A method for treating oxidation residues of terephthalic acid

Abstract

This invention relates to the field of terephthalic acid oxidation residue treatment technology, specifically a method for treating terephthalic acid oxidation residue. A method for treating terephthalic acid oxidation residue includes the following steps: S1. Pretreatment; S2. Separation; S3. Evaporation and concentration; S4. Incineration; S5. Ash dissolution; S6. Filtration; S7. Recovery of sodium carbonate and sodium bromide; S8. Recovery of cobalt-manganese catalyst; S9. Solid waste treatment; S10. Recycling of cobalt-manganese catalyst; S11. Recovery and reuse of sodium carbonate. This application achieves the recovery of sodium carbonate, sodium bromide, and cobalt-manganese compounds from the residue, as well as the recycling of sodium carbonate and cobalt-manganese compounds. The evaporation condensate is recycled during the treatment process, resulting in no waste discharge. The process is water-saving, energy-saving, and environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of terephthalic acid oxidation residue treatment technology, specifically a method for treating terephthalic acid oxidation residue. Background Technology

[0002] Terephthalic acid (PTA) is an important organic synthetic monomer in the chemical industry, mainly used in the production of polyethylene terephthalate (PET) and bottle-grade polyester. Currently, China's PTA production capacity has exceeded 50 million tons. To ensure the quality of PTA products, the mother liquor needs to be extracted during PTA production and sent to a thin-film evaporator to recover acetic acid. The distillation residue is discharged as waste, accounting for approximately 0.45-0.6% of the total PTA production. The main components of this residue are oxidation byproducts of organic acids, along with small amounts of cobalt, manganese, heavy metals, and bromides. Furthermore, during PTA manufacturing, alkaline solutions are often used for cleaning to remove blockages in various equipment and pipelines. Other waste materials from leaks, spills, and drips from the site and system are also discharged into waste collection ponds. These waste residues are also discharged into the PTA oxidation waste system. Because these waste residues are complex in composition and their composition and content fluctuate with the high-temperature oxidation process, comprehensive recycling and utilization of the waste residues presents challenges.

[0003] CN202110072703.5 discloses a comprehensive utilization process for PTA oxidation residue. This patent involves esterifying and distilling the PTA oxidation residue with octanol and other substances to obtain esters. The residue from the distillation vessel is then incinerated to obtain cobalt, manganese, and bromide salts. These are then extracted and purified to obtain cobalt sulfate and manganese sulfate. Further precipitation with sodium bicarbonate, washing, concentration, and crystallization yield cobalt acetate and manganese acetate. Sodium bromide is then dissolved, decolorized, concentrated, crystallized, and centrifuged to obtain the final sodium bromide product. This process is complex and unstable, generates large amounts of wastewater, and causes severe environmental pollution.

[0004] CN201810143964.X provides a system and method for the comprehensive utilization of PTA oxidation residue and sludge. This method recovers cobalt-manganese catalyst by incinerating PTA sludge and distillation residue. The cobalt-manganese metal contained therein is converted into cobalt-manganese oxide ash after high-temperature incineration, which is discharged from a ash cooler. The ash cooler is cooled to below 150°C using water cooling. The cooled ash, i.e., cobalt-manganese oxide, is sent to an ash storage tank for storage and packaging for sale after natural cooling. However, this method only converts the cobalt and manganese in the residue into cobalt-manganese oxide ash; it cannot be used as a catalyst and cannot recover and reuse bromine.

[0005] Therefore, it is necessary to design a method for treating terephthalic acid oxidation residue, simplifying the recycling process, reducing wastewater discharge, facilitating the recovery and reuse of cobalt-manganese catalysts, and achieving the goals of energy conservation, environmental protection, and improved recycling efficiency. Summary of the Invention

[0006] To address the above problems, this invention provides a method for treating terephthalic acid oxidation residue.

