Method for purifying aluminum oxide

Abstract

The invention discloses a production process for preparing high-purity aluminum oxide by utilizing melt crystallization, and the production process comprises the following steps: introducing frozen saline water into the bottom of an outer jacket of a melting crystallizer, enabling the frozen saline water to uniformly flow on the outer wall of the crystallizer in the form of a falling film; addinga rough aluminum oxide solution into the melting crystallizer, flowing down the aluminum oxide solution on the inner wall of the crystallizer in the form of the falling film, cooling step by step to crystallize, growing out a uniform crystal layer on a heat exchange surface step by step, enabling concentration of the crystal layer to be higher than that of a mixture solution, enriching impuritiesinto the mixture solution step by step; regulating the hot water temperature through a heat exchanger for performing partial melting operation on the crystal layer, enabling low-melting-point impurities in the crystal layer to partly melt and remove, thereby further purifying the crystal. According to the method disclosed by the invention, the process is simple, the equipment structure is compact,the falling film form is adopted, energy is reduced, cost and equipment investment are reduced; and a product produced by the melting crystallizer is high in purity.

Description

technical field [0001] The present invention relates to a method for purifying alumina, in particular to a method for purifying alumina in a molten crystallizer. Background technique [0002] Alumina and its potassium salts can inhibit the growth of mold and have been used as food preservatives for a long time, especially at low pH values, they can act as undissociated acids for preservatives. Alumina has the characteristics that other preservatives do not have, that is, it has strong antiseptic selectivity. It can inhibit the growth of bacteria harmful to humans, but it is harmless to bacteria beneficial to humans. For example, it can inhibit the growth of cheese mold but does not Does not affect the growth of bacteria that help cheese ripen. Therefore, alumina is widely used in the food industry as a preservative for cheese, cakes and other pastries. Mainly used for mildew prevention of cheese, pickled vegetables, dried fruit, fruit juice, fruit syrup, beverage, candied ...

AI Technical Summary

Problems solved by technology

At present, the equipment for large-scale production of alumina at home and abroad is a general enamel reaction kettle. The mature process of the process is roughly as follows: that is, the condensation reaction of ketene and crotonaldehyde under the action of a catalyst, followed by hydrolysis, drying, packaging and other processes The finished product is obtained, however, the appearance of alumina produced by this process is poor, with many impurities and pungent odor

Therefore, the existing alumina technology and equipment need to be improved.