A process for recovering glyphosate mother liquor

Abstract

The application discloses a glyphosate mother liquor recovery process and belongs to the technical field of glyphosate mother liquor recovery. The process comprises the following steps: filtering the obtained glyphosate mother liquor, adsorbing the filtered glyphosate mother liquor by using an adsorption resin, wherein the adsorption resin is an alkaline anion adsorption resin; desorbing the adsorbed glyphosate mother liquor by using an alkaline solution to obtain a pretreated solution; adding hydrochloric acid into the pretreated solution to adjust the pH value, concentrating the pretreated solution under heating, filtering the concentrated pretreated solution while hot, obtaining a filter cake, and cooling and crystallizing the obtained filtrate, drying the crystallized filtrate to obtain glyphosate powder. In the recovery process, resin adsorption is firstly performed, and then acid treatment is performed, so that the alkaline solution in the desorption agent can be recovered, and the use efficiency of the reagent is improved. The alkaline anion adsorption resin is used to adsorb glyphosate in the glyphosate mother liquor, and then a desorption agent is used to separate the glyphosate; the adsorption resin can be repeatedly used, the cost of treating the mother liquor is not increased, the obtained powder after treatment is high in purity, and the obtained filter cake can also be repeatedly used as industrial salt.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of glyphosate mother liquor recovery, and particularly relates to a glyphosate mother liquor recovery process. BACKGROUND

[0002] Glyphosate is synthesized by taking chloroacetic acid or hydrocyanic acid as raw material, and then the glyphosate is reacted with other raw materials. The process mainly has the stages of synthesis, hydrolysis, crystallization, centrifugal drying and packaging. The original process has a yield of 75%, which is relatively low. The main reason is that the loss in the glyphosate mother liquor treatment process is high. About 5.2 tons of mother liquor wastewater containing about 1.0% of glyphosate, about 10% of sodium chloride and other impurities are generated per ton of glyphosate produced by the glycine method.

[0003] Due to the presence of a large amount of inorganic salts and organic impurities such as formaldehyde, it is difficult to separate and purify by conventional methods, and the recovery and utilization of glyphosate in the mother liquor wastewater cannot be directly realized. The existing process is to evaporate and dehydrate the mother liquor by steam or concentrate by membrane method to obtain a 10% glyphosate water agent. For the water agent obtained by concentration, a large amount of inorganic salts (sodium chloride, sodium phosphite, etc.) also enter the environment and water body, causing soil compaction and salinization; therefore, the treatment of the mother liquor has become a major problem restricting the survival and development of glyphosate manufacturers. SUMMARY

[0004] The purpose of the application is to provide a glyphosate mother liquor recovery process to solve the problems of low yield of glyphosate production and treatment of glyphosate mother liquor.

[0005] The purpose of the application can be achieved by the following technical solutions:

[0006] A glyphosate mother liquor recovery process, comprising the following steps:

[0007] S1, filtering the glyphosate mother liquor, and then adsorbing the filtered glyphosate mother liquor by using an adsorption resin, wherein the adsorption resin is an alkaline anion adsorption resin; after the adsorption, using an alkaline solution with a mass fraction of 5-7% as a desorption agent to obtain a pretreated liquid by desorption;

[0008] S2, adding hydrochloric acid to the pretreated liquid to adjust the pH value to be less than or equal to 2, and then concentrating and filtering the pretreated liquid while hot to obtain a filter cake; and cooling and crystallizing the obtained filtrate, and then drying to obtain glyphosate powder.

[0009] Further, the alkaline anion adsorption resin is prepared by the following steps:

[0010] The chloromethyl polystyrene resin is added into N,N-dimethylformamide for swelling, guanidine hydrochloride is added, stirring is carried out at 80 DEG C for 6h, after the reaction is completed, cooling is carried out, filtration is carried out, and then water washing is carried out until neutral, then 1mol / L hydrochloric acid solution and 1mol / L sodium hydroxide solution are used for washing in sequence, and finally water washing is carried out until neutral, so that the pretreated resin is obtained;

[0011] The pretreated resin is added into N,N-dimethylformamide for swelling, then dimethyldichlorosilane is added, stirring is carried out at 30 DEG C for 3h, after the reaction is completed, filtration is carried out, and then 10% triethylamine ethanol solution, ethanol and distilled water are used for washing in sequence until neutral, so that the basic anion adsorption resin is obtained.

[0012] Further, the adsorption temperature is 60-80 DEG C, the flow rate in the adsorption process is 8-15BV / h, the desorption temperature is 90-100 DEG C, and the flow rate in the desorption process is 8-15BV / h.

