The Distribution Of Impurity In The Process Of Aqueous Solution Quasi Static Crystallization

Crystallization which is a kind of typical chemical engineering unit operation plays an important role in the process of separation and purification of products. With the rapid development of economy, the request of the purity of all kinds of materials is higher and higher, thereby, it promotes the development and application of the industrial crystallization technology. At present, our country for the research of aqueous solution crystallization process is less, so the research of the impurity migration in aqueous solution has high innovation and exploration value. And through the study of the impurity migration in the process of aqueous solution crystallization, the process parameters which we get can be applied to other production process, with wide application value.-This paper added univalent and bivalent inorganic salt impurities of different concentration into deionized water:NaCl, NaN03, Na2SO4, Na3PO4, MgCl2, MgSO4,then put it into low temperature cooling fluid circulation pump, set the highest temperature for-10℃, the lowest temperature for-15℃, researched the impurity distribution in the process of quasi static crystallization. From horizontal and vertical impurity distribution to discuss the effect of different impurities, different concentration of impurity on the migration rate, as well as the effect of different diameter height ratio experiment device on the migration rate. In the process of crystallization used many paths temperature recorder to record the temperature change of different time. The concentration of the solution after the quasi static crystallization was measured by atomic absorption spectral instrument.The result showed that impurities migrated to the center and below in the process of quasi static crystallization. With the concentration of impurity decreasing, the migration rate of impurity was bigger. When the cationic of impurities were the same, those whose anionic charge were smaller had bigger migration rate. The diameter height ratio of experiment device was bigger, the impurity migration rate was bigger.