WO2022156623A1

WO2022156623A1 - Comprehensive utilization process of pta oxidation residue

Info

Publication number: WO2022156623A1
Application number: PCT/CN2022/072303
Authority: WO
Inventors: 沈福昌; 沈建东; 沈世金; 张利
Original assignee: 泰兴市福昌环保科技有限公司
Priority date: 2021-01-20
Filing date: 2022-01-17
Publication date: 2022-07-28
Also published as: CN112851503A

Abstract

Disclosed is a comprehensive utilization process of PTA oxidation residue, the process comprising the following steps: S1, esterification; S2, rectification, involving: carrying out two-stage rectification on an esterification liquid, and separating crude octyl benzoate, crude dioctyl terephthalate and crude trioctyl trimellitate by means of condensation; and S3, impurity removal. In step S2, after two-stage rectification, kettle residues are incinerated to obtain a cobalt salt, a manganese salt, and a bromine salt. By means of the present invention, PTA oxidation residue is used as a raw material to produce dioctyl terephthalate plasticizer, and octyl benzoate and trioctyl trimellitate can also be produced; a cobalt salt, a manganese salt and a bromine salt obtained from second stage rectifying kettle residues can act as raw materials for industrial production; a cobalt salt and a manganese salt are produced, thereby increasing the profit of the product evaluation line, such that the utilization efficiency of the raw material is enhanced, energy use is reduced, the yield of the finished product is increased, and the efficiency is increased.

Description

A kind of comprehensive utilization process of PTA oxidation residue

technical field

The invention relates to the field of chemical production, in particular to a process for comprehensive utilization of PTA oxidation residues.

Background technique

PTA is an important chemical raw material, but a large amount of PTA residues will be produced during the production process, which mainly include benzoic acid, terephthalic acid, phthalic acid, isophthalic acid, and trimene. A large amount of residue not only needs a place for accumulation, but also poses a great threat to environmental pollution. At present, the technology of treating PTA residue by the separation method is immature and uneconomical, and the incineration method requires a large amount of naphtha or coal to support combustion, and the waste gas and dust generated by the combustion are discharged into the atmosphere and pollute the environment .

However, other treatment methods also have the disadvantages of low utilization rate and high cost. Therefore, it is necessary to design a comprehensive utilization process of PTA oxidation residue with high utilization rate and good production efficiency.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a comprehensive utilization process of PTA oxidation residue with high utilization rate and good production benefit.

The technical scheme for realizing the object of the present invention is: a comprehensive utilization process of PTA oxidation residue, comprising the following steps:

S1: Esterification: adding PTA oxidation residue, octanol and catalyst into the esterification reactor for heating and esterification, and filtering to obtain an esterification liquid;

S2: Rectification: the esterification solution is separated into crude octyl benzoate, crude dioctyl terephthalate and crude trioctyl trimellitic acid through two-stage rectification; the crude octyl benzoate is subjected to transesterification Then obtain the finished product of benzoic acid polyol ester;

S3: impurity removal: crude trioctyl trimellitic acid and crude dioctyl terephthalate are respectively neutralized, washed with water, stripped, adsorbed and decolorized and filtered to remove impurities;

The catalyst is tetrabutyl titanate.

In the step S1, the PTA oxidation residue is subjected to dehydration treatment before esterification, and the specific steps are as follows: the PTA oxidation residue is put into a heating kettle for heating, and the removed water phase is subjected to waste water treatment.

The ratio of the amount of PTA oxidation residue, octanol and catalyst added is: 1:2.001:0.0345, the heating temperature is 180-220°C; the end point of the esterification reaction: the acid value drops below 0.5; the gas during esterification is passed into the condenser to condense, After the condensed liquid is left to stand for stratification, the upper layer of octanol is taken and added to the esterification reactor for reuse.

During the described esterification step and rectification step, octanol is used as cooling liquid, the top of the esterification tower enters the alcohol-water separator after being condensed by the condenser, and the octanol returns to the top of the tower after separation, and the cooled octanol is at 40°C. ℃, after returning to the tower, the temperature rises to 184 ℃ to vaporize reflux with water, and the cycle goes back and forth to waste energy. Moreover, after the condenser vaporizes the water, the calcium and magnesium ions in the water will scale and cause pollution to the condenser. In order to solve the above problems, a pump is used to measure octanol through a flow meter and enter the condenser as a cooling medium. The advantage of this is that octanol and alcohol vapor exchange cold and heat in the condenser, so that octanol enters the esterification tower at about 140 °C, This saves heat energy and also solves the problem of condenser scaling.

After the esterification, the esterification liquid is dealcoholized, and the octanol removed and the octanol produced by steam stripping are jointly refluxed to the esterification step to participate in the reaction.

After the evaporation phase of the first-stage rectification is condensed, crude octyl benzoate is obtained; the crude octyl benzoate is added with mixed polyol and zinc acetate to carry out transesterification to obtain a transesterified product, and the mixing polyol and octyl benzoate charging ratio The formula is: 1:4.5, the input amount of zinc acetate is 0.1% of the total mass, and the temperature is 220° C.; the finished product of benzoic acid polyol ester is obtained after the transesterification product is rectified and condensed. The evaporative gas during the transesterification reaction is collected and condensed, the condensate is left to stand for stratification, and the upper octanol is taken and sent to the esterification reactor of the esterification reaction for reuse. The condenser uses octyl benzoate as the cooling liquid for recycling. The tower top vacuum degree of rectification is 0.15kpa, the tower still temperature is 220 ℃, the tower top temperature is 120 ℃, the reflux ratio is 5: 1, steams out excess octyl benzoate, the tower still temperature is 240 ℃, the tower top temperature At 200℃, reflux ratio: 1:1, benzoic acid polyol ester is distilled out, and octyl benzoate is used as cooling liquid in the condenser for recycling, which saves heat energy and solves the problem of condenser scaling. The mixed polyol is a mixture of diethylene glycol and dipropylene glycol.

When extracting octyl benzoate, the vacuum degree at the top of the tower is 0.15kpa, the temperature of the tower still is 250°C, the temperature at the top of the tower is 120°C, and the reflux extraction ratio is 5:1. When extracting dioctyl terephthalate, the vacuum degree at the top of the tower is 0.15kpa, the temperature of the tower still is 250-255°C, the temperature at the top of the tower is 220-230°C, and the reflux ratio is 1:1. When extracting trioctyl trimellitic acid, the vacuum degree at the top of the tower is 0.15kpa, the temperature of the tower still is 265°C, and the temperature at the top of the tower is 235-240°C, and the total extraction of trioctyl trimellitic acid has no reflux. The rectification adopts a vacuum unit, preferably a three-stage Roots unit combination. The unit has high efficiency and does not retain low boilers. It is more suitable for high vacuum distillation and operates very stably.

