A method for preparing brominated polymer

Abstract

The present invention discloses a method for preparing a brominated polymer, comprising the following steps: 1) contacting a polymer solution with liquid bromine to obtain a brominated polymer solution; 2) contacting the brominated polymer solution with hot water and water vapor to separate and obtain brominated colloid water and an organic solvent; 3) dehydrating the brominated colloid water obtained in step 2) to obtain a brominated polymer and bromine-containing wastewater; 4) contacting at least a portion of the bromine-containing wastewater obtained in step 3) with an organic extractant to obtain brominated wastewater free of colloid fines; 5) using the bromine-free bromine-containing wastewater as process water and / or to recover bromine; and 6) recycling the remaining portion of the bromine-containing wastewater obtained in step 3) as hot water for step 2). The bromine-free wastewater obtained by the method of the present invention can be used to recover bromine or as process water such as washing water, thereby stabilizing the process operations of the brominated polymer and bromine recovery, and reducing the loss of the brominated polymer and the discharge of wastewater.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer preparation, and particularly relates to a method for preparing a brominated polymer. Background Art

[0002] Bromination modification of polymers can improve or enhance their properties, broadening their applications. For example, bromobutyl rubber, obtained by brominating butyl rubber, overcomes its shortcomings, such as poor adhesion, slow vulcanization, and difficulty blending with other rubbers, making it a preferred material for tire innerliners. Industrially, bromobutyl rubber is produced by contacting an alkane solution of butyl rubber with liquid bromine via a bromine substitution reaction. The theoretical utilization rate of bromine atoms is 50%, with the remaining 50% converted to hydrogen bromide. However, the actual utilization rate in industry is less than 50%, resulting in more than half of the bromine entering wastewater as bromide ions, resulting in a high bromide ion content. Direct discharge of this wastewater would cause serious environmental pollution and waste resources. Therefore, the treatment of bromide-containing wastewater has significant social and economic benefits.

[0003] Industrial methods for recovering bromine from bromine-containing wastewater include extraction and distillation. The distillation method is based on the more established technique of seawater oxidation and bromine blowing: brominated butyl rubber wastewater is preheated, oxidized with chlorine, and steam distilled to produce crude bromine. This is then rectified to produce 98% liquid bromine. The recovered liquid bromine can be reused as a raw material for bromobutyl rubber production. However, since the bromine-containing wastewater originates from the separation of the adhesive and water, the presence of calcium stearate, antioxidants, and other substances in the 15-40 wt% adhesive makes separation of the adhesive and water difficult. The resulting bromine-containing wastewater contains polymeric macromolecules, known industrially as adhesive residue. Although the adhesive residue content in the wastewater is low, it easily aggregates and sticks, causing equipment blockage, necessitating regular shutdowns for treatment, and increasing operating costs. Furthermore, the presence of adhesive residue affects the use of the bromine-containing wastewater as wash water and process water, increasing wastewater discharge. Summary of the Invention

[0004] In order to improve the above technical problems, the present invention provides a method for preparing a brominated polymer, which comprises the following steps:

[0005] 1) contacting the polymer solution with liquid bromine to obtain a brominated polymer solution;

[0006] 2) contacting the brominated polymer solution with hot water and steam to separate the brominated colloidal water and the organic solvent;

[0007] 3) dehydrating the brominated colloids in step 2) to obtain a brominated polymer and bromine-containing wastewater;

[0008] 4) contacting at least a portion of the bromine-containing wastewater obtained in step 3) with an organic extractant to obtain bromine-containing wastewater free of gum powder;

[0009] 5) The bromine-containing wastewater without rubber dust is used as process water and / or for recovering bromine;

[0010] 6) reusing the remaining portion of the bromine-containing wastewater obtained in step 3) as hot water in step 2).

