Density of Na₃AIF₆-AIF₃-LiF-MgF₂-Al₂O₃-Sm₂O₃ molten salt melt for Al-Sm alloy

Yunfen Jiao£¬Xu Wang£¬Chunfa Liao£¬Jia Su£¬Hao Tang£¬Boqing Cai£¬Qiangchao Sun

Institute of Metallurgical and Chemical Engineering, Jiangxi University of Science and Technology

Õª Òª£ºSamarium£¨Sm£© has been widely used in making aluminum£¨Al£©-Sm magnet alloy materials. The research team for this study developed a molten salt electrolyte system which directly produces AI-Sm alloy to replace the energy intensive conventional distillation technology. In this study, molten melt density was measured and operation conditions were optimized to separate AI-Sm alloy product from the fluoride molten melt electrolysis media based on density differences, Archimedes¡¯ principle was applied to measure density for the basic molten fluoride system£¨BMFS: Na₃ AlF₆-AlF₃-LiF-MgF₂£©electrolysis media in the temperature range from 905 to 1055 ¡æ.The impact of temperature£¨t£© and the Al₂O₃ and Sm₂O₃ addition ratio(w_{£¨Al2O3£©},w_{£¨Sm2O3£©} in the basic fluoride system on molten melt density was examined. The fluoride molten melt density relationship was determined to be:¦Ñ=3.11701-0.00802 w_{£¨Al2O3£©}+0.027825 w_{£¨Sm2O3£©}-0.00117 t. The test results showed that molten density decreases with increase in temperature and Al₂O₃ addition ratio, and increases with the addition of Sm₂O₃, and/or Al₂O₃+Sm₂O₃. The separation of Al-Sm£¨density 2.3 g/cm³£© product melt from the BMFS melt is achieved by controlling the BMFS density to less than 2.0 g/cm3. It is concluded that the optimal operation conditions to control the BMFS molten salt density to less than 2.0 g/cm³ are:maintain addition of Al₂O₃+Sm₂ O₃(w_{£¨Al2O3£©}+w_{£¨Sm2O3£©}<9% of Na₃AlF₆,Al₂O₃/Sm₂O₃ ratio(w_{£¨Al2O3£©}:w_{£¨Sm2O3£©})> 7:3, and temperature between 965 and 995 ¡æ.

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