Cobalt salts, manganese salts and bromine salts are obtained after the residue of the second-stage rectification kettle is incinerated.

The rectification is carried out under the condition of negative pressure, the vacuum degree is 0.15kpa, the reaction time is shortened, the reaction temperature is lowered, and the conversion rate is improved.

In the step S3, the crude dioctyl terephthalate is added with liquid caustic soda to neutralize to a pH value of 7.5 to 8, and after neutralization, it is left to stand for stratification, and the upper oil phase is taken into pure water for washing, and after washing, it is left to stand for stratification. , take the upper oil phase and input it into steam stripping. After stripping, activated carbon and diatomaceous earth are used for adsorption and filtration to obtain the finished product of dioctyl terephthalate.

Crude trioctyl trimellitic acid is added with liquid caustic soda to neutralize to pH value of 7.5-8, after neutralization, stand for stratification, take the upper oil phase and add pure water for washing, after washing, stand for stratification, take the upper oil phase in turn Adopt activated carbon and diatomaceous earth to adsorb and filter to obtain the finished product of dioctyl terephthalate. The lye is sodium hydroxide solution.

In described step S2, the recovery of cobalt salt and manganese salt adopts cobalt-manganese extraction process to recover, specifically:

S21: extracting manganese extraction unit; the pre-extraction liquid is extracted and extracted by the reactor to obtain manganese extraction raffinate and manganese extraction extract; the manganese extraction extract is successively washed by manganese extraction, manganese extraction back-extraction and manganese extraction wash Iron gets manganese extraction liquid;

The extraction and manganese extraction steps include primary extraction of manganese extraction, secondary extraction of manganese extraction, and tertiary extraction of manganese extraction. Reacting with the pre-extraction liquid during the third-stage extraction of manganese extraction; the water phase after the third-stage extraction of manganese extraction and extraction flows to the second-stage extraction of manganese extraction; the water phase of the second-stage extraction of manganese extraction flows to the first-stage extraction of manganese extraction; The saponified extract is subjected to the first-stage extraction of manganese extraction with the water phase of the secondary extraction of manganese extraction to separate the manganese extraction raffinate. The composition of the extractant in the extraction and manganese extraction step is: volume of P204: volume of 260# solvent oil=1:3.

The saponification rate of the extractant is controlled at 55-60%, the feed amount is preferably 15-16 m ³ /h for the oil phase, and 750-800 L/h for the saponification agent.

The saponification agent is: 30-31% NaOH or 20% ammonia water.

The feeding amount of the pre-extraction liquid is adjusted according to the pH value of the raffinate liquid of 3.8-4.2, and the feeding amount is preferably: 2.5-3.5 m ³ /h.

The manganese extraction raffinate has Mn≤0.005g/L, Ca≤0.002g/L, Cu≤0.002g/L, Zn≤0.001g/L, Fe≤0.001g/L.

The manganese extraction washing adopts an acid pump to pump the washing acid and the manganese extraction extract to react in the reactor to obtain the manganese extraction washing organic phase and the manganese extraction post-liquid; the manganese extraction post-liquid is merged into the manganese extraction raffinate;

The washing acid adopts sulfuric acid, the concentration is preferably 60-80 g/L, and is prepared by adding 33-44 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feeding amount of the washing acid is based on the ability to control the pH value of the washing acid outlet = 3.0-3.5, preferably 1.5-2.0 m ³ /h.

The manganese-extraction stripping includes the manganese-extracting primary stripping and the manganese-extracting secondary stripping; the manganese-extracting primary stripping step is as follows: the manganese-extracting and washing organic phases are reacted in the reactor, and then phase-separated in the clarifier. ; The loaded phase of the primary stripping of manganese extraction and the acid of stripping are carried out in the reactor for secondary stripping of manganese, and then the phases are separated in the clarification tank, and the water phase of the secondary stripping of manganese extraction is refluxed to the primary stripping of manganese extraction. Extraction, the loaded organic phase enters the step of extracting manganese and washing iron;

The stripping acid for the first-stage stripping of manganese extraction is sulfuric acid, and the concentration is preferably: 180g/L, which is prepared by adding _95-100L 98% _H2SO4 per 1m ³ of pure water.

The amount of back-extraction acid feeding in the first-stage back-extraction of manganese extraction is subject to the pH value of the back-extraction acid outlet=3.0～3.2, preferably 0.9～1.1m ³ /h.

The PH value of the loaded organic phase for manganese extraction and stripping is 3.0～3.2, C _Mn2+ =95～100g/L; the content of impurity elements is controlled as follows: Ni≤0.005g/L, Cu≤0.005g/L, Zn≤0.002g/ L, Fe≤0.005g/L, Cd≤0.002g/L, Mg≤0.005g/L, Ca≤0.005g/L.

In the step of extracting manganese and washing iron, an acid pump is used to extract and wash the ferric acid and the organic loading phase of manganese extraction and stripping to react in the reactor, and then the phases are separated in the clarification tank to obtain the manganese extraction liquid and the manganese extraction and iron washing liquid. , the manganese-extracting and iron-washing liquid is returned to the manganese-extracting and iron-washing step for reuse.

The iron washing acid adopts hydrochloric acid, and the concentration is preferably: 6mol/L. When the recycling is lower than 4mol/L, 12mol/L of concentrated HCl is added to adjust, and the feeding amount is preferably: 1.8～2.0m ³ /h.

The manganese extraction liquid is concentrated and evaporated to obtain cooling crystals; the cooling crystals are centrifuged to obtain manganese salts.

S22: Extracting cobalt extraction unit; the manganese extraction raffinate is extracted by the reactor for cobalt extraction to obtain cobalt extraction raffinate and cobalt extraction extract; the cobalt extraction extract is successively washed by cobalt extraction, cobalt extraction back-extraction and extraction Cobalt washing iron to obtain cobalt extraction liquid;

The cobalt extraction and extraction steps include first-stage cobalt extraction, second-stage cobalt extraction, and third-stage cobalt extraction; the cobalt extraction uses the saponified extract after the first-stage cobalt extraction and the second-stage cobalt extraction. Reacting with the pre-extraction liquid during the third-stage extraction of cobalt extraction; the water phase after the third-stage extraction of cobalt extraction and extraction flows to the second-stage extraction of cobalt extraction; the water phase of the second-stage extraction of cobalt extraction flows to the first-stage extraction of cobalt extraction; The saponified extract is subjected to cobalt-extraction first-stage extraction with the water phase of cobalt-extraction secondary extraction to separate cobalt-extraction raffinate.

The extraction liquid is: P507 volume: 260# solvent oil volume=1:3.

The saponification agent is: 30-31% NaOH or 20% ammonia water.

The feed volume of the extract is subject to the saponification rate being controlled at 60-70, preferably: oil phase 12-14 m ³ /h, saponification agent 550-750 L/h.

