Inversion and optimization of CO₂+O₂in situ leaching of blasting-stimulated sandstone-type uranium deposits.

This article focuses on the development and application of a reaction-flow numerical model to simulate CO₂+O₂ in situ leaching (ISL) in blasting-stimulated low-permeability sandstone-type uranium deposits (LPSTUDs). Using the Shihongtan uranium deposit as a case study, the research establishes a numerical model that integrates blasting-induced fracture propagation with chemical leaching processes, validated by laboratory experiments on fractured rock samples. Results indicate that uranium recovery rate first increases and then decreases with blasting peak pressure, peaking at 1000 MPa, due to the balance between fracture connectivity and flow short-circuiting. Key factors influencing ISL effectiveness include matrix permeability, O₂ concentration, HCO₃⁻ concentration, injection rate, and average uranium grade, with O₂ concentration and matrix permeability having the greatest positive impact, while higher injection rates reduce recovery by shortening reaction time. The study provides theoretical and technical guidance for optimizing blasting and CO₂+O₂ ISL parameters to enhance uranium extraction efficiency in complex geological settings.