Alkaline copper oxide ore bioleaching by ammonia-producing bacteria

The bioleaching of a high alkaline copper oxide ore from Yunnan Province in southwest China was carried out in a shake flask with ammonia-producing bacteria Providencia JAT-1. It is found that temperature,liquidsolid ratio,species and concentration of the leaching aid,and initial bacteria inoculation have significant impact on the copper leaching rate. When the temperature is 30 ℃,the liquid-solid mass ratio is 7:1,the concentration of ammonium sulfate as the leaching aid is 0.024 mol·L-1,and the initial bacteria inoculation is 20%,the bioleaching for 144 h yields a copper recovery of 42.35%. The result of phase analysis shows that the copper leaching rate of secondary sulphide copper in the ore is the highest.