WO2022246866A1

WO2022246866A1 - Treatment method for acesulfame potassium waste liquid

Info

Publication number: WO2022246866A1
Application number: PCT/CN2021/097014
Authority: WO
Inventors: 周睿; 丁震; 陈永旭; 郑仁峰; 杨峰宝
Original assignee: 安徽金禾实业股份有限公司
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2022-12-01
Also published as: CN113474325A; CN113474325B

Abstract

A treatment method for an acesulfame potassium waste liquid. The acesulfame potassium waste liquid is a waste liquid generated in preparation of acesulfame potassium by adopting a diketene-sulfur trioxide method. The treatment method comprises: a pH adjustment step: adding a first material flow into the acesulfame potassium waste liquid until the pH value of the acesulfame potassium waste liquid is not less than 13, so as to obtain a second material flow, wherein the first material flow is a residual liquid generated in the following crystallization step or a saturated sodium hydroxide or potassium hydroxide solution; a neutralization and separation step: adding a sodium hydroxide or potassium hydroxide solid into the first material flow, stirring until the sodium hydroxide or potassium hydroxide solid is completely dissolved, standing for a period of time to obtain an organic phase and an aqueous phase, and recycling the organic phase as a triethylamine crude product; and a crystallization step: crystallizing the aqueous phase, and filtering same to obtain sodium sulfate or potassium sulfate and the residual liquid.

Description

Treatment method of acesulfame waste liquid

technical field

The invention belongs to the technical field of fine chemicals, and in particular relates to a treatment method for acesulfame potassium waste liquid.

Background of the invention

Acesulfame potassium (acesulfame potassium), also known as AK sugar, is a widely used sugar substitute food additive. Its appearance is white crystalline powder. As an organic synthetic salt, its taste is similar to sugarcane, and it is easily soluble in water. , Slightly soluble in alcohol, its chemical properties are stable, and it is not easy to break down and fail; it does not participate in the body's metabolism and does not provide energy; it has high sweetness and low price; it has no cariogenicity; it has good stability to heat and acid.

At present, in the synthesis of acesulfame potassium, the diketene-sulfur trioxide method is widely used. The specific reaction steps include: reacting sulfamic acid with amine to form amine sulfamic acid salt, and then reacting amine sulfamic acid with diketene , forming acetylacetamide salt; in the presence of sulfur trioxide, acetylacetamide salt undergoes a cyclization reaction to form a cyclic sulfur trioxide adduct; the cyclic compound is hydrolyzed to obtain a hydrolyzate; subsequent treatment with potassium hydroxide for hydrolysis The product is thus obtained as acesulfame potassium (ASK).

In the above-mentioned production process, when sulfamic acid and diketene are added to react, amines, especially triethylamine, are used as reaction catalysts. After the final product ASK is obtained, the remaining waste water mainly contains amine sulfate, sulfuric acid, impurities Organic matter (triethylamine, solvents, etc.), this part of the wastewater can be discharged after treatment; but on the one hand, this will generate a lot of treatment costs, on the other hand, the amine in the wastewater has a high economic value, and the discharge causes resource waste. waste.

In the prior art, there is a treatment method that uses ammonia (ammonia gas, liquid ammonia, etc.) to react with amine sulfate and sulfuric acid to generate ammonium sulfate and recover amine, such as Chinese patent CN103097297A, Chinese patent CN111630039A and Chinese patent CN112142602A, etc. , but these methods usually use heating and evaporation to obtain the crude amine product from the water phase. The crude product of the amine not only has a high water content, but also requires more steps for subsequent treatment; and the crude product of the amine is recovered in a layered manner. It needs to stand for a long time, and the time cost is high; the waste liquid retained after the crude amine product is separated is usually directly treated in a harmless manner to obtain sulfate by-products, which will also generate a large amount of treatment costs.

Contents of the invention

In view of the above problems, the present application is proposed in order to provide a method for treating waste acesulfame potassium that overcomes the above problems or at least partially solves the above problems.

