WO2020052577A1 - Process for producing h acid by recycling alkali fusion mother liquor - Google Patents

Abstract

A process for producing H acid by recycling an alkali fusion mother liquor. The alkali fusion mother liquor is used as a neutralization liquor for a denitration reaction liquor, or a neutralization liquor for a denitration liquor after cooling, crystallization, and filtration of filter cake. The neutralized denitration reaction liquor is then reduced to produce an amino T acid. The filtrate obtained after cooling and filtration of the denitration liquor is subjected to coordinaton extraction to obtain the amino T acid, and then subjected to reverse extraction and reduction to produce amino T acid. The diluted acid remaining after the nitro T acid in the denitrification liquor filtrate has been extracted is used for the acidification of the amino T acid, thereby reducing the amount of acid and alkali and the production cost in the production process of H acid.

Description

Process for producing H acid by recycling alkali melting mother liquor Technical field

The invention relates to the technical field of preparation of H acid, in particular to a process for producing H acid by continuously recycling a mother liquor.

Background technique

H acid (1-amino-8-naphthol-3,6-disulfonic acid monosodium) is an important intermediate for the production of reactive dyes. At present, the production of H acid uses refined naphthalene as raw material, and amino T acid is first prepared through sulfonation, nitration, denitration, neutralization, reduction, and sodium chloride salting out. The amino T acid is then subjected to alkaline melting and acidification. The production of H acid, however, the mother liquor produced during the production of H acid belongs to the "five high" organic wastewater with high concentration, high acidity, high salinity, high chroma, and high toxicity. Chemical Oxygen Demand (COD) Up to 80-100,000, salinity up to 10-20%, chroma up to 4000-6000 times, it is difficult to effectively treat these "five high" organic wastewater with traditional biochemical and physical and chemical methods; and unconventional extraction, pyrolysis, Treatment by adsorption and other methods, the cost of pretreatment alone is high, and it cannot be completely and effectively treated. At present, no domestic enterprise can effectively treat and treat the “five high” organic wastewater generated in the production of H acid, and make it reach the discharge standard. Although there are also some wastewaters that can be concentrated by MVR to produce mixed salts of ammonium sulfate and sodium chloride, this mixed salt contains only a large amount of organic matter and is difficult to purify, so it can only be treated as solid waste. Therefore, a clean and environmentally friendly H acid production process is very urgent and important.

The technical solution provided by the Chinese invention patent No. ZL201410816923.4 provides potassium hydroxide instead of traditional ammonia as a neutralizing solution to produce nitro T acid, and potassium hydroxide instead of sodium hydroxide, and alkali melting to generate potassium sulfate mother liquor through MVR Concentrated crystallization and high-temperature calcination to produce potassium sulfate have completely solved the environmental problems that plagued the enterprise, and also improved the yield of the product. However, the disadvantage of this method is that the amount of potassium hydroxide is too large, which consumes 48% per ton of H acid product. More than 11 tons of potassium hydroxide is not conducive to controlling the production cost of the product.

Based on this problem, the present invention further researches a process for producing H acid through recycling of an alkali melting mother liquor, so as to reduce the production cost of H acid on the basis of ensuring cleanliness and environmental protection.

Summary of the Invention

In view of the problems existing in the prior art, the present invention aims to provide a process for producing H acid through recycling of an alkali melting mother liquor, so as to reduce the production cost of H acid on the basis of ensuring cleanness and environmental protection.

One of the objects of the present invention is to provide the application of sulfite in the neutralization of a denitration reaction liquid produced by the production of H acid.

Another object of the present invention is to provide a process for producing H acid by recycling mother liquor.

A third object of the present invention is to provide a method for producing H acid by complex extraction.

To achieve the above-mentioned object of the invention, specifically, the present invention discloses the following technical solutions:

First, the present invention discloses an alkaline molten mother liquor for producing H acid. The alkaline molten mother liquor is a solution containing sulfite.

Preferably, the alkaline molten mother liquid is used for neutralization of the denitration reaction liquid in the H acid production process, that is, the application of the alkaline molten mother liquid in the H acid production to neutralize the denitration reaction liquid; the ratio of the alkaline molten mother liquid to the denitration reaction liquid may be Adjust according to actual needs.

Further, the ratio of the denitration reaction liquid to the alkaline molten mother liquid is 1: (0.4-2), parts by weight.

Further, the ratio of the denitration reaction liquid to the alkaline molten mother liquid is 1: (0.8-1.5), preferably 1: (0.9-1.2), by weight.

Further, the ratio of the denitration reaction liquid to the alkaline molten mother liquid is 1: (0.4-1.0), preferably 1: (0.5-0.8), parts by weight.

Further, the concentration of the sulfite solution in the alkaline molten mother liquor is 30% -50%, preferably 35% -45%, by mass.

Further, the sulfite includes sodium sulfite, potassium sulfite, and the like.

Secondly, the present invention discloses a process for producing H-acid through recycling of an alkali melting mother liquor, including the following steps:

(1) neutralize the reaction solution after the sulfonation, nitration, and denitration of the raw material for preparing the nitro T acid salt with an alkali molten mother liquid containing sulfite, remove the generated sulfur dioxide by heating, and then cool, crystallize, and separate, The nitro T acid salt solid and filtrate are obtained and used for future use. Sulfur dioxide is used for neutralization of H acid-base melt.

(2) Continue neutralizing the filtrate in step (1), and then reduce the temperature, crystallize, and separate to obtain sulfate and filtrate. The filtrate can be further extracted and then back-extracted with dilute alkali. The sulfate can be further washed, and the obtained washing liquid is used for later;

(3) dissolving the nitro T acid salt in step (1) with at least one of the filtrate, back-extraction liquid, and washing liquid in step (2), and the dissolved liquid undergoes catalytic hydrogenation or reduction reaction, acidification, crystallization, Amino T acid solid and filtrate were obtained after filtration;

(4) The amino T acid in step (3) is alkali-melted to obtain an alkali-melt reaction solution containing H acid. The alkali-melt reaction solution is acidified with sulfur dioxide obtained in step (1), cooled and filtered. , You can separate the H acid and the sulfite-containing mother liquor.

In step (1), the raw material for preparing the nitro T acid salt is refined naphthalene.

In step (1), the sulfite includes sodium sulfite and potassium sulfite.

The ratio of the denitration reaction liquid to the alkaline molten mother liquid is 1: (0.4-2), parts by weight.

Further, the ratio of the denitration reaction liquid to the alkaline molten mother liquid is 1: (0.8-1.5), preferably 1: (0.9-1.2), by weight.

Further, the ratio of the denitration reaction liquid to the alkaline molten mother liquid is 1: (0.4-1.0), preferably 1: (0.5-0.8), parts by weight.

Further, the concentration of the sulfite solution is 30% -50%, preferably 35% -45% by mass.

In step (1), the temperature for removing sulfur dioxide is 80 ° C-100 ° C.

In step (2), the substance for neutralization includes a sulfite solution, a potassium hydroxide solution, a sodium hydroxide solution, ammonia water, or lightly burned magnesium, etc., and the concentration of the substance for neutralization can be adjusted according to actual needs; further The sulfite includes sodium sulfite and potassium sulfite.

Preferably, in the step (2), the substance for neutralization is selected from sodium hydroxide and potassium hydroxide.