[0007] The technical solution adopted by this invention to solve its technical problem is: a method for treating terephthalic acid oxidation residue, comprising the following steps:

[0008] S1. Pretreatment: Add the phthalic acid oxidation residue to the mixing device, then add sodium carbonate or sodium hydroxide and an aqueous solution of sodium carbonate for stirring and reaction, and adjust the pH of the solution to 7-8. After dissolution, control the solid content in the solution to be 3-5%.

[0009] S2. Separation: The mixture after pretreatment in step S1 is filtered to obtain solid A and the first filtrate;

[0010] S3. Evaporation and concentration: The first filtrate obtained in step S2 is sent to an evaporator for concentration. The filtrate is concentrated to a solid content of 50-70% to obtain a concentrated liquid.

[0011] S4. Incineration: The concentrated liquid obtained in step S3 is sent to an incinerator for incineration to obtain ash residue;

[0012] S5. Ash and slag dissolution: Add the ash and slag obtained in step S4 to the dissolution tank, and then add pure water, wherein the ash and slag concentration is 15~25%, to obtain ash and slag dissolution solution;

[0013] S6. Filtration: The ash residue solution obtained in step S5 is filtered through a filter. The filtered solid filter cake is washed with pulping water and sent to a centrifuge to separate solid B. The filtrate is pumped to an evaporation and crystallization unit to collect the filtered solid B.

[0014] S7. Sodium carbonate and sodium bromide recovery: The filtrate sent to the evaporation and crystallization unit in step S6 is evaporated and crystallized, and solid sodium carbonate product is separated by centrifugation. The mother liquor is recycled. When the sodium bromide content in the mother liquor reaches 30~43%, it is sent to the sodium bromide recovery unit and obtained solid sodium bromide by evaporation and crystallization. Sodium bromide can be directly packaged and sold or used to manufacture hydrobromic acid.

[0015] S8. Recovery of cobalt-manganese catalyst: Add solid A obtained in step S2 to a mixer, add dilute acetic acid to the mixer, heat to 80℃~boiling, maintain for 30~180min, filter while hot to obtain catalyst filtrate and solid C;

[0016] S9. Precipitate treatment: Solid B obtained in step S6 and solid C obtained in step S8 are fed into the reactor, and hydrobromic acid and water are added to react. The molar ratio of cobalt and manganese to hydrobromic acid is 1:2.2~3.0. When the concentration of cobalt and manganese ions in the solution no longer changes or the dissolution is complete, cobalt carbonate and / or manganese carbonate are added to adjust the pH of the solution to 5~6 until it is completely dissolved. The solution is then filtered to obtain the catalyst filtrate.

[0017] S10. Recycling of cobalt-manganese catalyst: The catalyst filtrate obtained in steps S8 and S9 is returned to the catalyst blending system and mixed with fresh catalyst for use.

[0018] S11. Sodium carbonate recycling: The solid sodium carbonate product separated in step S7 is made into an aqueous solution and returned to step S1 for use.

[0019] Furthermore, in step S1, when using an aqueous solution of sodium hydroxide and sodium carbonate to dissolve the terephthalic acid oxidation residue, the order of addition is as follows: first add sodium hydroxide to adjust the pH of the solution to 3-6, then add sodium carbonate to adjust the pH of the solution to 7-8; when using only sodium carbonate, directly adjust the pH of the solution to 7-8.

[0020] The sodium hydroxide aqueous solution contains 20-40% sodium hydroxide, and the sodium carbonate aqueous solution contains 20-25% sodium carbonate.

[0021] Furthermore, the solid content in the first filtrate in step S2 is 3-5%.

[0022] Furthermore, pure water is added during the ash dissolution process in step S5. This pure water is the distilled water recovered from the evaporation and concentration process in step S3 or / and pure water from a pure water device.

[0023] Furthermore, the dilute acetic acid in step S8 is derived from the recovered dilute acetic acid in the terephthalic acid oxidation device or is prepared by mixing fresh acetic acid with the recovered acetic acid, wherein the acetic acid content is 25-40%, and the molar ratio of cobalt and manganese to acetic acid is 1:2.05-6.0.

