Alkali Leaching Characteristics of Sandstone-Type Uranium Ore without Oxidant
Received:October 08, 2018   Revised:October 08, 2018   Accepted:October 09, 2018      Published Online:November 19, 2018
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DOI:doi:10.3969/j.issn.1007-7545.2018.12.009
KeyWord:sandstone-type uranium deposit; reagent-free leaching; alkaline leaching; oxidant-free
              
AuthorInstitution
Zhou Yipeng 核资源与环境国家重点实验室
Xu Lingling 核资源与环境国家重点实验室
Li Guangrong 核资源与环境国家重点实验室
Sun Zhanxue 核资源与环境国家重点实验室
Shi Weijun 核资源与环境国家重点实验室
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Abstract:
      In order to study process of water - rock reaction and uranium leaching characteristics of sandstone-type uranium deposit during leaching without oxidant, two lab study of distilling water immersion and alkali leaching without oxidant was carried out. The results show that reagent-free water-rock salt ion complex and natural dissolved oxygen in water can weakly migrate uranium into water. Uranium migration intensity in oxidant-free alkali leaching is positively correlated with HCO3- concentration. The HCO3- concentration of 700~900 mg/L is a relatively significant interval for uranium migration. UO2(CO3)22- and UO2(CO3)34- are main dissolved forms of uranium complex in these two lab leaching study, and their proportion is related to HCO3- concentration and pH value. The alkali-impregnated uranium concentration is low since lacking oxidation. Uranium leaching rate for 40 days with L/S=1.5 is 17.17%~22.37%. Uranium leaching rate decays fast, which probably is related to tetravalent uranium content in ore. Nevertheless, the total migration amount of uranium over a long period of time cannot be ignored in alkaline groundwater systems, especially in alkali-drained mining areas.
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