Calcite is an important carbonate mineral in sandstone-type uranium deposits, and its corrosion-precipitation behavior directly affects the permeability of the deposits. To gain a deeper understanding of the mechanisms behind permeability decline during "CO2+O2" in-situ leaching of sandstone-type uranium deposits, the stirred leaching experiments using calcite in a high-pressure reactor under varying CO2 partial pressures was conducted. The results indicate that higher CO2 partial pressures lead to lower solution pH and higher concentrations, significantly enhancing calcite corrosion. However, the Ca2+released during corrosion can trigger secondary calcite precipitation. Differential corrosion was observed on the calcite surface, forming distinct corrosion pits. Additionally, the pore structure of calcite underwent notable changes, characterized by the disappearance of micropores, a reduction in pore volume, and an increase in average pore size. Based on the above findings, a dynamic control strategy of "high-pressure unclogging followed by low-pressure maintenance" was proposed for in-situ leaching operations, providing both theoretical foundation and engineering guidance for optimizing the "CO2+O2" in-situ uranium leaching process.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |