Abstract:In order to enhance uranium bioleaching of low-iron and low-sulfur uranium ore, adding different concentrations of Fe3+ and elemental sulfur was applied to improve uranium bioleaching rate. Effects of different concentrations of Fe3+ and elemental sulfur on pH value, Eh value, Fe3+ concentration, and uranium concentration during uranium leaching were investigated. The results show that different initial concentration of Fe3+ has a significant impact on uranium leaching rate. Uranium leaching rate is 81.85%，92.61%，89.15%，86.28% and 86.09% respectively with 0 g/L, 1, 2, 3 and 4 g/L Fe3+ addition. The optimum uranium leaching condition is 1 g/L of Fe3+ addition. Furthermore, in 2 g/L Fe3+ system, pH value of 2 g/L elemental sulfur system rises slower than that without elemental sulfur. Leaching rate of uranium in elemental sulfur system obviously rises by 1.63 percent points. SEM-EDS analysis show that specific surface area of ore particles rises due to rough surface of mineral and evacuation of ore structure after bioleaching. Jarosite precipitation is also found in leaching residue; however, jarosite precipitation on surface of uranium ore is obviously reduced in 2 g/L elemental sulfur system.