Abstract:High-silicon magnesite, with its high silicon content, fails to meet the raw material requirements for magnesium refractory materials and is currently regarded as solid waste without effective utilization. The silicothermal method for smelting metallic magnesium from high-silicon magnesite presents an effective approach to the recycling and valorization of solid waste resources. Magnesium smelting experiments were carried out with high silicon magnesite as raw material under high temperature and vacuum environment, and the reaction mechanism was studied by XRD and SEM-EDS. The results indicate that the reduction temperature has a significant impact on the experiment. When the reduction temperature is below 1 000 ℃, the reduction reaction is hardly to occur. In the process of magnesium smelting from high-silicon magnesite, a series of reactions occur, starting with the generation of Ca3SiO5 followed by the formation of intermediate phase CaSi2 and ultimately resulting in the production of Ca2SiO4. The results of reaction kinetics reveal that the average apparent activation energy is 383.05 kJ/mol in the process of magnesite smelting, and demonstrating the three-dimensional phase boundary reaction characteristic of interface spherical shrinkage.