In the actual experimental production process of the present invention, when the filtrate in step (1) is further neutralized by using sulfite, it is found that it is more beneficial to neutralize the filtrate in step (1) by using sodium hydroxide or potassium hydroxide. The actual production is due to the fact that sulfite is actually produced by dissolving sulfur dioxide in alkaline solution (such as sodium hydroxide). When sulfite neutralizes the acidic substances in the filtrate, it can be regarded as sulfite decomposing into sulfur dioxide first. Neutralization reaction with lye, lye and acid, and sulfur dioxide is released. Therefore, the neutralization reaction between sulfite and the filtrate in step (1) is equivalent to the direct neutralization of the lye and the acid in the filtrate. And the reaction, that is, when the sulfite is used for neutralization, it is equivalent to an additional step of dissolving sulfur dioxide in the lye, but this process does not bring additional effects. Instead, it collects the generated sulfur dioxide. 2. Leakage is likely to occur during storage (this gas must be collected and processed, and cannot be directly discharged), and sulfur dioxide not only has a strong pungent odor, but also once leaked into After entering the human respiratory tract and lungs, the corrosive sulfurous acid generated will cause damage to the human respiratory system. This must be avoided in actual production. When using sodium hydroxide or potassium hydroxide for direct neutralization, It can avoid the additional production of sulfur dioxide when sulfite neutralization is used, and neutralization with sodium hydroxide or potassium hydroxide can achieve the same neutralization effect as sulfite neutralization.

Further preferably, in the step (2), the substance for neutralization is selected from light-burned magnesium powder.

Light-burned magnesium is obtained from magnesite, brucite and other ore through high-temperature calcination. During the high-temperature calcination process, the ore is decomposed and the components such as CO ₂ and H ₂ O are discharged. This makes the light-burned magnesium powder loose. It contains a large number of micropores and has a high chemical reaction activity. When the lightly burned magnesium is used as the neutralizer of the filtrate in step (1), the lightly burned magnesium can not only neutralize the acid solution in the filtrate, In the neutralization process, the acid solution can modify the lightly burned magnesium particles, create richer micropores and cracks in the lightly burned magnesium particles, and produce rich Mg- on the surface of the lightly burned magnesium particles. O active site, so as to continuously improve the physical and chemical characteristics of lightly burned magnesium; in this way, the acid liquid achieves the modification of lightly burned magnesium, and the lightly burned magnesium that is more reactive after being modified also achieves the acid liquid Neutralization, the two promote each other, can quickly and efficiently complete the neutralization of the filtrate, and will not produce other additional toxic and harmful waste; In addition, the cost of light burning magnesium is low, which is more conducive to reducing the production of H acid Cost and sulfuric acid produced during neutralization After purification may also be sold as a by-product, the production cost can be further offset the H acid.

Further, in step (2), the filtrate in step (1) may be neutralized to a liquid acidity of 2% -10%, and the specific amount of the neutralization solution may be added according to actual needs.

Further, in step (2), the extraction agent used is N235 and 200 ^# solvent oil, and preferably, the extraction agent is a complex extraction agent formed by N235 and 200 ^# solvent oil with a mass ratio of 1: 3.

Further, in step (2), the dilute alkali is potassium hydroxide or sodium hydroxide, and preferably, the mass concentration of potassium hydroxide or sodium hydroxide is 5% -10%.

Further, in step (2), the sulfate is washed with water and the same quality as the sulfate.

Further, in step (3), the catalyst used in the catalytic hydrogenation reaction is a nickel catalyst.

Further, in step (3), the temperature of the catalytic hydrogenation reaction is 80 ° C-120 ° C.

Further, in step (3), the reducing agent used in the reduction reaction includes iron powder, zinc powder, and the like.

Further, in step (4), the alkaline solution for the alkali melting includes potassium hydroxide or sodium hydroxide solution.

Further, in step (4), the alkali melting reaction is performed between 160 ° C. and 195 ° C. for a time of 0.5 h to 5 h, preferably 0.5 h to 2 h.

The main reason for collecting sulfur dioxide produced by sulfite in step (1) is that it can be used for the neutralization of the alkali melting reaction solution in step (4), so that it can be used instead of the alkali melting in the acidification step (4). The acid of the mother liquor reduces the production cost of the H acid. The sulfur dioxide can be converted into sulfite through the reaction with the alkali molten mother liquor to obtain an alkali molten mother liquor containing sulfite; using the sulfite-containing solution obtained in step (4) The alkaline molten mother liquid neutralizes the reaction solution after denitration in step (1), so that not only the recycling of the alkaline molten mother liquid containing sulfite, but also the elimination of the sulfite containing liquid in step (4) The treatment of the "five high" organic waste water of the alkaline molten mother liquor, while greatly reducing the production cost of H acid, makes the production process of H acid cleaner and more environmentally friendly; in this way, the alkaline mother liquor can be recycled to save potassium hydroxide Or the consumption of sodium hydroxide solution, the purpose of reducing product production costs. In addition, if the concentration of the sulfite-containing alkali molten mother liquor obtained in step (4) is insufficient, it can also be solved by adding sulfite or concentrating.

The reason why the alkaline melt mother liquor is used to neutralize the filtrate in step (1) again is that the filtrate contains a part of the denitrated product. After the neutralization, a part of the nitro T acid can be obtained, and the nitro T acid Salt is an important intermediate product for the preparation of H acid in subsequent steps, which can improve the utilization of raw materials.

In step (2), after the separation, the obtained filtrate still contains a part of the nitro T salt product. Therefore, this part of the nitro T salt product can be extracted again from the filtrate by extraction. First, the oil After extraction (oil phase), the nitro T acid salt enters the oil phase, and then potassium hydroxide or sodium hydroxide (water phase) is used to back extract the oil phase, so that the nitro T acid salt can enter the back extraction liquid ( In the aqueous phase), the concentration of nitro T acid in the stripping solution is increased, which is more conducive to subsequent reactions.

Since a part of the nitro T acid salt product is still attached to the surface of the sulfate obtained in step (2), you can choose to wash the part of sulfate, and then use a washing solution containing nitro T acid salt after washing, step (2 The back extraction solution containing the nitro T acid salt obtained in step) dissolves the nitro T acid salt in step (1), and a mixed solution containing the nitro T acid salt can be obtained, and the mixed liquid will be used in the next step of the amino T acid. The preparation of acid can realize the maximum utilization of nitro T acid salt, washing liquid and back extraction liquid.

Further, the process for producing H-acid by recycling the mother liquor of the alkali melt further includes a step of preparing sulfate, as follows:

S1: The filtrate obtained after the amino T acid solid is separated in step (3) is reacted with an alkaline solution (preferably sodium hydroxide or potassium hydroxide), and the pH of the reaction solution is adjusted to neutral, and the mixture is evaporated, concentrated, and crystallized. A sulfate (preferably potassium sulfate or sodium sulfate) solid is obtained;

S2: The sulfate solid obtained in step S1 and the sulfate obtained in step (2) are calcined at a high temperature to remove impurities such as organic matter therein, and a sulfate in accordance with national standards can be obtained.

Preferably, in S2, the calcination temperature is 800 ° C-1000 ° C, and the calcination time can be adjusted according to the amount of sulfate, preferably 0.5h-1h.

Further, the step of preparing the sulfate salt further includes: a treatment step of the tail gas generated in the calcination process, preferably, the calcined tail gas is discharged after being processed by the RTO regenerative incinerator and meeting the standard.

It should be noted that, in the production process of the present invention, water vapor or distilled water generated in the processes of distillation, evaporation, and concentration can be recovered and used for production, so as to achieve the purpose of saving water.