The feed volume of the extract after saponification is based on the controllable pH value of the raffinate = 5.2-5.5, preferably: 5.0-6.0 m ³ /h. Raffinate C _C02+ ≦20mg/L, no light red.

The cobalt extraction washing adopts an acid pump to pump the washing acid and the manganese extraction extract to react in the reactor, and then separate phases in the clarification separation tank to obtain the cobalt extraction washing organic phase.

The washing acid adopts sulfuric acid, and the concentration is preferably: 60-80 g/L, and is prepared by adding 33-44 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feeding amount of the washing acid is based on the ability to control the pH value of the washing acid outlet to 3.2-3.5, preferably: 1.2-1.5 m ³ /h.

The cobalt-extraction stripping includes cobalt-extracting primary stripping and cobalt-extracting secondary stripping; the cobalt-extracting primary stripping step is: the cobalt extraction and washing organic phase react in a reactor, and then separate phases in a clarifier ; The loading phase of the cobalt-extraction primary stripping and the stripping acid are carried out in the reactor for cobalt-extraction secondary stripping, followed by phase separation in the clarification tank, and the aqueous phase of the cobalt-extracting secondary stripping is refluxed to the cobalt-extracting primary stripping. Extraction, the loaded organic phase enters the cobalt extraction and iron washing step.

The back-extraction acid adopts sulfuric acid, and the concentration is preferably: 180g/L H ₂ SO ₄ , which is prepared by adding 95-100L 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the back-extraction acid is based on the ability to control the pH value of the back-extraction acid outlet = 3.3 to 3.5, preferably: 0.8 to 1.1 m ³ /h.

In the cobalt extraction and iron washing step, an acid pump is used to extract the ferric acid and the organic loading phase of the cobalt extraction and back-extraction to react in the reactor, and then the phases are separated in the clarifier to obtain the cobalt extraction liquid and the cobalt extraction and iron washing liquid. , the liquid after cobalt extraction and iron washing is refluxed to the cobalt extraction and iron washing step for reuse.

The ferric acid is washed with hydrochloric acid, and the concentration is preferably: 6 mol/L, and 12 mol of concentrated HCl is added to adjust when the recycling is less than 4 mol. The feeding amount is preferably: 1.8-2.0 m ³ /h.

S23: The post-processing is that the cobalt extraction liquid is concentrated and evaporated to obtain cooling crystallization; the cooling crystallization is centrifuged to obtain manganese salt and cobalt salt.

The invention also provides a full-interface reactor for cobalt-manganese extraction process, comprising a premixing module, a multiphase reaction module and a continuous reaction module that are connected in sequence; the multiphase reaction module includes a reaction tube body; the reaction The pipe body includes a pre-mixing zone and a full-mixing zone; the full-mixing zone is provided with several mixing units along the direction of the reaction tube body to change the flow direction of the reaction phase; the end of the full-mixing zone is connected to the inlet end of the continuous reaction module.

The mixing unit is a high-speed turbine. Guide vanes designed according to the helical flow channel are installed on the high-speed turbine.

The adjacent high-speed turbine rotates in the opposite direction.

The front end of the premixing zone is provided with an oil phase inlet and a water phase inlet; the oil phase inlet is perpendicular to the axis direction of the water phase inlet. When the fluids in the two directions flow in, they collide with each other and play the role of preliminary mixing.

The cobalt-manganese extraction process, using the above-mentioned full-interface reactor, comprises the following steps:

S21: Extraction and extraction of manganese; the pre-extraction liquid is extracted by the reactor to extract manganese to obtain a manganese extraction raffinate and a manganese extraction extract; the manganese extraction extract is successively washed by manganese extraction, manganese extraction back-extraction and manganese extraction and iron washing Obtain manganese extraction liquid;

In the step S1, the extraction and extraction of manganese include primary extraction of manganese extraction, secondary extraction of manganese extraction, and tertiary extraction of manganese extraction; the extraction and extraction of manganese use the saponified extract after primary extraction of manganese extraction and extraction of manganese. After the secondary extraction, it reacts with the pre-extraction liquid during the tertiary extraction of manganese extraction; the water phase after the tertiary extraction of manganese extraction flows to the secondary extraction of manganese extraction; the water phase of the secondary extraction of manganese extraction flows to the extraction process. Manganese primary extraction; the saponified extract is subjected to manganese extraction primary extraction with the water phase of manganese extraction secondary extraction to separate the manganese extraction raffinate. The composition of the extractant in extracting manganese is: volume of P204: volume of 260# solvent oil=1:3.

The saponification agent is: 30-31% NaOH or 20% ammonia water.

S22: extracting cobalt; the manganese-extracting raffinate is extracted by the reactor to extract cobalt to extract cobalt-extracting raffinate and cobalt-extracting extract; the cobalt-extracting extract is successively washed by cobalt extraction, cobalt extraction back-extraction and cobalt extraction Washing iron to obtain cobalt extraction liquid;

The extraction liquid is: P507 volume: 260# solvent oil volume=1:3.

The saponification agent is: 30-31% NaOH or 20% ammonia water.

The feed volume of the extract is subject to the saponification rate being controlled at 60-70%, preferably: oil phase 12-14 m ³ /h, saponification agent 550-750 L/h.

The post-processing is that the cobalt extraction liquid is concentrated and evaporated to obtain cooling crystallization; the cooling crystallization is subjected to centrifugal separation to obtain manganese salt and cobalt salt.

Described manganese sulfate and cobalt sulfate are respectively used for producing manganese acetate, manganese carbonate and cobalt acetate;

The production technology of described manganese acetate and manganese carbonate is specifically:

A1: Preliminary replacement; adding sodium bicarbonate for initial replacement;

A2: washing with water; filtration to obtain manganese carbonate and filtrate;

A3: Secondary replacement: Add glacial acetic acid and pure water for secondary replacement to obtain manganese acetate solution.

In described step A2, add pure water to wash, then press filtration to obtain manganese carbonate and preliminary replacement liquid;

In the step A3, glacial acetic acid and pure water are added to the preliminary replacement solution for secondary replacement, and a manganese acetate solution is obtained after filtration.

The manganese acetate solution is successively subjected to evaporation concentration, cooling crystallization and centrifugal filtration to obtain finished manganese acetate for sale.

The production technique of described cobalt acetate is specifically:

B1: Preliminary replacement: adding sodium bicarbonate for initial replacement;

B2: water washing: filter to remove waste water;

B3: Secondary replacement; adding glacial acetic acid and pure water for secondary replacement to obtain a cobalt acetate solution.

In described step A2, add pure water to wash, then press filtration to obtain preliminary replacement fluid;

In the step A3, glacial acetic acid and pure water are added to the preliminary replacement solution for secondary replacement, and the cobalt acetate solution is obtained after filtration.

