Abstract: The roles of thiobacillus ferrooxidans in biological oxidation of sphalerite was studied, which was compared with the process of Fe³⁺ oxidation. The studies showed that Fe³⁺ has a higher oxidation efficiency than the bacteria, but the efficiency of bio-oxidation is more stable. In biological oxidation process of sphalerite, thiobacillus ferrooxidans experiences delay period, exponential phase, stable phase and decline stage in its growth. Some of bacterial attach to the mineral surface, but no precipitation of intermediate sulfur is appeared. While, in the chemical oxidation of sphalerite, a large number of sulfur are settled on the mineral surface, indicating that the biological oxidation is more thorough.

Key words:  Sphalerite, Biological oxidation, Thiobacillus ferrooxidans