铁黄合成体系流变特性

RHEOLOGICAL BEHAVIOR OF ULTRAFINE a-FeOOH PARTICLE SYNTHESIS PROCESS

针对碱法铁黄制备过程，研究了体系的流变特性．在反应初期铁黄合成体系粘度较小，随反应进行体系粘度显著增大，在反应中后期反应液为满足幂指数规律的假塑性流体，并具有很强的剪切稀化行为．反应温度、碱比、搅拌转速和通气量等通过改变粒子的生成过程和粒子的形态来改变铁黄合成体系的流变特征．在铁黄合成体系中加人硅酸纳会使体系粘度显著下降，流变特性随之发生变化．

The rheological properties in synthesis process of ultrafine а-FeOOH particle were inves tigated with RFS-Ⅱand concentric bob and cup measuring system.The results indicated that the rheological properties of the reaction slurry were mainly determined by formation mechanism and morphology of goethite.The reaction slurry was Newtonian liquid with low viscosity at the initial stage of goethite synthesis process,and was psuedoplastic fluid which fits power law at the middle-later stage.Thit slurry showed strong shear-thinning characteristic without thixtropy.The rheological properties were affect ed by reacion temperature,gas flow rate and stirring rate etc.which affected the formation process and particle morphology.The viscosity of the reaction slurry decreased strongly with doping NaSiO_3 in the synthesis system.