A method for selectively recovering glyphosate from a glyphosate mother liquor

Abstract

The application discloses a method for selectively recovering glyphosate from a glyphosate mother liquor, and specifically comprises the following steps: 1) adding a phosphide recovery agent into the glyphosate mother liquor, stirring, settling, and recovering phosphides in the glyphosate mother liquor; 2) collecting the obtained sediment, then adding a glyphosate separating agent into the sediment, stirring, and precipitating; and then filtering, cleaning, and drying to obtain a glyphosate product. The two-step treatment process based on the phosphide recovery agent and the glyphosate separating agent can realize efficient and selective precipitation of the glyphosate in the glyphosate mother liquor, the separation process is simple and easy to operate, the phosphide recovery agent and the glyphosate separating agent can be recycled and reused, and the method has good economic and environmental benefits, and can provide a new industrial treatment idea for selectively separating and recovering the glyphosate from the glyphosate mother liquor.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and purification, and particularly relates to a method for selectively recovering glyphosate from a glyphosate mother liquor. Background Art

[0002] Glyphosate mother liquor is characterized by high levels of salt, phosphorus, organic matter, and ammonia nitrogen (the "four highs"). Due to its complex composition, glyphosate separation and purification using traditional methods is difficult, presenting a pressing industrial challenge. Glyphosate is currently the most widely used pesticide. According to statistics, the production of one ton of glyphosate produces approximately 4.5 tons of glyphosate mother liquor, which contains 15.0-20.0% sodium chloride, 1.2-10.0% glyphosate, 1.0-15% glyphosate, and 0.1-13% phosphorous acid.

[0003] Currently, glyphosate mother liquor is industrially treated using concentrated incineration and wet oxidation methods, which not only produces large amounts of solid waste such as phosphorus and chlorine, but also leads to the waste of organophosphorus compounds such as glyphosate (market price: RMB 70,000 / ton). There are currently some methods for resource-based recovery of glyphosate. For example, Patent CN113072580A reports a method for recovering glyphosate from glyphosate acid mother liquor produced by the glycine process. While this method addresses the quality issues of glyphosate crystallization and reduces the production of glyphosate base mother liquor, it suffers from high energy consumption, a large amount of secondary wastewater, and an inability to recover high-purity glyphosate. Patent CN102408441A discloses a method for extracting glyphosate mother liquor by adding solvents such as methanol, ethanol, propanol, and acetone, followed by heating and distilling to recover the solvent for efficient glyphosate recovery. However, this method cannot simultaneously achieve effective separation of other phosphides such as phosphorous acid and glyphosate, making it difficult to recover a high-purity glyphosate product. Therefore, further exploration of simple and efficient means of glyphosate resource utilization, especially the process of selective separation of high-purity glyphosate, has important research and application significance. Summary of the Invention

[0004] The main purpose of the present invention is to address the deficiencies of the existing technology and provide a method for selectively recovering glyphosate from a glyphosate mother liquor. The method adopts a two-step treatment process based on a phosphide recovery agent and a glyphosate separation agent, thereby achieving efficient and selective precipitation of glyphosate from the glyphosate mother liquor. The separation process involved is simple and easy to operate, and the phosphide recovery agent and glyphosate separation agent used are recyclable and reusable, thereby achieving good economic and environmental benefits. The method can provide a new industrial treatment idea for the selective separation and recovery of glyphosate from a glyphosate mother liquor.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for selectively recovering glyphosate from a glyphosate mother liquor comprises the following steps:

[0007] 1) adding a phosphide recovery agent to a glyphosate mother liquor, stirring, settling, and separating and recovering the phosphide in the glyphosate mother liquor;

[0008] 2) collecting the obtained sediment, adding a glyphosate separating agent thereto, stirring to separate out the precipitate; filtering, washing, and drying to obtain the glyphosate product.

