Abstract:Using 3mol/L magnesium chloride hexahydrate solution as raw material, the thermal decomposition behavior of the product was studied to select the optimal calcination conditions, and the effects of calcination temperature, holding time, and alkaline preparation conditions on the properties of the product MgO were investigated. The results show that MgO prepared by calcination at 450 ℃ and holding for two hours is regular, but its particle size distribution is uneven and its activity is poor, D50=9.38 μm, and the color development time is 213 seconds. After the introduction of MgO suspension, O2- ions in MgO can rob H+ of H2O to form O-H bonds, and gradually replace O-Mg bonds between MgO molecules, so that MgO suspension continues to grow and develop with [Mg(H2O)6]2+ ion clusters as the core, and finally precipitates to form crystals. When the molar ratio of MgO to magnesium chloride hexahydrate is 0.48 and the reaction temperature is 50 ℃, the product MgO appeares as uniform small particle flake, D50=2.84 μm, and the color development time is 63 s, which has better performance. The results of this study provide valuable enlightenment for the comprehensive utilization of magnesium resources in salt lake and high-quality MgO from salt lakes.