Method for recovering glyphosate technical from glyphosate mother liquor

Abstract

The invention discloses a method for recycling glyphosate technical from glyphosate mother liquor. The method comprises the following steps: S01, absorbing hydrochloric acid tail gas generated in the production process of dimethyl phosphite by taking the glyphosate mother liquor as an absorbent; s02, fully mixing the glyphosate mother liquor absorbing the hydrochloric acid tail gas with hydrochloric acid, and storing for later use; s03, fully mixing the mixed solution stored for later use with the condensation solution, then stirring and controlling the temperature at 30-40 DEG C; s04, carrying out heating hydrolysis on the temperature-controlled mixed solution, and ensuring that the mass concentration of sodium chloride salt in hydrolysate is 5-8% after the hydrolysis reaction is finished; and S05, then carrying out cooling crystallization, and when the temperature is lower than 40 DEG C, separating the glyphosate mother liquor to obtain a glyphosate raw medicine wet product. According to the method, the glyphosate dissolved in the glyphosate mother liquor can be effectively recovered, and the yield of the glyphosate is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for recovering glyphosate technical from glyphosate mother liquor, belonging to the technical field of glyphosate production. BACKGROUND

[0002] At present, during the production of glyphosate by glycine method, unqualified glyphosate varieties such as sub-powder, dirty powder and tail powder are produced. Generally, the method of recovering glyphosate selects to dissolve in 30% hydrochloric acid, then recrystallizes by deacidification to obtain glyphosate raw powder meeting the quality standard. However, after the recovery of glyphosate technical, 6%-11% of glyphosate mother liquor is produced, which is generally selected to be transferred into the hydrolysis and crystallization process as seed crystals and recovered. However, this process scheme has the problems of large total amount of mother liquor, which cannot be completely recycled, and low recovery rate of glyphosate, 3%-6% of glyphosate cannot be recovered after the recycling of the mother liquor, resulting in the problems of large loss of finished product and high cost of wastewater disposal in the subsequent process. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the defects of the prior art and provide a method for recovering glyphosate technical from glyphosate mother liquor, which can effectively recover glyphosate dissolved in the glyphosate mother liquor and increase the recovery rate of glyphosate.

[0004] In order to solve the above technical problems, the technical scheme of the present application is as follows: a method for recovering glyphosate technical from glyphosate mother liquor, which comprises the following steps:

[0005] S01: absorbing the hydrochloric acid tail gas produced in the production of dimethyl phosphite with the glyphosate mother liquor as the absorbent;

[0006] S02: fully mixing the glyphosate mother liquor after absorbing the hydrochloric acid tail gas with hydrochloric acid and storing for standby;

[0007] S03: fully mixing the standby mixed liquid with the condensation liquid, then stirring and controlling the temperature, and controlling the temperature at 30-40℃;

[0008] S04: hydrolyzing the mixed liquid after temperature control, and ensuring that the mass concentration of sodium chloride salt in the hydrolysis liquid is 5%-8% after the hydrolysis reaction is completed;

[0009] S05: then cooling and crystallizing, and separating the glyphosate mother liquor to obtain glyphosate technical wet product when the temperature is lower than 40℃.

[0010] Further, in step S02, the hydrogen ion concentration in the glyphosate mother liquor after absorbing the hydrochloric acid tail gas is greater than or equal to 0.8 mol / L, then the glyphosate mother liquor is fully mixed with hydrochloric acid and stored for standby.

[0011] Further, in step S03, the condensation liquid is derived from a process for producing glyphosate by a glycine method.

[0012] Further, in step S03, the mass ratio of the mixed liquid to the condensation liquid is (3-5):(6-8).

[0013] Further, in step S03, the mass ratio of the mixed liquid to the condensation liquid is 4:7.

[0014] Further, in step S04, the temperature of the hydrolysis is 100-130 DEG C.

[0015] Further, in step S04, the temperature of the hydrolysis is 117-120 DEG C.

[0016] Further, in step S05, the cooling crystallization time is 8-12 h.

[0017] Further, in step S02, the hydrochloric acid is 30% hydrochloric acid.

[0018] Further, in step S02, the mass ratio of the glyphosate mother liquor after absorbing the hydrochloric acid tail gas to the hydrochloric acid is 1:(1-4).

