Abstract:In recent years, the nuclear power industry has been advancing at a remarkable pace globally, much like a high-speed train. China, closely trailing this energy development trend, has seen an escalating demand for uranium resources. Under the guidance of national strategies, numerous entities have substantially augmented their investment in uranium ore exploration. Employing advanced technologies and making unremitting efforts, significant breakthroughs have been attained in areas such as the Ordos Basin, Erlian Basin, Songliao Basin, and Bayingobi Basin. Multiple super-large, extra-large, and large-scale sandstone-type uranium deposits have been unearthed. In-situ leaching technology, being an efficient and environmentally friendly extraction method for sandstone-type uranium deposits, occupies a pivotal position in modern uranium mining. Nevertheless, due to disparities in ore particle size, lithology, and the forms in which minerals are hosted, the leaching parameters and indices of different deposits vary considerably. Laboratory leaching experiments function as a crucial approach to exploring the viability of in-situ leaching uranium mining and optimizing process parameters. By accurately controlling experimental conditions, the leaching efficiency of sandstone-type uranium ores under diverse circumstances can be ascertained, thereby enabling the determination of the composition and proportion of leaching solutions appropriate for deposits in specific regions. In this study, representative ore samples were chosen from the X sandstone-type uranium deposit on the southwestern fringe of the Ordos Basin. Leveraging technical means such as rock thin-section analysis, scanning electron microscopy, and electron probe microanalysis, the lithological features, mineral composition, and mineral occurrence patterns of the ores were meticulously investigated. Simultaneously, within the laboratory setting, the method of controlling variables was adopted to simulate field leaching conditions, and leaching process experiments were conducted. The leaching solution concentration, reagent dosage, liquid-to-solid ratio, leaching cycle, and other parameters suitable for this deposit were determined. Consequently, the optimal leaching solution ratio was selected, which provides key parameters and important basis for on-site leaching condition tests and technical-economic evaluation of ore deposits. The experimental results show that: 1) Uranium minerals mainly occur in medium - fine - grained feldspathic quartz sandstone, lithic quartz sandstone and feldspathic lithic quartz sandstone in the form of titanium-bearing uranium minerals and pitchblende. 2) The results of stirring tests with different leaching reagents (H?SO?, NH?HCO? and Na?CO?) show that the ore leaching effect is good, and the leaching rate can reach over 90%. 3) The amount of oxidant in the leaching solution has a significant impact on the leaching effect. Reducing the amount of oxidant will decrease the uranium leaching rate. 4) According to the results of column leaching test, the change of particle size has no obvious effect on the leaching efficiency of the ore, and the leaching rate of uranium is 74.3% when 10 g/L Na2CO3+5 mL/L H2O2 is used as continuous leaching agent in alkali method, and 83.3% when stopping the leaching and alternating with shower is used. The acid method used 10 mL/L H2SO4+10 mL/L H2O2 as leaching agent for continuous leaching, and the leaching rate can reach 93%. The findings of this research can effectively offer robust data support for the in-situ leaching mining of sandstone-type uranium deposits on the southwestern margin of the Ordos Basin, and provide support for on-site mining operations.