[0011] According to the present invention, the method comprises the following steps:

[0012] 1) contacting the polymer solution with liquid bromine to obtain a brominated polymer solution;

[0013] 2') contacting and washing the brominated polymer solution from step 1) with washing water, and separating the phases to obtain a brominated polymer solution phase at the top and a bromide ion-containing aqueous phase at the bottom;

[0014] contacting the brominated polymer solution with hot water and steam to separate the brominated colloidal water and the organic solvent;

[0015] 3) dehydrating the brominated colloids in step 2') to obtain a brominated polymer and bromine-containing wastewater;

[0016] 4) contacting at least a portion of the bromine-containing wastewater obtained in step 3) with an organic extractant to obtain bromine-containing wastewater free of gum powder;

[0017] 5) The bromine-containing wastewater without rubber dust is used as process water and / or for recovering bromine;

[0018] 6) The remaining portion of the bromine-containing wastewater obtained in step 3) is recycled as hot water in step 2') and / or as washing water in step 2').

[0019] According to the present invention, the method further comprises the following steps:

[0020] 7) contacting the bromide ion-containing aqueous phase in step 2′) with an organic extractant to obtain bromide ion-containing wastewater free of gum powder;

[0021] 8) The bromide ion-containing wastewater without the gum residue in step 7) is used to recover bromine.

[0022] According to the present invention, in step 1), the polymer may be at least one of butyl rubber, polybutadiene, and styrene-butadiene copolymer; and the brominated polymer may be one of brominated butyl rubber, brominated polybutadiene, and brominated styrene-butadiene copolymer, or a mixture thereof.

[0023] According to the present invention, in step 1), the polymer solution is obtained by dissolving a polymer in an organic solvent.

[0024] According to the present invention, the organic solvent in the polymer solution of step 1) includes but is not limited to C4-C8 alkanes; for example, it can be at least one of n-pentane, cyclopentane, hexane (for example, n-hexane, 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane or 2,2-dimethylbutane), cyclohexane or n-heptane, or a mixture thereof.

[0025] According to the present invention, in step 2), before the brominated polymer solution is contacted with the hot water and steam, an alkali and / or a reducing agent may be added to the brominated polymer solution. For example, the brominated polymer solution may be first contacted with the alkali and / or the reducing agent to react, and then contacted with the hot water and steam. For another example, when the alkali and the reducing agent are added simultaneously, the reducing agent is added first, and then the alkali is added, so that the pH of the system is 5-13, preferably 8-9.

[0026] According to the present invention, in step 2'), before the brominated polymer solution is contacted with hot water and steam, an alkali and / or a reducing agent may be added to the brominated polymer solution. For example, the brominated polymer solution may be first contacted with the alkali and / or reducing agent to react, and then contacted with the hot water and steam. For another example, when the alkali and reducing agent are added simultaneously, the reducing agent is added first, followed by the alkali, so that the pH of the system is 5-13, preferably 8-9.

[0027] Illustratively, the base is an alkali metal or alkaline earth metal hydroxide, alkali metal carbonate, or alkali metal bicarbonate, such as at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate; the reducing agent is used to reduce unreacted bromine in the brominated polymer solution, and is an alkali metal sulfite or pyrosulfite, such as sodium sulfite or sodium pyrosulfite.

[0028] Illustratively, the mass of the reducing agent is 0 to 0.1 wt % of the mass of the bromobutyl rubber solution.

[0029] According to the present invention, in step 2) and step 2'), the temperature of the hot water is 50-100°C, exemplified by 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C; the pressure of the water vapor is 0.2-4 MPa, exemplified by 0.2 MPa, 0.5 MPa, 0.8 MPa, 1.0 MPa, 1.5 MPa, 1.8 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa or 4 MPa.

[0030] According to the present invention, step 2') comprises: contacting and washing the brominated polymer solution with washing water in a container, separating the phases to obtain a brominated polymer solution phase at the top and a bromide ion-containing aqueous phase at the bottom. The brominated polymer solution phase is used for contact with hot water and steam.

[0031] Illustratively, the container in which the brominated polymer solution and washing water (eg, process water) are contacted and washed includes a tower, a kettle, a tank, and the like.

[0032] According to the present invention, step 2') specifically comprises: contacting and washing the brominated polymer solution with washing water in a washing tower, obtaining a brominated polymer solution phase at the top of the tower, and obtaining a bromide ion-containing aqueous phase at the bottom of the tower; sequentially adding a reducing agent and an alkali to the brominated polymer solution phase to adjust the pH of the system to 5-13; contacting the neutralized brominated polymer solution phase with hot water and water vapor, and separating to obtain brominated colloidal water and an organic solvent.

