The refractory steel retort used in the thermal magnesium production industry works in a high temperature of 1200 °C under high vacuum condition for a long time, with a service life of only about 2 months. Frequent replacement of the reduction retort results in high production costs for thermal magnesium production. The fundamental reason for the instability and deformation of refractory steel reduction retort is high temperature creep, while silicon carbide material has very strong creep resistance and high thermal conductivity at high temperature. Therefore, the silicon carbide material is introduced into the field of thermal magnesium production in this paper. Based on the structural size of the traditional reduction retort, the silicon carbide straight fin reduction retort is designed, and the coupling characteristics of heat and mass transfer and chemical reaction in the silicon carbide straight fin reduction retort are studied by numerical calculation. The results show that the silicon carbide straight fin reduction retort can effectively improve the pellet temperature rise rate, and the minimum temperature in the initial stage is about 700 °C higher than that of the traditional refractory steel retort. The average magnesium production rates of the silicon carbide straight fin reduction retort with 2, 3 and 4 fins are 4.81, 5.89 and 6.91 kg/h, respectively, which are 37 %, 68 % and 97 % higher than that of the traditional retort with 3.5 kg/h. To further improve the production efficiency, a silicon carbide double loop straight fin reduction retort was designed, and the energy saving, emission reduction and carbon reduction potential of this silicon carbide double loop straight fin reduction retort used in thermal magnesium production industry was quantitatively analyzed. The average magnesium production rates of the silicon carbide double loop retort with a fin height of 150 mm and a fin number of 6, 8 and 12 are 5, 5.88 and 8.93 kg/h respectively, which increased the production efficiency by 43 %, 68 % and 155 % respectively compared with the traditional retort. The overall effect of increasing fin height and number on magnesium production rate was to prolong the peak time of production, so that most of the magnesium production work was completed in a short time. The research results in this paper provide a scientific basis for the application of silicon carbide materials in thermal magnesium production industry and a new way for energy saving and carbon reduction.