Thermoacidophilic bioleaching of copper sulfide concentrate in the presence of chloride ions

The role of chloride ion in the performance of extreme thermophiles bacterium Sulfolobus acidocalarius in bioleaching process of copper sulfide concentrate at Midouk Shahr-e-Babak Complex was investigated. The gradual adaptation of bacteria to chloride ions at pH=1.5 showed that the presence of chloride ions in solution reduced the reproduction and growth rate of bacteria but did not prevent their growth. Results indicated that the effect of decreasing pH from 2.0 to 1.5 on bioleaching of copper sulfide concentrate is to increase the recovery of copper in the first few days, and nearly 100% of copper was extracted after 9 d. As the solid content in solution increases from 1% to 3%, about more 6 d was required to extract copper. Bioleaching of copper sulfide concentrate revealed that the dissolution of copper sulfide concentrates at constant pH=1.5, 1% solid content, and concentration of 0.5 mol/L and 1.0 mol/L NaCl after 9 d, was 98% and 80%, respectively; and after 21 d, it reached nearly 100% and 90%, respectively. Under the same conditions without microorganisms, copper extraction reached 62%. The kinetics of bioleaching and leaching is a combination of diffusion and chemical reaction.

Automated summary

The role of chloride ion in the performance of extreme thermophiles bacterium Sulfolobus acidocalarius in bioleaching process of copper sulfide concentrate at Midouk Shahr-e-Babak Complex was investigated. Gradual adaptation of bacteria to chloride ions at pH=1.5 showed that chloride ions in solution reduced the reproduction and growth rate of bacteria but did not prevent their growth. Lowering the pH from 2.0 to 1.5 increased the recovery of copper in the first few days of bioleaching.