Numerical Simulation Study On The Reactive Crystallization Process Of Cerium Carbonate

Cerium oxide polishing powder because of its advantages of excellent polishing performance and longer service life, has replaced the alumina and ferric oxide polishing powders, so well it is widely used in inpolishing industry. In this article,we use CFDsoftware to simulate and optimizate the crystallizer structure according to the characteristics of cerium carbonate optimization and process parameters; Simulatiing the process of reaction of cerium chloride and ammonium hydrogen carbonate formation of cerium carbonate particles, effect of cerium carbonate particles dispersion factor.Using multiphase flow model, standard k-ε model and multiple reference frame to simulate the flow field of fliud in three-dimensional DTB mold. The concentration distribution of particles and the mixing time, velocity distribution and shear rate distribution as the index, structure and process parameters of mould was optimized, mainly inspects the feeding blade installation location, height, and stirring speed on the mold of cerium carbonate particles dispersion characteristics influence. Through the simulation calculation shows that: in the blade near the feed, blade height is H/3, the mixing effect of particles; for the stirring speed, needs to be analyzed according to the specific hybrid properties of particles, stirring speed is greater than the calculated by the critical speed of particles suspended.Using multiphase flow model,standard k-ε model and multiple reference frame, to simulate the cerium chloride and ammonium hydrogen carbonate reaction process of two-dimensional mold. The velocity distribution of the size of the region and the reaction resultant cerium carbonate particles and chemical reaction zone by shear rate distribution as index, the process operation parameters were optimized, mainly inspects the dispersion speed, reactant concentration on the chemical reaction of cerium carbonate particles mixing effect. Through the simulation calculation shows that: the appropriate increase of stirring speed can increase the uniformity of resultant cerium carbonate particle size; along with the increase of reactant concentration, the reactant mass fraction of CeCl3is0.306, the mass fraction of NH4HCO3is0.408, the highest amount of cerium carbonate particles, the reaction efficiency is the highest, with increasing mass fraction of the reactant continue, cerium carbonate content and reaction rate of reaction decreased.