Method for extracting glyphosine from glyphosate mother liquor
By adjusting the pH value and adding calcium salts to the glyphosate mother liquor, the crystals of glyphosate calcium salt are generated and separated, and a series of treatments are followed. Finally, the glyphosate product is obtained through spray drying, which solves the problem of glyphosate in the glyphosate mother liquor that cannot be effectively recycled and utilized, and achieves the reuse of resources and the reduction of production costs.
Patent Information
- Application Number
- CN202411610133.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-12
- Publication Date
- 2025-03-14
AI Technical Summary
In the prior art, glyphosate, which is produced by-product in glyphosate mother liquor, cannot be effectively recycled, resulting in waste of organic phosphorus resources and high production costs.
By adding hydrochloric acid and calcium salt to the glyphosate mother liquor, the pH value of the solution is adjusted to generate crystals of glyphosate-containing calcium salt, followed by solid-liquid separation, alkaline dissolution, acidification reaction and evaporation and concentration under reduced pressure, and finally obtain glyphosate-enhancing product by spray drying.
It has achieved efficient extraction and increase of glyphosate from glyphosate mother liquor, which has reduced production costs, avoided the waste of organic phosphorus resources, and has significant environmental protection and social benefits.
Smart Images
Figure CN119613449A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for extracting glyphosate from a glyphosate mother liquor, and is particularly suitable for extracting and recovering glyphosate from a glyphosate mother liquor produced by a glycine method. Background Art
[0002] Product name: Glyphosate, chemical name: N,N-bis(phosphonomethyl)glycine, molecular formula: C4H11NO8P2, molecular weight: 263.08, molecular structure is as follows: .
[0003] Glyphosate is widely used as a ripening agent, sugar increaser and growth regulator for crops such as sugarcane and watermelon due to its significant ripening effect and little residue in plants.
[0004] There are two main methods for producing glyphosate. The first is to directly produce glyphosate from raw materials (commonly known as the "synthetic method"); the second is to extract and recover glyphosate from glyphosate mother liquor.
[0005] The synthesis method is divided into three types according to the raw materials used, namely the phosphorus trichloride method, the phosphorous acid method and the chloromethylphosphonic acid method. The phosphorus trichloride method is the mainstream process of the synthesis method, that is, phosphorus trichloride, glycine and polyformaldehyde are used as raw materials to synthesize glyphosate.
[0006] Glyphosate is one of the most widely used pesticides. Domestic glyphosate production has been scaled up, especially the glycine method is the mainstream process for glyphosate production in China. Every ton of glyphosate produced produces about 4.5 tons of glyphosate mother liquor, which contains 1.6-2.5% glyphosate, 3.8-5.1% glyphosate, 2.4-5.0% phosphorous acid and other phosphorus compounds. Among these phosphorus compounds, glyphosate has the highest value. Improper treatment will cause a large amount of phosphorus resources to be wasted. Extracting and recovering glyphosate from glyphosate mother liquor can realize the reuse of organic phosphorus resources, which is of great significance.
[0007] The first method of producing glyphosate has the advantage of high product purity, but the disadvantage is that all raw materials need to be purchased, which is costly. The second method of producing glyphosate is to use glyphosate mother liquor as a by-product, which has two advantages: first, low production cost; second, it can realize the recycling of organic phosphorus resources, turning "waste" into treasure, with significant environmental and social benefits. Summary of the invention
[0008] The object of the present invention is to provide a method for extracting glyphosate from glyphosate mother liquor, comprising the following steps (see Figure 1 shown): Step A: adding hydrochloric acid and calcium salt to the glyphosate mother solution, adjusting the pH value of the solution, and mixing and reacting to obtain a reaction solution containing glyphosate calcium salt crystals; Step B: filtering the reaction solution containing glyphosate calcium salt crystals to separate the solid from the liquid to obtain glyphosate calcium salt crystals; Step C: dissolving the separated calcium glyphosate crystals in alkali, and adjusting the pH value of the solution with a calcium hydroxide solution to completely dissolve the calcium glyphosate crystals to obtain a calcium glyphosate solution; Step D: adding ammonium sulfate solution to the glyphosate calcium salt solution, adjusting the pH value of the solution to make the solution acidic, and gradually converting the glyphosate calcium into glyphosate through the reaction, while generating calcium sulfate precipitation and releasing ammonia gas; Step E: filtering the above conversion reaction liquid to obtain a filter cake containing calcium sulfate precipitate and a filtrate containing glyphosate; Step F: Concentrating the filtrate containing glyphosate by reduced pressure evaporation in a reduced pressure evaporator to obtain a glyphosate concentrated solution; Step G: sending the glyphosate concentrate into a spray drying tower for spray drying to obtain a glyphosate product.
