An electrolysis-displacement-distillation approach for the production of Li, Mg, Ca, Sr, and Ba metals

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 26; no. 5; pp. 2763 - 2772
• Main Authors: Guo, Lei, Gao, Shuaibo, Hu, Zuojun, Wu, Yongxin, Pang, Fangzhao, Yin, Huayi, Wang, Dihua
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 04.03.2024
• Subjects: Alloys; Barium chloride; Calcium chloride; Chlorine; Current efficiency; Distillation; Electrolysis; Electrolytic cells; Emissions; Gas evolution; Heavy metals; Liquid metals; Lithium chloride; Magnesium chloride; Metals; Nickel; Sodium; Sodium carbonate; Sodium chloride; Strontium; Tin base alloys; Vacuum distillation
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d3gc03349j

Green metal-electrode batteries call for the clean production of s-block metals. Herein, we developed an electrolysis-displacement-distillation (EDD) approach for producing s-block metals with low-carbon emissions and no chlorine gas evolution. The clean production stems from the choice of a molten NaCl-Na 2 CO 3 electrolyte to prevent chlorine gas evolution, an inert nickel-based anode to produce oxygen, and a liquid metal cathode to make the cathodic product ( e.g. , Na-Sn) sit at the bottom of the electrolytic cell. Later, M-Sn (M = Li, Mg, Ca, Sr, and Ba) alloys were successfully prepared by a displacement reaction between the Na-Sn alloy and molten NaCl-LiCl, NaCl-MgCl 2 , NaCl-CaCl 2 , NaCl-SrCl 2 , or NaCl-BaCl 2 with a displacement efficiency of >96.0%. Furthermore, Li, Mg, Ca, Sr, and Ba metals were separated from M-Sn alloys using vacuum distillation with a separation rate of >95.0%. We achieved a current efficiency of 81.0% for the electrolytic production of 100 kg of a liquid Na-Sn alloy, which holds promise to produce s-block metals at a large scale. This paper describes a new advancement in the field of green energetic metal production, a finding that unlocks access to extracting Li, Mg, Ca, Sr, and Ba metals that are hitherto produced with the generation of Cl 2 and heavy CO 2 .