Treatment of copper cyanide solutions with the use of sulfate-reducing bacteria

The study was aimed at developing a technology for regenerating cyanide and precipitating copper from copper cyanide solutions through the sulfate reduction process. To this end, a mixture of strains of anaerobic sulfate-reducing bacteria was used: Desulfonatronum zhilinae, Desulfonatronum cooperativum, and Desulfonatronobacter acetoxidans from the S.N. Vinogradsky Institute of Microbiology of the Russian Academy of Sciences (Moscow). The sulfate reduction was carried out at temperatures of 20–40℃ and at pH>9.5. Ethanol was used as the electron donor, and sulfate ions were used as the acceptor. In order to ascertain the limiting substrate (ethanol or sulfate) and establish the optimal concentrations of the acceptor and the electron donor, a mathematical microbial growth model was used – the Monod equation. The calculation results indicate substrate competition for the right to limit the process. Thus, at concentrations of