In the above process, an alkali melting mother liquor is used to neutralize the denitration solution, which reduces the amount of alkali. In particular, lightly burned magnesium, lime, etc. can be used instead of ammonia to further neutralize the denitration solution, reduce the amount of wastewater generated, and greatly reduce the cost. However, magnesium sulfate or calcium sulfate is produced during the production process, and the amount of waste salt is relatively large, and these waste salts need to be disposed of. The invention provides a method for producing H acid by complex extraction. The complex extraction method can be combined with the above-mentioned process for producing H acid through recycling of an alkali molten mother liquor to solve the above technical problems.

The method for producing H acid by complex extraction provided by the present invention is to produce H acid by using combined complex extraction through recycling of an alkali melting mother liquor, comprising the following steps:

1) cooling the nitro T acid reaction solution of refined naphthalene after sulfonation, nitration and denitration to precipitate nitro T acid solids; the mass ratio of the precipitated nitro T acid solids to the filtrate is 1: 0.8-1.2;

2) After nitro T acid solids are beaten with water, neutralized with H acid-base molten mother liquor, and the generated sulfur dioxide is removed to obtain a nitro T acid salt solution;

3) The filtrate after filtering the nitro T acid is extracted with a complex extractant, and the sulfuric acid content in the remaining filtrate after extraction is 30% -50% (mass percentage). The extract is washed with water and lye back-extracted to obtain nitrate. Base T salt solution, sulfuric acid content in water washing solution is 15% -25% (mass percentage);

4) Add the nitro T acid salt solution obtained in steps 2) and 3) to the catalyst separately to catalyze hydrogenation or iron powder reduction. The reduced solution is acidified and filtered to obtain amino T acid. The acidified acid is used in step 3). The remaining filtrate after extraction as described in

5) Add alkali and methanol to the amino T acid to perform alkali melting. After the end of the alkali melting, the sulfur dioxide collected in step 2) is used to acidify the alkali molten solution. After filtering the obtained solid, it is added with water to beat and then used in step 3). The water washing solution was acidified and filtered, and the filter cake was washed with water, filtered, and dried to obtain a product.

The filtered nitro T acid solids and the back-extracted liquid after extraction of the nitro T acid are produced by hydrogenation or iron powder reduction to produce amino T acid. The acid used for acidification of amino T acid can be extracted with complexed nitro T acid. The remaining filtrate replaced the sulfuric acid. After the nitro T acid is extracted, the extract is first washed with water, and the sulfuric acid part extracted into the extract is washed into water. Control the amount of washing water, the sulfuric acid content in the washing water can reach about 20%. This part of dilute sulfuric acid is colorless and transparent, and the organic matter is very small. It can be used for acidification of H acid without affecting the product quality of H acid.

The method can not only reduce the alkali for neutralizing the denitration solution, the amount of sulfuric acid used in the acidification of the amino T acid, the amount of sulfuric acid used in the acidification of the H acid, but also use only one base in the entire production process, and only one salt in the mother liquor. Salt and concentrated water are used in production, and no waste gas, waste water and waste residue are produced during production. The production process is environmentally friendly, and the comprehensive cost is reduced by more than 25% compared with the traditional process.

In some examples of complex extraction and production of H acid, in step 1), the nitro T acid reaction solution is cooled to -5 ° C to 10 ° C.

In some examples of complex extraction and production of H acid, in step 2), the content of sodium sulfite in the H acid-base molten mother liquor is 35% -45%.

In some embodiments of complex extraction and production of H acid, in step 2), after the nitro T acid solid is slurried with water, it is neutralized with the H acid-base molten mother liquor until the pH value of the nitro T acid slurry is 4-6. .

In some embodiments of complex extraction to produce H acid, in step 3), the complex extractant is a mixture of N ₂₃₅ and a solvent oil and a phenalkyl ether, and the mass percentage of N ₂₃₅ in the complex extractant is 20% -50%, which can be 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

Further, the solvent oil is 200 # solvent oil or kerosene.

Further, the phenyl alkyl ether compounds include anisole, phenyl ether, butyl ether, phenyloctyl ether and the like.

In some embodiments, in step 3), the sulfuric acid content in the remaining filtrate after the extraction is 35% -45% (mass percentage).

In the filtrate after the extraction of nitro T acid, the content of nitro T acid can be reduced to less than 0.5%, and the sulfuric acid content is about 40%, which can be used for the acidification of amino T acid.

In some examples of complex extraction and production of H acid, in step 4), the catalyst is a nickel catalyst, and the temperature of catalytic hydrogenation is 80 ° C-120 ° C.

In some embodiments of complex extraction to produce H acid, in step 5), the base is sodium hydroxide or potassium hydroxide.

Further, the mass fraction of the base is 40% -50%.

Further, in step 5), the temperature of the alkali melting is 160 ° C-195 ° C, and the time of the alkali melting is 1-3 hours.

Compared with the prior art, the beneficial effects obtained by the present invention are:

(1) The process for producing H acid by recycling the mother molten liquor provided by the present invention. By replacing potassium hydroxide or sodium hydroxide with a sulfite as a neutralizing solution for the denitration reaction, the content of Sulfite mother liquor can be continuously recycled, which not only greatly reduces the consumption of potassium hydroxide or sodium hydroxide, but also reduces the amount of alkali molten mother liquor treatment, which effectively reduces the production cost of the product. Compared with the method provided in the Chinese invention patent with patent number ZL201410816923.4, the present invention circulates in the process of preparing H acid by replacing the potassium hydroxide neutralization denitration reaction solution with a sulfite-containing H acid-base molten mother liquor. Utilization, the reductions reached 54.5% and 56.25% respectively, greatly reducing the consumption of potassium hydroxide or sodium hydroxide, effectively reducing the production cost of the product.

(2) The process for producing H-acid by recycling the alkali melting mother liquor provided by the present invention effectively reduces the amount of waste liquid generated after the reaction of the alkali-melting mother liquor. The actual application shows that: 25-30 per ton of H-acid produced by the traditional process The ton of waste liquid is reduced to about 15 tons, and the production costs and environmental protection treatment costs are greatly reduced.

(3) The process for producing H-acid by recycling the molten mother liquor provided by the present invention can use light-burned magnesium and ammonia water as further neutralizing substances. During the neutralization process, the acid liquid realizes the modification of light-burned magnesium and is modified. The more reactive light-burned magnesium after neutralization has realized the neutralization of the acid solution. The two promote each other and can quickly complete the neutralization of the filtrate. In addition, the light-burned magnesium has low cost and is more conducive to reducing the production of H acid. Cost, and the magnesium sulfate produced in the neutralization process can be sold as a by-product after purification treatment, which can further offset the production cost of H acid.

(4) The method for producing H acid by complex extraction provided by the present invention is to reduce the temperature of the denitrified crystals and filter out the nitro T acid. The nitro T acid is neutralized with an alkaline molten mother liquor and further reduced to produce amino T acid. The mother liquor after the nitro T acid was filtered, the filtrate was extracted with N ₂₃₅ and solvent oil, and then back-extracted with an alkaline solution, and the back-extracted liquid was reduced to produce amino T acid. The filtrate after the extraction of nitro T acid, the content of nitro T acid can be reduced to less than 0.5%, and the sulfuric acid content is about 40%, which can be used as an acid for the acidification of amino T acid. Extract the extract of nitro T acid, wash the sulfuric acid extracted into the extract with water before back extraction, adjust the amount of washing water, the sulfuric acid concentration can reach about 20%, colorless and transparent, can be used for the acid of H acid Without affecting the quality, through this cycle, not only the alkali used for neutralizing the denitration solution, but also the sulfuric acid used for the acidification of amino T acid and H acid, and only one base is used in the entire production process, and only one salt is used in the mother liquor , The mother liquor is concentrated and crystallized to recover the sulfate, and the concentrated water is applied to the production, and no waste gas, waste water and waste residue are produced during the production process. The production process is green and environmentally friendly, which effectively solves the environmental protection problem of H-acid enterprises, and the comprehensive production cost is reduced by more than 25% compared with the traditional process.

detailed description

It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is only for describing specific embodiments, and is not intended to limit the exemplary embodiments according to the present application. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise, and it should also be understood that when the terms "including" and / or "including" are used in this specification, they indicate There are features, steps, operations, devices, components, and / or combinations thereof.