[0024] Generally, the recovered dilute acetic acid from the terephthalic acid oxidation unit contains 25-40% acetic acid and the remainder is water, which can be used directly. This reduces the use of glacial acetic acid or fresh acetic acid and also reduces the load on the dilute acetic acid concentration unit in the PTA unit to some extent.

[0025] When the molar ratio of cobalt and manganese to acetic acid is greater than 1:2.05, solid A dissolves incompletely and at a slow rate. When the molar ratio of cobalt and manganese to acetic acid is less than 1:6.0, the dissolution time and dissolution effect of solid A do not change significantly.

[0026] Furthermore, in step S9, the molar ratio of cobalt and manganese to hydrobromic acid in both solids B and C is 1:2.2~3.0.

[0027] In step S9, cobalt carbonate and / or manganese carbonate are added to adjust the pH of the solution to 5-6. The purpose is to promote the conversion of metal ions such as iron in the solution into ferric hydroxide precipitate, and then filter to remove iron to obtain catalyst filtrate.

[0028] Furthermore, the recycling of the cobalt-manganese catalyst in step S10 involves mixing the catalyst filtrate obtained in steps S8 and S9 with fresh catalyst in any proportion to obtain a cobalt-manganese-bromine mixed catalyst, which is then returned to the system for recycling.

[0029] Furthermore, in step S11, sodium carbonate recycling involves directly preparing an aqueous solution from the solid sodium carbonate separated in step S7 without drying it, and then returning it to step S1 for use.

[0030] In this application, a 20-25% sodium carbonate aqueous solution is used to adjust the pH value of the solution. The control of the sodium carbonate concentration is mainly based on the convenience of long-term storage, transportation and use. After dissolution, the solid content in the solution is in the range of 3-5%. At this time, the precipitate formed is conducive to filtration and separation and reduces entrainment.

[0031] This invention controls the pH to be 7-8 after alkali dissolution. When the pH is below 7, there will be insufficient dissolution or instability, and the cobalt manganese carbonate precipitation will be insufficient, and the cobalt manganese metal ions will not be fully recovered. When the pH is above 8, further increasing the amount of alkali will not have a significant effect on dissolution and cobalt manganese precipitation, and will increase the post-processing load and result in waste.

[0032] The water vapor generated during the evaporation process is cooled and then recycled as PTA pulping water.

[0033] The beneficial effects of this solution are as follows: A method for treating terephthalic acid oxidation residue has the following advantages:

[0034] The organic matter in the terephthalic acid oxidation residue is converted into carbonate and recycled.

[0035] The recovery of cobalt, manganese and bromine catalysts from terephthalic acid oxidation residue was achieved. Cobalt and manganese were recovered and reused, and bromine was recovered in compound form, laying the foundation for recycling.

[0036] The water generated during the treatment process is recycled, with no wastewater discharge; fourth, the residue treatment process is green and energy-saving, with no waste discharge. Detailed Implementation

[0037] Example 1:

[0038] A method for treating terephthalic acid oxidation residue includes the following steps:

[0039] S1. Pretreatment: Add the phthalic acid oxidation residue to the mixing device, then add an aqueous solution of sodium carbonate and stir to react. Adjust the pH of the solution to 7 and control the solid content in the solution to 3% after dissolution.

[0040] The sodium carbonate aqueous solution contains 20% sodium carbonate.

[0041] S2. Separation: The mixture after pretreatment in step S1 is filtered to obtain solid A and a first filtrate; the solid content in the first filtrate is 3%;

[0042] S3. Evaporation and concentration: The first filtrate obtained in step S2 is sent to an evaporator for concentration. The filtrate is concentrated to a solid content of 50% to obtain a concentrated liquid.

