Abstract:Iron is not only one of the energy material for microorganisms growth, but also is main oxidant for ore leaching during microbial leaching process. For low content of FeS2 deposit, indoor shake flask test was conducted with addition of different proportion of pyrite. The results show that uranium leaching rate is 95.8% with addition of pyrite, which is 3.6 percent point higher than that without pyrite addition, and leaching cycle is shortened significantly. When pyrite content is higher than 3%, microbial growth is inhibited and leaching rate drops. With pulp concentration being kept at 10%, and pyrite content is 0%, 1%, 2%, 3% and 4%, respectively, uranium leaching rate is 92.2%, 95.8%, 90%, 85.5% and 82.3%, respectively.