[0019] After the above technical solution is adopted, the present application has the following beneficial effects:

[0020] 1. The method of the present application provides a recovery method of glyphosate technical in the glyphosate mother liquor, which can effectively recover the glyphosate dissolved in the glyphosate mother liquor, and reduce the loss of glyphosate technical through the glyphosate mother liquor process route;

[0021] 2. The method of the present application provides a recycling method of the glyphosate mother liquor, which can effectively reduce the output of the glyphosate mother liquor, reduce the output amount of the glyphosate mother liquor, and realize the cost saving of the harmless treatment of the mother liquor in the subsequent process;

[0022] 3. The method of the present application utilizes the mechanism that the solubility of sodium chloride is higher than that of glyphosate, realizes the salting-out effect, and increases the crystallization rate of glyphosate, thereby increasing the yield;

[0023] 4. The method of the present application realizes the increase of the concentration of sodium chloride in the crystallization system, which can reduce the use amount of the hydroxide in the crystallization liquid, and brings the cost saving of raw materials. DETAILED DESCRIPTION

[0024] The application provides a method for recovering glyphosate technical from glyphosate mother liquor, and those skilled in the art can refer to the content herein and appropriately improve the process parameters to realize it. It is particularly pointed out that all similar replacements and changes are obvious to those skilled in the art and belong to the protection scope of the application. The method and application of the application have been described through preferred embodiments, and relevant personnel can obviously make changes or appropriate changes and combinations to the method and application herein without departing from the content, spirit and scope of the application to realize and apply the technology of the application.

[0025] A method for recovering glyphosate technical from glyphosate mother liquor, wherein the method comprises the following steps:

[0026] S01: absorbing the hydrochloric acid tail gas generated in the dimethyl phosphite production process with glyphosate mother liquor as the absorbent;

[0027] S02: storing the glyphosate mother liquor after absorbing the hydrochloric acid tail gas for standby use after being fully mixed with hydrochloric acid;

[0028] S03: fully mixing the standby mixed solution with condensation liquid, then stirring and controlling the temperature, and controlling the temperature at 30-40℃;

[0029] S04: warming and hydrolyzing the mixed solution after temperature control, and ensuring that the mass concentration of sodium chloride salt in the hydrolysis solution is 5-8% after the hydrolysis reaction is completed, which is always greater than the sodium chloride salt concentration in the original process condition; since the solubility of sodium chloride salt is always greater than that of glyphosate, the water in the crystallization solution will preferentially dissolve sodium chloride salt, so the corresponding water used to dissolve glyphosate is occupied, so the crystallization section will be more conducive to the crystallization of glyphosate, and the yield of glyphosate is indirectly increased; the concentration of sodium chloride salt in the hydrolysis solution will be greater than that in the original process condition, so the demand for liquid alkali in the crystallization system will be greatly reduced, and cost savings are realized;

[0030] S05: then cooling and crystallizing, and separating the glyphosate mother liquor to obtain glyphosate technical when the temperature is lower than 40℃, at this time, the content of glyphosate in the separated mother liquor is reduced to below 1.5%, so that the recovery rate of glyphosate technical from the mother liquor is greatly improved, the glyphosate mother liquor is greatly reduced, the efficiency is improved, and cost savings are realized in the harmless treatment of the mother liquor in the subsequent process.

[0031] In the application, in step S03, the controlled temperature can be 30℃, 32℃, 34℃, 36℃, 38℃, 40℃, and of course can also be a range value with any of the above values as the upper limit or lower limit.

[0032] In the application, in step S04, the mass concentration of sodium chloride salt in the hydrolysis solution after the hydrolysis reaction is completed can be 5%, 6%, 7%, 8%, and of course can also be a range value with any of the above values as the upper limit or lower limit.

[0033] Specifically, in step S02, the hydrogen ion concentration in the glyphosate mother liquor after absorbing the hydrochloric acid tail gas reaches 0.8 mol / L or more, and then the glyphosate mother liquor is fully mixed with hydrochloric acid and stored for later use.

[0034] Specifically, in step S03, the condensation liquid is derived from the process of producing glyphosate by the glycine method; that is, the condensation liquid is generated by reacting methanol, triethylamine, glycine, dimethyl phosphite, and paraformaldehyde.

[0035] Specifically, in step S03, the mass ratio of the mixed liquid to the condensation liquid is (3-5):(6-8); in the present application, the mixed liquid can be specifically 3, 4, or 5 parts by mass, and of course can also be a range value with any of the above values as the upper limit or lower limit, and the condensation liquid can be specifically 6, 7, or 8 parts by mass, and of course can also be a range value with any of the above values as the upper limit or lower limit, and most preferably, the mass ratio of the mixed liquid to the condensation liquid is 4:7.

[0036] Specifically, in step S04, the temperature of hydrolysis is 100-130°C, and can be specifically 100°C, 110°C, 120°C, or 130°C, and of course can also be a range value with any of the above values as the upper limit or lower limit; most preferably, the temperature of hydrolysis is 117-120°C.

[0037] Specifically, in step S05, the cooling crystallization time is 8-12 h, and can be specifically 8, 9, 10, 11, or 12 h, and of course can also be a range value with any of the above values as the upper limit or lower limit.

