Abstract:During acid leaching of uranium, the chemical composition of leachate usually changes significantly, along with the production of clay minerals. Taking the Inner Mongolia Manglai uranium ore as the research object, the indoor acid immersion uranium test under four acidity (5, 10, 15, 20 g/L H2SO4) conditions was carried out, and the changes of U6+, U4+, Na+, K+, Ca2+, Mg2+ and Al3+ in the leachate during the test were analyzed, and the clayification alteration characteristics of minerals and characteristics of uranium leaching during the test process were systematically discussed. The results show that the leaching rate of uranium in slag is 83.73%—88.07%, while the leaching rate of uranium(Ⅵ) is fast and that of uranium(Ⅳ) is slow. The minerals containing uranium, sodium, potassium, calcium, iron and aluminum in the ore dissolve, making the concentration of U6+, U4+, Na+, K+, Ca2+, Al3+, Fe2+ and Fe3+ in the leaching solution increase significantly. Feldspar minerals in the ore have obvious clay alteration and illite is the main clay minerals. These research results can provide technical support for determining the development technology of Manglai uranium deposit and preventing the blockage of ore-bearing strata.