Growth of Thiobacillus ferrooxidans in different media and leaching of sphalerite concentrate

Studies on the growth of Thiobacillus ferrooxidans in terms of ferrous iron oxidation rate and cell count in four different broth media revealed that the medium proposed by Barron and Luecking (medium B) had the best bacterial growth compared to the other three media. The iron oxidation rate constant was 0.536 with a cell count of 7.1 × 10⁷ mL⁻¹. Leaching of sphalerite concentrate and pure ZnS at initial iron free condition in each of the four media was studied. Zinc leaching after 49 d from sphalerite concentrate (76, 61.97, 56.92 and 33.09) showed better bacterial leaching compared to ZnS (21.4, 18.9, 14.7 and 6.36) in all the four media tested. Medium B was found to be best for zinc bioleaching with T. ferrooxidans.