Characteristic and Significant of Uraninite in Danfeng Uranium Ore-fields

Development of nuclear energy needs the support of considerable uranium reserves. Danfeng uranium ore-fields was the unique pegmatite-type uranium deposits been found in China. Characteristic, mineral paragenesis, alteration and secondary-mineral-assemble of uraninite in this area been studied by Microscope, SEM and EPMA. The results revealed: 1) Uraninite was the only primary uranium mineral, displayed in automorphic-hypautomorpuic granular texture, disseminated embedded within gangue minerals or among their grains. 2) U, Th and Pb were the major elements,Y, Ca, Si, Na, Hf, Fe, Zr, Mg, P, Mn were the minor elements in uraninite. 3) Uraninite subjected to hydrothermal alteration and some of it were surrounded by secondary minerals included secondary uranium minerals, sulfide, oxides and other silicate minerals. 4) Mineralization of uranium was mainly controlled by crystallization differentiation of primary pegmatitic magma, later hydrothermal alteration and/or supergenetic oxidation had influence on it.