Abstract:XRD, TG-DTA, SEM and chemical detection methods were used to study the roasting decomposition of Baotou rare earth concentrate with magnesium chloride. The results show that under the conditions including roasting temperature of 500 ℃ and addition amount of magnesium chloride of 25%, the bastnaesite in Baotou concentrate can be completely decomposed, and the products are rare earth oxychloride and magnesium fluoride. Under the conditions including roasting temperature of 700 ℃ and addition amount of magnesium chloride of 60%, bastnaesite and monazite in Baotou concentrate can be completely decomposed, and the products are rare earth oxychloride, complex rare earth oxide, magnesium fluoride, and magnesium phosphate. At the same time, The kinetics of thermal decomposition process was calculated. The activation energy required for decomposition of bastnaesite in the first stage is 163.92 kJ/mol, and the reaction order is 1.30; the activation energy required for decomposition of monazite in the second stage is 276.14 kJ/mol, and the reaction order is 0.77. Finally, carbon powder was added when roasting Baotou concentrate with magnesium chloride. When addition amount of carbon powder is 20%, the oxidation rate of cerium is reduced to 1.46%, which has great significance to prevent the oxidation of rare earth.