Significance of Acid Washing after Biooxidation of Sulfides in Sequential Biotreatment of Double Refractory Gold Ore from the Syama Mine, Mali

Environmentally friendly pretreatment of double refractory gold ores (DRGO) to improve recovery without emitting pollutant gas is challenging. Sequential biotreatment, including iron-oxidizing microorganisms decompose sulfides, followed by the enzymatic decomposition carbonaceous matter, was recently developed. The effect acid washing 1 M HCl for 24 h between two bioprocesses evaluated using a real ore from Syama mines, Mali, which includes g/t Au and 5.27 wt% carbon with relatively higher graphitic degree. addition process significantly improved cyanidation yield 84.9 ± 0.7% 64.4 9.2% (n = 2). positive effects can be explained chemical alteration matter facilitate accessibility lignin peroxidase (LiP) manganese (MnP) in cell-free spent medium (CFSM), although agglomeration enhanced an attack structural Fe(III) clay minerals. treatment DRGO basically consists oxidative dissolution sulfides degradation prior extraction gold; however, details should modified depending on elemental mineralogical compositions degree matter.