Synergistic enhancement effect of Ag+ and organic ligands on the bioleaching of arsenic-bearing gold concentrate

Bio-oxidation of arsenic-bearing gold concentrate is generally slow and prone to passivation. To alleviate this concern, it pivotal explore the possible catalysts reduce passivation during bio-oxidation. In present work, enhancing effects Ag+, ethylenediamine tetraacetic acid (EDTA) oxalate (Ox) on bio-oxidation mechanisms were investigated by leaching experiments, thermodynamic calculation, XRD SEM analyses. Results indicated that addition Ag+ organic ligands could effectively accelerate bioleaching process. Especially, under synergistic action EDTA, efficiency As reached highest value 87.4% after 10 days. Thermodynamic calculations demonstrated from onset bio-oxidation, rate was significantly retarded due formation S0, As2S2, As2S3 jarosite. However, As2S2 be dissolved in presence Ag2S intermediate easily Fe3+. Moreover, EDTA Ox further facilitated extraction, for reason inhibited jarosite mineral surface forming corresponding complexes. This mechanism confirmed Overall, work bind can substantially enhance concentrate.