[0043] S4. Incineration: The concentrated liquid obtained in step S3 is sent to an incinerator for incineration to obtain ash residue;

[0044] The heat energy generated during the incineration process is recovered through a recycling device.

[0045] S5. Ash and slag dissolution: Add the ash and slag obtained in step S4 to the dissolution tank, and then add pure water, wherein the ash and slag concentration is 15%, to obtain ash and slag dissolution solution; the pure water is a mixture of distilled water recovered from the evaporation and concentration process in step S3 and pure water from the pure water device;

[0046] S6. Filtration: The ash residue solution obtained in step S5 is filtered through a filter. The filtered solid filter cake is washed with pulping water and sent to a centrifuge to separate solid B. The filtrate is pumped to an evaporation and crystallization unit to collect the filtered solid B.

[0047] S7. Sodium carbonate and sodium bromide recovery: The filtrate sent to the evaporation and crystallization unit in step S6 is evaporated and crystallized, and solid sodium carbonate product is separated by centrifugation. The mother liquor is recycled. When the sodium bromide content in the mother liquor reaches 30%, it is sent to the sodium bromide recovery unit and obtained by evaporation and crystallization.

[0048] S8. Recovery of cobalt-manganese catalyst: Add solid A obtained in step S2 to a mixer, add dilute acetic acid to the mixer, heat to boiling, maintain for 180 min, filter while hot to obtain catalyst filtrate and solid C;

[0049] The dilute acetic acid is recovered from the terephthalic acid oxidation unit, with an acetic acid content of 40.4% and a molar ratio of cobalt and manganese to acetic acid of 1:2.05.

[0050] S9. Precipitate treatment: Solid B obtained in step S6 and solid C obtained in step S8 are fed into the reactor, and hydrobromic acid and water are added to react. The molar ratio of cobalt manganese to hydrobromic acid is 1:2.2. When the concentration of cobalt manganese ions in the solution no longer changes, cobalt carbonate is added to adjust the solution, and the solution is stirred and dissolved. The pH of the solution is 5. The solution is filtered to obtain catalyst filtrate.

[0051] The molar ratio of cobalt and manganese to hydrobromic acid in both solids B and C is 1:2.2;

[0052] S10. Recycling of cobalt-manganese catalyst: The catalyst filtrate obtained in steps S8 and S9 is returned to the catalyst blending system and mixed with fresh catalyst for use.

[0053] The catalyst filtrate obtained in steps S8 and S9 can be mixed with fresh catalyst in any proportion according to the ratio of cobalt, manganese and bromine in the catalyst.

[0054] S11. Sodium carbonate recycling: The solid sodium carbonate product separated in step S7 is made into an aqueous solution and returned to step S1 for use;

[0055] Solid sodium carbonate is directly converted into an aqueous solution without drying and returned to step S1 for use.

[0056] Example 2:

[0057] A method for treating terephthalic acid oxidation residue includes the following steps:

[0058] S1. Pretreatment: Add the phthalic acid oxidation residue to the mixing device, then add an aqueous solution of sodium hydroxide and sodium carbonate, stir and react, and adjust the pH of the solution to 8. After dissolution, control the solid content in the solution to be 5%.

[0059] The order of addition is as follows: first, sodium hydroxide is added to adjust the pH of the solution to 3.3, and then sodium carbonate is added to adjust the pH of the solution to 8. The sodium hydroxide aqueous solution contains 20% sodium hydroxide, and the sodium carbonate aqueous solution contains 25% sodium carbonate.

[0060] S2. Separation: The mixture after pretreatment in step S1 is filtered to obtain solid A and a first filtrate; the solid content in the first filtrate is 5%;

[0061] S3. Evaporation and concentration: The first filtrate obtained in step S2 is sent to an evaporator for concentration. The filtrate is concentrated to a solid content of 70% to obtain a concentrated liquid.

[0062] S4. Incineration: The concentrated liquid obtained in step S3 is sent to an incinerator for incineration to obtain ash residue;

[0063] The heat energy generated during the incineration process is recovered through a recycling device.

