Preparation method of sodium citrate crystal through solvent-out crystallization

Abstract

The invention relates to a preparation method of sodium citrate crystal through solvent-out crystallization. The preparation method comprises the following steps: (A) carrying out salt-forming reactions: preparing critic acid and a salt forming agent according to a certain mole ratio, dissolving the salt forming agent into water at first, then slowly adding critic acid into the water, controlling the reaction temperature at a range of 20 to 30 DEG C, wherein the pH value of the solution is in a range of 7.5 to 9.0 when the reactions finish, and filtering the solution after the reactions so as to obtain a mixed solution, wherein the mixed solution concentration calculated by waterless sodium citrate is 285 g/L to 570 g/L; (B) carrying out solvent-out crystallization: adding a solvent-out agent into the mixed solution obtained in the step (A) according to a certain volume ratio to crystallize the sodium citrate crystals, and controlling the crystallization temperature at 20 to 75 DEG C; (C) filtering and drying so as to obtain the sodium citrate product; wherein the sodium citrate product comprises waterless sodium citrate, dihydrate sodium citrate, and pentahydrate sodium citrate. The provided preparation method is simple and convenient, the yield is high, the crystal is large, the purity is high, and the sodium citrate quality is largely improved.

Description

technical field [0001] The invention relates to an industrial preparation method of sodium citrate, in particular to a method for preparing sodium citrate by a dissolution and crystallization method. Background technique [0002] Sodium citrate is a white or colorless organic compound crystal, which is widely used in food, beverage, chemical and pharmaceutical fields. It can be used as flavoring agent, buffer, emulsifier and stabilizer in food, and can also As a blood anticoagulant in medicine, an acidity buffer for body fluids and urine, etc., the current production of sodium citrate is to use calcium citrate salt neutralization method and ion exchange to prepare sodium citrate, and then the obtained sodium citrate After purification, the finished product of sodium citrate is obtained. [0003] The existing industrial preparation of sodium citrate generally adopts the crystallization method of evaporating and concentrating mother liquor, that is, heating and concentrating ...

AI Technical Summary

Problems solved by technology

[0003] The existing industrial preparation of sodium citrate generally adopts the crystallization method of evaporating and concentrating mother liquor, that is, heating and concentrating the mother liquor of sodium citrate to precipitate crystals. This method needs to evaporate a large amount of water, and has the problems of high energy consumption and low efficiency. The mother liquor contains high iron and other metal ions, a small amount of easily carbonized substances such as protein colloids and organic impurities, and these impurities are likely to remain in the product with heat and water loss, making the color of the sodium citrate mother liquor darker, Viscosity becomes bigger, and then affects the quality of gained sodium citrate product