According to one aspect of the present application, a kind of processing method of acesulfame potassium waste liquid is provided, and acesulfame potassium waste liquid is the waste liquid produced by adopting diketene-sulfur trioxide method to prepare acesulfame potassium, comprising:

pH value adjustment step: adding a first material flow to the acesulfame waste liquid until the pH value of the acesulfame waste liquid is not less than 13, to obtain a second material flow, wherein the first material flow It is the raffinate or saturated sodium hydroxide or potassium hydroxide solution produced in the following crystallization steps;

Neutralization and separation step: adding sodium hydroxide or potassium hydroxide solid to the second material flow, stirring until completely dissolved, and standing for a period of time to obtain an organic phase and an aqueous phase, and using the organic phase as triethylamine Crude product recovery; and

Crystallization step: crystallize and filter the water phase to obtain sodium sulfate or sodium sulfate and residual liquid.

Optionally, in the above method, the mass ratio of sodium hydroxide or potassium hydroxide solid to the acesulfame potassium waste liquid is 100:10-32.

Optionally, in the above method, when the acesulfame-K waste liquid is treated for the first time, in the pH adjustment step, at room temperature, add acesulfame-K waste liquid with a mass equal to the quality of the acesulfame-K waste liquid 20-60% saturated sodium hydroxide or potassium hydroxide solution to adjust the pH value of the acesulfame potassium waste liquid.

Optionally, in the above method, based on the total mass of the acesulfame potassium waste liquid, the acesulfame potassium waste liquid includes: 10-30wt% sulfuric acid, 5-20wt% triethylamine sulfate, 3-5wt% impurity organic matter.

Optionally, in the above method, in the neutralization and separation step, a period of time is 1-30min.

Optionally, in the above method, in the neutralization and separation step, a period of time is 10-20min.

Optionally, in the above method, in the crystallization step, the water phase is evaporated to crystallize sodium sulfate, wherein the evaporated water has a mass of 5-70% of the mass of the acesulfame potassium waste liquid.

Optionally, the above method further includes: a recrystallization step, dissolving sodium sulfate in sulfuric acid, adjusting the pH value to 6-8, and then performing recrystallization.

Optionally, in the above method, before the crystallization step, the method further includes: adjusting the pH value of the aqueous phase to 6-8 by using acesulfame potassium waste liquid.

Optionally, in the above method, the water content in the recovered crude triethylamine product is not more than 5wt%.

The beneficial effects of the present application are: the acesulfame potassium waste liquid is adjusted to strong alkalinity by sodium hydroxide or potassium hydroxide, on the one hand because sodium hydroxide or potassium hydroxide can be combined with the triethylamine sulfuric acid in the acesulfame potassium waste liquid Salt and sulfuric acid react quickly to generate triethylamine and sodium sulfate or potassium sulfate. On the other hand, because sodium hydroxide or potassium hydroxide dissolves in waste water, a large amount of heat is generated, which makes the temperature of acesulfame potassium waste liquid rise and promote The generated triethylamine can be quickly separated from the water phase, which greatly saves the treatment time of acesulfame potassium waste liquid; the generated sodium sulfate or potassium sulfate exists in the water phase, which can be crystallized during the natural cooling process Precipitation, no special process is required, and the treatment cost is low; the remaining waste liquid can be directly mixed into the acesulfame waste liquid for recycling, and the entire treatment process does not generate additional waste that needs to be reprocessed. This application greatly shortens the time for acesulfame waste liquid treatment, reduces the cost of waste liquid treatment, greatly simplifies the process of acesulfame waste liquid treatment, and simplifies the recovery of products such as triethylamine and sodium sulfate or The follow-up treatment process of potassium sulfate; the price of raw materials input in this application is relatively low, and the products produced have economic value, and various valuable components of wastewater are comprehensively utilized to maximize economic benefits. The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Modes of Carrying Out the Invention

Exemplary embodiments of the present application will be described in more detail below. It should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for thorough understanding of this application, and to fully convey the scope of this application to those skilled in the art.

