Abstract: Studied the effect of pH，temperature and the additives on the bio-oxidation process|including the specific cell growth rate and the specific bio-oxidation rate of refractory gold concentrate by .Acidithiobacillus ferrooxidans(At.ferrooxidans).Results showed that:the maximal specific growth rate was achieved at pH range of 1.1~2.0, and a temperature of 41 ℃.The maximal specific bio-oxidation rate was achieved at a pH range of 1.1~1.4, and a temperature of 41~44 ℃.The peptone improved the concentrate bio-oxidation rate from 0.41±0.02 g/(L·d) to 0.92±0.05 g/(L·d), and the cysteine 0.41±0.02 g/(L·d) to 0.57±0.03  g/(L·d).The optimal adding concentrates of them were 10-3 g/mL and 6.4×10-5 mol/L, respectively.The best time for adding them was before the bacteria logarithmic phase.

Key words: Acidithiobacillus ferrooxidans, Refractory gold concentrate, Bio-oxidation, Bioleaching