CO2 supply in the biooxidation of an ena

The study investigates the impact of CO2 supply on the biooxidation of a specific gold concentrate, consisting of 41% enargite and 43% pyrite, using Thiobacillus ferrooxidans in a controlled bioreactor environment. The objective was to determine how varying CO2 concentrations affect leaching efficiencies of metals within the concentrate. A 2-l bioreactor was utilized, with tests conducted at 4% solids concentration, a constant temperature of 35°C, and acidic pH levels of 2.4. Results demonstrated that the introduction of CO2 at 4% (v/v) in air significantly enhanced metal extraction rates: iron increased from 21% to 69%, arsenic from 19% to 25%, and copper from 16% to 19%. Additionally, the suspended biomass of Thiobacillus ferrooxidans increased markedly, with cell counts rising from 2.6·10^7 to 1.2·10^8 cells/ml. The findings suggest that biooxidation processes were previously constrained by the limited CO2 availability in standard air mixtures, thus indicating the potential for optimized bioleaching operations through CO2 enrichment strategies.