For preparing the waste liquid produced by acesulfame potassium, the existing treatment means is to adopt alkaline substances, including ammonia (water), caustic soda, calcium oxide (calcium hydroxide) etc. to treat waste water, thereby converting triethylamine from triethylamine Released from sulfate, distillation can be obtained crude triethylamine. But there is azeotropic phenomenon in triethylamine and water, the water content of the triethylamine crude product that adopts the means of distillation to obtain is higher (water content is about 15-20wt%), also needs to carry out further treatment; In addition, reclaim triethylamine The ammonium sulfate or calcium sulfate produced will generate more waste water, waste liquid and waste gas during the further treatment process, and the treatment cost is high.

In view of this, the present application aims at the problems of complex, time-consuming and high-cost acesulfame waste liquid treatment processes in the prior art, and provides a treatment method for acesulfame potassium, by adding excessive Sodium hydroxide or potassium hydroxide, using sodium hydroxide or potassium hydroxide to dissolve and release a lot of heat, promotes the rapid separation of triethylamine and water phase; and the whole process does not generate additional waste that needs to be treated, forming an automatic Circulation system, the residual liquid can be directly refluxed, which significantly shortens the processing time and reduces the complexity of the processing process, and the recovered products have high economic value.

The treatment method of acesulfame-K waste liquid provided by this application includes at least step S110 to step S130:

pH value adjustment step S110: Adding the first material flow to the acesulfame potassium waste liquid until the pH value of the acesulfame potassium waste liquid is not less than 13 to obtain the second material flow, wherein the first material flow is the following crystallization step The residual liquid or saturated sodium hydroxide or potassium hydroxide solution.

The acesulfame potassium waste liquid in this application is the waste liquid produced by the preparation of acesulfame potassium by diketene-sulfur trioxide method. Taking triethylamine as a catalyst, there is a sulfate of triethylamine in the acesulfame potassium waste liquid , sulfuric acid, impurity organic matter, such as triethylamine, and water.

In the process of preparing acesulfame potassium, triethylamine exists as a catalyst. In the whole preparation process, the amount of triethylamine is not consumed. At the end of the reaction, triethylamine is almost completely converted into triethylamine sulfate, and there is A very small amount of triethylamine remains in the impurity organic matter.

The application provides a self-circulating acesulfame waste liquid treatment method. In this method, since sodium hydroxide or potassium hydroxide is excessive, there is also With a large amount of sodium hydroxide or potassium hydroxide, this part of the residual liquid can be used as the first material flow and added to the waste liquid of acesulfame potassium. On the one hand, this part of the residual liquid can regulate the pH value of the waste liquid of acesulfame potassium The role of the acesulfame potassium waste liquid is strongly alkaline. On the other hand, this part of the remaining liquid does not need additional treatment, which greatly saves the treatment cost and simplifies the treatment process.

When treating the acesulfame potassium waste liquid for the first time, there is no residual liquid. In this case, a saturated sodium hydroxide or potassium hydroxide solution can be added to the acesulfame potassium waste liquid to achieve the purpose of pH adjustment. In some embodiments of the present application, when acesulfame potassium waste liquid is treated for the first time, in the pH adjustment step, acesulfame potassium waste liquid with a mass of acesulfame potassium waste liquid can be added at room temperature. 20-60% saturated sodium hydroxide or potassium hydroxide solution to adjust the pH value of the acesulfame potassium waste liquid to not less than 13.

The addition amount of the first material stream can be determined according to the pH value of the waste acesulfame potassium, so as to adjust until the pH value of the waste acesulfame potassium is not less than 13.

The acesulfame potassium waste liquid after adjusting the pH value is the second material stream.

It should be noted that the words "first" and "second" appear in this application, and "first" and "second" do not have any practical meaning, but are only used as distinguishing marks, and will not be described in detail below.

Neutralization and separation step S120: Add sodium hydroxide or potassium hydroxide solids to the second material flow, stir until completely dissolved, and let stand for a period of time to obtain an organic phase and an aqueous phase, and use the organic phase as a crude triethylamine Product recycling.

