Assessment of minerals and iron-bearing phases present in hydrometallurgical residues from a nickel sulfide concentrate and availability of residue associated metals

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 °C, 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 °C. This solid contained 15.6% copper and 0.54% nickel. Thus, the biobeneficiation of bulk sulfide concentrates can be a promising field of biohydrometallurgy.

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Molecular Dynamics Simulation on Microstructure and Physicochemical Properties of FexO-SiO2-CaO-MgO-“NiO” Slag in Nickel Matte Smelting under Modulating CaO Content

Minerals ◽

10.3390/min10020149 ◽

2020 ◽

Vol 10 (2) ◽

pp. 149

Author(s):

Guohua Wang ◽

Yaru Cui ◽

Xiaoming Li ◽

Shufeng Yang ◽

Junxue Zhao ◽

...

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Physicochemical Properties ◽

Nickel Sulfide ◽

Dynamics Simulation ◽

Iron Extraction ◽

Nickel Smelting ◽

Matte Smelting ◽

Nickel Sulfide Concentrate ◽

Sulfide Concentrate

To improve the conditions of extracting iron from nickel smelting residues, the composition modulating from FexO-SiO2-CaO-MgO-“NiO” slag source for matte smelting using high MgO nickel sulfide concentrate was carried out. Based on the molecular dynamics simulation and experimental characterization, the effect of CaO content in nickel slags on the physicochemical properties, the microstructure evolution, and the feasibility of subsequent iron extraction were analyzed. The results showed that, for nickel smelting slag with 9 wt.% MgO, 13–15 wt.% CaO and Fe/SiO2 ratio of 1.2, the melting temperature of nickel slag was lower than 1200 °C, and the viscosity was lower than 0.22 Pa·s at 1350 °C. The electric conductivity was similar to that of the industrial slag, and the interfacial tension between slag and matte was relatively large, which ensured a good separating characteristic. It not only met the requirements for the slag performances in the existing flash smelting process but also improved conditions for the subsequent iron extraction. Additionally, it could be adapted to the current situation where an increasing MgO content exists in the nickel sulfide concentrate.

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