As described in the background art, although in the previous research of the present invention, potassium hydroxide was used to replace the traditional ammonia water to produce nitro T acid, and potassium hydroxide was used instead of sodium hydroxide to melt the alkali, which completely solved the environmental problems that plagued the enterprise. The yield of the product is also improved, but the disadvantage of this method is that the amount of potassium hydroxide is too large, which consumes more than 11 tons of potassium hydroxide of 48% per ton of H acid product, which is not conducive to controlling the production cost of the product; therefore, the present invention A process for producing H-acid by recycling the molten mother liquor is proposed, and the present invention will be further described below with reference to specific embodiments.

It should be noted that, in Example 1, the sulphite-containing alkali molten mother liquor described in step (1) was generated in step (4) when the H acid was produced using the process of the present invention. A newly prepared sulfate solution is added as a neutralization solution of the reaction solution obtained by denitration. After the sulfur dioxide generated in the neutralization process is used to acidify the alkali melting reaction solution in step (4), a sulfite-containing solution is finally obtained. The alkaline molten mother liquor can be used for neutralization of the reaction solution obtained in step (1) of Example 1 by denitration.

Example 1

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 400 parts of nitro T acid reaction solution (parts by weight, the same below) obtained from refined naphthalene through traditional process sulfonation, nitration and denitrification, and take 560 parts of alkaline molten mother liquor containing 45% potassium sulfite and nitro T The acid reaction solution was neutralized, and sulfur dioxide generated during the neutralization reaction was removed at 80-100 ° C for 1 hour. Then, the reaction solution was cooled to room temperature, crystallized, and filtered to obtain a nitro T acid salt solid and a filtrate, which are reserved for use. ; Centralized collection of sulfur dioxide, standby;

(2) Take 250 parts of 45% by weight potassium sulfite alkali molten mother liquor, continue to neutralize with the filtrate generated in step (1), and remove sulfur dioxide generated during the neutralization reaction at 80-100 ° C for 1 h Then, cool down, crystallize, and filter to obtain potassium sulfate solids and filtrate, and wash potassium sulfate with water of the same quality as potassium sulfate solids, and use the washing solution for future use. The filtrate is complexed with an extractant (N235: 200 # solvent oil = 1: 3, (Mass ratio) extraction, and then back-extracted with 10% potassium hydroxide to obtain a back-extracted liquid, ready for use;

(3) Dissolve the nitro T acid salt in step (1) with the washing solution and back-extract solution in step (2), add 32 parts of nickel catalyst, and catalyze hydrogenation to the end point at 80 ° C, reduce to room temperature, and filter , Acidified with 50% sulfuric acid, filtered to obtain 227 parts of amino T acid, amino T acid content 38%;

(4) Take 200 parts of amino T acid in step (3), add 120 parts of 48% potassium hydroxide to alkali melting, control the reaction temperature between 160-170 ° C for 3 hours, discharge and dilute with 1 times water The sulfur dioxide obtained in steps (1) and (2) is used for acidification, filtration, water washing, and then filtration and flash drying to obtain H acid and an alkali molten mother liquor containing potassium sulfite, wherein H acid is 72.3 parts , Content 82.56%, purity 98.89%;

(5) The filtrate obtained after the amino T acid solid is separated in step (3) is reacted with potassium hydroxide, the pH of the reaction solution is adjusted to neutral, and potassium sulfate solid is obtained after evaporation, concentration and crystallization. The potassium sulfate solid and the potassium sulfate produced in step (2) are calcined at 1000 ° C for 0.5 h, and impurities such as organic matter are removed to obtain sulfates in accordance with national standards;

(6) The tail gas generated in the calcination process in step (5) is discharged after being treated by the RTO regenerative incinerator and reaches the standard.

Example 2

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 1000 parts of nitro T acid reaction solution obtained by sulfonation, nitration and denitration of refined naphthalene through the traditional process (parts by weight, the same below), and use 1200 parts of an alkaline molten mother solution containing 40% sodium sulfite and nitro T acid The reaction solution is neutralized, and sulfur dioxide generated during the neutralization reaction is removed at 80-100 ° C. for 3 hours, and then the reaction solution is cooled to room temperature, crystallized, and filtered to obtain a nitro T salt solid and a filtrate, which are used for later; Sulfur dioxide is collected centrally and used for future use;

(2) Take 600 parts of 40% sodium sulfite alkali molten mother liquor, continue to neutralize with the filtrate generated in step (1), and remove sulfur dioxide generated during the neutralization reaction at 80-100 ° C for 3h, Then cool down, crystallize, and filter to obtain sodium sulfate solid and filtrate. Wash the sodium sulfate with the same quality of water as the sodium sulfate solid. The washing solution is reserved. The filtrate is complexed with an extractant (N235: 200 # solvent oil = 1: 3, mass). Ratio) extraction, then back extraction with 5% sodium hydroxide to obtain a back extraction solution, ready for use;

(3) Dissolve the nitro T acid salt in step (1) with the washing solution and back-extracting solution in step (2), add 60 parts of nickel catalyst, and catalyze hydrogenation to the end point at 80 ° C, reduce to room temperature, and filter , Acidified with 50% sulfuric acid, filtered to obtain 530 parts of amino T acid, amino T acid content 39.56%, mass;

(4) Take 500 parts of amino T acid in step (3), add 400 parts of 48% sodium hydroxide alkali melt, 100 parts of methanol, control the reaction temperature between 190-195 ° C, time is 5h, discharge, use Diluted 1.5 times with water, acidified with sulfur dioxide obtained in steps (1) and (2), filtered, and flash-dried to obtain H acid and an alkaline molten mother liquor containing sodium sulfite, of which 192.1 parts of H acid, the content of 86.15%, Chromatographic purity 99.05%;

(5) The filtrate obtained after separating the amino T acid solid in step (3) is reacted with sodium hydroxide, and the pH of the reaction solution is adjusted to neutral. After evaporation, concentration, and crystallization, sodium sulfate solid is obtained. The sodium sulfate solid and the potassium sulfate produced in step (2) are calcined at 750 ° C for 1 hour, and impurities such as organic matter are removed to obtain sulfates in accordance with national standards;

(6) The tail gas generated in the calcination process in step (5) is discharged after being treated by the RTO regenerative incinerator and reaches the standard.