The cobalt acetate solution is successively subjected to evaporation concentration, cooling crystallization and centrifugal filtration to obtain finished cobalt acetate products for sale.

The bromine salt is recovered by a bromine-containing waste salt recovery process; the bromine-containing waste salt recovery process includes:

C1: dissolve; filter: add pure water to the ash containing sodium bromide to dissolve, then filter by pressure,

C2: Decolorization; chromaticity detection is carried out before decolorization, activated carbon is added to absorb and fade according to the chromaticity detection results, and then the waste activated carbon is removed by filtration;

C3: Concentration; Crystallization: The sodium bromide solution after decolorization is evaporated and concentrated in turn, crystallized by cooling and centrifuged to obtain the sodium bromide product.

The above overall process can realize 6600t/a benzoic acid, 3000t/a sodium bromide, 1000t/a cobalt salt and manganese salt when 50000t/a PTA residue is recovered, the comprehensive production utilization rate is high, the waste is less, and the PTA residue can be realized comprehensive utilization.

Having adopted the above-mentioned technical scheme, the present invention has the following beneficial effects:

(1) the present invention can also produce octyl benzoate and trioctyl trimellitic acid while taking PTA oxidation residue as raw material to produce dioctyl terephthalate plasticizer, second-stage rectifying still residue The obtained cobalt salts, manganese salts and bromine salts can be used as raw materials for industrial production to be made into cobalt salts and manganese salts, which can increase the income of the production evaluation line, strengthen the utilization efficiency of raw materials, save energy, increase the harvest of finished products, and expand the benefits.

(2) the present invention adopts octanol and octyl benzoate as cooling liquid, condenses while reacting, saves the cost of setting up coolant separately, and cooling effect is good, and transformation efficiency is high

(3) The present invention performs dehydration pretreatment before the esterification reaction, removes the liquid in the PTA oxidation residue, reduces the COD value, and reduces the difficulty of the reaction and the production cost.

(4) The octanol evaporated during the esterification of the present invention is recovered and used, which reduces the consumption of octanol and saves costs.

(5) The octyl benzoate of the present invention is subjected to transesterification, and then rectified and condensed to obtain a finished product of benzoic acid polyol ester, which improves the utilization rate, increases the product diversity, expands the production line income, and reduces the discharge waste.

(6) The present invention adopts two production lines to extract the pre-extraction liquid respectively, mainly removes manganese element and cobalt element, so that it meets the discharge standard. Compared with the traditional extraction and impurity removal process, the reaction time is greatly reduced, and the Productivity.

Description of drawings

In order to make the content of the present invention easier to understand clearly, the present invention will be described in further detail below according to specific embodiments and in conjunction with the accompanying drawings, wherein

FIG. 1 is a schematic structural diagram of the present invention.

Fig. 2 is the cobalt-manganese extraction process flow diagram of the present invention.

Fig. 3 is the production process flow diagram of cobalt acetate of the present invention.

Fig. 4 is the flow chart of manganese acetate, manganese carbonate production technology of the present invention.

Detailed ways

Referring to Fig. 1, the present application solves the problems in the prior art that the PTA oxidation residue yield is large and the utilization rate is low by providing a PTA oxidation residue comprehensive utilization process, and the general idea is as follows:

Include the following steps:

S1: Esterification: PTA oxidation residue, octanol and catalyst are added to the esterification reactor for heating and esterification, and the esterification liquid is obtained after filtration.

The catalyst uses tetrabutyl titanate.

The PTA oxidation residue is subjected to dehydration treatment before esterification, and the specific steps are as follows: the PTA oxidation residue is put into a heating kettle for heating, and the removed water phase is treated with waste water.

The gas during esterification is passed into the condenser for condensation, and after the condensed liquid is left to stand for stratification, the upper layer of octanol is taken and added to the esterification reactor for reuse.

S2: Rectification: The esterification liquid is separated into crude octyl benzoate, crude dioctyl terephthalate and crude trioctyl trimellitic acid through two-stage rectification. The crude octyl benzoate is subjected to transesterification to obtain the finished product of benzoic acid polyol ester.

In step S2, crude octyl benzoate is obtained after the evaporation phase of the first-stage rectification is condensed. Crude octyl benzoate is added with diethylene glycol and zinc acetate for transesterification to obtain transesterification products. After the transesterification product is rectified and condensed, the finished product of benzoic acid polyol ester is obtained. The evaporative gas during the transesterification reaction is collected and then condensed, and the condensate is left to stand for stratification, and the upper layer octanol is taken and sent to the esterification reactor of the esterification reaction for reuse.

The rectification adopts a vacuum unit, preferably a three-stage Roots unit combination. The unit has high efficiency and does not retain low boilers. It is more suitable for high vacuum distillation and operates very stably.

The rectification is carried out under the condition of negative pressure, which shortens the reaction time, reduces the reaction temperature, and improves the conversion rate.

S3: Removal of impurities: crude trioctyl trimellitic acid and crude dioctyl terephthalate are respectively neutralized, washed with water, stripped, adsorbed and decolorized and filtered to remove impurities.

Both the esterification step and the rectification step use octanol as the cooling liquid, and the octanol is condensed at the same time of the esterification, and the heat is dissipated quickly.

Crude dioctyl terephthalate is added to liquid caustic soda for neutralization, and after neutralization, it is left to stand for stratification, the upper oil phase is added to pure water for washing, and after washing, it is left to stand for stratification, and the upper oil phase is input to steam stripping, stripping Then, activated carbon and diatomaceous earth are used for adsorption and filtration in turn to obtain the finished product of dioctyl terephthalate.

Crude trioctyl trimellitic acid was added to liquid caustic soda for neutralization. After neutralization, it was left to stand for stratification. The upper oil phase was added to pure water for washing. After washing, it was left to stand for stratification. By adsorption and filtration, the finished product of trioctyl trimellitic acid is obtained.

The reaction equation of the process design is as follows:

Referring to Figure 2, in step S2, cobalt salts, manganese salts and bromine salts are obtained after the two-stage rectification residue is incinerated. Cobalt salt and manganese salt are pre-extracted to obtain pre-extraction liquid, and the pre-extraction liquid is recovered by cobalt-manganese extraction process. The cobalt-manganese extraction process includes the following steps:

S21: extracting manganese. The pre-extraction liquid is extracted by the reactor to extract manganese to obtain a manganese-extracted raffinate and a manganese-extracted extract. The manganese extraction extract is successively washed with manganese extraction, back-extracted with manganese extraction, and washed with iron by manganese extraction to obtain a manganese extraction liquid.

