Bioleaching of Au-Containing Ore Slates and Pyrite Wastes

Abstract

The influence of the environment and bacterial cultures on the degree of gold leaching from Au-containing raw materials of different compositions, origins, and with different contents of gold, selected in the Ural Federal District (Russia), was determined. The leaching degree was determined according to the change of the gold concentration in the ore by means of mass-spectrometry with inductively-coupled plasma. It was demonstrated that the degree of Au bioleaching from carbonaceous-argillaceous slates, containing 2.17 g/t of gold, and from pyritic technogenic raw materials, containing 1.15 g/t, when holding them in peptone water and Leten medium reached 92.17% and 87.83%, respectively.

Bioleaching Potential of Indigenous Bacterial Consortia from Gold-Bearing Sulfide Ore of Ta Nang Mine in Vietnam

“…Mining residues and mine drainage samples were collected in January 2019 from different sites at the Ta Nang gold deposit, Duc Trong district, Lam Dong province, central highland of Vietnam (11°34'23''N; 108°32'33"W) for further study on mineralogical characteristics, bacterial identification and composition, and bioleaching efficiency using indigenous microbial consortia. Around 20 kg of the sample were crushed in a jaw crusher and then ground by a ball mill to the fraction with particle size of 1 mm [1]. Ground goldbearing sulfide ores were then sieved through a mesh grid to obtain a size fraction of 74 μm.…”

“…Over several decades, the yield for precious metal mining such as gold, silver, and copper has significantly increased due to the development of advanced technologies and global demands [1,2]. However, the estimated reserves of some crucial metals Cu, Pb, Au, Ag will be depleted within 50 years or fewer [3].…”

“…Notably, approximate 7% of the world's copper production was statistically produced from low-grade copper ore and mine tailing by using bioleaching technologies [4]. In fact, bioleaching technology has been shown to strictly rely on indigenous bacterial consortia colonizing sulfide ores, consisting of members of the genera Acidithiobacillus, Pseudomonas, Leptospirillum, Sulfobacillus, and Bacillus [1,5,6]. The most studied leaching bacteria are the genus Acidithiobacillus, which includes sulfur-oxidizing species (A. caldus, A. thiooxidans, A. albertensis) and sulfur-and ferrousoxidizing bacteria (A. ferrooxidans, A. ferrivorans, A. ferriphilus, A. ferridurans) [7].…”

“…Acidithiobacillus spp., a group of acidophilic chemolithoautotrophic Gram-negative bacteria, are common inhabitants of extremely acidic metal-rich ecological niches, which were widely applied in the bioleaching of metal-sulfide ore minerals, ore concentrates, and waste sludge [8][9][10]. Despite the high bioleaching efficiency, the genus Acidithiobacillus is often found in low density in indigenous microbial consortia [1,11], which has not been fully understood to date. By contrast, the most abundant genera commonly found in bioleaching models are Acinetobacter, Bacillus, Pseudomonas, and Streptococcus [11].…”

“…A huge amount of Cu (77.7 ± 3.6%) and Zn (70.6 ± 3.8%) extraction were obtained from low-grade copper ore by using mixtures of A. ferrooxidans, L. ferriphilum, and L. ferrooxidans [10]. More than 92% of Au was leached from carbonaceous-argillaceous shales by using the bacterial consortium comprising predominantly Pseudomonas, Bacillus, Stenotrophomonas [1]. Among these heterotrophs, the genus Bacillus has been emerging as a promising candidate for the extraction of heavy metals from non-sulfidic minerals such as Ni-laterite and silicate ores [15,16].…”