Example 3

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 400 parts of nitro T acid reaction solution (parts by weight, the same below) obtained from refined naphthalene through traditional process sulfonation, nitration and denitrification, and take 560 parts of alkaline molten mother liquor containing 45% potassium sulfite and nitro T The acid reaction solution was neutralized, and sulfur dioxide generated during the neutralization reaction was removed at 80-100 ° C for 1 hour. Then, the reaction solution was cooled to room temperature, crystallized, and filtered to obtain a nitro T acid salt solid and a filtrate, which are reserved for use. ; Centralized collection of sulfur dioxide, standby;

(2) Take 300 parts of light-burned magnesium powder, continue to neutralize with the filtrate generated in step (1), then cool down, crystallize, and filter to obtain magnesium sulfate solids and filtrate, and wash the magnesium sulfate with water of the same quality as magnesium sulfate solids The washing solution is used as a spare, and the filtrate is extracted with a complex extractant (N235: 200 # solvent oil = 1: 3, mass ratio), and then back-extracted with 8% potassium hydroxide to obtain a back-extracted solution, which is used as a spare;

(3) Dissolve the nitro T acid salt in step (1) with the washing solution and back-extract solution in step (2), add 32 parts of nickel catalyst, and catalyze hydrogenation to the end point at 80 ° C, reduce to room temperature, and filter , Acidified with 50% sulfuric acid, filtered to obtain 148 parts of amino T acid, amino T acid content 40.34%, mass;

(4) Take 135 parts of amino T acid in step (3), add 120 parts of 48% potassium hydroxide to alkali melting, control the reaction temperature between 160-170 ° C for 3 hours, discharge and dilute with 1 times water , Acidify, filter, wash with sulfur dioxide obtained in step (1), and then filter and flash dry to obtain H acid and an alkali molten mother liquor containing potassium sulfite, wherein the H acid is 52.1 parts, the content is 81.21%, Purity was 99.16%.

Example 4

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 500 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through traditional process sulfonation, nitration and denitrification, and take 1000 parts of alkaline molten mother liquor containing 35% potassium sulfite and nitro T The acid reaction solution was neutralized, and sulfur dioxide generated during the neutralization reaction was removed at 80-100 ° C for 1 hour. Then, the reaction solution was cooled to room temperature, crystallized, and filtered to obtain a nitro T acid salt solid and a filtrate, which are reserved for use. ; Centralized collection of sulfur dioxide, standby;

(2) Take 450 parts of 28% ammonia water and continue neutralizing with the filtrate produced in step (1), and then cool, crystallize and filter to obtain the wet salt solids of potassium sulfate and ammonium sulfate and the filtrate;

(3) Use the filtrate in step (2) to dissolve the nitro T acid salt in step (1), add 30 parts of nickel catalyst, catalyze hydrogenation to the end point at 120 ° C, drop to room temperature, filter, and use 50% Acidified with sulfuric acid and filtered to obtain 153 parts of amino T acid, with an amino T acid content of 45.34%, mass;

(4) Take 145 parts of amino T acid in step (3), add 115 parts of 50% sodium hydroxide to alkali melt, control the reaction temperature between 160-170 ° C, time is 2.5h, discharge, use 1 times water Dilute, acidify with sulfur dioxide obtained in step (1), filter, wash with water, and then filter and flash dry to obtain H acid and an alkaline molten mother liquor containing potassium sulfite. Among them, H acid is 58.2 parts, and the content is 83.19%. , Purity 99.28%.

Example 5

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 400 parts (parts by weight, the same hereinafter) of the nitro T acid reaction solution obtained by sulfonation, nitration, and denitration of refined naphthalene through the traditional process, and take the sodium sulfite-containing alkaline molten mother liquid 600 produced in step (4) of Example 4 It is formulated into a neutralization solution with a mass concentration of 45% sodium sulfite, and a neutralization reaction with a nitro T acid reaction solution, and the sulfur dioxide generated during the neutralization reaction is removed at 80-100 ° C for 1 hour, and then The reaction solution was cooled to room temperature, crystallized, and filtered to obtain a solid salt of the nitro T salt and the filtrate, which were reserved; the sulfur dioxide was collected centrally, and was reserved;

(2) Take 300 parts of 30% sodium hydroxide by mass, continue to neutralize with the filtrate generated in step (1), and then cool, crystallize, and filter to obtain sodium sulfate solids and filtrates. Wash sodium sulfate with water and wash solution for later use;

(3) Dissolve the nitro T acid salt in step (1) with the filtrate and washing solution in step (2), add 35 parts of nickel catalyst, and catalyze hydrogenation to the end point at 80 ° C, reduce to room temperature, filter, and use 50% sulfuric acid was acidified and filtered to obtain 272 parts of amino T acid, the content of amino T acid was 45.51%, mass;

(4) Take 250 parts of amino T acid in step (3), add 200 parts of 45% sodium hydroxide to alkali melt, control the reaction temperature between 160-170 ° C, time is 0.5h, discharge, use 1 times water Diluted, acidified with sulfur dioxide obtained in step (1), filtered, washed with water, and then filtered and flash-dried to obtain H acid and an alkaline molten mother liquor containing sodium sulfite. Among them, H acid is 113.96 parts, content is 80.33%, purity 98.83%.

Example 6

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 1000 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through traditional process sulfonation, nitration, and denitration, and take the sodium sulfite-containing alkaline molten mother liquid 800 produced in step (4) of Example 5 It is formulated into a neutralization solution with a mass concentration of 45% sodium sulfite, and a neutralization reaction with a nitro T acid reaction solution, and the sulfur dioxide generated during the neutralization reaction is removed at 80-100 ° C for 1 hour, and then The reaction solution was cooled to room temperature, crystallized, and filtered to obtain a solid salt of the nitro T salt and the filtrate, which were reserved; the sulfur dioxide was collected centrally, and was reserved;

(2) Take 530 parts of potassium hydroxide with a concentration of 35% by mass, continue neutralizing with the filtrate generated in step (1), and then cool, crystallize, and filter to obtain a potassium sulfate solid and the filtrate. Use a complexing extractant (N235: 200 # solvent oil = 1: 3, mass ratio) extract the filtrate, and then back-extract with 8% potassium hydroxide to obtain a back-extracted liquid for future use;

(3) Dissolve the nitro T acid salt in step (1) with the extract in step (2), add 40 parts of iron powder to perform the reduction reaction at 100 ° C, reduce to room temperature, filter, and acidify with 50% sulfuric acid , Filtered to obtain 433 parts of amino T acid, amino T acid content 46.47%, mass;

(4) Take 370 parts of amino T acid in step (3), add 300 parts of 50% potassium hydroxide to alkali melt, and control the reaction temperature between 170-180 ° C for 2 hours, discharge and dilute with 1 times water , Acidify, filter, wash with sulfur dioxide obtained in step (1), and then filter and flash dry to obtain H acid and an alkali molten mother liquor containing potassium sulfite, wherein H acid is 94.2 parts, and the content is 83.22%, Purity was 99.19%.

Example 7

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 600 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through sulfonation, nitration, and denitration in the traditional process, and take 240 parts of an alkaline molten mother liquid containing 50% by weight of sodium sulfite. The nitro T acid reaction solution is neutralized, and sulfur dioxide generated during the neutralization reaction is removed at 80-100 ° C for 2 hours. Then the reaction solution is cooled to room temperature, crystallized, and filtered to obtain a nitro T acid salt solid and Filtrate, reserve; Sulfur dioxide is collected centrally, reserve;

(2) Take 400 parts of 25% ammonia water by mass, continue to neutralize with the filtrate generated in step (1), then cool, crystallize, and filter to obtain ammonium sulfate solid and filtrate. Use a complexing extractant (N235: 200 # Solvent oil = 1: 3, mass ratio) The filtrate is extracted, and then back-extracted with 5% sodium hydroxide to obtain a back-extracted liquid for future use;

(3) Dissolve the nitro T acid salt in step (1) with the extract in step (2), add 40 parts of zinc powder to carry out the reduction reaction at 110 ° C, reduce to room temperature, filter, and acidify with 50% sulfuric acid , Filtered to obtain 112 parts of amino T acid, amino T acid content 44.45%, mass;

(4) Take 200 parts of amino T acid in step (3), add 170 parts of 45% sodium hydroxide to alkali melt, control the reaction temperature between 180-195 ° C for 1 hour, discharge, and dilute with 1 times water The sulfuric acid obtained in step (1) is used for acidification, filtration, water washing, and then filtration and flash evaporation to obtain H acid and an alkali molten mother liquor containing sodium sulfite. Among them, the H acid is 82.4 parts, the content is 85.22%, and the purity is 99.01. %.