[0009] In the above scheme, the glyphosate mother liquor is a glyphosate-containing waste liquid generated during the preparation of glyphosate by the glycine method or the iminodiacetic acid method, or a waste liquid treated by concentration, desalination or other pretreatment methods, or other glyphosate-containing solutions.

[0010] In the above scheme, the organophosphorus recovery agent is a solvent selected from ketones, phenols, ethers, alcohols, lipid compounds, benzene solvents and derivatives thereof, or a mixed solvent of several of them.

[0011] Furthermore, the ketone solvent can be selected from one or more of acetone, butanone, 3-methyl butanone, 2-pentanone, 3-pentanone, etc.; the phenol solvent can be selected from one or more of phenol, catechol, resorcinol, hydroquinone, α-naphthol, β-naphthol, etc.; the ether solvent can be selected from one or more of methyl ether, ethyl ether, propyl ether, methyl ethyl ether, methyl propyl ether, phenyl ether, etc.; the alcohol solvent can be selected from one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, glycerol, etc.; the lipid compound solvent can be selected from one or more of methyl formate, ethyl formate, ethyl acetate, ethyl benzoate, methyl benzoate, diethyl oxalate, etc.; the benzene solvent can be selected from one or more of benzene, toluene, o-xylene, p-xylene, m-xylene, mesitylene, unsimilar trimethylol, etc.

[0012] In the above scheme, the mass ratio of the organophosphorus recovery agent to the glyphosate mother liquor is (0.1-100):1.

[0013] In the above scheme, the stirring time in step 1) is 1-300 min, and the stirring speed is 1-600 r / min.

[0014] In the above scheme, the sedimentation time in step 1) is 1-2880 min.

[0015] In the above scheme, the glyphosate separating agent is one or more of a phenolic compound solution, an amine compound, an organic acid solution, an inorganic acid solution, an organic alkali solution, an inorganic alkali solution, and an aromatic hydrocarbon solution.

[0016] Furthermore, the phenol compound solution can be selected from one or more of phenol, catechol, resorcinol, hydroquinone, α-naphthol, β-naphthol, etc.; the amine compound can be selected from one or more of methylamine, ethylamine, propylamine, ethylenediamine, triethylamine, butylamine, etc.; the inorganic acid solution can be selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, phosphoric acid, hydrofluoric acid, etc.; the organic alkali solution can be selected from one or more of sodium methoxide, potassium methoxide, lithium methoxide, sodium ethoxide, lithium ethoxide, potassium ethoxide, calcium ethoxide, etc.; the inorganic alkali solution can be selected from one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, etc.; the aromatic hydrocarbon solution can be selected from one or more of benzene, toluene, o-xylene, p-xylene, m-xylene, mesitylene, unsimilar trimethylolene, etc.

[0017] In the above scheme, the concentration of the glyphosate separating agent is 0.1-20 mol / L.

[0018] In the above scheme, the mass ratio of the glyphosate separating agent to the glyphosate mother liquor is (0.01-100):1.

[0019] In the above scheme, the stirring method for precipitating glyphosate is magnetic stirring, electric stirring or manual stirring; the stirring time is 30-2880 min, and the stirring speed is 2-500 r / min.

[0020] In the above scheme, the glyphosate separation method is filtration, vacuum filtration, membrane filtration or centrifugation.

[0021] In the above scheme, the glyphosate cleaning reagent is one or more of water, formic acid, acetic acid, methanol, ethanol, and ethyl acetate; and the number of cleaning times is 1-10 times.

[0022] In the above scheme, the drying method is air drying, reduced pressure drying, freeze drying or spray drying.

