Extraction of uranium from low-permeability sandstone is a long-standing challenge in mining. The improvement of sandstone permeability has therefore become a key research focus to improve the uranium leaching effect. To address the low-permeability problem and corresponding leaching limits, leaching experiments are performed using newly developed equipment that could apply low-frequency vibration to the sandstone samples. The test results indicate that low-frequency vibration significantly improves the uranium leaching performance and permeability of the sandstone samples. The leaching effect of low-frequency vibration treatment is approximately nine times more effective than ultrasonic vibration treatment, whereas the concentration of uranium ions generated without vibration treatment is not detectable. Mathematical model that considers the combined action of physico-mechanical vibration and chemical erosion is established to describe the effect of low-frequency vibration on the permeability. The calculated results are in good agreement with the tested permeability values. This study thus offers a new method to effectively leach more uranium from low-permeability sandstone using CO2+O2 and provides an insight into the impact of low-frequency vibration on the uranium leaching process.

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Keywords: Uranium leaching, Low-frequency vibration, Chemical erosion, Low permeability, Permeability model