Extraction and extraction of manganese include primary extraction of manganese extraction, secondary extraction of manganese extraction, and tertiary extraction of manganese extraction. Extraction and extraction of manganese use the saponified extract to react with the pre-extraction liquid during the third-level extraction of manganese extraction after the first-level extraction of manganese extraction and the second-level extraction of manganese extraction. The water phase after the third-stage extraction of manganese extraction and extraction flows to the second-stage extraction of manganese extraction. The aqueous phase of the secondary extraction of manganese extraction flows to the primary extraction of manganese extraction. The manganese extraction raffinate is separated from the saponified extract and the water phase of the manganese extraction secondary extraction. The composition of the extractant in extracting manganese is: volume of P204: volume of 260# solvent oil=1:3.

The manganese extraction washing adopts acid pump to pump the washing acid and the manganese extraction extract to react in the reactor to obtain the manganese extraction washing organic phase and the manganese extraction post-liquid. The manganese-extracted liquid was merged into the manganese-extracted raffinate.

The manganese extraction stripping includes the first-level stripping of manganese extraction and the second-level stripping of manganese extraction. The first-stage stripping step of manganese extraction is as follows: the organic phase of manganese extraction and washing is reacted in the reactor, and then the phases are separated in the clarification tank. The loaded phase of the first-stage stripping of manganese extraction and the stripping acid are carried out in the reactor for the second-stage stripping of manganese extraction, and then the phases are separated in the clarification tank, and the water phase of the second-stage stripping of manganese extraction is refluxed to the first-stage stripping of manganese extraction. , the loaded organic phase enters the step of extracting manganese and washing iron.

In the step of extracting manganese and washing iron, an acid pump is used to extract the ferric acid and the organic loading phase of manganese extraction and stripping to react in the reactor, and then the phases are separated in the clarification tank to obtain the manganese extraction liquid and the manganese extraction and iron washing liquid, and the extraction process is as follows: After the manganese washing iron, the liquid is refluxed to the manganese extraction and iron washing step for reuse.

The manganese extraction liquid is concentrated and evaporated to obtain cooling crystallization. Cooling crystallization and centrifugation to obtain manganese salt.

S22: Extraction and extraction of cobalt. The manganese extraction raffinate is extracted by the reactor for cobalt extraction to obtain cobalt extraction raffinate and cobalt extraction extract. The cobalt extraction extract is successively subjected to cobalt extraction washing, cobalt extraction back-extraction and cobalt extraction and iron washing to obtain a cobalt extraction solution.

The cobalt extraction and extraction steps include cobalt extraction first-level extraction, cobalt extraction second-level extraction, and cobalt-extraction third-level extraction. The cobalt extraction extraction adopts the saponified extraction liquid to react with the pre-extraction liquid during the cobalt extraction first stage extraction and the cobalt extraction second stage extraction during the cobalt extraction third stage extraction. The water phase after the third-stage extraction of cobalt extraction and extraction flows to the second-stage extraction of cobalt extraction. The aqueous phase of the cobalt extraction secondary extraction flows to the cobalt extraction primary extraction. The saponified extract is subjected to the first-stage extraction of cobalt extraction with the aqueous phase of the secondary extraction of cobalt extraction to separate the cobalt extraction raffinate.

The cobalt extraction washing adopts an acid pump to pump the washing acid and the manganese extraction extract to react in the reactor, and then separate the phases in the clarification separation tank to obtain the cobalt extraction washing organic phase.

Cobalt extraction stripping includes cobalt extraction first-level stripping and cobalt extraction second-level stripping. The cobalt extraction first-stage stripping step is as follows: the cobalt extraction washing organic phase reacts in the reactor, and then separates the phases in the clarification tank. The loading phase of the cobalt extraction primary stripping and the stripping acid are carried out in the reactor for cobalt extraction secondary stripping, and then the phases are separated in the clarification tank, and the water phase of the cobalt extraction secondary stripping is refluxed to the cobalt extraction primary stripping. , the loaded organic phase enters the cobalt extraction and iron washing step.

In the step of cobalt extraction and iron washing, an acid pump is used to pump the ferric acid and the organic loading phase of cobalt extraction and stripping to react in the reactor, and then the phases are separated in the clarification tank to obtain a cobalt extraction liquid and a cobalt extraction and iron washing liquid. After cobalt washing and iron washing, the liquid is refluxed to the cobalt extraction and iron washing step for reuse.

After treatment, the cobalt extraction liquid is concentrated and evaporated to obtain cooling crystallization. Cooling crystallization and centrifugation to obtain manganese salts and cobalt salts.

In this application, two production lines are used to extract the pre-extraction liquid, mainly to remove manganese and cobalt elements, so that they meet the emission standards. Compared with the traditional extraction and impurity removal process, the use of a brand-new reactor greatly reduces the reaction time. , improve production efficiency.

Compared with dozens of reaction stages of traditional extraction reaction, it can be reduced to at least seven stages of full-interface extraction when using a new reactor, which greatly reduces the footprint of the device, reduces equipment maintenance consumption, reduces the operating cost per unit of electricity, and reduces production. cost. The reaction efficiency is high, the number of reaction stages is small, the stock of the organic tank is reduced, the specific surface area of the organic phase is greatly reduced, the amount of organic evaporation is reduced, and the operating cost due to the evaporation of the organic tank is reduced. At the same time, the equipment noise is low, and the specific surface area of the organic phase is It is greatly reduced, the organic evaporation is reduced, the overflow of organic waste gas is reduced, and the air quality on site is improved.

The full-interface reactor used in this application includes a premixing module, a multiphase reaction module and a continuous reaction module that are connected in sequence. The multiphase reaction module includes a reaction tube body. The reaction tube body includes a premixing zone and a total mixing zone. A number of mixing units for changing the flow direction of the reaction phase are arranged along the direction of the reaction tube body in the total mixing zone. The end of the total mixing zone is connected to the inlet end of the continuous reaction module.

The mixing unit is a high-speed turbine. The high-speed turbine is equipped with guide vanes designed according to the helical flow channel.

The adjacent high-speed turbine rotates in the opposite direction.

The front end of the premixing zone is provided with an oil phase inlet and a water phase inlet. The axis direction of the oil phase inlet is perpendicular to the axis direction of the water phase inlet. When the fluids in the two directions flow in, they collide with each other and play the role of preliminary mixing.

The manganese extraction and iron washing and cobalt extraction and iron washing processes are carried out in a brand-new reactor, which improves the reaction efficiency, greatly improves the cleanliness of iron washing, reduces the retention of iron ions in the extractant, not only improves the iron washing efficiency, but also At the same time, the use efficiency of the extractant is improved, the service life of the extractant is prolonged, the consumption of the extractant is reduced, and the production cost is reduced.

Manganese sulfate and cobalt sulfate are used to produce manganese acetate, manganese carbonate and cobalt acetate, respectively.

See Figure 3, the production process of manganese acetate and manganese carbonate is as follows:

A1: Preliminary replacement. Sodium bicarbonate was added for initial replacement.

