Method for resource full utilization of sodium chloride waste residue salt by esterification process

Abstract

The invention belongs to the technical field of industrial waste salt slag treatment, and discloses a method for resource full utilization of sodium chloride waste slag salt by an esterification process. The method comprises the following steps: adding acyl chloride and an alkali catalyst into alcohol-containing sodium chloride waste salt slag, stirring and mixing, reacting, and filtering; addingn-hexane into the obtained solution, uniformly stirring and mixing, standing for layering, and recycling the obtained supernatant to obtain an esterification product; and adding a sodium carbonate solution into the obtained lower-layer solution, standing, filtering, drying and recycling obtained filter residues, adding hydrochloric acid into the filtrate, standing, heating for concentrating, separating separated crystals, and drying to obtain purified sodium chloride. According to the method disclosed by the invention, alcohol organic matters in the salt slag are efficiently and thoroughly esterified through normal-temperature treatment, so that the purpose of purifying sodium chloride is achieved, meanwhile, ester substances capable of being recycled are recycled, a technical support is provided for realizing energy conservation and emission reduction in the chemical industry, and sustainable coordinated development of the chemical industry is promoted.

Description

technical field [0001] The invention belongs to the technical field of industrial waste salt slag treatment, and in particular relates to a method for fully utilizing sodium chloride waste slag salt in the esterification method. Background technique [0002] In the production process of many fine chemicals and chemical pesticide products or intermediates, a large amount of by-product waste salt containing toxic and harmful chemicals is produced. For example, every ton of hydrazine hydrate produces 4 to 5 tons of by-products containing Alcohol sodium chloride waste salt slag produces 1.1 to 1.4 tons of by-product sodium chloride salt slag containing toxic and harmful chemicals for every ton of glyphosate pesticide produced, and the production of trimethyl orthoformate produces toxic and harmful chemical substances The by-product of alcohol-containing sodium chloride waste salt slag, the annual by-product of sodium chloride waste salt in the national chemical industry is more ...

AI Technical Summary

Problems solved by technology

However, these methods require pre-drying of waste salt slag and require the particles of waste salt slag to be uniform and as small as possible, and it is very easy to cause blockage and damage to the device

(2) Secondary concentration and crystallization treatment after dissolution and refining: This method is to redissolve the waste salt slag in fresh water, and recycle it after concentration and crystallization after chemical treatment. For example, CN 105883911 B molten salt chlorination slag recycling method, CN103979576 A method for evaporating and crystallizing salt slag from organic waste water containing ammonium sulfate; but these methods have high disposal costs, and secondary waste water is produced, and the effect of physical and chemical treatment after dissolution is difficult to guarantee. The water content of recrystallized salt is high, and some There is a large amount of crystal water, and the secondary use value is low

However, this method uses low-temperature roasting first to convert part of the organic impurities into carbon materials for recovery, but this will inevitably result in higher energy consumption; then, the remaining organic matter in the waste salt is further recovered by using an interface regulator. However, the qualitative and quantitative analysis of the organic matter in it is not carried out, and the organic matter that occupies the dominant position in it cannot be recovered in a targeted manner, resulting in a low recovery efficiency of the final organic matter