[0038] Specifically, in step S02, the hydrochloric acid can be 30% hydrochloric acid.

[0039] Specifically, in step S02, the mass ratio of the glyphosate mother liquor after absorbing the hydrochloric acid tail gas to hydrochloric acid can be 1:(1-4); in the present application, the glyphosate mother liquor after absorbing the hydrochloric acid tail gas is 1 part by mass, and the hydrochloric acid can be 1, 2, 3, or 4 parts by mass, and of course can also be a range value with any of the above values as the upper limit or lower limit.

[0040] In the present application, glyphosate mother liquor is used as an absorbent for hydrochloric acid gas, replacing the traditional process of using soft water as an absorbent, greatly reducing the amount of soft water entering the system, directly reducing the amount of mother liquor harmless treatment in the subsequent process; and thereby achieving cost savings;

[0041] In the method of the present application, the prepared glyphosate mother liquor and hydrochloric acid mixed solution replaces the traditional process mother liquor directly into the hydrolysis for production, which has disadvantages. For example, the direct entry of the mother liquor into the hydrolysis will cause uneven material concentration for a period of time, which directly affects the first yield of glyphosate. At the same time, the direct entry into the hydrolysis will cause the fluctuation of the hydrolysis temperature index, which will affect the quality and yield of glyphosate. The method of the present application adopts a plurality of means such as glyphosate mother liquor tail gas absorption, acid mixing, condensation liquid acidification, and stirring cooling to keep the reaction liquid in a homogeneous state and does not cause the influence of temperature control and concentration in the hydrolysis process, which fully guarantees the reaction conditions.

[0042] In step S03, the prepared condensation liquid mixed acid liquid is cooled before entering the hydrolysis, which avoids the rapid temperature rise of the mixed acid liquid entering the hydrolysis kettle directly, causing a large amount of methanol and methylal in the mixed acid liquid to volatilize, avoiding the boiling overflow of the hydrolysis kettle, causing the material to enter the gas phase and unable to generate glyphosate, which affects the yield;

[0043] In the present application, the glyphosate mother liquor recycling production system does not need to be desalted compared with the traditional process, and the hydrochloric acid tail gas is directly mixed with hydrochloric acid, which realizes the recycling of glyphosate TC in the glyphosate mother liquor, saves the desalting operation process required in the original process, and saves the process cost, energy consumption cost, equipment investment and depreciation cost;

[0044] In addition, in the present application, the mass concentration of sodium chloride salt in the hydrolysis liquid is 5%-8%, which is always greater than the sodium chloride salt concentration under the original process conditions. Since the solubility of the salt is always greater than that of glyphosate, the water in the crystallization liquid will preferentially dissolve the sodium chloride salt, so the corresponding water used to dissolve glyphosate is occupied, so the crystallization section will be more conducive to the crystallization of glyphosate, and indirectly realizes the increase of the yield of glyphosate.

[0045] In order to make the content of the present application more easily understood, the present application will be further described in detail according to specific examples.

[0046] Example 1

[0047] S01: The glyphosate mother liquor is used as an absorbent to absorb the hydrochloric acid tail gas generated in the dimethyl phosphite production process;

[0048] S02: When the glyphosate mother liquor absorbs hydrogen chloride gas and the hydrogen ion concentration reaches 0.8 mol / L, it is mixed with 30% hydrochloric acid product in a static mixer for sufficient mixing, and finally transported to a buffer tank for storage for standby use; wherein the glyphosate mother liquor for absorbing the hydrochloric acid tail gas is 1.25 tons; the 30% hydrochloric acid is 3.75 tons, and the mass ratio of the two is 1:3;

[0049] S03: Take the material in the buffer tank 4 tons, condensation liquid 7 tons through flow metering after the mass ratio of 4:7 into the static mixer for fully mixing, and finally transported to the mixed acid buffer tank for stirring cooling, and control the temperature at 30-40℃;

[0050] S04: After stirring for 20 minutes at 30-40℃, transported to the hydrolysis kettle for heating to 117℃ for hydrolysis, the hydrolysis reaction was finished and discharged to the crystallization kettle, at this time the mass of sodium chloride salt in the hydrolysis liquid was 0.803 tons, and the mass concentration was 7.3%;

[0051] S05: Cooling crystallization for 8h, when the temperature is lower than 40℃, separate the glyphosate mother liquor to obtain glyphosate technical material wet product 1.476 tons, at this time the separated glyphosate mother liquor is 4.562 tons, and the content of glyphosate is reduced to 1.31%, which is below 1.5%.

