formation of low-toxicity solid waste, and pyrometallurgical processing of only high-grade copper concentrates. This approach can be a promising solution for the efficient processing of polymetallic bulk concentrates.
开发具有成本效益且环境友好的技术对于加强金属回收至关重要。在这里，我们提出了一种新的方向，即在处理复杂硫化矿时采用两步法。在第一步中，矿石浮选可以获得铜锌混合精矿和低毒性废物。在第二步中，锌通过用生物成因的高铁溶液进行化学浸出选择性地浸出，而铜则在浸出渣中积累。重要的是，这一步的效率取决于多金属精矿的化学和矿物组成。已经在 80°C、10%的浆体密度和 pH 值 1.3-1.5 下对四种铜锌硫化物精矿（铜含量和锌含量不同）进行了多次循环浸出。对含有 14.7%铜和 5.0%锌的精矿进行了三个浸出循环（总时间为 5.75 小时），得到了浸出渣，其中铜和锌的含量分别为 15.3%和 0.14%。同时，对另一种含有 19.2%铜和 2.64%锌的精矿进行了一次浸出循环（总时间为 0.67 小时），得到了浸出渣中铜和锌的含量分别为 19.1%和 0.72%。因此，仅处理两种精矿就可以获得含锌量低的高品位铜精矿。在 40°C 下，使用以 Leptospirillum ferriphilum、Sulfobacillus spp. 和 Ferroplasma acidiphilum 为主导的嗜酸微生物群落，在 30-35 小时内，浸出液中的硫化物矿物氧化剂高铁完全再生。生物再生中固体废物中铜和锌的损失分别不超过 1.0%和 1.8%。与传统技术相比，该批量精矿处理的工艺流程具有几个重要优势，包括浸出时间短、形成低毒性固体废物以及仅对高品位铜精矿进行火法冶金处理。这种方法可能是有效处理多金属混合精矿的一种有前途的解决方案。