[0023] The present invention targets glyphosate mother liquor with complex components and realizes the selective precipitation of glyphosate through a two-step operation of adding a phosphide recovery agent and a glyphosate separation agent step by step. The purity of the obtained glyphosate product reaches over 90%, the recovery rate reaches over 50%, and the amount of wastewater generated is small. The phosphide recovery agent and the glyphosate separation agent can be recycled, and industrialization can be well realized, providing a new approach for the high value and resource utilization of the glyphosate mother liquor.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The present invention can achieve efficient recovery of glyphosate while ensuring both the recovery rate and purity of glyphosate, is easy to industrialize, and provides a new approach for efficient recovery of glyphosate;

[0026] 2) The recovery process of the present invention is simple and easy to operate, and the reagents used can be reused repeatedly, the cost is low, and it is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The infrared spectra of the glyphosate product obtained in Example 1 and the standard glyphosate are shown. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] In the following examples, the main components and their mass percentages of the glyphosate mother solution used include: glyphosate 1.2-10.0%, glyphosate 1.8-11.6%, phosphorous acid 0.1-12.3%, sodium chloride 0.6-40%, density 1.10×10 3 -1.45×10 3 kg / m 3 , pH 7.0-10.5.

[0030] Example 1

[0031] A method for selectively recovering glyphosate from a glyphosate mother liquor, wherein the main components and their mass percentages of the glyphosate mother liquor include: 3.3% glyphosate, 5.3% glyphosate, 3.7% phosphorous acid, and 1.1% sodium chloride, and the density thereof is 1.29×10 3 kg / m 3 , pH value is 7.5-7.6; the specific recovery steps include:

[0032] 1) Add 2.25 kg of cyclohexanol, a phosphide recovery agent, to 1.0 kg of glyphosate mother liquor, stir at 378 r / min for 30 min, allow to settle for 120 min, collect the resulting sediment, and measure the total phosphorus content in the supernatant to calculate the total phosphorus recovery rate;

[0033] 2) 400 g of a 3.0 mol / L glyphosate separating agent, mellitic acid solution, was added to the collected sediment, and the mixture was stirred at 200 r / min for 12 h to precipitate. The precipitate was filtered and the resulting white solid was collected. The solid was washed three times with a small amount of deionized water, freeze-dried, and then a white powder was collected. The mass was weighed and the purity was tested by ion chromatography.

[0034] Figure 1 The infrared spectra of the glyphosate product obtained in Example 1 and the standard glyphosate are shown in FIG. 1 . The results show that the infrared spectrum of the product obtained in this example is basically consistent with that of the standard glyphosate.

[0035] The product obtained in this example and a glyphosate standard were subjected to ion chromatography tests, wherein 0.0100 g of the glyphosate product and the glyphosate standard were weighed and fixed to a 250 mL volumetric flask, and the measurements were performed under the same conditions. The results showed that the glyphosate product obtained in this example had a peak elution time of 12.274 min and a peak area of ​​3.628, while the glyphosate standard (McLean, purity 95%) had a peak elution time of 12.261 min and a peak area of ​​3.418, indicating that the obtained glyphosate product had high purity.

[0036] The test results show that: using the recovery method described in this embodiment, after adding the phosphide recovery agent, the total phosphorus recovery rate is 90.8%; after adding the glyphosate separation agent, the glyphosate recovery rate is 69.1%, and the glyphosate purity is 92.3%.

[0037] Example 2

[0038] A method for selectively recovering glyphosate from a glyphosate mother liquor. The main components and their mass percentages of the glyphosate mother liquor used include: 6.4% glyphosate, 11.8% glyphosate, 4.9% phosphorous acid, and 1.3% sodium chloride. The density of the glyphosate mother liquor is 1.39×10 3 kg / m 3 , pH value is 7.5-7.6; the specific recovery steps include:

[0039] 1) Add 1.5 kg of butyl ether, a phosphide recovery agent, to 1.0 kg of glyphosate mother liquor, stir at 360 r / min for 10 min, allow to settle for 490 min, collect the resulting sediment, and measure the total phosphorus content in the supernatant to calculate the total phosphorus recovery rate;

[0040] 2) To the collected sediment was added 260 g of perchloric acid (4.5 mol / L glyphosate separating agent), and the mixture was stirred at 200 r / min for 24 h to precipitate. The resulting white solid was collected by filtration, washed three times with a small amount of methanol and water, and dried under forced air at 80° C. for 8 h to collect a white powder. The powder was weighed and its purity was determined by ion chromatography.

