A New Method to Produce High-Purity Magnesium with a Low Aluminum Content

Magnesium is commonly used as a reducing agent to produce sponge titanium. And the aluminum impurities in magnesium will contaminate titanium, increasing the difficulty of producing high-purity electronic-grade titanium. Although our previous research has shown that eliminating the use of fluorite can effectively reduce aluminum impurities in the magnesium produced by silicothermic process, it also causes an increase in cost. Therefore, it is crucial to explore a new method to produce low aluminum magnesium in a cost-effective way. Since removing the sticking slag on the retort outlet is a long-standing challenge in industry, we analyzed its composition and found a substantial presence of Ca-Al-F-O compounds. Inspired by this observation, we propose a novel method that utilizes CaO to induce the deposition of aluminum impurities. Thermodynamic analysis confirms the feasibility, and experimental results demonstrate aluminum removal rates exceeding 90%. These findings pave the way for the cost-effective production of low aluminum high-purity magnesium.