[0033] Illustratively, the mass ratio of the brominated polymer solution to the washing water (such as process water) is (1-6):1, for example, it can be 1:1, 1.2:1, 1.3:1, 1.5:1, 1.8:1, 2:1, 3:1, 4:1, 5:1 or 6:1.

[0034] Illustratively, the washing water is one of process water, alkali liquor, aqueous solution containing a reducing agent, bromine-containing wastewater, or bromine-containing wastewater without rubber powder.

[0035] Illustratively, the alkali solution is an aqueous solution of an alkali, and the alkali and the reducing agent have the definitions above.

[0036] According to the present invention, in step 2), the container in which the brominated polymer solution contacts with hot water and steam includes a tower, a kettle, a tank, etc.

[0037] According to the present invention, in step 2'), the container in which the brominated polymer solution contacts with hot water and steam includes a tower, a kettle, a tank, and the like.

[0038] According to the present invention, the content of the rubber powder in the bromine-containing wastewater in step 3) is not higher than 0.35 wt%.

[0039] According to the present invention, the powder comprises a brominated polymer.

[0040] According to the present invention, in step 3), the bromine-containing wastewater can also be reused as washing water for contact with the brominated polymer solution in step 2').

[0041] According to the present invention, in step 4), the mass ratio of bromine-containing wastewater to organic extractant is 1:(0.1-1); and the contact temperature is 20-100°C. For example, it can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C.

[0042] According to the present invention, in step 4), the mass of the bromine-containing wastewater in contact with the organic extractant is 1 to 30 wt % of the total mass of the bromine-containing wastewater, illustratively 2, 3, 5, 7, 10, 12.5, 15, 20, 25 or 30%.

[0043] Illustratively, the bromine-containing wastewater and the organic extractant are contacted in a container. Specifically, the contact container includes a tower, a kettle, a tank, etc.

[0044] According to the present invention, in step 7), the mass ratio of the bromide ion-containing aqueous phase to the organic extractant is 1:(0.1-1); and the contact temperature is 20-100°C. For example, it can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C.

[0045] According to the present invention, in step 7), the entire bromide ion-containing aqueous phase is contacted with the organic extractant. Exemplarily, the bromide ion-containing aqueous phase and the organic extractant are contacted in a container, specifically, the container includes a tower, a kettle, a tank, etc.

[0046] According to the present invention, the organic extractant is an organic solvent in which a brominated polymer is dissolved. Exemplarily, the organic extractant contains 0-5 wt % of an organic solvent containing a brominated polymer.

[0047] According to the present invention, as described in step 5), the bromine-containing wastewater obtained in step 4) that does not contain any gelatin residue can be used as process water in the preparation process of the brominated polymer or enter the debromination recovery unit for recovering bromine. The process water includes water for washing the brominated polymer solution (for example, in step 1, the water used for washing the brominated polymer solution in contact with water can be the wastewater that does not contain any gelatin residue), water for preparing the alkali solution (for example, the alkali added above is added in the form of alkali solution, and the water for preparing the alkali solution can be the wastewater that does not contain any gelatin residue), water for preparing the reducing agent solution (for example, the reducing agent added above is added in the form of reducing agent solution, and the water for preparing the reducing agent solution can be the wastewater that does not contain any gelatin residue), water for pump sealing, water for flushing equipment, etc.

[0048] According to the present invention, as described in step 8), the bromide ion-containing wastewater without the rubber powder obtained in step 7) is all used to recover bromine.

[0049] According to the present invention, in step 6), the remaining part of the bromine-containing wastewater is divided into two parts, 0-30 wt% is used as washing water in step 2'), and 70-100% is reused as hot water in step 2').

[0050] According to the present invention, in step 6), the mass of the remaining part of the bromine-containing wastewater is 70-97wt% of the total mass of the bromine-containing wastewater, for example, 70-95wt%, and for example, 80-90wt%, illustratively 70, 75, 76, 77, 78, 79, 80, 85 or 90wt%.