[0041] The test results show that: using the recovery method described in this embodiment, after adding the phosphide recovery agent, the total phosphorus recovery rate is 94.9%; after adding the glyphosate separation agent, the glyphosate recovery rate is 70.1%, and the glyphosate purity is 90.0%.

[0042] Example 3

[0043] A method for selectively recovering glyphosate from a glyphosate mother liquor, wherein the main components and their mass percentages of the glyphosate mother liquor include: 1.7% glyphosate, 3.8% glyphosate, 0.1% phosphorous acid, and 18% sodium chloride, and the density is 1.20×103 kg / m 3 , pH value is 9.5-9.6; the specific recovery steps include:

[0044] 1) 1.5 kg of phosphide recovery agent butyl propionate is added into 1.0 kg of glyphosate mother liquor, stirred at 360 r / min for 120 min, settled for 30 min, the obtained sediment is collected, and the content of total phosphorus in the supernatant is detected to calculate the total phosphorus recovery rate;

[0045] 2) 270 g of glyphosate separating agent calcium hydroxide solution with a concentration of 0.5 mol / L is added into the collected sediment, precipitate is separated out after stirring at 360 r / min for 12 h, filtered, the obtained white solid substance is collected, washed with a small amount of methanol water once, dried at 80°C under blast drying for 8 h to collect white powder substance, weighed and the purity is detected by ion chromatography.

[0046] The test results show that: by using the recovery method described in the embodiment, after adding the phosphide recovery agent, the total phosphorus recovery rate is 91.4%, after adding the glyphosate separating agent, the glyphosate recovery rate is 60.1%, and the purity of glyphosate is 93.0%.

[0047] Comparative Example 1

[0048] A method for selectively recovering glyphosate from glyphosate mother liquor, the main components in the glyphosate mother liquor and the mass percentage thereof include: 3.3% of glyphosate, 5.3% of nicosulfuron, 3.7% of phosphorous acid, 1.1% of sodium chloride, and the density thereof is 1.29 x 10 3 kg / m 3 , pH value is 7.5-7.6; the specific recovery steps include:

[0049] 2.25 kg of phosphide recovery agent cyclohexanol is added into 1.0 kg of glyphosate mother liquor, stirred at 378 r / min for 30 min, settled for 120 min, then 400 g of glyphosate separating agent acetic acid with a concentration of 12.0 mol / L is added, stirred at 200 r / min for 12 h, filtered, the white solid substance is collected, washed with a small amount of deionized water for 3 times, freeze-dried to collect white powder substance, weighed and the purity is detected by ion chromatography.

[0050] The test results show that: by using the recovery method described in the comparative example, after adding the phosphide recovery agent, the total phosphorus recovery rate is 90.8%; after directly adding the glyphosate separating agent, the glyphosate recovery rate is 7.8%, and the purity of glyphosate is 90.3%. In the embodiment, although the total phosphorus recovery rate and the purity of the glyphosate product are higher, the recovery of the obtained glyphosate product is very low.

[0051] Comparative Example 2

[0052] A method for selectively recovering glyphosate from a glyphosate mother liquor. The main components and their mass percentages of the glyphosate mother liquor used include: 6.4% glyphosate, 11.8% glyphosate, 4.9% phosphorous acid, and 1.3% sodium chloride. The density of the glyphosate mother liquor is 1.39×10 3 kg / m 3 , pH value is 7.5-7.6; the specific recovery steps include:

[0053] To 1.0 kg of glyphosate mother liquor, 260 g of sulfuric acid, a glyphosate separating agent with a concentration of 9.0 mol / L, was directly added. The mixture was stirred at a speed of 200 r / min for 24 h. The white solid was collected by filtration. The solid was washed three times with a small amount of methanol water. The white powder was collected by forced air drying at 80°C for 8 h. The mass was weighed and the purity was detected by ion chromatography.

