Abstract: Micromixing of reactant is the controlling step in the reaction precipitation process because chemical reaction of the formation of sparingly soluble materials is generally very fast, which would lead to uneven supersaturation distribution at the macro-level. This results in wider crystal size distribution. In order to eliminate the effect of micromixing on crystal size distribution, micromixing must be complete prior to nucleation and growth of crystal to acheve uniformity of supersaturation distribution. A new method for preparing monodispersed nanopowder is proposed. In this method, the effect of reactant micromixing on precipitation is effectively resolved in terms of the supersaturation metastable zone principle that there is a metastable zone for supersaturation and its width can be altered. The nanopowder of strontium sulfate was prepared by using this method. The morphology of crystal was observed and the particle size and particle size distribution were measured by TEM and multi-angle sub-micron particle size analyzer. The phase of matter and purity were characterized by X-ray powder diffraction. The result showed that particle size distribution of the nanopowder prepared with this method was very narrow and powder morphology was identical. In terms of the phenomenological level, the mechanism of the action of EDTA and alcohol in the reaction system was assumed.

摘要： 利用过饱和溶液存在介稳区且其宽度可调节的原理,使反应物在沉淀形成前充分微混,制备出纳米硫酸锶粉体.分析了反应条件的改变对产品粒径和粒度分布的影响,利用正交试验确定适宜的工艺条件.产品用TEM及X射线粉末衍射进行表征,并测定其粒度分布.结果表明：通过改变溶液介稳区宽度可以制备粒度分布窄、晶型一致的纳米硫酸锶粉体.并从唯象层面上推测了向反应体系中加入EDTA和乙醇的作用机理.