Imitation experiments on metallogenic environment of in-situ leachable sandstone uranium deposit No.512

The author introduces the experiment model established on the basis of field observation and sampling, as well as the results of 6 groups of dissolution and reduction experiments of uranium, molybdenum and selenium, and 179 analytical data and about 100 pH value data have been obtained. Experiment results indicate that the intensity oxidized solution resulting in the formation of interlayer oxidation zone is acidic oxygen-bearing solution, and the main factor leading to the precipitation of uranium is the change of pH value, the gas reduction of CH4 and other gases, and the change of concentration ratio SO42- and HCO3- in solution. Unlike the uranium and molybdenum, selenium may be precipitated in the oxidation subzone. Experiments also indicate that the initial uranium-bearing solution is acidic and sodium-rich . It obviously 'expels calcium (as well as uranium, molybdenum and selenium) and reserves silica and iron'. At the moment of roll orebody formation, the solution is changed from acidic to neutral-weakly alkalic, and selenium, uranium and molybdenum are successively precipitated in the interlayer oxidation zone forming certain zonation