[0064] S5. Ash and slag dissolution: Add the ash and slag obtained in step S4 to the dissolution tank, and then add pure water, wherein the ash and slag concentration is 25%, to obtain ash and slag dissolution solution; the pure water is a mixture of distilled water recovered from the evaporation and concentration process in step S3 and pure water from the pure water device;

[0065] S6. Filtration: The ash residue solution obtained in step S5 is filtered through a filter. The filtered solid filter cake is washed with pulping water and sent to a centrifuge to separate solid B. The filtrate is pumped to an evaporation and crystallization unit to collect the filtered solid B.

[0066] S7. Sodium carbonate and sodium bromide recovery: The filtrate sent to the evaporation and crystallization unit in step S6 is evaporated and crystallized, and solid sodium carbonate product is separated by centrifugation. The mother liquor is recycled. When the sodium bromide content in the mother liquor reaches 43%, it is sent to the sodium bromide recovery unit and obtained solid sodium bromide by evaporation and crystallization.

[0067] S8. Recovery of cobalt-manganese catalyst: Add solid A obtained in step S2 to a mixer, add dilute acetic acid to the mixer, heat to boiling, maintain for 30 minutes, filter while hot to obtain catalyst filtrate and solid C;

[0068] The dilute acetic acid is prepared by mixing recovered dilute acetic acid from the terephthalic acid oxidation unit with fresh acetic acid. The acetic acid content is 25.2%, and the molar ratio of cobalt and manganese to acetic acid is 1:6.0.

[0069] S9. Precipitate treatment: Solid B obtained in step S6 and solid C obtained in step S8 are fed into the reactor, and hydrobromic acid and water are added to react. The molar ratio of cobalt and manganese to hydrobromic acid is 1:3.0. When the cobalt and manganese in the solution are completely dissolved, manganese carbonate is added, stirred and dissolved, the pH of the solution is adjusted to 6, and the catalyst filtrate is obtained by filtration.

[0070] The molar ratio of cobalt and manganese to hydrobromic acid in both solids B and C is 1:3.0;

[0071] S10. Recycling of cobalt-manganese catalyst: The catalyst filtrate obtained in steps S8 and S9 is returned to the catalyst blending system and mixed with fresh catalyst for use.

[0072] The catalyst filtrate obtained in steps S8 and S9 can be mixed with fresh catalyst in any proportion according to the cobalt, manganese and bromine element composition of the catalyst required by the user.

[0073] S11. Sodium carbonate recycling: The solid sodium carbonate product separated in step S7 is made into an aqueous solution and returned to step S1 for use; the solid sodium carbonate is directly made into an aqueous solution without drying and returned to step S1 for use.

[0074] Example 3:

[0075] A method for treating terephthalic acid oxidation residue includes the following steps:

[0076] S1. Pretreatment: Add the phthalic acid oxidation residue to the mixing device, then add an aqueous solution of sodium hydroxide and sodium carbonate, stir and react, and adjust the pH of the solution to 7.5. After dissolution, control the solid content in the solution to be 4%.

[0077] The order of addition is as follows: first, sodium hydroxide is added to adjust the pH of the solution to 3, then sodium carbonate is added to adjust the pH of the solution to 7.5. The sodium hydroxide aqueous solution contains 40% sodium hydroxide, and the sodium carbonate aqueous solution contains 23% sodium carbonate.

[0078] S2. Separation: The mixture after pretreatment in step S1 is filtered to obtain solid A and a first filtrate; the solid content in the first filtrate is 4.62%;

[0079] S3. Evaporation and concentration: The first filtrate obtained in step S2 is sent to an evaporator for concentration. The filtrate is concentrated to a solid content of 60% to obtain a concentrated liquid.

[0080] S4. Incineration: The concentrated liquid obtained in step S3 is sent to an incinerator for incineration to obtain ash residue;

[0081] The heat energy generated during the incineration process is recovered through a recycling device.