[0013] Further, the chlorine content of the chloromethyl polystyrene resin is 2.0-4.5mmol / g.

[0014] Further, the amount ratio of the chloromethyl polystyrene resin, guanidine hydrochloride and N,N-dimethylformamide is 1g:10mL:0.2g.

[0015] Further, the amount ratio of the pretreated resin, dimethyldichlorosilane and N,N-dimethylformamide is 1g:10mL:0.26g.

[0016] Further, the basic solution is one of sodium hydroxide solution and ammonia water.

[0017] Further, the temperature of the temperature-increasing concentration is 110-120 DEG C. Through the temperature-increasing concentration, the solubility of glyphosate in the pretreatment liquid is larger, the inorganic salt changes less with temperature, the concentration of the inorganic salt is increased after the temperature-increasing concentration, the inorganic salt in the pretreatment liquid is precipitated, hot filtration is carried out, the inorganic salt is recovered, and can be used as industrial salt in the reaction process.

[0018] Further, the temperature of the cooling crystallization is 15-30 DEG C.

[0019] The beneficial effects of the present application are as follows:

[0020] The application provides a glyphosate mother liquor recovery process, wherein resin adsorption is first performed, then acid treatment is performed, the alkaline solution in the desorption agent can be recovered, and the use efficiency of the reagent is improved. The alkaline anion adsorption resin is used to adsorb glyphosate in the glyphosate mother liquor, then the desorption agent is used to separate the glyphosate, more outstandingly, the adsorption resin can be reused, the cost of treating the mother liquor is not increased, the purity of the powder obtained after treatment is high, and the filter cake obtained can also be reused as industrial salt.

[0021] The commercially available alkaline anion adsorption resin has poor thermal stability, and can usually be used only below 60 DEG C. In the application, the thermal stability of the resin is improved by treating the resin, and the desorption temperature is improved, which is beneficial to improving the recovery speed and recovery efficiency and is beneficial to industrial production. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0023] Embodiment 1

[0024] The application provides a kind of alkaline anion adsorption resin, which is prepared by the following steps:

[0025] Chloromethyl polystyrene resin is added to N,N-dimethylformamide for swelling, guanidine hydrochloride is added, stirring is carried out at a temperature of 80 DEG C for 6 hours, after the reaction is completed, cooling and filtration are carried out, water washing is carried out until neutral, then 1 mol / L hydrochloric acid solution and 1 mol / L sodium hydroxide solution are sequentially used for washing, and finally water washing is carried out until neutral to obtain pretreated resin; the chlorine content of the chloromethyl polystyrene resin is 2.0-4.5 mmol / g; the amount ratio of chloromethyl polystyrene resin, guanidine hydrochloride and N,N-dimethylformamide is 1 g:10 mL:0.2 g.

[0026] The pretreated resin is added to N,N-dimethylformamide for swelling, then dimethyldichlorosilane is added, stirring is carried out at a temperature of 30 DEG C for 3 hours, after the reaction is completed, filtration is carried out, 10% triethylamine ethanol solution, ethanol and distilled water are sequentially used for washing until neutral to obtain alkaline anion adsorption resin. The amount ratio of pretreated resin, dimethyldichlorosilane and N,N-dimethylformamide is 1 g:10 mL:0.26 g.

[0027] Embodiment 2

[0028] A glyphosate mother liquor recovery process comprises the following steps:

[0029] S1, the glyphosate alkaline mother liquor recovered by glycine method of triethylamine is filtered, and after filtration, adsorption is carried out by using adsorption resin, the adsorption resin is the basic anion adsorption resin prepared in example 1; after adsorption, a mass fraction 5% sodium hydroxide solution is used as a desorption agent, and a pretreatment liquid is obtained by desorption; the adsorption temperature is 60 DEG C, the flow rate in the adsorption process is 8 BV / h, the desorption temperature is 90 DEG C, and the flow rate in the desorption process is 8 BV / h; the glyphosate content in the mother liquor is 1.2%;

[0030] S2, hydrochloric acid is added to the pretreatment liquid, the pH value is adjusted to be less than or equal to 2, heating and concentration are carried out, hot filtration is carried out, a filter cake is obtained, and the obtained filtrate is subjected to cooling crystallization and drying to obtain glyphosate powder. The temperature of heating and concentration is 110 DEG C; the temperature of cooling crystallization is 15 DEG C. The glyphosate recovery rate is 96.1%, and the glyphosate purity is 96.7%.

