Abstract
The aim of the present work was to perform copper, nickel, and platinum group metals (PGMs) recovery from low-grade copper–nickel concentrate containing pyrrhotite, pentlandite, and chalcopyrite by bioleaching in stirred tank reactors in batch mode and subsequent cyanidation. The concentrate contained (%) Fe 32.7, Cu 0.7, Ni 2.3, Stotal 20.9, Ssulfide 17, 0.1 g/t Pt, and 1.35 g/t Pd. The bioleaching was performed at 30 and 40 °C using two different microbial consortia. At 30 °C, bioleaching was performed using mixed culture including Acidithiobacillus ferrivorans strains isolated from the sample of acid mine drainage from copper–nickel deposit. At 40 °C, bioleaching was performed using microbial population formed during long-term bioleaching of copper-zinc concentrate at 40 °C. Bioleaching was performed for 40 days at pulp density of 10% (solid to liquid ratio 1:10). At 30 °C, 70% Ni and 14% Cu were leached, while 72% Ni and 34% Cu were recovered in the solution at 40 °C. PGM were extracted from the concentrate and bioleaching residue obtained at 40 °C by cyanidation. Cyanidation made it possible to extract 5.5% Pt and 17.3% Pd from the concentrate and 37.8% Pt and 87.8% Pd from the bioleaching residue. Thus, it was shown that the concentrate studied might be processed using bioleaching and subsequent cyanidation to extract both non-ferrous metals and PGM.
Highlights
The currently applied biohydrometallurgical technologies make it possible to process low-grade and refractory ores, refractory sulfide gold-bearing concentrates, and in some cases non-ferrous metal (Ni, Co) concentrates [1–7]
stirred tank reactor (STR) biooxidation provides high productivity, but requires relative high costs due to complex equipment. It is usually used for processing refractory sulfide gold-bearing concentrates [1,7], but it has been successfully used for processing non-ferrous metal (Ni, Co) concentrates [2,6,7]
Biohydrometallurgical processes used for the treatment of sulfide ores and concentrates are performed by mixed populations of acidophilic iron and sulfur-oxidizing microorganisms, which are active at low pH values and in a wide temperature range [1,4,5,7]
Summary
The currently applied biohydrometallurgical technologies make it possible to process low-grade and refractory ores, refractory sulfide gold-bearing concentrates, and in some cases non-ferrous metal (Ni, Co) concentrates [1–7]. The most widespread biohydrometallurgical technologies are dump and heap bioleaching of low-grade copper ores [3–5,8]. As dump and heap bioleaching does not require large capital and operating costs, these processes are used to process low-grade metal ores, including copper, zinc, nickel, and uranium [3,8–10], and can be used to treat refractory gold-bearing ores [11]. STR biooxidation provides high productivity, but requires relative high costs due to complex equipment. It is usually used for processing refractory sulfide gold-bearing concentrates [1,7], but it has been successfully used for processing non-ferrous metal (Ni, Co) concentrates [2,6,7]. Biohydrometallurgical processes used for the treatment of sulfide ores and concentrates are performed by mixed populations of acidophilic iron and sulfur-oxidizing microorganisms, which are active at low pH values and in a wide temperature range [1,4,5,7]
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