[0051] Beneficial effects of the present invention:

[0052] The present invention extracts and separates bromine-containing wastewater or a bromide-ion-containing aqueous phase in a preparation process of a brominated polymer using an organic solvent to obtain wastewater free of gelatin fines. The wastewater free of gelatin fines can be fed into a bromine recovery unit for bromine recovery or used as process water for preparing auxiliary agents (such as alkali, reducing agent, etc.). The process operation of the brominated polymer and bromine recovery is stabilized, and the loss of the brominated polymer and the discharge of wastewater are reduced. DETAILED DESCRIPTION

[0053] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0054] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0055] Example 1

[0056] 1) contacting bromine with a butyl rubber hexane solution to cause a substitution reaction, thereby obtaining a hexane solution containing bromobutyl rubber and bromohydrogen, i.e., a bromobutyl rubber reaction solution.

[0057] 2) To the obtained brominated butyl rubber reaction liquid (6700 kg / h (containing 1020 kg / h of brominated butyl rubber) was added 40 kg / h of a 10% aqueous sodium sulfite solution, and then neutralized with a sodium hydroxide solution to a pH of 9. The neutralized brominated butyl rubber solution was then placed in a hydrolysis and coagulation unit and contacted with 2 MPa steam and 75° C. hot water to separate the hexane solvent and brominated colloidal water.

[0058] 3) Dehydrating the brominated rubber particles in step 2) to obtain brominated butyl rubber and 80° C. bromine-containing wastewater with a flow rate of about 16 t / h.

[0059] 4) 2 t / h of bromine-containing wastewater (colour content 0.35 wt%) and 1 t / h of hexane are contacted in an extraction tower to remove the colloidal matter in the bromine-containing wastewater, and 2 t / h of wastewater without colloidal matter is obtained by phase separation.

[0060] 5) The wastewater without rubber powder is used as process water for preparing sodium sulfite solution and sodium hydroxide solution, and the remaining 1.5t / h is debrominated and recovered.

[0061] 6) The remaining 14 t / h of bromine-containing wastewater at about 80° C. in step 3) is reused as hot water in step 2).

[0062] The hexane extraction reduced the amount of fines in the wastewater, which was free of fines, from 0.35 wt% to undetectable levels. The operating cycle of the bromine recovery equipment was extended from 15 days to one year. The fines-free wastewater replaced fresh process water to prepare solutions for additives such as sodium sulfite and was used as flushing water for mechanical seals, reducing fresh process water usage and wastewater discharge.

[0063] Example 2

[0064] 1) contacting bromine with a butyl rubber hexane solution to cause a substitution reaction, thereby obtaining a hexane solution containing bromobutyl rubber and bromohydrogen, i.e., a bromobutyl rubber reaction solution.

[0065] 2') At 55°C, 6700 kg / h of bromobutyl rubber reaction liquid (including 25.3 kg / h of brominated hydrogen and 1020 kg / h of bromobutyl rubber) was introduced into a packed tower from the bottom. Simultaneously, 1500 kg / h of wash water was introduced from the top of the packed tower and contacted with the bromobutyl rubber reaction liquid in countercurrent within the packed tower. 1520 kg / h of bromide ion-containing aqueous phase was obtained from the bottom of the packed tower; and 6680 kg / h of bromobutyl rubber solution phase was obtained from the top of the tower.

[0066] 40 kg / h of 10% sodium sulfite aqueous solution is added to the 6680 kg / h brominated butyl rubber solution phase obtained at the top of the tower, and then neutralized with sodium hydroxide solution to pH = 9. The neutralized brominated butyl rubber solution enters the hydrolysis and coagulation unit and contacts with 2 MPa water vapor and 75°C hot water to separate the hexane solvent and brominated colloidal water.

[0067] 3) Dehydrating the brominated rubber particles in step 2') to obtain brominated butyl rubber and bromine-containing wastewater at 80° C. with a flow rate of about 16 t / h.