Example 8

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 600 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through the traditional process sulfonation, nitration, and denitrification, and take 600 parts of an alkaline molten mother liquor containing 35% by weight of sodium sulfite, and The nitro T acid reaction solution was neutralized, and sulfur dioxide generated during the neutralization reaction was removed at 80-100 ° C for 3 hours. Then the reaction solution was cooled to room temperature, crystallized, and filtered to obtain a nitro T acid salt solid and Filtrate, reserve; Sulfur dioxide is collected centrally, reserve;

(2) Take 400 parts of light-burned magnesium powder, continue to neutralize the filtrate generated in step (1), and then cool, crystallize, and filter to obtain a magnesium sulfate solid and a filtrate;

(3) dissolving the nitro T acid salt in step (1) with the filtrate in step (2), adding 80 parts of iron powder to perform a reduction reaction at 100 ° C, lowering to room temperature, filtering, and acidifying with 50% sulfuric acid, Filtration yielded 293 parts of amino T acid with an amino T acid content of 43.88%;

(4) Take 400 parts of amino T acid in step (3), add 65 parts of 45% sodium hydroxide to alkali melt, and control the reaction temperature between 180-190 ° C for 2 hours, discharge and dilute with 1 times water , Acidify, filter, wash with sulfur dioxide obtained in step (1), and then filter and flash dry to obtain H acid and an alkaline molten mother liquor containing sodium sulfite, wherein H acid is 161.4 parts, the content is 82.41%, and the purity is 99.2 %.

Example 9

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 600 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through traditional process sulfonation, nitration, and denitrification, and take 540 parts of 50% alkaline molten mother liquor containing potassium sulfite Neutralize reaction with nitro T acid reaction solution, and remove sulfur dioxide generated during neutralization reaction at 80-100 ° C for 3 h, then reduce the reaction solution to room temperature, crystallize, and filter to obtain nitro T acid salt Solids and filtrates, reserve; Sulfur dioxide is collected centrally, reserve;

(2) Take 400 parts of light-burned magnesium powder, continue to neutralize the filtrate generated in step (1), and then cool, crystallize, and filter to obtain solids and filtrates of magnesium sulfate and potassium sulfate;

(3) dissolving the nitro T acid salt in step (1) with the filtrate in step (2), adding 80 parts of iron powder to perform a reduction reaction at 100 ° C, lowering to room temperature, filtering, and acidifying with 50% sulfuric acid, Filtration yielded 293 parts of amino T acid with an amino T acid content of 43.88%;

(4) Take 400 parts of amino T acid in step (3), add 65 parts of 48% potassium hydroxide to alkali melt, control the reaction temperature between 165-175 ° C, time is 1 hour, discharge and dilute with 1 times water , Acidify, filter, wash with sulfur dioxide obtained in step (1), and then filter and flash dry to obtain H acid and an alkali molten mother liquor containing potassium sulfite, in which H acid is 119.46 parts and the content is 82.41%, Purity 99.2%.

Example 10

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 600 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through sulfonation, nitration, and denitration in the traditional process. The nitro T acid reaction solution is neutralized, and sulfur dioxide generated during the neutralization reaction is removed at 80-100 ° C for 2 hours. Then the reaction solution is cooled to room temperature, crystallized, and filtered to obtain a nitro T acid salt solid and Filtrate, reserve; Sulfur dioxide is collected centrally, reserve;

(2) Take 180 parts of light-burned magnesium powder, continue to neutralize the filtrate generated in step (1), and then cool, crystallize, and filter to obtain a magnesium sulfate solid and a filtrate;

(3) Dissolve the nitro T acid salt in step (1) with the filtrate in step (2), add 25 parts of nickel catalyst, and catalyze hydrogenation at 100 ° C to the end point, reduce to room temperature, filter, and use 50% Acidified with sulfuric acid and filtered to obtain 124 parts of amino T acid, with an amino T acid content of 41.31%, mass;

(4) Take 100 parts of amino T acid in step (3), add 80 parts of 45% sodium hydroxide to alkali melt, control the reaction temperature between 180-190 ° C for 2 hours, discharge and dilute with 1 times water The sulfuric acid obtained in step (1) is used for acidification, filtration, water washing, and then filtration and flash evaporation to obtain H acid and an alkali molten mother liquor containing sodium sulfite. Among them, the H acid is 39.7 parts, the content is 83.97%, and the purity is 99.23. %.

Example 11

A process for producing H acid by recycling mother liquor, including the following steps:

(1) Take 600 parts of nitro T acid reaction solution (parts by weight, the same hereinafter) obtained from refined naphthalene through traditional process sulfonation, nitration, and denitrification, and take 720 parts of alkali molten mother liquor containing 30% potassium sulfite. Neutralize reaction with nitro T acid reaction solution, and remove sulfur dioxide generated during neutralization reaction at 80-100 ° C for 3 h, then reduce the reaction solution to room temperature, crystallize, and filter to obtain nitro T acid salt Solids and filtrates, reserve; Sulfur dioxide is collected centrally, reserve;

(2) Take 400 parts of light-burned magnesium powder, continue to neutralize the filtrate generated in step (1), and then cool, crystallize, and filter to obtain magnesium sulfate and potassium sulfate solids and filtrate;

(3) Dissolve the nitro T acid salt in step (1) with the filtrate in step (2), add 50 parts of nickel catalyst, catalyze hydrogenation to the end point at 90 ° C, reduce to room temperature, filter, and use 50% Acidified by sulfuric acid and filtered to obtain 418 parts of amino T acid, with an amino T acid content of 42.07%, mass;

(4) Take 300 parts of amino T acid in step (3), add 320 parts of 48% potassium hydroxide to alkali melt, and control the reaction temperature between 165-170 ° C, the time is 1.5h, discharge and use 1 time water Diluted, acidified with sulfur dioxide obtained in step (1), filtered, washed with water, and then filtered and flash-dried to obtain H acid and an alkali molten mother liquor containing sodium sulfite, wherein H acid is 121.75 parts, content is 81.22%, purity 99.17%.

Example 12

A method for producing H acid by H acid-base molten mother liquor and complex extraction, including the following steps;

1) Take 600 parts (parts by weight) of nitro T acid reaction solution of refined naphthalene after sulfonation, nitration and denitration by traditional process, cool to 5 ° C with stirring, and filter to obtain 280 parts of nitro T acid solids and 320 parts of filtrate.

2) Nitro T acid solids are slurried with 280 parts of water and neutralized with 360 parts of H acid-base molten mother liquor (sodium sulfite content 39.82%) to produce sulfur dioxide (removing sulfur dioxide produced during the neutralization reaction at 80-100 ° C) It is used for neutralization of H acid-base melt, and after removing sulfur dioxide, a sodium nitroT solution is obtained.

3) The filtrate in step 1) is extracted with a complex extractant (N ₂₃₅ : 200 # solvent oil: anisole = 3: 4: 3, weight ratio), and the remaining post-extraction water sulfuric acid after nitro T acid extraction is 41.3%, the extract was first washed with 80 parts of water to obtain 100 parts of washing water with a sulfuric acid content of about 20%, and then the extract was back-extracted with 15% sodium hydroxide solution, and the back-extracted solution was 287 parts (the back-extracted solution is Is a sodium nitro T solution).