Add excessive sodium hydroxide or potassium hydroxide solid in the waste liquid of acesulfame potassium, the added sodium hydroxide or potassium hydroxide are solid alkaline matter, sodium hydroxide or potassium hydroxide are dissolved in the waste liquid of acesulfame potassium During the process, a large amount of heat will be released; the sodium hydroxide or potassium hydroxide dissolved in the waste liquid exists in an ion state, and the sodium hydroxide or potassium hydroxide reacts with the triethylamine sulfate and sulfuric acid in the waste liquid of acesulfame potassium The reaction generates triethylamine and sodium sulfate or potassium sulfate, triethylamine is separated from the water phase as an organic matter, and sodium sulfate and potassium sulfate are dissolved in water.

The inventors have found that the dissolution of sodium hydroxide or potassium hydroxide makes the acesulfame potassium waste liquid mixture more alkaline and the temperature rises rapidly. In the acesulfame potassium waste liquid mixture, the organic phase mainly composed of triethylamine The speed of stratification with the water phase is greatly accelerated, and the water phase and the organic phase can be separated in a short time.

In some embodiments of the present application, in the neutralization and separation step, there is no limit to the standing time, and the organic phase and the aqueous phase can be separated. In some embodiments of the present application, acesulfame potassium waste After the liquid reacts with sodium hydroxide or potassium hydroxide, the effective separation of the organic phase and the water phase can be realized by standing for 1-30 minutes. In other embodiments, the separation of the organic phase and the water phase can be realized by standing for 10-20 minutes. effective separation.

The second material stream reacts with sodium hydroxide or potassium hydroxide. After standing for a period of time, the organic phase and the aqueous phase will be separated. In the camera, it contains the generated triethylamine and the triethylamine used in the preparation of acesulfame potassium. Solvent; in the water phase, there are also unreacted sodium hydroxide or potassium hydroxide, sodium sulfate or potassium sulfate, unreacted sulfate radicals and a very small amount of impurity organic matter in the water phase, i.e. triethylamine.

The organic phase can be directly recovered as the crude product of triethylamine; the aqueous phase continues to be processed.

Crystallization step S130: crystallize and filter the water phase to obtain sodium sulfate or potassium sulfate and a residual liquid. The solubility of sodium sulfate or potassium sulfate varies with temperature. Taking sodium sulfate as an example, at 40°C, the solubility of sodium sulfate is 48.8g/100mL, and at 20°C, the solubility of sodium sulfate is 19.9g/100mL. Therefore, as the temperature decreases, sodium sulfate solution will precipitate from the waste acesulfame potassium. Therefore, the obtained water phase can be introduced into the crystallization tank for natural cooling and crystallization, and the obtained sodium sulfate, which is crystallized by natural cooling, usually exists in the form of hydrate, i.e. sodium sulfate hydrate, after crystallization The resulting raffinate is the first stream.

In order to accelerate the crystallization of sodium sulfate or potassium sulfate, in some embodiments of the present application, the water phase can be evaporated and/or further cooled to crystallize sodium sulfate or potassium sulfate. What is obtained is anhydrous sodium sulfate or potassium sulfate, and the crystallization by cooling is used to obtain sodium sulfate or potassium sulfate hydrate. In some embodiments of the present application, the evaporative crystallization method is adopted, and the mass of the evaporated water is 5%-70% of the mass of the acesulfame potassium waste liquid. If the quality of evaporated water is less than 5% of the total mass of acesulfame-K waste liquid, it cannot promote the precipitation of sodium sulfate or potassium sulfate; if the quality of evaporated water is more than the total mass of acesulfame-K waste liquid 70%, other substances may separate out in the water, resulting in low purity of sodium sulfate or potassium sulfate obtained.

In order to further improve the purity of sodium sulfate or potassium sulfate crystals, in some embodiments of the present application, a recrystallization step is also included: dissolving sodium sulfate or potassium sulfate in sulfuric acid for recrystallization. Among them, sulfuric acid is preferably dilute sulfuric acid. First, sodium sulfate or potassium sulfate is dissolved in dilute sulfuric acid, and its pH is adjusted to neutrality, and then recrystallized, which can effectively prevent other particles from being accompanied by sodium sulfate or potassium sulfate during recrystallization. Potassium sulfate is precipitated, causing the phenomenon that the purity is not high.

