<p>The electrolysis of aluminum–silicon (Al–Si) alloys using molten salts offers advantages, including a simplified process, fine alloy grain size, and excellent uniformity. However, the production process often results in the emission of silicon tetrafluoride (SiF₄) gas, which negatively impacts the Al–Si ratio in the alloys. Additionally, it poses significant environmental hazards and endangers the health and safety of workers. In light of these challenges, this study investigated the mechanism of SiF₄ gas generation during the molten salt electrolysis of Al–Si alloys. Experimental results indicated that the primary source of SiF₄ gas was the reaction between aluminum fluoride (AlF₃) and silicon dioxide (SiO₂). At temperatures exceeding 734&#xa0;°C, penta-sodium tri-aluminum tetra-decafluoride (Na₅Al₃F₁₄) decomposed, yielding aluminum fluoride (AlF₃), sodium fluoride (NaF), and cryolite (Na₃AlF₆). The AlF₃ formed through this decomposition subsequently reacted with SiO₂ to generate SiF₄ and Al₂F₂(SiO₄). Subsequently, as the temperature increased, the reaction between Na₃AlF₆ and trace amounts of alumina (Al₂O₃) led to additional AlF₃ formation. Furthermore, the generation of SiF₄ gas was influenced by several factors, including the molecular ratios in the system, as well as SiO₂ and Al₂O₃ additions. The study of the mechanism underlying SiF₄ gas generation during the production of Al–Si alloys offers a theoretical foundation for the reduction of harmful SiF₄ emissions. This not only improved product quality but also enhanced workplace safety and environmental protection.</p> Graphical Abstract <p>This paper investigates the mechanism of SiF₄ gas generation during the molten salt electrolysis of aluminum–silicon alloys in the Na₃AlF₆–AlF₃–Al₂O₃–SiO₂ electrolyte system, providing important theoretical foundations for controlling the aluminum–silicon ratio and reducing SiF₄ gas emissions during the production of aluminum–silicon alloys.</p> <p></p>