4) Add 15 parts of nickel catalyst obtained in step (2) to the nickel nitrate solution, hydrogenate at 120 ° C to the end point, filter off the catalyst, acidify with dilute sulfuric acid generated after extraction in (3), and obtain amino group by filtration T acid was 298 parts, and amino T acid was 38.5%.

5) Add 5 parts of nickel catalyst to the stripping solution in step (3), and add hydrogen to the end point at 120 ° C. The catalyst was filtered off, and then acidified and filtered to obtain 89 parts of amino T acid with a content of 32.8%.

6) Add 290 parts of amino T acid to 195 parts of 48% sodium hydroxide and 60 parts of methanol for alkali melting, alkali melting at 185-188 ° C for 1.5 hours, discharge, dilute with water, and use sulfur dioxide produced in (2) Acidify and filter to obtain a solid. The solid is slurried with water, washed with water from step 3) to generate dilute sulfuric acid, filtered, the filter cake is washed with 1x water, and then filtered and dried to obtain 108 parts of the product with a content of 85.77% and a purity of 99.15%.

Example 13

A method for producing H acid by H acid-base molten mother liquor and complex extraction method, comprising the following steps:

1) Take 800 parts (parts by weight) of the nitro T acid reaction solution of refined naphthalene after sulfonation, nitration and denitration by the traditional process, stir to cool to 0 ° C, and filter to obtain 409 parts of nitro T acid solids and 391 parts of the filtrate.

2) 409 parts of nitro T acid are beaten with water, neutralized with 660 parts of H acid-base molten mother liquor (potassium sulphite content 42.36%) to produce sulfur dioxide, neutralized with H acid-base molten solution, and then obtained Potassium nitro T acid solution.

3) The filtrate after filtering the nitro T acid solid in step 1) is extracted with a complex extractant (N ₂₃₅ : 200 # solvent oil: phenyl ether = 2: 4: 4, weight ratio), and after the nitro T acid extraction The remaining aqueous solution was 39.8% dilute sulfuric acid. The extract was washed with 100 parts of water to obtain 128 parts of 19.3% dilute sulfuric acid. The extract was then back-extracted with 20% potassium hydroxide, and 362 parts of back-extracted solution was Potassium nitro T acid solution.

4) Combine step 2) and the potassium nitrate solution obtained in step 2 and add 20 parts of nickel catalyst, hydrogenate to the end point at 80 ° C, filter off the catalyst, and generate dilute sulfuric acid (content 39.8%) after extraction in (3) ) Neutralization and filtration to obtain 370 parts of amino T acid, the content of amino T acid is 41.3%.

5) 6 parts of nickel catalyst was added to the back-extraction liquid in Example 3, and hydrogen was added to the end point at 120 ° C. The catalyst was filtered off, and then acidified and filtered to obtain 108 parts of amino T acid with a content of 34.6%.

6) 350 parts of amino T acid is added to 360 parts of 48% potassium hydroxide and 90 parts of methanol for alkali melting, alkali melting at 165 ° C to 168 ° C for two hours, discharging, diluting with water, and using sulfur dioxide collected in step 1). Acidify, filter after acidification, solidify the pulp with water, acidify with the dilute sulfuric acid (content 19.3%) produced by washing the extract in step 3), then filter, filter the cake and wash with 1x water, filter and dry to obtain monopotassium H acid 180 parts of salt, content 81.6%, purity 99.46%.

Example 14

A method for producing H acid by H acid-base molten mother liquor and complex extraction, including the following steps;

1) Take 600 parts (parts by weight) of nitro T acid reaction solution of refined naphthalene after sulfonation, nitration and denitration by traditional process, stir to cool to -5 ° C, and filter to obtain 300 parts of nitro T acid solids and 300 parts of filtrate .

2) Nitro T acid solids are added to 300 parts of water for beating, and 360 parts of H acid and alkali molten mother liquor (sodium sulfite content 39.82%) is neutralized to produce sulfur dioxide, which is used for neutralization of H acid and alkali molten liquor, and is obtained after removing sulfur dioxide Sodium nitro T solution.

3) The filtrate in step 1) is extracted with a complex extractant (N ₂₃₅ : 200 # solvent oil: phenylbutyl ether = 2: 5: 3, weight ratio), and the aqueous solution after acid extraction with nitro T is 38% dilute Sulfuric acid, the extract was first washed with 90 parts of water to obtain 100 parts of washing water with 18% sulfuric acid content, and then the extract was back-extracted with 15% sodium hydroxide solution, and the back-extracted solution was 290 parts (the back-extracted solution was nitrate Sodium T-solution).

4) Combine the sodium nitro T sodium solution obtained in step (2), add 50 parts of nickel catalyst, hydrogenate at 100 ° C to the end point, filter off the catalyst, acidify with dilute sulfuric acid generated after extraction in (3), and filter to obtain 290 parts of amino T acid, the content of amino T acid was 40.5%.

5) Add 4 parts of the nickel catalyst to the stripping solution in step 3, hydrogenate at 100-120 ° C to the end point, filter off the catalyst, and then acidify and filter to obtain 86 parts of amino T acid with a content of 35.3%.

6) Add 290 parts of amino T acid to 197 parts of 48% sodium hydroxide and 61 parts of methanol for alkali melting, alkali melting at 185-188 ° C for 1.5 hours, discharge, dilute with water, and use sulfur dioxide collected in (2) The solid was acidified and filtered to obtain a solid. The solid was slurried with water, acidified with dilute sulfuric acid in step 3), filtered, the filter cake was washed with 1 times water, and then filtered and dried to obtain 109 parts of the product with a content of 85.57% and a purity of 99.25%.

The above description is only a preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, or improvement made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims (32)

1. A process for producing H acid through recycling of an alkali melting mother liquor, which is characterized by comprising the following steps:

   (1) neutralize the reaction solution after the sulfonation, nitration, and denitration of the raw material for preparing the nitro T acid salt with an alkali molten mother liquid containing sulfite, remove the generated sulfur dioxide by heating, and then cool, crystallize, and separate, The nitro T acid salt solid and filtrate are obtained and used for future use. Sulfur dioxide is used for neutralization of H acid-base melt.

   (2) Continue neutralizing the filtrate in step (1), and then reduce the temperature, crystallize, and separate to obtain sulfate and filtrate. The filtrate can be further extracted and then back-extracted with dilute alkali. The sulfate can be further washed, and the obtained washing liquid is used for later;

   (3) dissolving the nitro T acid salt in step (1) with at least one of the filtrate, back-extraction liquid, and washing liquid in step (2), and the dissolved liquid undergoes catalytic hydrogenation or reduction reaction, acidification, crystallization, Amino T acid solid and filtrate were obtained after filtration;

   (4) An alkali melting reaction of the amino T acid in step (3) with an alkali solution to obtain an alkali melting reaction solution containing H acid, and the alkali melting reaction solution is acidified with sulfur dioxide obtained in steps (1) and (2). After cooling down and filtering, H acid and sulfite-containing mother liquor can be separated.
2. The process for producing H-acid by recycling alkali melting mother liquor according to claim 1, characterized in that the ratio of the reaction solution after denitration to the alkali melting mother liquor is 1: (0.4-2), parts by weight;

   Or, in step (1), the sulfite is sodium sulfite and / or potassium sulfite;