Similarly, in order to make the sodium sulfate or potassium sulfate crystals of high purity, before the crystallization step, acesulfame waste liquid can also be used to adjust the pH value of the aqueous phase to 6-8, and then introduce it into the crystallization tank for crystallization.

In the first material stream, there are unreacted sodium hydroxide or potassium hydroxide, a small amount of sodium triethylamine sulfate or potassium sulfate, sulfuric acid, a very small amount of triethylamine, etc., therefore, no additional substances to be treated are produced , the first material flow can be directly returned to the acesulfame waste liquid for recycling treatment, which greatly simplifies the complexity of acesulfame waste liquid treatment.

In the first material stream, there is also part of unreacted sodium hydroxide or potassium hydroxide, these sodium hydroxide or potassium hydroxide are dissolved in the waste liquid, equivalent to forming sodium hydroxide or potassium hydroxide solution, in In this application, the inventors found that a part of the residual liquid produced in the previous cycle treatment process was first added to the waste liquid obtained from the production of acesulfame potassium, and the pH of the acesulfame waste liquid was adjusted in advance, which is equivalent to Adding a part of sodium hydroxide or potassium hydroxide solution to the liquid, and then adding excess sodium hydroxide or potassium hydroxide solid, can promote the separation of the organic phase and the aqueous phase mainly based on triethylamine. The aqueous and triethylamine phases can be separated within a short period of time.

The application is by first adjusting the waste liquid of acesulfame to strong alkalinity, then adding sodium hydroxide or potassium hydroxide solid to react, on the one hand because sodium hydroxide can be combined with the triethylamine sulfate and the triethylamine sulfate in the waste liquid of acesulfame Sulfuric acid reacts quickly to generate triethylamine and sodium sulfate. On the other hand, a large amount of heat is generated when sodium hydroxide or potassium hydroxide dissolves in wastewater, which increases the temperature of acesulfame potassium waste liquid and promotes the generation of triethylamine. It can be quickly separated from the water phase, thereby greatly saving the treatment time of acesulfame potassium waste liquid; there is sodium sulfate or sodium sulfate formed in the water phase, which can be crystallized during natural cooling without special processes , low treatment cost; the remaining waste liquid can be directly mixed into the acesulfame waste liquid for recycling, and the whole treatment process does not generate additional waste that needs to be reprocessed. The present application greatly shortens the time for acesulfame waste liquid treatment, reduces the cost of waste liquid treatment, greatly simplifies the process of acesulfame waste liquid treatment, and simplifies the recovery of products such as triethylamine and sodium sulfate. Subsequent treatment process: The price of raw materials input in this application is relatively low, and the products produced have economic value, and various valuable components of wastewater are comprehensively utilized to maximize economic benefits.

Dosage of Sodium Hydroxide or Potassium Hydroxide

In the present application, in the neutralization and separation step, the amount of sodium hydroxide or potassium hydroxide is not limited, but in order to achieve the purpose of rapidly stratifying the acesulfame potassium waste liquid, in some embodiments of the application, it is recommended Use sodium hydroxide or potassium hydroxide with a mass ratio of 100:10-32 to the waste liquid of acesulfame potassium. On the one hand, the amount of sodium hydroxide or potassium hydroxide affects the separation effect of triethylamine. On the other hand, from the perspective of the entire treatment process, sodium hydroxide or potassium hydroxide is subsequently converted into sodium sulfate to be removed from the reaction system. Within the above recommended range, ideal results can be achieved.

Sources of acesulfame waste liquid and the content of each substance in it

The source of acesulfame-K waste liquid is that the factory adopts the diketene-sulfur trioxide method in the prior art to prepare acesulfame-K. Usually based on the total mass of acesulfame potassium waste liquid, the acesulfame potassium waste liquid includes 10-30wt% sulfuric acid, 5-20wt% triethylamine sulfate and 3-5wt% impurity organic matter, and the rest is water.

