螺旋通道型旋转床可控制备超细氢氧化镁

用螺旋通道型旋转床(rotating bed with helix channels,RBHC),采用超重力法制备了分散均匀的片状超细氢氧化镁.考察了加料方式对产品分散性的影响及氨镁摩尔比对产品的收率和形貌的影响.通过扫描电镜、激光粒度仪、X射线衍射仪、热重-差热分析仪对样品进行表征.结果表明:采用反向加料可较好改善片状氢氧化镁的分散性;当氨水与氯化镁摩尔比为6:1时样品为规则六方片状,平均粒径为0.7 μm;用RBHC超重力法能可控地制备出超细氢氧化镁,与传统搅拌釜反应沉淀法相比,反应时间缩短至原来的1/8,生产能力至少增加7倍.

CONTROLLABLE PREPARATION OF SUPERFINE PARTICLES OF MAGNESIUM HYDROXIDE BY ROTATING BED WITH HELIX CHANNELS

The lamellar superfine particles of magnesium hydroxide were prepared in a rotating bed with helix channels (RBHC). Some parameters (such as addition method and mole ratio of NH_3 to Mg~(2+) ) on the yield and morphological structure were investi-gated. The prepared product was characterized by scanning electron microscope, laser granularity tester, X-ray diffraction and ther-mogravimetric analysis-differential scanning calorimetry. The results show that the particles with the hexagonal plate morphology and the average size of 0.7 μm can be obtained when the mole ratio of NH_3 to Mg~(2+) is 6:1. The dispersion of the particles obtained by the RBHC is improved. Compared to the conventional stirring method, the RBHC method can shorten the reaction duration to 1/8 of the original and increase the productivity at least 7 times.