A2: Washed with water. Filtration gave manganese carbonate and a filtrate.

In step A2, pure water is added for washing, and then pressure filtration is performed to obtain manganese carbonate and a preliminary replacement solution.

In step A3, glacial acetic acid and pure water are added to the preliminary replacement solution for secondary replacement, and a manganese acetate solution is obtained after filtration.

See Figure 4, the production process of cobalt acetate is specifically:

B1: Preliminary replacement: adding sodium bicarbonate for initial replacement.

B2: Water washing: filter to remove waste water.

B3: Secondary permutation. Add glacial acetic acid and pure water for secondary replacement to obtain cobalt acetate solution.

In step A2, pure water is added for washing, and then pressure filtration is performed to obtain a preliminary replacement solution.

In step A3, glacial acetic acid and pure water are added to the preliminary replacement solution for secondary replacement, and the cobalt acetate solution is obtained after filtration.

The technical solutions of the present application will be further described below with reference to different embodiments.

Sampling, take the dry base PTA oxidation residue that can be purchased in the market for component analysis, the specific data of each kg component is shown in the following table:

Unit: g

厂家factory	苯甲酸benzoic acid	混合二元酸mixed dibasic acid	偏苯三酸trimellitic acid	杂质impurities
嘉兴桐昆Jiaxing Tongkun	360360	450450	6060	130130
上海亚东Shanghai Yadong	310310	430430	3030	230230
江阴海伦Jiangyin Helen	330330	420420	4040	210210
四川能投Sichuan Energy Investment	340340	440440	6060	160160

(Example 1)

Add 1000 g (dry basis) of Jiaxing Tongkun PTA oxidation residue into the reactor, add 2001 g of octanol, and turn on heating and stirring. When the temperature of the material rises to 184°C, 3.45g of tetrabutyl titanate catalyst is added, and the octanol is refluxed with water at this time. Wait for the temperature in the kettle to rise to about 220°C and no water droplets are extracted, which is regarded as the end point of the esterification reaction. When the acid value of the esterification solution is detected to be 0.5 or less, the esterification reaction is completed. When the temperature of the esterified liquid is lowered to 90°C, filtration is started to obtain a transparent esterified liquid, and the rectification step is started.

Pour the transparent esterification liquid into the distillation tower still, when the vacuum at the top of the tower reaches 0.15kpa, heat the tower still, and when the temperature at the top of the tower rises and stabilizes at about 43°C, the excess octanol begins to be extracted, and the extraction of octanol is completed. , the temperature at the top of the tower is stable at about 120 ° C, and the octyl benzoate obtained by the reaction is started to be collected (the reflux ratio is 5:1). The obtained octyl benzoate was 688.7 g (material loss in the process was 3.3 g), and the transesterification reaction was started.

The obtained octyl benzoate was poured into the reactor, 153 g of polyol and 1 g of zinc acetate were added, heated and stirred, and when the temperature reached about 220°C and no octanol was extracted, it was regarded as the reaction end point.

See Table 2 for the product generation and consumption per kg of dry basis of the oxidation residue.

(Example 2)

1000g (dry basis) of Shanghai Yadong PTA oxidation residue was taken into the reactor, 2001g of octanol was added, and heating and stirring were turned on. When the temperature of the material rises to 184°C, 3.45g of tetrabutyl titanate catalyst is added, and the octanol is refluxed with water at this time. Wait for the temperature in the kettle to rise to about 220°C and no water droplets are extracted, which is regarded as the end point of the esterification reaction. When the acid value of the esterification solution is detected to be 0.5 or less, the esterification reaction is completed. When the temperature of the esterified liquid is lowered to 90°C, filtration is started to obtain a transparent esterified liquid, and the rectification step is started.

Pour the transparent esterification liquid into the distillation tower still, when the vacuum at the top of the tower reaches 0.15kpa, heat the tower still, and when the temperature at the top of the tower rises and stabilizes at about 43°C, the excess octanol begins to be extracted, and the extraction of octanol is completed. , the temperature at the top of the tower is stable at about 120 ° C, and the octyl benzoate obtained by the reaction is started to be collected (the reflux ratio is 5:1). The obtained octyl benzoate was 593.2 g (material loss in the process was 2.8 g), and the transesterification reaction was started.

The obtained octyl benzoate was poured into the reactor, 132 g of polyol and 1 g of zinc acetate were added, heated and stirred, and when the temperature reached about 220°C and no octanol was extracted, it was regarded as the reaction end point.

(Example 3)

Add 1000 g (dry basis) of Jiangyin Hailun PTA oxidation residue into the reactor, add 2001 g of octanol, and turn on heating and stirring. When the temperature of the material rises to 184°C, 3.45g of tetrabutyl titanate catalyst is added, and the octanol is refluxed with water at this time. Wait for the temperature in the kettle to rise to about 220°C and no water droplets are extracted, which is regarded as the end point of the esterification reaction. When the acid value of the esterification solution is detected to be 0.5 or less, the esterification reaction is completed. When the temperature of the esterified liquid is lowered to 90°C, filtration is started to obtain a transparent esterified liquid, and the rectification step is started.

Pour the transparent esterification liquid into the distillation tower still, when the vacuum at the top of the tower reaches 0.15kpa, heat the tower still, and when the temperature at the top of the tower rises and stabilizes at about 43°C, the excess octanol begins to be extracted, and the extraction of octanol is completed. , the temperature at the top of the tower is stable at about 120 ° C, and the octyl benzoate obtained by the reaction is started to be collected (the reflux ratio is 5:1). The obtained octyl benzoate was 632.1 g (material loss in the process was 2.9 g), and the transesterification reaction was started.

Pour the obtained octyl benzoate into the reactor, add 141 g of polyol and 1 g of zinc acetate, heat and stir, and when the temperature reaches about 220°C and no octanol is extracted, it is regarded as the reaction end point.

(Example 4)

1000g (dry basis) of Sichuan Nengtou PTA oxidation residue was added into the reactor, 2001g of octanol was added, and heating and stirring were turned on. When the temperature of the material rises to 184°C, 3.45g of tetrabutyl titanate catalyst is added, and the octanol is refluxed with water at this time. Wait for the temperature in the kettle to rise to about 220°C and no water droplets are extracted, which is regarded as the end point of the esterification reaction. When the acid value of the esterification solution is detected to be 0.5 or less, the esterification reaction is completed. When the temperature of the esterified liquid is lowered to 90°C, filtration is started to obtain a transparent esterified liquid, and the rectification step is started.

Pour the transparent esterification liquid into the distillation tower still, when the vacuum at the top of the tower reaches 0.15kpa, heat the tower still, and when the temperature at the top of the tower rises and stabilizes at about 43°C, the excess octanol begins to be extracted, and the extraction of octanol is completed. , the temperature at the top of the tower is stable at about 120 ° C, and the octyl benzoate obtained by the reaction is started to be collected (the reflux ratio is 5:1). The obtained octyl benzoate was 650.9 g (material loss in the process was 3.1 g), and the transesterification reaction was started.