[0054] The test results show that: using the recovery method described in this comparative example, the glyphosate recovery rate after directly adding the glyphosate separator is 1.2%, and the glyphosate purity is 46.6.0%; the recovery rate and purity of the obtained glyphosate product are both very low.

[0055] Comparative Example 3

[0056] A method for selectively recovering glyphosate from a glyphosate mother liquor, wherein the main components and their mass percentages of the glyphosate mother liquor include: 1.7% glyphosate, 3.8% glyphosate, 1.9% phosphorous acid, and 18% sodium chloride, and the density is 1.20×10 3 kg / m 3 , pH value is 9.5-9.6; the specific recovery steps include:

[0057] 5 kg of benzyl alcohol, a phosphide recovery agent, was added to 1.0 kg of glyphosate mother liquor, and the mixture was stirred at a speed of 360 r / min for 120 min, allowed to settle for 30 min, and solid matter was collected by filtration. The total phosphorus content in the supernatant was detected, and the total phosphorus recovery rate was calculated; 6.0 g of a glyphosate separation agent-succinic acid solution with a concentration of 15.0 mol / L was added to the collected solid matter, and the mixture was stirred at a speed of 360 r / min for 12 h. The mixture was filtered to collect a white solid matter, and the solid matter was washed once with a small amount of methanol water. The white powder matter was collected by air drying at 80° C. for 8 h, and the mass was weighed and the purity was detected by ion chromatography.

[0058] The test results show that: using the recovery method described in this comparative example, after adding the phosphide recovery agent, the total phosphorus recovery rate is 99.9%, and after adding the glyphosate separator, the glyphosate recovery rate is 25.3%, and the glyphosate purity is 77%; the total phosphorus recovery rate using the above method is high, but the amount of glyphosate separator added is small, which affects the recovery rate and purity of the glyphosate product.

[0059] The above embodiments are merely examples for illustrative purposes only and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications may be made based on the above descriptions. It is not necessary and impossible to enumerate all implementation methods here. Therefore, any obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for selectively recovering glyphosate from a glyphosate mother liquor, characterized in that: The steps include: 1) adding a phosphide recovery agent to a glyphosate mother liquor, stirring, settling, and recovering the phosphide in the glyphosate mother liquor; The glyphosate mother solution includes 1.2-10.0% glyphosate, 1.8-11.6% glyphosate, 0.1-12.3% phosphorous acid, 0.6-40% sodium chloride, and a density of 1.10×10 3 -1.45×10 3 kg / m 3 , pH 7.0-10.5, wherein the proportions of glyphosate, glyphosate, phosphorous acid, and sodium chloride are all percentages by mass; The phosphide recovery agent is selected from cyclohexanol, butyl ether or butyl propionate; 2) collecting the resulting sediment, adding a glyphosate separating agent thereto, stirring and precipitating; filtering, washing, and drying to obtain a glyphosate product; wherein the glyphosate separating agent is a perchloric acid or mellitic acid solution; The concentration of the glyphosate separating agent is 0.1-20 mol / L; The mass ratio of the glyphosate separating agent to the glyphosate mother liquor is (0.01-100):

1.

2. The method according to claim 1, characterized in that The mass ratio of the phosphide recovery agent to the glyphosate mother liquor is (0.1-100):

1.

3. The method according to claim 1, characterized in that In step 1), the stirring time is 1-300 min, the stirring speed is 1-600 r / min, and the sedimentation time is 1-2880 min.

4. The method according to claim 1, wherein The stirring time used in step 2) is 30-2880 min, and the stirring speed is 2-500 r / min.

5. The method according to claim 1, wherein The recovery rate of the glyphosate product is 50-85%, and the purity is above 90%.

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