EFFECT OF ARGON FLOW RATE ON THE CONDENSATION OF MAGNESIUM VAPOR FROM CARBOTHERMIC REDUCTION OF MAGNESIA

摘要

To increase both the recovery rate and purity of magnesium in carbothermic reduction process, magnesium vapor was condensed in a certain concentration of argon to avoid the occurrence of reverse reaction of CO and magnesium vapor. A cylinder by pressing a mixture of graphite and MgO with a molar ratio (2:1) was reacted at 1723K for 2.5h in an vacuum atmosphere of 1(±0.05) KPa. Then the mixture was cooled in different flow rates of argon atmosphere at a constant cooling rate. The condensation products were collected and characterized by XRD and SEM/EDS. The results show that increasing the argon flow rate enhanced diffusion of magnesium vapor and CO, meanwhile, diluted the CO concentration resulting in restraining the adverse reaction. The recovery rate of the condensation product reached a maximum of 95.6% with magnesium (strip-like) purity of 94.8% when the argon flow rate was 3.5 L/min.