[0009] In the step A, a certain amount of glyphosate mother liquor, 30% hydrochloric acid and calcium salt solution are added to a mixed reaction kettle, and the pH of the glyphosate mother liquor is adjusted to 4.0-5.0 by adding hydrochloric acid; the calcium salt is then added and stirred for reaction, and hydrochloric acid is then added to adjust the pH value to between 1.1-1.3, and the reaction is carried out under stirring conditions to obtain a reaction solution containing glyphosate calcium salt crystals.
[0010] The calcium salt can be any one or more of calcium chloride, calcium glycinate, calcium lysine and calcium aspartate.
[0011] In the step B, the reaction solution is subjected to solid-liquid separation using a filter to obtain glyphosate calcium salt crystals.
[0012] In the step C, a certain amount of calcium hydroxide solution is added to the dissolving kettle, and then the calcium salt of glyphosate is added to the alkaline solution for dissolution (alkaline dissolution), the pH is adjusted between 8-9, and the liquid-to-solid ratio is controlled between (15-18):1 to obtain the calcium salt of glyphosate solution.
[0013] In the step D, an ammonium sulfate solution is added to the glyphosate calcium salt solution, and the pH value of the solution is adjusted to between 5 and 6 to make the solution acidic, and the glyphosate calcium is gradually converted into glyphosate through the reaction, and calcium sulfate precipitate is generated, and ammonia is released. The above conversion reaction liquid is filtered again to obtain a filter cake containing calcium sulfate precipitate and a filtrate containing glyphosate.
[0014] In the step E, the filtrate containing glyphosate is pumped into an evaporator by a delivery pump, and evaporated and concentrated to 25-28% of the original volume under reduced pressure to obtain a glyphosate concentrate. The glyphosate concentrate is pumped into a spray drying tower by a pressure pump for spray drying to obtain a glyphosate product. Technical Effects A method for extracting glyphosate from glyphosate mother liquor has the following environmental and social benefits: Glyphosate is one of the most widely used pesticides. Every ton of glyphosate produced produces about 4.5 tons of glyphosate mother liquor. If a large amount of glyphosate mother liquor is not properly handled, it will not only cause environmental pollution, but also cause a waste of phosphorus resources. Extracting and recovering glyphosate from glyphosate mother liquor can realize the reuse of organic phosphorus resources, and its environmental protection and social benefits are obvious. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 : Diagram of glyphosate extraction steps.
[0016] Figure 2 : Physical picture of the glyphosate product of Example 2. DETAILED DESCRIPTION
[0017] Example 1 (1) About 4.8 tons of glyphosate mother liquor was pumped into the mixing reactor. The stirring of the mixing reactor was turned on. First, 30% hydrochloric acid was slowly added into the reactor to adjust the pH value of the solution to about 4.3. Then, 1.2 tons of 33% calcium chloride solution was slowly added. Finally, 30% hydrochloric acid was slowly added to adjust the pH value of the solution to about 1.2. While stirring was turned on, the mixed solution was allowed to react fully to form crystals.
[0018] (2) Install the filter cloth in the filter, open the vacuum valve on the filter, make the vacuum degree in the filter reach about -0.065MPa, open the discharge valve at the bottom of the mixed reactor, slowly put the reaction solution containing glyphosate calcium salt crystals in the mixed reactor into the filter, and filter out the glyphosate calcium salt crystals in the solution by vacuum filtration.