The obtained octyl benzoate was poured into the reactor, 145 g of polyol and 1 g of zinc acetate were added, heated and stirred, and when the temperature reached about 220°C and no octanol was extracted, it was regarded as the reaction end point.

The product generation and consumption of 1kg oxidation residue dry basis in the embodiment of table 2:

(Example 5)

In the extraction of manganese, the saponification rate of the extractant is controlled at 55%, the feed amount is preferably 16m ³ /h for the oil phase, and 750L/h for the saponification agent.

The saponification agent is: 30% NaOH.

The feeding amount of the pre-extraction liquid is adjusted according to the pH value of the raffinate liquid from 3.8 to 4.2, and the feeding amount is: 2.5 m ³ /h.

In the manganese extraction and washing step, sulfuric acid is used as the washing acid, and the concentration is preferably 60 g/L, which is prepared by adding 33 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the washing acid is based on the ability to control the pH value of the washing acid outlet = 3.0 to 3.5, which is 1.5 m ³ /h in this embodiment.

In the manganese extraction and stripping step, the stripping acid for the first-stage stripping of manganese extraction is sulfuric acid, and the concentration is preferably: 180g/L, which is prepared by adding _95-100L of 98% _H2SO4 per 1m ³ of pure water.

The amount of back-extraction acid feeding in the first-stage back-extraction of manganese extraction is subject to the pH value of the back-extraction acid outlet = 3.0-3.2, which is 0.9 m ³ /h in this example.

The PH value of the loaded organic phase for manganese extraction and stripping is 3.0-3.2, and C _Mn2+ =95-100g/L. Control the content of impurity elements as follows: Ni≤0.005g/L, Cu≤0.005g/L, Zn≤0.002g/L, Fe≤0.005g/L, Cd≤0.002g/L, Mg≤0.005g/L, Ca≤ 0.005g/L.

In the step of extracting manganese and washing iron, hydrochloric acid is used for washing ferric acid, and the concentration is preferably: 6mol/L, and the concentrated HCl of 12mol/L is added to adjust when the recycling is lower than 4mol/L, and the present embodiment is: 1.8m ³ /h .

In the extraction step of extracting cobalt: the extraction liquid is: volume of P507: volume of 260# solvent oil=1:3.

The saponification agent is: 20% ammonia water.

The feed volume of the extract is subject to the saponification rate being controlled at 60-70%. In this example, the oil phase is 12 m ³ /h, and the saponification agent is 550 L/h.

The feed volume of the extract after saponification is based on the controllable pH value of the raffinate = 5.2 to 5.5, in this example: 5.0 m ³ /h. Raffinate C _C02+ ≦20mg/L, no light red.

In the cobalt extraction and washing step, sulfuric acid is used as the washing acid. In this example, 60 g/L is prepared by adding 33 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the washing acid is based on the ability to control the pH value of the washing acid outlet to 3.2 to 3.5, in this example: 1.2 m ³ /h.

In the cobalt extraction and back-extraction step, sulfuric acid is used as the back-extraction acid. The concentration of this embodiment is: 180g/L H ₂ SO ₄ , which is prepared by adding 95-100 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

In the step of extracting cobalt and washing iron, hydrochloric acid is used for washing iron, and the concentration is preferably: 6mol/L, and 12mol of concentrated HCl is added to adjust when the recycling is lower than 4mol. The feeding amount is preferably: 1.8-2.0 m ³ /h.

(Example 6)

In the extraction of manganese, the saponification rate of the extractant is controlled at 55-60%, the feed amount is preferably 15-16 m ³ /h for the oil phase, and 750-800 L/h for the saponification agent.

The saponification agent is: 30-31% NaOH or 20% ammonia water.

In the manganese extraction and washing step, sulfuric acid is used as the washing acid, and the concentration is preferably 60-80 g/L, which is prepared by adding 33-44 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

In the step of extracting manganese and washing iron, hydrochloric acid is used for washing ferric acid, and the concentration is preferably: 6 mol/L, and the concentrated HCl of 12 mol/L is added to adjust when the recycling is lower than 4 mol/L, and the feed amount in this embodiment is: 2.0 m ³ /h.

The saponification agent is: 30-31% NaOH or 20% ammonia water.

The feed volume of the extract is subject to the saponification rate being controlled at 60-70%. In this example, the oil phase is 14 m ³ /h, and the saponification agent is 750 L/h.

The feed volume of the extract after saponification is based on the controllable pH value of the raffinate = 5.2 to 5.5, in this example: 6.0 m ³ /h. Raffinate C _C02+ ≦20mg/L, no light red.

In the cobalt extraction and washing step, sulfuric acid is used as the washing acid, and the concentration in this example is: 80g/L, which is prepared by adding 33-44L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the washing acid is based on the ability to control the pH value of the washing acid outlet to 3.2 to 3.5, in this example: 1.5 m ³ /h.

In the cobalt extraction and back extraction step, sulfuric acid is used as the back extraction acid, and the concentration in this embodiment is: 180g/L H ₂ SO ₄ , which is prepared by adding 95-100 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the back-extraction acid is based on the ability to control the pH value of the back-extraction acid outlet = 3.3 to 3.5, in this example: 1.1 m ³ /h.

In the cobalt extraction and iron washing step, the iron washing acid adopts hydrochloric acid, and the concentration is preferably: 6mol/L, when the recycling is lower than 4mol, 12mol of concentrated HCl is added to adjust, the feed amount in this embodiment is: 2.0m ³ /h.

(Example 7)

In the extraction of manganese, the saponification rate of the extractant is controlled at 55-60%. In this embodiment, the feed amount is 15.5 m ³ /h for the oil phase and 780 L/h for the saponification agent.

The saponification agent is: 30-31% NaOH.

The feeding amount of the pre-extraction liquid is adjusted based on the pH value of the raffinate liquid from 3.8 to 4.2. The feeding amount in this embodiment is: 3.0 m ³ /h.

In the manganese extraction and washing step, sulfuric acid is used as the washing acid, and the concentration in this embodiment is 70 g/L, which is prepared by adding 38 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the washing acid is based on the ability to control the pH value of the washing acid outlet = 3.0 to 3.5, which is 1.75 m ³ /h in this embodiment.

The amount of back-extraction acid feeding in the first-stage back-extraction of manganese extraction is subject to the pH value of the back-extraction acid outlet = 3.0 to 3.2, which is 1.0 m ³ /h in this embodiment.

In the step of extracting manganese and washing iron, the iron washing acid adopts hydrochloric acid, and the concentration is preferably: 6 mol/L, and the concentrated HCl of 12 mol/L is added to adjust when the recycling is lower than 4 mol/L, and the feeding amount of the present embodiment is: 1.9 m ³ /h.

