摘要：用水镁石矿粉矿作原料,用差热-热重分析和动态高温X射线衍射法研究水镁石的热分解过程,以及在不同温度和保温时间下的相变机理。结果表明:400℃是Mg(OH)₂向MgO转变的相变点,水镁石在450～800℃的升温区间,产物均为纳米级MgO粉体,其晶粒度由23 nm增加到176 nm。水镁石在900℃下煅烧3 h,Mg(OH)₂已经完全分解为MgO,杂质主要存在形式是CaMgSiO₄和Mg₂SiO₄,约占总质量的2%左右。

关键词： 水镁石；动态高温X射线衍射；热分解

Abstract：The differential thermal analysis and dynamic high-temperature X-ray diffraction were applied to study the phase-change mechanism of thermal decomposition process of brucite at different temperatures and holding time. The experimental results indicated that 400 ℃ was the phase transition point of Mg（OH)₂to MgO and with the temperature increasing from 450 ℃ to 800 ℃， the nano-sized MgO particles were produced， and their crystal grain size increased from 23 nm to 176 nm. When the brucite powders were calcinated at 900 ℃ for 3 h， Mg （OH)₂was completely decomposed into MgO and the impurities were mainly CaMgSiO₄ and Mg₂SiO₄， the mass fraction of them was about 2 %. 

Keywords： brucite； dynamic high-temperature X-ray diffraction； thermal decomposition