[0052] Example two

[0053] S01: The glyphosate mother liquor is used as an absorbent to absorb the hydrogen chloride tail gas generated in the dimethyl phosphite production process;

[0054] S02: When the glyphosate mother liquor absorbs hydrogen chloride gas and the hydrogen ion concentration reaches 0.8 mol / L, it is mixed with 30% hydrochloric acid product in a static mixer, and finally transported to a buffer tank for storage;

[0055] S03: Take the material in the buffer tank 4 tons and 7 tons of condensation liquid through flow metering after the mass ratio of 4:7 into the static mixer for fully mixing, and finally transported to the mixed acid buffer tank for stirring cooling, and control the temperature at 30-40℃;

[0056] S04: After stirring for 30 minutes at 30-40℃, transported to the hydrolysis kettle for heating to 110℃ for hydrolysis, the hydrolysis reaction was finished and discharged to the crystallization kettle, at this time the mass concentration of sodium chloride salt in the hydrolysis liquid was 7.5%;

[0057] S05: Cooling crystallization for 12h, when the temperature is lower than 40℃, separate the glyphosate mother liquor to obtain glyphosate technical material wet product 1.479 tons, at this time in the 5.7 tons of glyphosate mother liquor, there are 0.0741 tons of glyphosate, the content is 1.3%, which is reduced to below 1.5%.

[0058] Example three

[0059] S01: The glyphosate mother liquor is used as an absorbent to absorb the hydrogen chloride tail gas generated in the dimethyl phosphite production process;

[0060] S02: When the glyphosate mother liquor absorbs hydrogen chloride gas, and the hydrogen ion concentration reaches 0.8 mol / L, it is mixed with 30% hydrochloric acid product in a static mixer, and finally transported to a buffer tank for storage; wherein the glyphosate mother liquor for absorbing hydrochloric acid tail gas is 1.3 tons; 30% hydrochloric acid is 3.7 tons;

[0061] S03: 4 tons of material in the buffer tank and 7 tons of condensation liquid are mixed in a static mixer according to the mass ratio of 4:7, and finally transported to an acid mixing buffer tank for stirring and cooling, and the temperature is controlled at 30-40℃;

[0062] S04: After stirring for 25 minutes at 30-40℃, it is transported to a hydrolysis kettle for heating to 125℃ for hydrolysis, and the hydrolysis reaction is discharged to a crystallization kettle, at this time the mass concentration of sodium chloride salt in the hydrolysis liquid is 7.37%;

[0063] S05: Crystallization for 10h, when the temperature is lower than 40℃, separate the glyphosate mother liquor to obtain 1.487 tons of glyphosate wet product, at this time, 0.0729 tons of glyphosate is contained in 5.53 tons of glyphosate mother liquor after separation, the content is 1.32%, which is reduced to below 1.5%.

[0064] The above specific embodiments further illustrate the technical problems solved by the present application, technical solutions and beneficial effects. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for recovering glyphosate technical from glyphosate mother liquor, characterized in that: The method steps include: S01: Using glyphosate mother liquor as an absorbent to absorb the hydrochloric acid tail gas generated during the production of dimethyl phosphite; S02: The glyphosate mother liquor after absorbing the hydrochloric acid tail gas is fully mixed with hydrochloric acid and stored for future use; S03: fully mixing the stored mixed solution with the condensation solution, and then stirring and controlling the temperature to 30°C to 40°C; S04: heating the temperature-controlled mixed solution for hydrolysis, and ensuring that the mass concentration of sodium chloride in the hydrolyzate is 5% to 8% after the hydrolysis reaction is completed; S05: Then, the temperature is lowered and crystallized. When the temperature is lower than 40°C, the glyphosate mother liquor is separated to obtain the glyphosate technical wet product.

2. The method according to claim 1, characterized in that In step S02, after the hydrogen ion concentration in the glyphosate mother liquor after absorbing the hydrochloric acid tail gas reaches above 0.8 mol / L, it is fully mixed with hydrochloric acid and stored for later use.

3. The method according to claim 1, characterized in that In step S03, the condensation liquid is derived from the process of producing glyphosate by the glycine method.

4. The method according to claim 1, wherein In step S03, the mass ratio of the mixed liquid to the condensation liquid is: (3-5): (6-8).

5. The method according to claim 4, characterized in that In step S03 , the mass ratio of the mixed liquid to the condensation liquid is 4:

7.

6. The method according to claim 1, characterized in that In step S04, the hydrolysis temperature is 100°C to 130°C.

7. The method according to claim 6, characterized in that In step S04, the hydrolysis temperature is 117-120°C.

8. The method according to claim 1, characterized in that In step S05, the cooling crystallization time is 8 to 12 hours.

9. The method according to claim 1, characterized in that In step S02, the hydrochloric acid is 30% hydrochloric acid.

10. The method according to claim 1, characterized in that In step S02, the mass ratio of the glyphosate mother liquor after absorbing the hydrochloric acid tail gas to the hydrochloric acid is 1:(1-4).