结晶法提纯钛白副产硫酸亚铁的数学模型与实验研究

摘要

Titanium dioxide production by sulfuric acid processes usually results in the formation of ferrous sulfate. This study used crystallization to purify ferrous sulfate. The impurity segmentation and mass transfer were investigated, and the effects of crystallization time and stirring speed on purification were studied. A numerical model of crystallization purification was proposed based on the solid-liquid boundary layer theory of impurity diffusion. The experimental results indicate that the impurities (Mn, Mg, Zn, Ni) are effectively removed, and the numerical model can be used to predict impurity concentration, especially for impurities with low concentration. The crystallization process is found to be affected by stirring due to the change of the solid-liquid boundary lay between crystal and solution, and thus affects the impurity segmentation, which proves the mass transfer process of impurity.%针对硫酸法生产钛白粉过程中副产的硫酸亚铁，采用结晶法对硫酸亚铁进行了提纯。实验分析了结晶过程中杂质的残留及传质方式，同时考察了结晶次数、搅拌速率对硫酸亚铁结晶提纯的影响，并依据固液边界层扩散传质理论，建立了结晶提纯的理论模型。结果表明，结晶法能有效去除杂质(Mn、Mg、Zn、Ni)；所建立的结晶提纯模型能较好地预测杂质浓度，尤其是低含量的杂质浓度；搅拌通过影响晶体与溶液间的固液边界层，进而影响杂质的残留，从而验证了结晶过程中杂质的传质方式。