Novel Efficient Reduction Route for Magnesium Production Using Silicothermic Process

Abstract

A novel efficient reduction route was developed for preparing porous pellets to enhance mass transfer during magnesium production, which can improve the reactivity of pellet reaction to improve the reduction efficiency. A porous pellet precursor was prepared at 150 MPa using NH4HCO3 as a pore-forming agent, and the reaction characteristics of the pellets with 0, 5%, 10%, 20%, and 30% pore-forming agents were measured under a high vacuum of approximately 10 Pa heat-treated from 100 °C to 1400 °C. The results showed that the instantaneous maximum reduction rate first increased and then decreased with the increase in pore-forming agents. When the reduction conversion was 80%, the reduction efficiency of pellets with 5% pore-forming agent was 36% greater than that without pore-forming agent pellets. When the reduction conversion was 90%, the reduction efficiency of pellets with 5% pore-forming agent was 29% greater than that without pore-forming agent pellets. The results indicate that the diffusion rate of magnesium vapor in pellets is significantly increased; the time of chemical reaction reaching equilibrium is shortened; the chemical reaction rate and the magnesium production efficiency are increased by adding a proper ratio of NH4HCO3 compared to that obtained without NH4HCO3 at the identical reduction temperature.