[0019] (3) Start the agitator on the dissolving kettle, add a certain amount of 5% calcium hydroxide solution and water into the dissolving kettle, put the separated calcium salt of glyphosate crystals into the dissolving kettle, continue to add 5% calcium hydroxide solution to adjust the pH value of the solution to about 8.3, so that the calcium salt of glyphosate crystals are completely dissolved, and control the liquid-to-solid ratio of the solution to about 16:1, thereby obtaining a calcium salt of glyphosate solution.
[0020] (4) Use a delivery pump to deliver the calcium glyphosate solution to the conversion reactor, and slowly add the ammonium sulfate solution while stirring, and adjust the pH value of the solution to about 5.3. The calcium glyphosate and ammonium sulfate react, and the calcium glyphosate is gradually converted into glyphosate through the reaction. At the same time, calcium sulfate precipitate is generated and ammonia gas is released.
[0021] (5) The above conversion reaction liquid is vacuum filtered again to obtain a filter cake containing calcium sulfate precipitate and a filtrate containing glyphosate.
[0022] (6) The above-mentioned filtrate containing glyphosate is delivered to an evaporator by a delivery pump, the agitator on the evaporator is started, and the vacuum valve on the evaporator is opened to make the vacuum degree in the evaporator reach about -0.075 MPa; the circulating water inlet and outlet valves of the condenser behind the evaporator are opened to introduce circulating cooling water into the condenser jacket, and at the same time, the steam valve of the evaporator jacket is slowly opened to introduce steam into the evaporator jacket, and the filtrate containing glyphosate in the evaporator is evaporated and concentrated to about 26% of the original volume under reduced pressure to obtain a glyphosate concentrated solution.
[0023] (7) Turn on the cooling water of the atomizer on the spray drying tower, start the induced draft fan and the blower of the spray drying tower in turn, turn on the electric heater to provide hot air to the spray drying tower, and control the inlet air temperature at about 185°C; send the glyphosate concentrate into the atomizer on the spray drying tower by a pressure pump, and the glyphosate concentrate is atomized and dried in contact with the hot air in the tower to obtain glyphosate powder, which settles to the bottom of the drying tower and is packaged into products.
[0024] Example 2 (1) About 6 tons of glyphosate mother liquor was pumped into a mixing reactor. Stirring was started on the mixing reactor. First, 30% hydrochloric acid was slowly added into the reactor to adjust the pH value of the solution to about 4.1. Then, 1.5 tons of 10% calcium lysine solution was slowly added. Finally, 30% hydrochloric acid was slowly added to adjust the pH value of the solution to about 1.1. While stirring was turned on, the mixed solution was allowed to react fully to form crystals.
[0025] (2) Install the filter cloth in the filter, open the vacuum valve on the filter, make the vacuum degree in the filter reach about -0.068MPa, open the discharge valve at the bottom of the mixed reactor, slowly put the reaction solution containing glyphosate calcium salt crystals in the mixed reactor into the filter, and filter out the glyphosate calcium salt crystals in the solution by vacuum filtration.
[0026] (3) Start the agitator on the dissolving kettle, add a certain amount of 5% calcium hydroxide solution and water into the dissolving kettle, put the separated calcium salt of glyphosate crystals into the dissolving kettle, continue to add 5% calcium hydroxide solution to adjust the pH value of the solution to about 8.5, so that the calcium salt of glyphosate crystals are completely dissolved, and control the liquid-to-solid ratio of the solution to about 17:1, thereby obtaining a calcium salt of glyphosate solution.
[0027] (4) Use a delivery pump to deliver the calcium glyphosate solution to the conversion reactor, and slowly add the ammonium sulfate solution while stirring, and adjust the pH value of the solution to about 5.5. The calcium glyphosate and ammonium sulfate react, and the calcium glyphosate is gradually converted into glyphosate through the reaction. At the same time, calcium sulfate precipitate is generated and ammonia gas is released.
[0028] (5) The above conversion reaction liquid is vacuum filtered again to obtain a filter cake containing calcium sulfate precipitate and a filtrate containing glyphosate.
