Uranium Mining and Metallurgy
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2025, 44(2): 60-70
• MINING AND HYDROMETALLURGY •
Simulation Study on Mineral Dissolution and Precipitation During the “CO2+O2” In-situ Leaching Process
Full
Haicheng WENG, Yuan YUAN, Zhengbang LIU, Chunru HOU
Affiliations
- Beijing Research Institute of Chemical Engineering and Metallurgy, CNNC, Beijing 101149, China
Published: 2025-05-20
doi: 10.13426/j.cnki.yky.2024.09.02
Outline
The "CO2+O2" leaching process is an artificially intensified water-rock interaction process that leads to the dissolution of non-uranium minerals, which enter the leaching solution system and cause changes in the dissolution and precipitation state of the minerals in the leachate. Geochemical simulation methods were used to simulate ion species in the leachate and the mineral leaching equilibrium studying the dissolution, migration, and precipitation of minerals during the in-situ leaching mining process. For the first time, the conditions and influencing factors for the precipitation of manganese minerals were studied, targeting the characteristics of strong groundwater reducibility and high carbonate content in the target deposit.The results show that under neutral leaching conditions, uranium in the leachate mainly exists in the form of UO2(CO3${)}_{3}^{4-}$ followed by UO2(CO3${)}_{2}^{2-}$, and the proportions of the two are affected by pH. The saturation indices of carbonate minerals in the neutral leaching leachate of the study area are all greater than zero, indicating a supersaturated state, and pH is the main factor controlling the precipitation of carbonates, with the critical pH for calcium carbonate precipitation being 6.7 and for calcium magnesium carbonate precipitation being 6.5. The saturation indices of sulfate minerals are all less than zero, and no precipitation of calcium sulfate will occur in the formation, and the precipitation of calcium sulfate is mainly controlled by the content of calcium ions and sulfate ions. Under neutral leaching conditions, iron mineral precipitation is likely to occur and is greatly affected by pH conditions; at the same time, manganese-containing minerals will precipitate in the leachate, and the redox conditions are the main factors affecting their dissolution and precipitation; some silicon-containing minerals in the leachate are in a supersaturated state, and their dissolution and precipitation are greatly affected by pH The research results are of great significance for the prevention of precipitation in in-situ leaching mining.
"CO2+O2" leaching
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geochemical simulation
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PHREEQC
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leachate
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ion species
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mineral dissolution and precipitation
Haicheng WENG, Yuan YUAN, Zhengbang LIU, Chunru HOU.
Simulation Study on Mineral Dissolution and Precipitation During the “CO2+O2” In-situ Leaching Process[J].
Uranium Mining and Metallurgy,
2025
, 44
(2)
: 60
-70
.
DOI: 10.13426/j.cnki.yky.2024.09.02
Year 2025 volume 44 Issue 2
PDF
306
126
Cite this Article
BibTeX
Article Info
doi: 10.13426/j.cnki.yky.2024.09.02
- Receive Date:2024-09-02
- Online Date:2025-07-04
- Published:2025-05-20