Abstract:In-situ leaching(ISL) is a typical flow process coupled with chemical reaction and solute transport. The permeability distribution of porous ore deposits will change dramatically during leaching process,and it may lead to preferential flow or “dead leaching zone” that decreases the overall recovery rate of minerals. Existing leaching apparatuses mainly focus on the chemical process under atmospheric pressure,and can not perfectly model the in- situ condition with high confining pressure and fluid pressure. Permeability of uranium orebody may change by several orders of magnitude during leaching process. These apparatuses are not suitable for high precise and large-scale permeability monitoring. For these reasons,a new rock-fluid reaction-flow coupling testing apparatus is developed. The flow rate,pressure,different pressure,fluid component can be gained simultaneously with this apparatus. Permeability,solution transport coefficient,and chemical reaction rate can be obtained by analytical methods. The apparatus is used for natural reagent leaching experiment with natural ore bearing aquifer groundwater. Experiment results show that uranium recovery rate is about 60% when the liquid solid ratio reaches 4,and permeability changes by 3 orders of magnitude during natural reagent leaching process. The experiment proves that the rock-fluid reaction-flow coupling testing apparatus works well and efficiently,and in-situ uranium leaching by natural ore bearing aquifer groundwater under oxygen oxidizing condition is applicable and effective. The results also show that field leaching experiment may face non-uniformity flow which will decrease recovery rate.