Research on cultivation of Acidithiobacillus ferrooxidans by microwave mutation for bioleaching of low-grade copper tailings

Microwave mutation on Acidithiobacillus ferrooxidans (At.f₆ bacteria) was made in this study. The results showed that the microwave mutation could produce an evident mutation in the At.fβ bacteria, which could improve its bio-activity and its bio leaching properties for low-grade copper tailings. The At.f₆ bacteria had the best oxidation after microwave radiating 60 seconds. The oxidation rate of Fe²⁺ reached 100 % after 24 hours, which was at least 18 hours in advanced comparing the original bacteria. The copper leaching rate of the At.f₆ bacteria after mutation was improved by 20 %, which showed that the bio leaching properties of mutant bacteria were much better than that of unmutated. The XRD analysis of leached residues indicated that Cu oxidized fast and dissolved to ion state with the bacterial action in the leaching solutions. Our study shows that mutant bacteria from microwave irradiation have great potentials for copper recovery from low-grade copper tailings.