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以MgCl2·6H2O、NH3·H2O原料,分别使用液相沉淀法合成氢氧化镁粉体及以乙醇/水为溶剂,使用溶剂热法合成十二烷基苯磺酸钠(SDBS)修饰的氢氧化镁粉体,利用不同升温速率的热重及差热分析研究两种方法制备氢氧化镁的热分解动力学。研究表明,两种氢氧化镁在560~700 K均有一个明显的吸热峰,利用Doyle-Ozawa法和Kissinger法分别计算了两种氢氧化镁的表观活化能,用Kissinger法确定反应级数和频率因子,并给出了氢氧化镁热分解的动力学方程。使用液相沉淀法合成的氢氧化镁的平均表观活化能为157.18 kJ·mol-1,而溶剂热合成SDBS修饰氢氧化镁的平均表观活化能高达175.66 kJ·mol-1。
MgCl2 · 6H2O, NH3 · H2O raw materials were synthesized by liquid-phase precipitation of magnesium hydroxide powder and ethanol / water as solvent, the use of solvothermal synthesis of sodium dodecyl benzene sulfonate (SDBS) modified hydroxide Magnesium powder, the thermal decomposition kinetics of magnesium hydroxide prepared by the two methods were studied by TG and DTA at different heating rates. The results show that both magnesium hydroxides have a distinct endothermic peak at 560-700 K. The apparent activation energies of two magnesium hydroxides are calculated by Doyle-Ozawa method and Kissinger method. The Kissinger method is used to determine the reaction order Number and frequency factor, and gives the kinetic equation of magnesium hydroxide thermal decomposition. The average apparent activation energy of magnesium hydroxide prepared by liquid-phase precipitation method was 157.18 kJ · mol-1, while the average apparent activation energy of the hydrothermal synthesis of SDBS-modified magnesium hydroxide was as high as 175.66 kJ · mol-1.