Co-Bioleaching of Chalcopyrite and Silver-Bearing Bornite in a Mixed Moderately Thermophilic Culture

Abstract

Chalcopyrite and bornite are two important copper minerals, and they often coexist. In this study, the co-bioleaching of chalcopyrite and silver-bearing bornite by mixed moderately thermophilic culture at 50 • C was investigated. The bioleaching results show that the extraction percentage of Cu for co-bioleaching of chalcopyrite (Ccp) and silver-bearing bornite (Bn) (Ccp/Bn = 3:1) was 94.6%. Compared to bioleaching of chalcopyrite or silver-bearing bornite alone, the Cu extraction percentage was greatly enhanced when they were bioleached together. The leaching residues were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Silver-bearing bornite dissolved preferentially compared to chalcopyrite, due to galvanic interactions. Simultaneously, Ag + was released from the silver-bearing bornite into solution. Ag 2 S formed on the surface because Cu and Fe in the chalcopyrite were replaced by Ag + , accelerating chalcopyrite dissolution and enrichment of Ag on the surface of the chalcopyrite.Chalcopyrite and bornite are two important Cu-Fe-S minerals, and they often coexist [47][48][49]. The objective of this research was to investigate the co-bioleaching of chalcopyrite and silver-bearing bornite using a mixed moderately thermophilic culture at 50 • C. The leaching residues were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Materials and Methods Mineral SamplesThe chalcopyrite used in this study was obtained from Tonglvshan Mine, Daye, China. The bornite samples were purchased from GaoWanTong fossil specimen museum, Guilin, China. High-quality natural mineral samples were splintered into small fragments using a geological hammer, and then dry ground with porcelain ball milling. The particle size of the samples used for the bioleaching experiments was less than −0.074 mm. Chemical analysis of the samples showed that the chalcopyrite sample consisted of 33.91% Cu, 30.62% Fe, 32.90% S, 0.039% Pb, 0.018% Zn and 6.91 g/t Ag; and the bornite samples, of 62.38% Cu, 10.55% Fe, 22.60% S, 0.500% Pb, 0.048% Zn and 4635.48 g/t Ag. Aside from the special notes, all of the percentages (%) in this paper refer to weight percentage (wt %).

Ultrathin 2D silver sulphate nanosheets for visible-light-driven NO2 sensing at room temperature

“…1d). 47,49 Moreover, the chemical compositions of the obtained Ag 2 SO 4 nanosheets were verified using elemental mapping using energy dispersive spectrometry (EDS). Fig.…”

Analysis of the Oxidation: Reduction Potential and Bacterial Population of Acidithiobacillus ferrooxidans during the Bioleaching Study of Sulfide Ores

“…It should be noted that sulfide minerals often coexist with several mineral species, which act synergistically during the leaching process, allowing the dissolution of certain elements. In the case of leaching of chalcopyrite and silver-bearing bornite [8], by thermophilic culture (50°C), 94.6% copper was extracted, quite superior to the results of separate leaching of chalcopyrite and bornite, silver was released to the solution, forming Ag 2 S on the surface of chalcopyrite. In recent studies of bioprocesses, bioleaching is considered a process with multiple advantages such as low cost, environmental friendliness, simplicity of requirements, and suitability for the treatment of low-grade ores.…”

“…In bioleaching and abiotic tests with chalcopyrite samples, it was identified that the common phases on the surface of the leached samples during different periods of time were elemental sulfur and iron oxyhydroxides, which were identified by XPS spectrometer as jarosite, being the cause of the difficulty in dissolution [26]. The kinetics of chalcopyrite dissolution is fast when the solution potential is lower than 648 mV (SHE), and it cannot be effectively leached when the solution potential is higher than 698 mV due to the production of polysulfides, elemental sulfur, and jarosite on the surface, reaching surface passivation; it is not possible to oxidize with Fe 3+ , but it can be oxidized by stronger oxidants [8].…”

Carbon Material with High Specific Surface Area Improves Complex Copper Ores’ Bioleaching Efficiency by Mixed Moderate Thermophiles

“…It has been documented that some catalytic agents (e.g., Ag + , polyethylene glycol and Cl − ) were used to improve the copper sulfide ores dissolution [4,5]. Ag + catalysis is due to the formation of a complex porous layer on sulfide mineral particles instead of the deposition of a tenacious sulfur layer.…”