Purification method for industrial byproduct salt and purification device therefor

Abstract

The invention belongs to the technical field of the purification of sodium chloride, and particularly relates to a purification method for industrial byproduct salt and a purification device for industrial byproduct salt. The purification method comprises the following steps of: mixing industrial byproduct salt with a sodium chloride water solution to obtain a turbid liquid; adding aqueous alkali into the turbid liquid to obtain a mixed solution with the pH value of 7-8, inputting the cleaning saturated sodium chloride water solution into a lower layer of the mixed solution, and overflowing the upper-layer solution of the mixed solution to obtain an overflowing liquid; sequentially filtering the overflowing liquid through a filter screen, an oil-water separator and a film to obtain the cleaning saturated sodium chloride water solution; and inputting the obtained cleaning saturated sodium chloride water solution into a lower layer of the mixed solution for washing in a recycling way to obtain the pure white sodium chloride particles, and carrying out the solid-liquid separation to obtain the high-purity industrial sodium chloride solid. The organic matters separated out of the method can be recycled. The method comprises the step of washing in a recycling way by saturated salt water, so that the yield of sodium chloride can be improved, and discharge of wastewater is avoided, and the consumption of heat energy is not needed.

Description

technical field [0001] The invention belongs to the technical field of sodium chloride purification, and in particular relates to a purification method and a purification device for by-product sodium chloride in the production process of dibenzoylmethane (DBM). Background technique [0002] The synthesis process of dibenzoylmethane (DBM) is to use methyl benzoate and acetophenone as raw materials, use ethanol / sodium ethylate as catalyst, and use xylene as solvent to carry out synthesis and preparation of cresenone ester condensation. With the increase of production scale, a large amount of sodium chloride by-products are produced in the production process. Since the reaction is carried out in xylene solvent, a certain amount of organic matter, such as xylene and DBM, adheres to the surface of the by-product sodium chloride solid particles. The appearance is light yellow, with a strong pungent odor, and the pH range is 1 ~2 between. This large amount of sodium chloride by-p...

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Problems solved by technology

[0004] The calcination method is to calcine the by-product sodium chloride in a kiln at high temperature, so that the organic matter adhering to its surface is completely oxidized into carbon dioxide and water, while the sodium chloride remains unchanged during the calcination process, so as to achieve the purpose of purification; this method The disadvantage is that calcination consumes a lot of energy, and at the same time, it is accompanied by the generation of waste gas during the calcination process.

[0005] Dissolution and recrystallization is to completely dissolve the by-product sodium chloride in the aqueous solution, while the organic matter is insoluble in water, and obtain an aqueous sodium chloride solution without organic matter through the separation of oil and water, and then concentrate and crystallize the aqueous solution to achieve The purpose of purification; the disadvantage of this method is that it needs to use a lot of water and consume a lot of heat in the process of concentration

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