Supercritical CO₂on Uranium Leaching Rate From Sandstone Uranium Ores

Compared with conventional mining techniques, and as a new uranium miningmethod, in-situ leaching uranium mining has a lot of merits, such as little solid wastegenerated, specially no waste rock and trailing-mills. So a series of environmentalmatter caused by conventional mining didn’t occur during in-situ leaching uraniummining, such as a great deal of radon-222releasing and seepage from waste rock andtrailing-mills, dump and mill-tailings impoundment need not to be built and so on.But the groundwater in wellfield was polluted seriously, which during the course ofleaching some poisonous substances were soaked out by chemical reagent pulled inthe underground. If it couldn’t been remediated in time, the polluted groundwatermigrated toward outside of the wellfield. In order to reduce the leaching of uraniumpollution of the environment, we have launched a new leaching of uraniumtechnology research.Based on the national natural science fund project “new uranium leaching agentand the mechanism of leaching of uranium ores”（project number:91026015）, thispaper was carried out a large number of test for stone uranium deposit in Xinjiang.Research of ore under the condition of natural grain size, new types of leaching agentfor sandstone uranium deposits by CO₂involved in the process of uranium leachingoxidant, pressure leaching, leaching temperature, leaching time and add surfactant onuranium leaching rate.The results show that new leachant CO₂for leaching uranium in the sandstoneuranium when1.96g/L of ferric chloride as the oxidant, leaching pressure of10MPa,leaching temperature of45°C, leaching time2h and OP-10: FSO that the complexsystem in a mass concentration is0.1g/L mass ratio is7:3to reach the maximumleaching rate of93.31%.The effect of uranium ore leaching rate is higher thanconventional situ leaching of uranium （acid leaching and soda situ leaching）, thereare a certain positive significance to improve the uranium concentration and reduce the cost of uranium mining environmental governance after the uranium mining.