[0029] (6) The above-mentioned filtrate containing glyphosate is delivered to an evaporator by a delivery pump, the agitator on the evaporator is started, and the vacuum valve on the evaporator is opened to make the vacuum degree in the evaporator reach about -0.072 MPa; the circulating water inlet and outlet valves of the condenser behind the evaporator are opened to introduce circulating cooling water into the condenser jacket, and at the same time, the steam valve of the evaporator jacket is slowly opened to introduce steam into the evaporator jacket, and the filtrate containing glyphosate in the evaporator is evaporated and concentrated to about 27% of the original volume under reduced pressure to obtain a glyphosate concentrated solution.
[0030] (7) Turn on the cooling water of the atomizer on the spray drying tower, start the induced draft fan and the blower of the spray drying tower in turn, turn on the electric heater to provide hot air to the spray drying tower, and control the inlet air temperature at about 190°C; send the glyphosate concentrate into the atomizer on the spray drying tower by a pressure pump, and the glyphosate concentrate is atomized and dried in contact with the hot air in the tower to obtain glyphosate powder, which settles to the bottom of the drying tower and is packaged into a product.
[0031] Example 3 (1) About 5.5 tons of glyphosate mother liquor was pumped into a mixing reactor. Stirring was started on the mixing reactor. 30% hydrochloric acid was slowly added into the reactor to adjust the pH value of the solution to about 4.4. Then about 1.38 tons of 18% calcium aspartate solution was slowly added. Then 30% hydrochloric acid was slowly added to adjust the pH value of the solution to about 1.3. While stirring was turned on, the mixed solution was allowed to react fully to form crystals.
[0032] (2) Install the filter cloth in the filter, open the vacuum valve on the filter, make the vacuum degree in the filter reach about -0.063MPa, open the discharge valve at the bottom of the mixed reactor, slowly put the reaction solution containing glyphosate calcium salt crystals in the mixed reactor into the filter, and filter out the glyphosate calcium salt crystals in the solution by vacuum filtration.
[0033] (3) Start the agitator on the dissolving kettle, add a certain amount of 5% calcium hydroxide solution and water into the dissolving kettle, put the separated calcium salt of glyphosate crystals into the dissolving kettle, continue to add 5% calcium hydroxide solution to adjust the pH value of the solution to about 8.7, so that the calcium salt of glyphosate crystals are completely dissolved, and control the liquid-to-solid ratio of the solution to about 18:1, thereby obtaining a calcium salt of glyphosate solution.
[0034] (4) Use a delivery pump to deliver the calcium glyphosate solution to the conversion reactor, and slowly add the ammonium sulfate solution while stirring, and adjust the pH value of the solution to about 5.7. The calcium glyphosate and ammonium sulfate react, and the calcium glyphosate is gradually converted into glyphosate through the reaction. At the same time, calcium sulfate precipitate is generated and ammonia gas is released.
[0035] (5) The above conversion reaction liquid is vacuum filtered again to obtain a filter cake containing calcium sulfate precipitate and a filtrate containing glyphosate.
[0036] (6) The above-mentioned filtrate containing glyphosate is delivered to an evaporator by a delivery pump, the stirrer on the evaporator is started, and the vacuum valve on the evaporator is opened to make the vacuum degree in the evaporator reach about -0.073 MPa; the circulating water inlet and outlet valves of the condenser behind the evaporator are opened to introduce circulating cooling water into the condenser jacket, and at the same time, the steam valve of the evaporator jacket is slowly opened to introduce steam into the evaporator jacket, and the filtrate containing glyphosate in the evaporator is evaporated and concentrated to about 28% of the original volume under reduced pressure to obtain a glyphosate concentrated solution.
[0037] (7) Turn on the cooling water of the atomizer on the spray drying tower, start the induced draft fan and the blower of the spray drying tower in turn, turn on the electric heater to provide hot air to the spray drying tower, and control the inlet air temperature at about 195°C; send the glyphosate concentrate into the atomizer on the spray drying tower by a pressure pump, and the glyphosate concentrate is atomized and dried in contact with the hot air in the tower to obtain glyphosate powder, which settles to the bottom of the drying tower and is packaged into a product.