[0068] 4) 0.5 t / h of bromine-containing wastewater (0.35 wt% of gelatin content) from step 3) was contacted with 0.25 t / h of hexane in an extraction column to remove gelatin from the bromine-containing wastewater, and phase separation was performed to obtain 0.5 t / h of bromine-containing wastewater free of gelatin.

[0069] 5) Bromine-containing wastewater without rubber powder is used as process water for preparing sodium sulfite solution, sodium hydroxide solution and process flushing.

[0070] 6) 14 t / h of the bromine-containing wastewater at about 80° C. in step 3) is reused in step 2') as a partial substitute for hot water; 1.5 t / h of the bromine-containing wastewater is reused as washing water in step 2').

[0071] 7) 1520 kg / h of the bromide ion-containing aqueous phase in step 2') was contacted with 750 kg / h of hexane in an extraction tower at a contact temperature of 50° C., and the bromide ion-containing aqueous phase free of gum powder was obtained by phase separation.

[0072] 8) The bromide ion-containing aqueous phase without the gum residue is sent to a bromine recovery unit for recovering bromine.

[0073] Hexane extraction yields brominated wastewater free of bromide, or a bromide-containing aqueous phase free of bromide. The bromide content in the bromide-containing wastewater is reduced from 0.35 wt% to undetectable levels. The operating cycle of the bromine recovery equipment has been extended from 15 days to one year. The bromide-free wastewater replaces fresh process water for preparing solutions for additives such as sodium sulfite and for use as flushing water for mechanical seals, reducing fresh process water usage and wastewater discharge.

[0074] The above is an exemplary description of the embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for preparing a brominated polymer, characterized in that: The method comprises the following steps: 1) contacting the polymer solution with liquid bromine to obtain a brominated polymer solution; 2) contacting the brominated polymer solution with hot water and water vapor to separate the brominated colloidal water and the organic solvent; in step 2), the temperature of the hot water is 50 to 75° C.; the pressure of the water vapor is 1.0 to 3.0 MPa; 3) dehydrating the brominated colloid particles in step 2) to obtain a brominated polymer and bromine-containing wastewater; the bromine-containing wastewater in step 3) has a content of colloid powder of no more than 0.35 wt%; 4) contacting at least a portion of the bromine-containing wastewater obtained in step 3) with an organic extractant to obtain bromine-containing wastewater free of gum dust; in step 4), the mass of the bromine-containing wastewater contacted with the organic extractant is 1 to 30 wt% of the total mass of the bromine-containing wastewater; in step 4), the mass ratio of the bromine-containing wastewater to the organic extractant is 1:(0.1 to 1); 5) The bromine-containing wastewater without rubber powder is used as process water and / or to recover bromine; 6) The remaining portion of the bromine-containing wastewater obtained in step 3) is reused as hot water in step 2).

2. The preparation method according to claim 1, characterized in that The method comprises the following steps: 1) contacting the polymer solution with liquid bromine to obtain a brominated polymer solution; 2') contacting and washing the brominated polymer solution from step 1) with washing water, and separating the phases to obtain a brominated polymer solution phase at the top and a bromide ion-containing aqueous phase at the bottom; The brominated polymer solution is contacted with hot water and water vapor to separate the brominated colloidal water and the organic solvent; in step 2'), the temperature of the hot water is 50 to 75° C.; the pressure of the water vapor is 1.0 to 3.0 MPa; 3) dehydrating the brominated colloid particles in step 2') to obtain a brominated polymer and brominated wastewater; the content of the brominated wastewater in step 3) is not higher than 0.35 wt%; 4) contacting at least a portion of the bromine-containing wastewater obtained in step 3) with an organic extractant to obtain bromine-containing wastewater free of gum dust; in step 4), the mass of the bromine-containing wastewater contacted with the organic extractant is 1 to 30 wt% of the total mass of the bromine-containing wastewater; in step 4), the mass ratio of the bromine-containing wastewater to the organic extractant is 1:(0.1 to 1); 5) The bromine-containing wastewater without rubber dust is used as process water and / or for recovering bromine; 6) The remaining portion of the bromine-containing wastewater obtained in step 3) is recycled as hot water in step 2') and / or as washing water in step 2').

