水热改性对氢氧化镁的影响

Effect of hydrothermal modification on magnesium hydroxide

为了提高氢氧化镁的使用性能,以轻烧粉为原料,并与氨水反应制得氢氧化镁,再以氢氧化钠为介质,经水热处理制备得到高纯氢氧化镁.采用扫描电子显微镜(SEM)、X射线荧光光谱仪(XRF)、X射线衍射仪(XRD)对制备的样品进行表征.结果表明,升高温度与延长水热时间有助于改善颗粒的晶形和尺寸,添加氢氧化钠可以显著改变晶体的生长方式.当反应温度为220℃、反应时间为12 h、氢氧化钠含量为6 mol·L-1时,氢氧化镁的极性较弱、形貌规则、分散性良好、结晶度高,其纯度可高达99.94%,且收率为87.92%.

In order to improve the service performance of magnesium hydroxide, the magnesium hydroxide was prepared through taking light calcined powder as raw material and reacting with ammonia water. Then through taking sodium hydroxide as medium, the high purity magnesium hydroxide was obtained with hydrothermal treatment. The prepared samples were characterized with scanning electron microscope （SEM）, X ray fluorescence spectrometer （XRF） and X ray diffractometer （XRD）. The results show that with increasing the temperature and prolonging hydrothermal time, the crystal shape and size of particles can be improved, and the way of crystal growth can be significantly changed by adding the sodium hydroxide. When the reaction temperature is 220 ℃, the reaction time is 12 h and the sodium hydroxide concentration is 6 mol·L^-1, the magnesium hydroxide has weak polarity, regular morphology, good dispersion and high crystallizability. Moreover, the purity of magnesium hydroxide is over 99.94%, and the yield is 87.92%.