After testing, it is found that the water content in the crude triethylamine product recovered by the method of the present application is not more than 5wt%.

Acquisition of waste liquid: acesulfame potassium is prepared by diketene-sulfur trioxide method, and the aqueous phase and organic phase are separated after the salt-forming step, wherein the aqueous phase is the waste liquid that needs to be treated in this application. In the waste liquid, the mass of sulfuric acid The fraction is 10-30%, the mass fraction of triethylamine sulfate is 5-20%, the mass fraction of impurity organic components is 3-5%, and the balance is water. If there is no special instruction, the used acesulfame potassium waste liquid is obtained by this method. If there is a special instruction, it is obtained according to the instruction.

Example 1

Get 1000kg waste liquid, get sample, measure and contain through high performance liquid chromatography analysis method: 30kg triethylamine sulfate, 100kg sulfuric acid. First, at room temperature (about 20° C.), 185 kg of saturated aqueous solution of sodium hydroxide was added, and the measured pH value was greater than 13.

Add 92kg of sodium hydroxide therein again, after stirring and dissolving, separate layers after standing for 10min, wherein the oil phase, that is, the organic phase is taken out as the crude product of triethylamine and recovered.

The water phase is introduced into the evaporator, and the amount of evaporated water is controlled to be about 730kg, and 368kg of sodium sulfate decahydrate is crystallized by natural cooling; and the remaining liquid is collected.

The remaining liquid was added to 1000kg of acesulfame-K waste liquid, and the pH value of the acesulfame-K waste liquid was measured to be greater than 13, and the next cycle treatment reaction was carried out. In the acesulfame potassium waste liquid, at room temperature (about 20°C), add 185kg of saturated aqueous solution of sodium hydroxide; then add 92kg of sodium hydroxide, stir evenly and wait for the sodium hydroxide to dissolve, then let it stand for about 15 minutes, then divide Layer, wherein the organic phase is taken out, the water phase is introduced in the evaporator, the amount of water evaporated is controlled to be about 730kg, and 368kg of sodium sulfate decahydrate is separated out by natural cooling and crystallization.

Example 2

Get 1000kg acesulfame waste liquid, contain about 50kg triethylamine sulfate, 150kg sulfuric acid through measuring.

At room temperature (20° C.), add 280 kg of saturated sodium hydroxide aqueous solution; then add 140 kg of sodium hydroxide, after dissolving, let stand for 15 minutes, separate layers, and take out the organic phase as a crude product of triethylamine for recovery.

The water phase was introduced into the MVR evaporator, and the amount of water evaporated was controlled to be about 580kg. After cooling and crystallizing, 560kg of sodium sulfate decahydrate was precipitated, and a residual liquid was obtained.

The remaining liquid was added to 1000kg of acesulfame waste liquid, and the pH value of the acesulfame waste liquid was measured to be greater than 13, and the next cycle treatment process was carried out. At room temperature (20°C), add 280kg of saturated aqueous solution of sodium hydroxide; then add 140kg of sodium hydroxide, after dissolving, let it stand for 15 minutes, separate layers, take out the organic phase, and introduce the water phase into the MVR evaporator or other In the type evaporation crystallizer, the amount of water to be evaporated is controlled to be about 580kg, and 560kg of sodium sulfate decahydrate is precipitated by cooling and crystallization, and a residual liquid is obtained.

Example 3

Get 1000kg acesulfame waste liquid, contain about 90kg triethylamine sulfate, 200kg sulfuric acid through measuring.

At room temperature (20°C), add 390kg of saturated sodium hydroxide aqueous solution; then add 195kg of sodium hydroxide, after dissolving, let stand for 30min, separate layers, take out the organic phase and recover it as a crude triethylamine product.

The water phase was introduced into the MVR evaporator, and the amount of water evaporated was controlled to be about 415kg. After cooling and crystallizing, 780kg of sodium sulfate decahydrate was precipitated, and a residual liquid was obtained.

