Research on Migration Intensity and Saturation State of Main Element in Different In-situ Leaching of Uranium Processes

According to the characteristics of high calcium carbonate content of ore at a uranium deposit in Xinjiang, in order to master the migration intensity of main elements and mineral saturation state using acid leaching, alkali leaching and CO₂+O₂ neutral in-situ leaching (ISL) processes, three different leaching tests were carried out indoors and outdoors. The hydrogeochemical principles were used to calculate saturation index of calcium carbonate and calcium sulfate. The results show that the migration intensity of U, Ca, Mg, Al and Fe using acid ISL is stronger than using alkali and neutral ISL. The migration intensity of U using alkali ISL is basically the same as using neutral ISL. The migration intensity of Ca and Mg using neutral ISL is stronger than using alkali. The alkali and neutral ISL migration of Fe and Al are weaker than U, Ca and Mg. During neutral leaching, calcium sulfate never precipitates, when the pH value is controlled below 6.6, calcium carbonate will not precipitate. Calcium carbonate precipitation is inevitable in alikaline leaching, and calcium sulfate precipitation is inevitable in acid leaching. For this deposit, CO₂+O₂ neutral leaching process is the first selection. Controlling the pH value below 6.6 can effectively avoid the precipitation of calcium carbonate and ensure the normal leaching of uranium.