Abstract: Magnesium hydroxide nanoparticles were prepared via ordinal precipitation method, reverse precipitation method, double precipitation method and high-gravity precipitation method using magnesium chloride hexahydrate as raw material and sodium hydroxide as precipitant. The settling velocity was selected as the index to investigate the effects of different preparation methods on the settlement property of magnesium hydroxide slurry. The morphology, particle size and its distribution, and crystal phase of the samples were characterized by transmission electron microscope (TEM), laser particle size analyzer (LPSA), and X-ray diffractometer (XRD), respectively. The results showed that the settling velocity increased evidently via high-gravity precipitation method, which was 4.7 times, 12.4 times and 2.1 times of that by the ordinal precipitation method, reverse precipitation method and double precipitation method. It was also found that the samples prepared by high-gravity precipitation method were hexagonal flake-like shape with narrow particle size distribution, high purity and good dispersity.

Key words: liquid precipitation method, high gravity, sedimentation, magnesium hydroxide, slurry

摘要： 以六水氯化镁为原料,氢氧化钠为沉淀剂,分别采用正向沉淀法、反向沉淀法、双向沉淀法和超重力沉淀法制备了纳米氢氧化镁,以沉降速度为评价指标,考察了制备方法对氢氧化镁料浆沉降性能的影响.利用透射电子显微镜(TEM)、纳米激光粒度分布仪、X射线衍射仪(XRD)对产物的形貌、粒径、粒径分布和晶型进行表征.结果表明,采用超重力沉淀法,氢氧化镁料浆的沉降速度明显加快,分别是正向沉淀法、反向沉淀法、双向沉淀法的4.7倍、12.4倍、2.1倍;所得氢氧化镁的分散性好,纯度高,粒度分布均匀并呈六方片状晶体.

关键词: 液相沉淀法, 超重力, 沉降, 氢氧化镁, 浆料