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| Interaction between Gangue Mineral and Leaching Agent in CO2+O2 In-situ Leaching |
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Received:October 13, 2022
Revised:October 24, 2022
Accepted:October 31, 2022
Published Online:February 13, 2023
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| DOI：doi：10.3969/j.issn.1007-7545.2023.03.010 |
| KeyWord:gangue mineral; CO2+O2 leaching uranium; calcite; congestion risk |
| Author | Institution |
| ZHAO Kai |
东华理工大学 水资源与环境工程学院 |
| ZHANG Yi-nuo |
核资源与环境国家重点实验室 |
| ZHOU Yi-peng |
核资源与环境国家重点实验室 |
| LI Guang-rong |
东华理工大学地球科学学院 |
| SUN Zhan-xue |
核资源与环境国家重点实验室 |
| LIU Jin-hui |
核资源与环境国家重点实验室 |
| XU Ling-ling |
核资源与环境国家重点实验室 |
| YUAN Xin |
东华理工大学 水资源与环境工程学院 |
| HU Min-tao |
东华理工大学 水资源与环境工程学院 |
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| Abstract: |
| In the process of uranium mining by CO2+O2 in-situ leaching, leaching agent reacts not only with uranium-carrying materials but also with gangue minerals. In order to study the interaction between main gangue minerals of sandstone type uranium deposit and leaching agent, the static leaching tests of gangue single minerals and natural uranium ore were carried out under neutral conditions (pH values of 6.20, 6.40, 6.60, 6.80 and 7.00). The changes of ions concentration in leaching solution and morphologies of the slag samples after reaction were compared. The results show that: 1) The dissolution of calcite can produce HCO3- and Ca2+. The increase of HCO3- can accelerate the leaching of uranium, while the increase of Ca2+ concentration will increase the risk of gypsum and calcite precipitation. 2) The reaction between pyrite and leaching agent is easy to produce H+, which hinders the reaction between CO2 and water to form HCO3-, which is not conducive to uranium leaching. However, when pyrite and calcite exist simultaneously, the interaction between pyrite and leaching agent will accelerate the dissolution of calcite. Therefore, for calcite rich ores, the presence of pyrite is conducive to uranium leaching. 3) The dissolution of potassium feldspar can form clay minerals, which have certain adsorbability to the dissolved uranyl ions. Furthermore, the clay particles are small, which increases the risk of physical clogging of clay in the process of in-situ leaching industrial application. 4) During the leaching process, kaolinite will release other ions adsorbed by it and adsorb uranyl at the same time. The results of slag mineralogical analysis show that all minerals dissolved differently during the leaching process, among which calcite dissolved most obviously, the surface is gradually eroded rough, and feldspar surface dissolved weakly. The surface of pyrite is gradually covered with a layer of iron oxides or iron hydroxides with the action of leaching agent. The morphology of kaolinite does not change obviously. |
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