Thermodynamic Analysis Of Mg-Li Alloys Preparation By A Vacuum Carbothermic Reduction Method

A new preparation method of Mg-Li alloys by vacuum carbothermic reduction was proposed. The thermodynamics of the reduction reactions were analyzed and the equations of the reduction reactions, the Gibbs free energy and critical temperature of reactions have also been studied. The results show that vacuum carbothermic reduction producing Mg-Li alloys is thermodynamically feasible. Under the condition of other factors unchanged, with the increase of vacuum degree and reaction temperature, the Gibbs free energy of reduction reaction declines. Under the same vacuum degree condition, the critical temperature of the vacuum carbothermic reduction producing Mg-Li alloys is lower than that of producing metallic Mg or metallic Li, and the reaction is easier. When the vacuum degree is 10 Pa and the relative proportion of Li2O is 0.1, the critical temperature of the vacuum carbothermic reduction producing Mg-Li alloys is 1345 K. Under the reaction temperature (about 1473 K) and vacuum degree (about 13.3 Pa) of conventional Pidgeon process (producing metallic magnesium by vacuum silicothermic reduction) conditions, no matter what the relative proportions of magnesium oxide and lithium oxide in the hybrid system, the vacuum carbothermic reduction producing Mg-Li alloys is thermodynamically feasible.