Production of magnesium during carbothermal reduction of magnesium oxide by differential condensation of magnesium and alkali vapours

摘要

Most of researchers believed that the developments on the condensation of magnesium produced by carbothermic reduction just concentrated on two process routes: the “quench” route and the “solvent” route. But this paper will briefly analyzes the major challenges in magnesium vapor condensation during the vacuum carbothermic reduction of calcined dolomite, on equipment upgrade, heat transfers alter, to achieve condensation control and production collection. Solutions are then proposed using theoretical calculations and experiment results. Comparative analysis of the experiment results shows that the burning and even explosion of condensation products during the vacuum carbothermic reduction of calcined dolomite are mainly due to the burning of crystallized powder magnesium, which results from the self-ignition of alkali metals. Finally, this paper proposes a multistage condensation solution to improve traditional vacuum condensation equipment. And result show that the condensation equipment can effectively mitigate the burning and loss during condensation, also the morphology of the condensation products clearly improved, the grain size increased, and the oxidation rate decreased. The potassium/sodium vapor and the magnesium vapor were separately condensed.