Measurment Of The Basal Crystallization Data And A Study On The Crystallization Technology Of Folic Acid

Folate (folic acid) is an important basic vitamin, whose demand is rising. But more waste, poor product quality, technical backwardness and other problems hinder folic acid production.Crystallization as the final step in the production of folic acid refining process, is a key step to ensure product quality. The data and process of folic acid crystallization were studied in this paper.Crystal habit is an important issue in crystal quality, because it has main impact on the downstream processings(such as filtering, washing and drying) and the quality of the final product. The crystal habit were observed under microscope. And the effects of the crystal methods on crystal habit were studied. Alkali recrystallization method is selected to get ideal leafy crystal products.Crystallization thermodynamics is the fundamental basis for operating and determining the yield of crystallization. The solubilities of folic acid at different temperatures in pure water were measured and researched the impact of salts on them. Then the solubilities and supersolubilities of folic acid in different pH aqueous solutions at different temperatures were studied by the static method and the laser method. The fitting curves of the metastable zone data is established. Other basic physical constants of folic acid are also measured such as viscosity, density, and dissociation constants, which are the basis data for crystallizer design. According to the nucleation theory using the induction period data to estimate the surface tension and surface entropy factor data, inferred that folic acid crystal growth model was continuous growth mode. According to the nucleation theory, the interfacial tension and entropy factor were estimated by the induction period data, and then inferred folic acid crystal growth model was continuous growth mechanism.The operating conditions, including acid addition rate, acid concentration, crystallization temperature, initial concentration, and filtration, were optimized by examing the quality (crystal form, CSD) and yield goals.