| Evaluating the chemical stability of SiO2 , Al2O3 , and MgO in LiCl-based molten salts for enhanced oxide reduction |
| Eun-Young Choi1,2 |
1Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon, 34057, Republic of Korea
2Department of Nuclear Science and Technology, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea |
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Received: August 2, 2024; Revised: October 7, 2024 Accepted: November 11, 2024. Published online: December 4, 2024. |
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| ABSTRACT |
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Producing metals, alloys, and semiconductors using traditional industrial pyrometallurgical techniques results in high energy consumption and significant CO2 emissions. Oxide reduction using molten salts is a promising alternative that exhibits reduced energy requirements and cost-effectiveness to address these environmental concerns. This study focuses on the chemical stabilities of three ceramic materials—crystalline SiO2 (c-SiO2), Al2O3, and MgO—in pure LiCl and LiCl salts containing Li metal or Li2O. Systematic tests were conducted for evaluating changes in the crystallinity, microstructure, and concentration of ceramic material in salts. Our findings indicate that, MgO exhibited the highest chemical stability, showing no reactivity with pure LiCl salt and Li metal or Li2O in salt, thereby making it a potential candidate for use in oxide reduction. Conversely, c-SiO2 was the most chemically unstable, reacting with residual H2O in the LiCl salt to form Li2Si2O5. It also reacted with Li and Li2O to form Si and Li2SiO3, respectively, both of which demonstrated some solubility in water. Al2O3 reacted with Li and Li2O in LiCl to form Al and LiAlO2, respectively. LiAlO2 tended to exist in the alpha phase when the Li2O concentration in the salt was low, and in the beta and gamma phases when it was high. These results provide systematic data on the chemical stability of ceramics in LiCl molten salt systems, offering a basis for selecting the most appropriate ceramics. |
| Key words:
Chemical reaction · Lithium metal · Li2O · LiCl salt · Si2O · Al2O3 · MgO |
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