The saponification agent is: 20% ammonia water.

The feed volume of the extract is subject to the saponification rate being controlled at 60-70%. In this example, the oil phase is 13 m ³ /h, and the saponification agent is 650 L/h.

The feed volume of the extract after saponification is based on the controllable pH value of the raffinate = 5.2 to 5.5, in this example: 5.5 m ³ /h. Raffinate C _C02+ ≦20mg/L, no light red.

In the cobalt extraction and washing step, sulfuric acid is used as the washing acid, and the concentration in this embodiment is: 70g/L, which is prepared by adding 33-44L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the washing acid is based on the ability to control the pH value of the washing acid outlet to 3.2 to 3.5, in this example: 1.35 m ³ /h.

In the cobalt extraction and back-extraction step, sulfuric acid is used as the back-extraction acid, and the concentration is preferably: 180g/L H ₂ SO ₄ , which is prepared by adding 95-100 L of 98% H ₂ SO ₄ per 1 m ³ of pure water.

The feed amount of the back-extraction acid is based on the ability to control the pH value of the back-extraction acid outlet = 3.3 to 3.5, in this example: 0.95 m ³ /h.

In the step of extracting cobalt and washing iron, hydrochloric acid was used for washing iron, and the concentration was 6 mol/L, and 12 mol of concentrated HCl was added for adjustment when the recycling was lower than 4 mol. The feed rate in this example is: 1.9 m ³ /h.

The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

A PTA oxidation residue comprehensive utilization process is characterized in that comprising the following steps:

S1: Esterification: adding PTA oxidation residue, octanol and catalyst into the esterification reactor for heating and esterification, and filtering to obtain an esterification liquid;

S2: rectification: after the two-stage rectification of the esterification liquid, through condensation separation, crude octyl benzoate, crude dioctyl terephthalate and crude trioctyl trimellitic acid are obtained; the crude octyl benzoate and The mixed polyol is subjected to transesterification to obtain benzoic acid polyol ester;

S3: impurity removal: crude trioctyl trimellitic acid and crude dioctyl terephthalate are respectively neutralized, washed with water, stripped, adsorbed and decolorized and filtered to remove impurities;

In the step S2, cobalt salts, manganese salts and bromide salts are obtained after the residue of the two-stage rectification is incinerated; the cobalt salts and manganese salts are subjected to pre-extraction treatment to obtain a pre-extraction liquid, and the pre-extraction liquid is subjected to a cobalt-manganese extraction process Recover; the cobalt-manganese extraction process comprises the following steps:

S21: extracting manganese extraction unit; the pre-extraction liquid is extracted and extracted by the reactor to obtain manganese extraction raffinate and manganese extraction extract; the manganese extraction extract is successively washed by manganese extraction, manganese extraction back-extraction and manganese extraction wash Iron gets manganese extraction liquid;

S22: Extracting cobalt extraction unit; the manganese extraction raffinate is extracted by the reactor for cobalt extraction to obtain cobalt extraction raffinate and cobalt extraction extract; the cobalt extraction extract is successively washed by cobalt extraction, cobalt extraction back-extraction and extraction Cobalt washing iron to obtain cobalt extraction liquid;

S23: The manganese extraction liquid and the cobalt extraction liquid are respectively post-treated to obtain cobalt salt and manganese salt.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, it is characterized in that: described esterification step adopts octanol as cooling liquid, is specially: measure octanol by flow meter and pump into condenser to be cooling medium, raise temperature The latter cooling medium is passed into the reactor as a reactant.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S1, PTA oxidation residue is dehydrated before esterification, and concrete steps are: put PTA oxidation residue into heating kettle for heating , and the water phase removed goes to waste water treatment.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S1, the addition ratio of PTA oxidation residue, octanol and catalyst is: 1:2.001:0.0345, heating temperature is 180～ 220℃; end point of esterification reaction: acid value drops below 0.5; gas during esterification is condensed in condenser, and the condensed liquid is left to stand for stratification, and the upper octanol is added to esterification reactor for reuse.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S2, after the evaporation phase of first-stage rectification is condensed to obtain crude octyl benzoate; Described crude octyl benzoate Add mixed polyol and zinc acetate to carry out transesterification reaction to obtain a transesterified product. The ratio of mixing polyol to octyl benzoate is 1:4.5, the input amount of zinc acetate is 0.1% of the total mass, and the temperature is 220°C; the After the transesterification product is rectified and condensed, the finished product of benzoic acid polyol ester is obtained.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S3, crude dioctyl terephthalate is added liquid caustic soda to neutralize to pH value 7.5～8, after neutralization, static Set stratification, take the upper oil phase and add pure water to wash with water, after washing, let stand for stratification, take the upper oil phase and input steam stripping, after stripping, use activated carbon and diatomaceous earth for adsorption and filtration in turn to obtain dioctyl terephthalate Ester finished products.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S3, crude trioctyl trimellitic acid is added liquid caustic soda to neutralize to pH value 7.5～8, after neutralization, static Set to stratification, take the upper oil phase and add pure water to wash with water, leave it to stand for stratification after washing, take the upper oil phase and use activated carbon and diatomaceous earth for adsorption and filtration in turn to obtain the finished product of dioctyl terephthalate.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S21, described extracting and extracting manganese comprises one-level extraction of manganese extraction, two-level extraction of manganese extraction, and three-level extraction of manganese extraction; The extraction and manganese extraction adopts the saponified extraction liquid to react with the pre-extraction liquid during the third-level extraction of manganese extraction after the first-level extraction of manganese extraction and the second-level extraction of manganese extraction; The second-stage extraction of manganese extraction is carried out; the water phase of the second-stage extraction of manganese extraction flows to the first-stage extraction of manganese extraction; the saponified extract is subjected to the first-stage extraction of manganese extraction with the water phase of the second-stage extraction of manganese extraction to separate the extract. Manganese raffinate.
A kind of PTA oxidation residue comprehensive utilization process according to claim 1, is characterized in that: in described step S22, described cobalt extraction step comprises cobalt extraction first-level extraction, cobalt extraction second-level extraction, cobalt extraction third-level extraction The cobalt extraction extraction adopts the saponified extraction liquid to react with the pre-extraction liquid during the cobalt extraction tertiary extraction after cobalt extraction first-level extraction and cobalt extraction second-level extraction; the water phase after the cobalt extraction third-level extraction and extraction flow to the secondary extraction of cobalt extraction; the water phase of the secondary extraction of cobalt extraction flows to the primary extraction of cobalt extraction; the extract after the saponification and the water phase of the secondary extraction of cobalt extraction are subjected to primary extraction of cobalt extraction and separated out. Extract cobalt raffinate.