[0082] S5. Ash and slag dissolution: Add the ash and slag obtained in step S4 to the dissolution tank, and then add pure water, wherein the ash and slag concentration is 20%, to obtain ash and slag dissolution solution; the pure water is the distilled water recovered in the evaporation and concentration process of step S3;

[0083] S6. Filtration: The ash residue solution obtained in step S5 is filtered through a filter. The filtered solid filter cake is washed with pulping water and sent to a centrifuge to separate solid B. The filtrate is pumped to an evaporation and crystallization unit to collect the filtered solid B.

[0084] S7. Sodium carbonate and sodium bromide recovery: The filtrate sent to the evaporation and crystallization unit in step S6 is evaporated and crystallized, and solid sodium carbonate product is separated by centrifugation. The mother liquor is recycled. When the sodium bromide content in the mother liquor reaches 36%, it is sent to the sodium bromide recovery unit and obtained solid sodium bromide by evaporation and crystallization.

[0085] S8. Recovery of cobalt-manganese catalyst: Add solid A obtained in step S2 to a mixer, add dilute acetic acid to the mixer, heat to 92°C, maintain for 100 min, filter while hot to obtain catalyst filtrate and solid C;

[0086] The dilute acetic acid is recovered from the terephthalic acid oxidation unit, with an acetic acid content of 33% and a molar ratio of cobalt and manganese to acetic acid of 1:4.

[0087] S9. Precipitate treatment: Solid B obtained in step S6 and solid C obtained in step S8 are fed into the reactor, and hydrobromic acid and water are added to react. The molar ratio of cobalt and manganese to hydrobromic acid is 1:3.6. When the concentration of cobalt and manganese ions in the solution no longer changes, cobalt carbonate and manganese carbonate are added and stirred to dissolve. The pH of the solution is adjusted to 5.5, and the catalyst filtrate is obtained by filtration.

[0088] The molar ratio of cobalt and manganese to hydrobromic acid in both solids B and C is 1:3.6;

[0089] S10. Recycling of cobalt-manganese catalyst: The catalyst filtrate obtained in steps S8 and S9 is returned to the catalyst blending system and mixed with fresh catalyst for use.

[0090] The catalyst filtrate obtained in steps S8 and S9 can be mixed with fresh catalyst in any proportion according to the cobalt, manganese and bromine element composition of the catalyst required by the user.

[0091] S11. Sodium carbonate recycling: The solid sodium carbonate product separated in step S7 is made into an aqueous solution and returned to step S1 for use; the solid sodium carbonate is directly made into an aqueous solution without drying and returned to step S1 for use.

[0092] The above-described specific embodiments are merely specific examples of the present invention. The patent protection scope of the present invention includes, but is not limited to, the product form and style of the above-described specific embodiments. Any method for treating terephthalic acid oxidation residue that conforms to the claims of the present invention, and any appropriate changes or modifications made thereto by those skilled in the art, shall fall within the patent protection scope of the present invention.

