Abstract:The indoor leaching process experiment is a necessary link between scientific research and industrial production. In view of the differences between the indoor experimental conditions and industrial production conditions for the leaching process of in-situ leachable sandstone-type uranium deposits, the large number of physical experiment groups, and the difficulty of mining and rock sampling, a set of numerical simulation model construction methods for in-situ leachable uranium mining column leaching based on the coupling of COMSOL and PHREEQC is proposed. Taking the indoor leaching experiment of a certain uranium deposit in Inner Mongolia as an example, a comparative study of physical experiments and numerical simulation experiments was carried out. The results show that the numerical simulation method based on the coupling of COMSOL and PHREEQC has good feasibility in the simulation of acid leaching indoor column leaching experiments. Under the same pressure conditions, the leaching rules of dissolved components such as pH value, U, Fe₃₊^{, Ca}₂₊^{, and SO}_4^2- are basically consistent, and the time of peak occurrence is relatively consistent. Under different pressure conditions, the results of the numerical simulation model conform to the general rules under pressure adjustment. There are still differences in the peak values of U and Ca^₂₊ concentrations in the constructed numerical simulation model, which needs further improvement of the simulation model.