Then the remaining liquid enters the next cycle treatment process, and the remaining liquid is added to 1000kg of acesulfame potassium waste liquid, and the pH value of the acesulfame potassium waste liquid is measured to be greater than 13, and 195kg of sodium hydroxide is added, dissolved, and left to stand for 30 minutes , layering, wherein the organic phase is taken out, the water phase is introduced in the MVR evaporator, the amount of water evaporated is controlled to be about 415kg, and 780kg of sodium sulfate decahydrate and residual liquid are separated out by cooling and crystallization.

Example 4

Get 1000kg acesulfame waste water, contain about 200kg triethylamine sulfate, 300kg sulfuric acid through determination. At room temperature (about 20°C), add 640kg of saturated aqueous solution of sodium hydroxide to it; then add 320kg of sodium hydroxide, stir and dissolve, let stand for 20 minutes, separate layers, take out the organic phase, and introduce the water phase In the evaporation crystallizer, the amount of water to be evaporated is controlled to be about 50kg, and 1280kg of sodium sulfate decahydrate is separated out by cooling and crystallization, and a residual liquid is obtained.

Subsequently, the remaining liquid enters the next cycle treatment process, and the remaining liquid is added to 1000 kg of acesulfame waste liquid, and the pH value of the acesulfame potassium waste liquid is measured to be greater than 13. Add 320kg of sodium hydroxide to it, stir and dissolve, let it stand for 20 minutes, separate layers, take out the organic phase, introduce the water phase into the evaporation crystallizer, control the amount of evaporated water to be about 60kg, and cool and crystallize to precipitate sodium sulfate decahydrate 1280kg, and obtain residual liquid.

In the above embodiments, the waste liquid is treated with sodium hydroxide as an example, and the waste liquid can also be treated with potassium hydroxide. The addition of potassium hydroxide solution and potassium hydroxide solid can be adjusted accordingly according to the total amount of triethylamine sulfate and sulfuric acid in the waste liquid. In the present application, only sodium hydroxide or potassium hydroxide is used in a single embodiment; in one embodiment, sodium hydroxide solution and sodium hydroxide solid are added successively, or potassium hydroxide solution and potassium hydroxide solid are added successively; The case of adding sodium hydroxide solution and potassium hydroxide solid or separately adding potassium hydroxide solution and sodium hydroxide solid is not included.

Comparative example 1

See CN111518056A. Take 100mL crystallization waste liquid in a 1000mL beaker, put in a water bath at 40°C, and slowly add 20mL of 50% hydrogen peroxide while stirring. After the addition, a large number of bubbles are generated, and the temperature is naturally raised to above 90°C. After the reaction is completed, almost no bubbles emerge. After about 20 minutes, after cooling down, the solution has changed from dark brown before the reaction to about 110 mL of bright yellow transparent solution, and almost no organic components are detected by gas chromatography.

Take 110mL of the bright yellow transparent solution obtained above, and add dropwise to 500mL of the acidic dichloromethane organic phase (the dichloromethane solution after sulfonation and cyclization hydrolysis in the production process of acesulfame potassium), and there will be bubbles continuously, and when there are at least a small amount of bubbles, The pH value is about 7-8. A small amount of 40% potassium hydroxide was added until the pH value of the solution was 9-10, dichloromethane was distilled off, decolorized with activated carbon, evaporated and crystallized to obtain 70 g of acesulfame-K crude product. The results show that the average yield (68-70g) of acesulfame potassium primary sugar is almost unchanged, the content is >98.0%, the color is slightly yellow, does not contain sulfate, and the crude product is consistent.

In the comparison example, hydrogen peroxide is used to treat the waste liquid, and other solutions are added, the product treatment is complicated, and more energy is needed, so it is not economical.

