Effect of Temperature on Biobeneficiation of Bulk Copper-Nickel Concentrate with Thermoacidophilic Microbial Communities

Abstract

Bioleaching of the bulk copper–nickel sulfide concentrate was proposed as a method to remove nickel from it and to obtain a concentrate containing copper as chalcopyrite. This approach is based on the different refractoriness of sulfide minerals in ferric sulfate solutions and oxidation by acidophilic microorganisms. The bulk concentrate contained 10.8% copper in the form of chalcopyrite (CuFeS2) and 7.2% nickel that occurred in pentlandite ((Ni,Fe)9S8) and violarite (FeNi2S4). Three microbial communities grown at 35, 40, and 50 °C were used for bioleaching. The microbial community at 40 °C was the most diverse in the genus and species composition. At all temperatures of the process, the key roles in bioleaching belonged to mixotrophic and heterotrophic acidophiles. The highest levels of nickel leaching of 97.2 and 96.3% were observed in the case of communities growing at 40 and 50 °С, respectively. At the same time, the bioleach residue, which could be characterized as a marketable high-grade copper (chalcopyrite) concentrate, was obtained only at 40 °С. This solid contained 15.6% copper and 0.54% nickel. Thus, the biobeneficiation of bulk sulfide concentrates can be a promising field of biohydrometallurgy.

Old Sulfidic Ore Tailing Dump: Ground Features, Mineralogy, Biodiversity—A Case Study from Sibay, Russia

“…Analysis of the structure of microbial communities in the studied zones of the tailing dump was carried out by the metabarcoding analysis of hypervariable regions of the 16S rRNA genes. As previously shown [20,25], some species of acidophiles can be successfully predicted by metabarcoding due to the high variability of the V3-V4 regions within the corresponding genera, although the differences in the V3-V4 region are usually not sufficient to differentiate closely related microbial species. In this research, acidophilic bacteria and archaea were also successfully assigned to the known species.…”

“…The biomass was sequentially washed with the iron-free 9K medium base (pH 1.5) and with the same medium with a neutral pH by centrifugation (10,000× g, 5 min). The structure of the microbial communities from mine tailing samples was determined by the metabarcoding method using the 16S rRNA gene hypervariable region (V3-V4) as described [20]. Sequencing of DNA libraries was carried out with a MiSeq instrument (Illumina, San Diego, CA, USA) and the Miseq reagent kit v3 (Illumina, San Diego, CA, USA).…”

Advanced Technologies in Bio/Hydrometallurgy for Recovery and Recycling of Metals

“…In one study, bioleaching was proposed as a method for the removal of nickel from bulk copper-nickel sulfide concentrate and the acquisition of a concentrate containing copper as a chalcopyrite [8]. This approach is based on the variable refractoriness of sulfide minerals in ferric sulfate solutions and oxidation by acidophilic microorganisms.…”

A Case of Predominance of Alicyclobacillus tolerans in Microbial Community during Bioleaching of Pentlandite-Chalcopyrite Concentrate

“…Among these approaches, biotreatment of sulfide raw materials containing precious and nonferrous metals is widely applied. It is based on the activity of acidophilic microbial communities oxidizing iron and sulfur components and contributing to the dissolution of valuable metals or their selective accumulation in solids [2][3][4]. Biooxidation/bioleaching of sulfide ores, concentrates, and industrial wastes can be carried out by environmentally sound and cost-effective technologies that are based on chemical and biological principles [1,[5][6][7].…”

“…In particular, bioleaching has been shown to be a promising method for processing bulk concentrates of nonferrous metals to obtain selective concentrates [4,8,9]. Bioleaching techniques may allow the obtainment of marketable high-grade products [4,9], contributing to the resource-efficient management of raw materials. Leaching the violarite-pentlandite-chalcopyrite concentrates is determined by the properties of refractory and readily oxidized minerals composing them.…”