Claims

1. A method for treating terephthalic acid oxidation residue, characterized in that: Includes the following steps: S1. Pretreatment: Add the phthalic acid oxidation residue to the mixing device, then add sodium carbonate or sodium hydroxide and an aqueous solution of sodium carbonate for stirring and reaction, and adjust the pH of the solution to 7-8. After dissolution, control the solid content in the solution to be 3-5%. S2. Separation: The mixture after pretreatment in step S1 is filtered to obtain solid A and the first filtrate; S3. Evaporation and concentration: The first filtrate obtained in step S2 is sent to an evaporator for concentration. The filtrate is concentrated to a solid content of 50-70% to obtain a concentrated liquid. S4. Incineration: The concentrated liquid obtained in step S3 is sent to an incinerator for incineration to obtain ash residue; S5. Ash and slag dissolution: Add the ash and slag obtained in step S4 to the dissolution tank, and then add pure water, wherein the ash and slag concentration is 15~25%, to obtain ash and slag dissolution solution; S6. Filtration: The ash residue solution obtained in step S5 is filtered through a filter. The filtered solid filter cake is washed with pulping water and sent to a centrifuge to separate solid B. The filtrate is pumped to an evaporation and crystallization unit to collect the filtered solid B. S7. Sodium carbonate and sodium bromide recovery: The filtrate sent to the evaporation and crystallization unit in step S6 is evaporated and crystallized, and solid sodium carbonate product is separated by centrifugation. The mother liquor is recycled. When the sodium bromide content in the mother liquor reaches 30~43%, it is sent to the sodium bromide recovery unit and obtained solid sodium bromide by evaporation and crystallization. S8. Recovery of cobalt-manganese catalyst: Add solid A obtained in step S2 to a mixer, add dilute acetic acid to the mixer, heat to 80℃~boiling, maintain for 30~180min, filter while hot to obtain catalyst filtrate and solid C; S9. Solid treatment: Solid B obtained in step S6 and solid C obtained in step S8 are fed into the reactor, and hydrobromic acid and water are added to react. The molar ratio of cobalt and manganese to hydrobromic acid is 1:2.2~3.

0. When the concentration of cobalt and manganese ions in the solution no longer changes or the dissolution is complete, cobalt carbonate and / or manganese carbonate are added to adjust the pH of the solution to 5~6 until it is completely dissolved. The solution is then filtered to obtain the catalyst filtrate. S10. Recycling of cobalt-manganese catalyst: The catalyst filtrate obtained in steps S8 and S9 is returned to the catalyst preparation system and mixed with fresh catalyst for reuse. S11. Sodium carbonate recycling: The solid sodium carbonate product separated in step S7 is made into an aqueous solution and returned to step S1 for use.

2. The method for treating terephthalic acid oxidation residue according to claim 1, characterized in that: In step S1, when using an aqueous solution of sodium hydroxide and sodium carbonate to dissolve the terephthalic acid oxidation residue, the order of addition is as follows: first add sodium hydroxide to adjust the pH of the solution to 3-6, then add sodium carbonate to adjust the pH of the solution to 7-8. The sodium hydroxide aqueous solution contains 20-40% sodium hydroxide, and the sodium carbonate aqueous solution contains 20-25% sodium carbonate.

3. The method for treating terephthalic acid oxidation residue according to claim 2, characterized in that: The solid content in the first filtrate in step S2 is 3-5%.

4. The method for treating terephthalic acid oxidation residue according to claim 1, characterized in that: In step S5, pure water is added during the ash dissolution process. This pure water is the distilled water recovered from the evaporation and concentration process in step S3 or / and pure water from a pure water device.

5. The method for treating terephthalic acid oxidation residue according to claim 1, characterized in that: The dilute acetic acid in step S8 comes from the recovered dilute acetic acid in the terephthalic acid oxidation device or is prepared by mixing fresh acetic acid with the recovered acetic acid. The acetic acid content is 25-40%, and the molar ratio of cobalt and manganese to acetic acid is 1:2.05-6.

0.

6. The method for treating terephthalic acid oxidation residue according to claim 1, characterized in that: In step S9, the molar ratio of cobalt and manganese to hydrobromic acid in both solid B and precipitate C is 1:2.2~3.

0.

7. The method for treating terephthalic acid oxidation residue according to claim 1, characterized in that: The recycling of the cobalt-manganese catalyst in step S10 involves mixing the catalyst filtrate obtained in steps S8 and S9 with fresh catalyst in any proportion to obtain a cobalt-manganese-bromine mixed catalyst, which is then returned to the system for recycling.

8. The method for treating terephthalic acid oxidation residue according to claim 1, characterized in that: The sodium carbonate recycling step S11 involves directly preparing an aqueous solution from the solid sodium carbonate separated in step S7 without drying it and returning it to step S1 for use.