Abstract: To improve the activity of bacteria used for the pre-oxidation of arsenic-containing gold ore, study was made on the activation of the moderate thermophiles long domesticated by arsenic-containing gold ore and the activated bacteria was used in the biological pre-oxidation test. The result indicates that when 10 g/L FeSO₄·7H₂O and 5% gold were combined and used as energy for the bacterial activation, the arsenic removal rate of the biological pre-oxidation of gold ore can reach 75.0%, when 5% gold ore was used for the second bacterial activation, the arsenic removal rate can be further increased to 89.0%.

Key words: Biological pre-oxidation, Arsenic-containing gold ore, Moderate thermophiles, Arsenic removal rate, Activation