Method for treating and recycling waste water in anthranilic acid production technology

Abstract

The invention discloses a method for treating and recycling waste water in an anthranilic acid production technology. Through the adoption of the method provided by the invention, waste water in the anthranilic acid production technology can be treated, and recycled organic substances can be directly subjected to cyclic utilization; the CODCr being about 24000 mg / L of waste water before treatment is reduced to 80 mg / L below after treatment to reach the national-level emission standard; coarse sodium chloride salt can be recycled; resin is subjected to desorption and regeneration by using 4-6% of dilute sodium hydroxide solution or dilute hydrochloric acid, and a desorption solution can be taken as raw materials to be input in the acidizing step or degrading step of the original production technology, so that the product quality is not affected, 99% of anthranilic acid and phthalimide in the waste water can be recycled, and distilled effluent can be utilized repeatedly; waste water can be treated while the waste recycling can be realized.

Description

technical field [0001] The invention relates to a process wastewater (CODc) produced by degrading and acidifying phthalic anhydride and urea to produce phthalimide as raw materials to obtain anthranilic acid. r 23000~24000mg / L) treatment and recycling method for recovering organic matter. Specifically, it is the recycling of organic matter anthranilic acid and phthalimide in process wastewater, and at the same time realizes the purification and reuse of wastewater or discharges up to the standard, and finally realizes the treatment and protection of anthranilic acid production process wastewater. resourceful. Background technique [0002] The synthetic route applicable to this method is to use phthalic anhydride and excess urea as starting materials for amidation to obtain phthalimide, and then degrade it with sodium hypochlorite under alkaline conditions to obtain sodium anthranilic acid , to obtain anthranilic acid after acidification with hydrochloric acid, the main pri...

AI Technical Summary

Problems solved by technology

Each ton of product will produce 15-18m of waste water 3 , the wastewater is reddish brown, CODc r 23000-24000mg / L, of which phthalimide is 7800-8100mg / L, the content of anthranilic acid is 6000-6500mg / L, and the content of sodium chloride is 100-120g / L. The salt content is high. The current treatment method is mainly to concentrate the process wastewater and treat it as a hazardous solid waste. Not only the treatment cost is high, but also the expensive phthalimide, anthranilic acid and Sodium chloride; or use ethyl acetate extraction method to recover, the recovery rate is only about 63%, and the consumption of ethyl acetate is relatively large, and the energy consumption is relatively high, so there is no economical and effective treatment method for the waste water of this process so far

[0010] Invention patents such as Zhao Yuming (ZL200610041529.3) adopted weakly basic ion exchange resins or styrene-divinylbenzene type strong polar resins, and proposed a method for reclaiming anthranilic acid from mother liquor or waste water. What the invention relates to is a kind of process waste water (CODc r 23000~24000mg / L), containing a large amount of inorganic salts, so the process of ion exchange adsorption cannot realize the resource utilization of anthranilic acid and phthalimide in wastewater

[0011] The invention patent applied by Meng Fanqiu and others (application number 201110073494.2) relates to a preparation method for recovering anthranilic acid from methyl anthranilate mother liquor wastewater, which is based on the mother liquor wastewater generated during the production of methyl anthranilate and the saccharin production process. The waste acid water that produces obtains anthranilic acid through preparation of copper salt, alkali dissolution, pressure filtration, decolorization, acid analysis, suction filtration, and drying. process wastewater

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