In summary, the application adjusts the acesulfame potassium waste liquid to strong alkalinity first, and then adds sodium hydroxide or potassium hydroxide solid to react. The triethylamine sulfate in the liquid reacts quickly with sulfuric acid to generate triethylamine and sodium sulfate or potassium sulfate. On the other hand, a large amount of heat is generated when sodium hydroxide or potassium hydroxide dissolves in wastewater, making acesulfame potassium waste The temperature of the liquid increases, and the triethylamine that is promoted can be separated from the water phase quickly, thereby saving the treatment time of the acesulfame potassium waste liquid to a great extent; there is sodium sulfate or potassium sulfate generated in the water phase. It can be crystallized and precipitated during the natural cooling process, no special process is required, and the treatment cost is low; the remaining waste liquid can be directly mixed into the acesulfame waste liquid for recycling treatment, and the entire treatment process does not generate additional waste that needs to be reprocessed. This application greatly shortens the time for acesulfame waste liquid treatment, reduces the cost of waste liquid treatment, greatly simplifies the process of acesulfame waste liquid treatment, and simplifies the recovery of products such as triethylamine and sodium sulfate or The follow-up treatment process of potassium sulfate; the price of raw materials input in this application is relatively low, and the products produced have economic value, and various valuable components of wastewater are comprehensively utilized to maximize economic benefits.

The above description is only a specific implementation manner of the present application, and those skilled in the art can make other improvements or modifications on the basis of the above embodiments under the above teaching of the present application. Those skilled in the art should understand that the above specific description is only to better explain the purpose of the present application, and the protection scope of the present application should be based on the protection scope of the claims.

In addition, those skilled in the art will appreciate that although some embodiments described herein include some features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the present application. and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

Claims

A kind of processing method of acesulfame potassium waste liquid, described acesulfame potassium waste liquid is the waste liquid that adopts diketene-sulfur trioxide method to prepare acesulfame potassium to produce, it is characterized in that, comprises:

pH value adjustment step: adding a first material flow to the acesulfame waste liquid until the pH value of the acesulfame waste liquid is not less than 13, to obtain a second material flow, wherein the first material flow It is the raffinate or saturated sodium hydroxide or potassium hydroxide solution produced in the following crystallization steps;

Neutralization and separation step: adding sodium hydroxide or potassium hydroxide solid to the first material flow, stirring until completely dissolved, and standing for a period of time to obtain an organic phase and an aqueous phase, and using the organic phase as triethylamine Crude product recovery; and

Crystallization step: crystallize and filter the water phase to obtain sodium sulfate or potassium sulfate and residual liquid.
method according to claim 1, is characterized in that, the mass ratio of described sodium hydroxide or potassium hydroxide solid and described acesulfame potassium waste liquid is 100:10-32.
The method according to claim 1, characterized in that, when the acesulfame-K waste liquid is treated for the first time, in the pH value adjustment step, at room temperature, the acesulfame-K waste liquid A saturated sodium hydroxide or potassium hydroxide solution whose mass is 20-60% of the mass of the acesulfame-K waste liquid is added to adjust the pH value of the Acesulfame-K waste liquid.
The method according to claim 1, characterized in that, taking the total mass of the acesulfame-K waste liquid as a benchmark, the acesulfame-K waste liquid comprises: 10-30wt% sulfuric acid, 5-20wt% triethyl ether Amine sulfate, and 3-5 wt% impurity organics.
The method according to claim 1, characterized in that, in the neutralization and separation step, the period of time is 1-30min.
The method according to claim 5, characterized in that, in the neutralization and separation step, the period of time is 10-20min.
The method according to claim 1, characterized in that, in the crystallization step, the water phase is evaporated to crystallize sodium sulfate or potassium sulfate, wherein the quality of the evaporated water is equal to that of the waste acesulfame potassium 5-70% of liquid mass.
The method according to claim 1, further comprising:

Recrystallization step: dissolving the sodium sulfate or potassium sulfate in sulfuric acid, adjusting the pH value to 6-8, and then performing recrystallization.
The method according to claim 1, further comprising: before the crystallization step:

The pH value of the aqueous phase was adjusted to 6-8 by using the acesulfame potassium waste liquid.
The method according to any one of claims 1-9, characterized in that the water content in the recovered triethylamine crude product is not more than 5wt%.