[0038] Embodiment 4: The method and steps are the same as those of Example 1, except that the calcium salt in step (1) is 0.3 tons of 33% calcium chloride solution and 0.4 tons of 24% calcium glycinate solution.
[0039] Embodiment 5: The method and steps are the same as those of Example 1, except that the calcium salt in step (1) is 0.4 tons of 10% calcium lysine and about 0.3 tons of 18% calcium aspartate solution.
[0040] The glyphosate mother solution contains 1.6-2.5% glyphosate, 3.8-5.1% glyphosate, 2.4-5.0% phosphorous acid and other phosphorus-containing compounds.
[0041] A method for extracting glyphosate from glyphosate mother liquor, the product quality is tested as shown in the following table: Example Glyphosate% Glyphosate% Dimethyl phosphite% Calcium ion% Glyphosate stock solution 3.8-5.1% 1.6-2.5% 2.4-5.0% - Example 1 95.8 0.65 0.41 0.47 Example 2 96.2 0.58 0.27 0.25 Example 3 98.5 0.22 0.15 0.19 Example 4 98.3 0.25 0.17 0.18 Example 5 98.4 0.16 0.16 0.13 It can be seen from the above table that all indicators of the product have met the quality requirements specified in the standard "Technical Specifications for Selective Separation and Recovery of Glyphosate from Glyphosate Mother Solution".
Claims
1. A method for extracting glyphosate from glyphosate mother liquor, characterized in that: The steps include: Step A: adding hydrochloric acid and calcium salt to the glyphosate mother solution, adjusting the pH value of the solution, and mixing and reacting to obtain a reaction solution containing glyphosate calcium salt crystals; Step B: performing solid-liquid separation on the reaction solution containing glyphosate calcium salt crystals obtained by the reaction to obtain glyphosate calcium salt crystals; Step C: dissolving the separated calcium glyphosate crystals in alkali, and adjusting the pH value of the solution with a calcium hydroxide solution to completely dissolve the calcium glyphosate crystals to obtain a calcium glyphosate solution; Step D: adding ammonium sulfate solution to the glyphosate calcium salt solution, adjusting the pH value of the solution to make the solution acidic, and gradually converting the glyphosate calcium into glyphosate through the reaction, while generating calcium sulfate precipitate; Step E: filtering the above conversion reaction liquid to obtain a filter cake containing calcium sulfate precipitate and a filtrate containing glyphosate; Step F: Concentrating the filtrate containing glyphosate by evaporation under reduced pressure to obtain a glyphosate concentrate; Step G: spray-drying the glyphosate concentrate to obtain a glyphosate product.
2. The method for extracting glyphosate from glyphosate mother liquor according to claim 1, characterized in that: In the step A, the calcium salt is selected from any one or more of calcium chloride, calcium glycinate, calcium lysine, and calcium aspartate.
3. The method for extracting glyphosate from glyphosate mother liquor according to claim 2, characterized in that: In step A, hydrochloric acid is first added to the glyphosate mother solution to adjust the pH to 4.0-5.0; then calcium salt is added and stirred for reaction, and then hydrochloric acid is added to adjust the pH to between 1.1-1.3 to allow sufficient reaction to generate crystals.
4. The method for extracting glyphosate from glyphosate mother liquor according to claim 1, characterized in that: In the step C, during the alkaline dissolution process, alkali is added to adjust the pH value to between 8 and 9, so that the glyphosate calcium salt crystals are completely dissolved, and the liquid-to-solid ratio is controlled to be between (15-18):1 to obtain a glyphosate calcium salt solution.
5. The method for extracting glyphosate from glyphosate mother liquor according to claim 1, characterized in that: In the step D, ammonium sulfate solution is added while stirring to adjust the pH value of the solution to between 5 and 6.
6. The method for extracting glyphosate from glyphosate mother liquor according to claim 1, characterized in that: In the step F, the filtrate containing glyphosate is concentrated by reduced pressure evaporation at -0.01 to -0.1 MPa to 25-28% of the original volume to obtain a glyphosate concentrated solution.
7. The method for extracting glyphosate from glyphosate mother liquor according to claim 1, characterized in that: The spray drying temperature was controlled at 180-200°C.