Recent Advances in Recovery Enhancement Technologies for In Situ Leaching of Sandstone-Hosted Uranium Deposits

Sandstone-hosted uranium deposits represent one of the world’s most important uranium resources and are strategically significant for nuclear energy development, energy transition, and carbon emission reduction. Compared with conventional open-pit or underground mining, in situ leaching has become the dominant approach for sandstone-hosted uranium deposits due to its minimal surface disturbance, higher resource utilization efficiency, and reduced environmental footprint. However, most sandstone-hosted uranium deposits exhibit pronounced reservoir heterogeneity, including permeability contrasts, uneven flow pathways, complex uranium occurrence, and non-uniform advancement of reaction fronts. These factors collectively restrict leaching solution transport, limit uranium mobilization, and reduce recovery efficiency and sustainability of in situ leaching operations. Therefore, achieving efficient, environmentally friendly, and sustainable development of complex heterogeneous sandstone uranium deposits has become a key challenge in in situ leaching research and engineering practice. This review summarizes recent advances in recovery enhancement technologies for in situ leaching of sandstone-hosted uranium deposits over the past decade. Based on the geological and hydrogeochemical characteristics of these deposits, the mechanisms of in situ leaching are first outlined, followed by technological developments in four areas: flow field regulation, reservoir permeability enhancement, geochemical regulation, and reactive-transport coupling enhancement. Current challenges and future research directions are also discussed. This review provides a systematic framework for improving uranium recovery while advancing efficient, environmentally responsible, and sustainable in situ leaching development.