[0031] Example 3

[0032] A glyphosate mother liquor recovery process comprises the following steps:

[0033] S1, the glyphosate alkaline mother liquor recovered by glycine method of triethylamine is filtered, and after filtration, adsorption is carried out by using adsorption resin, the adsorption resin is the basic anion adsorption resin prepared in example 1; after adsorption, a mass fraction 5% sodium hydroxide solution is used as a desorption agent, and a pretreatment liquid is obtained by desorption; the adsorption temperature is 60 DEG C, the flow rate in the adsorption process is 8 BV / h, the desorption temperature is 90 DEG C, and the flow rate in the desorption process is 8 BV / h; the glyphosate content in the mother liquor is 1.2%;

[0034] S2, hydrochloric acid is added to the pretreatment liquid, the pH value is adjusted to be less than or equal to 2, heating and concentration are carried out, hot filtration is carried out, a filter cake is obtained, and the obtained filtrate is subjected to cooling crystallization and drying to obtain glyphosate powder. The temperature of heating and concentration is 110 DEG C; the temperature of cooling crystallization is 15 DEG C. The glyphosate recovery rate is 96.1%, and the glyphosate purity is 96.7%.

[0035] Example 4

[0036] A glyphosate mother liquor recovery process comprises the following steps:

[0037] S1, the glyphosate alkaline mother liquor recovered by glycine method of triethylamine is filtered, and after filtration, adsorption is carried out by using adsorption resin, the adsorption resin is the basic anion adsorption resin prepared in example 1; after adsorption, a mass fraction 5% sodium hydroxide solution is used as a desorption agent, and a pretreatment liquid is obtained by desorption; the adsorption temperature is 60 DEG C, the flow rate in the adsorption process is 8 BV / h, the desorption temperature is 90 DEG C, and the flow rate in the desorption process is 8 BV / h; the glyphosate content in the mother liquor is 1.2%;

[0038] S2, adding hydrochloric acid to the pretreated solution to adjust the pH value to be less than or equal to 2, warming and concentrating, filtering while hot to obtain a filter cake, and cooling and crystallizing the obtained filtrate, and drying to obtain glyphosate powder. The temperature of warming and concentrating is 120°C; the temperature of cooling and crystallizing is 30°C. The glyphosate recovery rate is 96.0%, and the glyphosate purity is 96.7%.

[0039] Comparative Example 1

[0040] This comparative example is compared with Example 4, the basic anion adsorption resin prepared in Example 1 is replaced with WD-XF strong basic high exchange capacity anion adsorption resin from Anhui Wandong Chemical Factory, and the rest of the raw materials and preparation process remain unchanged. The glyphosate recovery rate is 85.8%, and the glyphosate purity is 95.7%.

[0041] It should be noted that the relational terms herein such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0042] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A glyphosate mother liquor recovery process, characterized in that, Includes the following steps: S1, filter the glyphosate mother liquor, and then adsorb it with an adsorption resin, wherein the adsorption resin is an alkaline anion adsorption resin; after adsorption, use a 5-7% (w / w) alkaline solution as a desorbent to desorb and obtain a pretreated solution. S2, add hydrochloric acid to the pretreatment solution to adjust the pH value to ≤2, heat and concentrate, filter while hot to obtain filter cake, and cool and crystallize the obtained filtrate to obtain glyphosate powder; The basic anion adsorption resin is prepared by the following steps: Chloromethyl polystyrene resin was added to N,N-dimethylformamide for swelling, guanidine hydrochloride was added, and the mixture was stirred and reacted at 80°C for 6 hours. After the reaction was completed, the mixture was cooled, filtered, and washed to obtain the pretreated resin. The pretreated resin was swollen by adding N,N-dimethylformamide, and then dimethyldichlorosilane was added. The mixture was stirred and reacted at 30°C for 3 hours. After the reaction was completed, the resin was filtered and washed to obtain an alkaline anion adsorption resin.

2. The glyphosate mother liquor recovery process according to claim 1, characterized in that, The adsorption temperature is 60-80℃, the flow rate during the adsorption process is 8-15 BV / h, the desorption temperature is 90-100℃, and the flow rate during the desorption process is 8-15 BV / h.

3. The glyphosate mother liquor recovery process according to claim 1, characterized in that, The alkaline solution is either sodium hydroxide solution or ammonia solution.

4. The glyphosate mother liquor recovery process according to claim 1, characterized in that, The temperature for concentration is 110-120℃.

5. The glyphosate mother liquor recovery process according to claim 1, characterized in that, The cooling crystallization temperature is 15-30℃.

6. The glyphosate mother liquor recovery process according to claim 1, characterized in that, The chlorine content of chloromethyl polystyrene resin is 2.0-4.5 mmol / g.