   Alternatively, in step (1), the temperature for removing sulfur dioxide is 80 ° C-100 ° C.
3. The process for producing H-acid by recycling alkali melting mother liquor according to claim 1, characterized in that the ratio of the reaction solution after denitration to the alkali melting mother liquor is 1: (0.8-1.5).
4. The process for producing H-acid by recycling alkali melting mother liquor according to claim 3, wherein the ratio of the reaction solution after denitration to the alkali melting mother liquor is 1: (0.9-1.2), parts by weight.
5. The process for producing H-acid by recycling alkali melting mother liquor according to claim 1, characterized in that the ratio of the reaction solution after denitration to the alkali melting mother liquor is 1: (0.4-1.0).
6. The process for producing H-acid by recycling alkali melting mother liquor according to claim 5, characterized in that the ratio of the reaction solution after denitration to the alkali melting mother liquor is 1: (0.5-0.8), parts by weight.
7. The process for producing H-acid by recycling alkali melting mother liquor according to claim 1, characterized in that in step (2), the substances for neutralization are sulfite solution, potassium hydroxide solution, sodium hydroxide Solution, ammonia or lightly burned magnesium;

   Or, in step (2), the filtrate in step (1) is neutralized to a liquid acidity of 2% -10%;

   Or, in step (2), the extraction agent used is N235 and / or 200 # solvent oil;

   Or, in step (2), the back extraction uses a dilute solution of potassium hydroxide or sodium hydroxide;

   Alternatively, in step (2), the sulfate is washed with water of the same quality as the sulfate.
8. The process for producing H-acid by recycling alkali mother liquor according to claim 7, wherein in step (2), the sulfite is sodium sulfite and / or potassium sulfite.
9. The process for producing H-acid by recycling alkali molten mother liquor according to claim 7, wherein in step (2), the substance for neutralization is selected from sodium hydroxide and / or potassium hydroxide.
10. The process for producing H-acid by recycling alkali melting mother liquor according to claim 7, characterized in that in step (2), the substance for neutralization is selected from light-burned magnesium powder.
11. The process for producing H-acid by recycling alkali molten mother liquor according to claim 7, characterized in that in step (2), the extractant used is formed by N235 and 200 # solvent oil with a mass ratio of 1: 3 Complexing extractant.
12. The process for producing H-acid by recycling alkali molten mother liquor according to claim 7, characterized in that in step (2), the back extraction uses a dilute solution of potassium hydroxide or sodium hydroxide, and potassium hydroxide or The mass concentration of sodium hydroxide is 5-10%.
13. The process for producing H-acid through recycling of an alkali melting mother liquor according to claim 1, wherein in step (3), the catalyst used in the catalytic hydrogenation reaction is a nickel catalyst;

    Or, in step (3), the temperature of the catalytic hydrogenation reaction is 80 ° C-120 ° C;

    Or, in step (3), the reducing agent used in the reduction reaction is iron powder and / or zinc powder;

    Or, in step (3), if the nitro T salt cannot be completely dissolved, an appropriate amount of water can be added.
14. The process for producing H-acid by recycling alkali mother liquor as claimed in claim 1, characterized in that in step (4), the alkali liquor is potassium hydroxide or sodium hydroxide solution;

    Or, in step (4), the alkali melting reaction is performed between 160 ° C and 195 ° C, and the reaction time is 0.5h-5h.
15. The process for producing H-acid by recycling alkali melting mother liquor according to claim 13, wherein in step (4), the reaction time of the alkali melting reaction is 0.5h-2h.
16. The process for producing H-acid by recycling the mother liquor of alkali according to claim 1, further comprising the step of preparing sulfate, as follows:

    S1: reacting the filtrate in step (3) with an alkaline solution, and adjusting the pH of the reaction solution to neutral, and obtaining a sulfate solid after evaporation, concentration, and crystallization;

    S2: The sulfuric acid salt produced in step S1 and the sulfuric acid salt produced in step (2) are calcined at high temperature to remove the organic impurities therein.
17. The process for producing H-acid by recycling alkali melting mother liquor according to claim 16, characterized in that: in S2, the calcination temperature is 800 ° C-1000 ° C, and the calcination time is 0.5h-1h.
18. The process for producing H-acid by recycling alkali mother liquor as claimed in claim 16, wherein in S1, the alkali liquor is sodium hydroxide and / or potassium hydroxide.
19. The process for producing H-acid by recycling alkali mother liquor as claimed in claim 16, wherein the step of preparing sulfates further comprises a step of treating tail gas generated in the calcination process.
20. The process for producing H-acid by recycling alkali melting mother liquor according to claim 19, wherein the treatment step of the tail gas generated in the calcination process is: the calcined tail gas is discharged after being processed by the RTO regenerative incinerator and reaches the standard. .
21. A method for producing H acid by complex extraction, which is characterized in that the method comprises the following steps:

    1) The nitro T acid reaction solution of refined naphthalene after sulfonation, nitration, and denitration is cooled to precipitate nitro T acid solids, so that the mass ratio of the precipitated nitro T acid solids to the filtrate is 1: 0.8-1.2;

    2) After nitro T acid solids are beaten with water, neutralized with H acid-base molten mother liquor, and the generated sulfur dioxide is removed to obtain a nitro T acid salt solution;

    3) The filtrate is extracted with a complexing extractant. The sulfuric acid content in the remaining filtrate after extraction is 30% -50% by mass percentage. After the extract is washed with water and the alkaline solution is back-extracted, a nitro T acid salt solution is obtained. Sulfuric acid content is 15% -25%, mass percentage;

    4) Add the nitro T acid salt solution obtained in step 2) to the catalyst to catalyze hydrogenation or iron powder reduction. The reduced solution is acidified and filtered to obtain an amino T acid solution. The acid used in the acidification is described in step 3). The remaining filtrate after extraction;

    5) Add alkali and methanol to the amino T acid for alkali melting, acidify the alkali molten solution with sulfur dioxide generated in step 2), filter the solid obtained after filtering, add water to beat, and acidify with the water washing solution in step 3) , Filtration, the filter cake was washed with water, filtered, and dried to obtain the product.
22. The method for producing H acid by complex extraction according to claim 21, wherein in step 1), the temperature of the nitro T acid reaction solution is lowered to -5 ° C to 10 ° C.
23. The method for producing H acid by complex extraction according to claim 21, wherein in step 2), the content of sodium sulfite in the H acid-alkali melt mother liquor is 35% -45%.
24. The method for producing H-acid by complex extraction according to claim 21, characterized in that in step 2), after solidifying the nitro T-acid with water and pulping, the H-acid-melt mother liquor is used to neutralize the The pH is 4-6.
25. The method for producing H acid by complex extraction according to claim 21, wherein in step 3), the complex extractant is a mixture of N ₂₃₅ solvent oil and phenyl alkyl ether, and N _{235 is} in a complex extraction The mass percentage in the agent is 20% -50%.
26. The method of claim 25, wherein the solvent oil is 200 # solvent oil or kerosene.
27. The method of claim 25, wherein the phenylalkyl ether is anisole, phenylethyl ether, phenylbutyl ether, phenyloctyl ether.
28. The method for producing H-acid by complex extraction according to claim 21, wherein in step 3), the sulfuric acid content in the remaining filtrate after extraction is 35% -45%, mass percentage.
29. The method for producing H acid by complex extraction according to claim 21, wherein in step 4), the catalyst is a nickel catalyst, and the temperature for catalytic hydrogenation is 80 ° C-120 ° C.
30. The method for producing H acid by complex extraction according to claim 21, wherein in step 5), the base is sodium hydroxide or potassium hydroxide.
31. The method for producing H acid by complex extraction according to claim 30, wherein the mass fraction of the alkali is 40% -50%.
32. The method for producing H acid by complex extraction according to claim 21, wherein in step 5), the temperature of the alkali melting is 160 ° C to 195 ° C, and the time of the alkali melting is 1 hour to 3 hours.