天然气还原热解硫酸镁制备高纯氧化镁

利用盐湖氯化镁和硫酸制备七水硫酸镁,将七水硫酸镁脱水得到无水硫酸镁.采用天然气还原热解无水硫酸镁得到高纯氧化镁.通过单因素实验考察了还原热解温度、热解时间、硫酸镁的粒径和天然气气体流量对硫酸镁转化率的影响,通过正交试验优化了还原热解的条件.采用X射线衍射和扫描电镜对还原热解产物进行分析和表征.氧化镁的最佳制备条件:热解温度为1000℃,热解时间为30min,硫酸镁粒径为75μm,天然气气体流量为25mL·min^-1.温度是影响硫酸镁转化率的主要因素.在最佳制备条件下,硫酸镁的转化率达到99.27%,氧化镁的纯度达到99.5%,制取的氧化镁单分子均匀,表面为多孔蓬松,具有高比表面积.

Preparation of high-purity magnesia from magnesium sulfate by natural gas reduction pyrolysis

Magnesium sulfate heptahydrate was made from salt lake magnesium chloride and sulfuric acid, then anhydrous magnesium sulfate was obtained from magnesium sulfate heptahydrate by dehydration, and finally high-purity magnesia was prepared from anhydrous magnesium sulfate by natural gas reduction pyrolysis. The effects of pyrolysis temperature, pyrolysis time, particle size, and gas flow rate on the conversion rate of magnesium sulfate were investigated by single factor experiment. These experimental parameters were optimized by orthogonal experiment. The reduction pyrolysis product was analyzed and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optimal experimental parameters are as follows:the pyrolysis temperature is 1000℃, the pyrolysis time is 30 min, the particle size of anhydrous magnesium sulfate is 75 μm, and the flow rate of natural gas is 25 mL·min-1. The pyrolysis temperature is the main factor which influences the conversion rate. Under the optimal condition, the conversion rate of magnesium sulfate reaches 99.27%, and the purity of magnesia is 99.5%. The unimolecular MgO features well-distributed particle size, porous and fluffy surfaces, and high specific surface area.