3. The preparation method according to claim 2, characterized in that The method further comprises the following steps: 7) contacting the bromide ion-containing aqueous phase in step 2′) with an organic extractant to obtain bromide ion-containing wastewater free of gum powder; 8) The bromide ion-containing wastewater without the gum residue in step 7) is used to recover bromine.

4. The preparation method according to claim 1 or 2, characterized in that In step 1), the polymer is at least one of butyl rubber, polybutadiene, and styrene-butadiene copolymer; the brominated polymer is one of brominated butyl rubber, brominated polybutadiene, and brominated styrene-butadiene copolymer, or a mixture thereof; In step 1), the polymer solution is obtained by dissolving the polymer in an organic solvent; The organic solvent in the polymer solution in step 1) is at least one of n-pentane, cyclopentane, hexane, cyclohexane or n-heptane.

5. The preparation method according to claim 1, characterized in that In step 2), before the brominated polymer solution contacts with hot water and steam, a base and / or a reducing agent is added to the brominated polymer solution.

6. The preparation method according to claim 5, characterized in that The alkali is an alkali metal or alkaline earth metal hydroxide, alkali metal carbonate, or alkali metal bicarbonate; the reducing agent is used to reduce unreacted bromine in the brominated polymer solution and is an alkali metal sulfite or pyrosulfite.

7. The preparation method according to claim 6, characterized in that The alkali is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate; The reducing agent is sodium sulfite or sodium metabisulfite.

8. The preparation method according to claim 5, characterized in that The mass of the reducing agent is 0 to 0.1 wt % of the mass of the bromobutyl rubber solution.

9. The preparation method according to claim 1, characterized in that In step 2), the container in which the brominated polymer solution contacts with hot water and steam includes a tower, a kettle, and a tank.

10. The preparation method according to claim 2, characterized in that In step 2'), before the brominated polymer solution phase contacts with hot water and steam, a base and / or a reducing agent may be added to the brominated polymer solution phase.

11. The preparation method according to claim 10, characterized in that: The alkali is an alkali metal or alkaline earth metal hydroxide, alkali metal carbonate, or alkali metal bicarbonate; the reducing agent is used to reduce unreacted bromine in the brominated polymer solution and is an alkali metal sulfite or pyrosulfite.

12. The preparation method according to claim 11, characterized in that The alkali is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate; The reducing agent is sodium sulfite or sodium metabisulfite.

13. The preparation method according to claim 11, characterized in that The mass of the reducing agent is 0 to 0.1 wt % of the mass of the bromobutyl rubber solution phase.

14. The preparation method according to claim 2, characterized in that Step 2') comprises: contacting and washing the brominated polymer solution with washing water in a container, separating the phases, obtaining a brominated polymer solution phase at the top and a bromide ion-containing aqueous phase at the bottom; wherein the brominated polymer solution phase is used for contacting with hot water and water vapor; The containers for contacting and washing the brominated polymer solution with the washing water include towers, kettles and tanks.

15. The preparation method according to claim 2, characterized in that Step 2') is specifically as follows: contacting the brominated polymer solution with washing water in a washing tower to obtain a brominated polymer solution phase at the top of the tower and a bromide ion-containing aqueous phase at the bottom of the tower; sequentially adding a reducing agent and an alkali to the brominated polymer solution phase to adjust the pH of the system to 5-13; contacting the neutralized brominated polymer solution phase with hot water and water vapor to separate the brominated colloidal water and the organic solvent.

16. The preparation method according to claim 2, characterized in that In step 2'), the mass ratio of the brominated polymer solution to the washing water is (1-6):1; The washing water is one of process water, alkali liquor, aqueous solution containing reducing agent, bromine-containing wastewater, or bromine-containing wastewater without rubber powder; In step 2'), the container in which the brominated polymer solution contacts hot water and steam includes a tower, a kettle, and a tank.

17. The preparation method according to claim 1 or 2, characterized in that: The gelling agent includes a brominated polymer.

18. The preparation method according to claim 1 or 2, characterized in that: In step 4), the contact temperature is 20 to 100° C.; The bromine-containing wastewater and the organic extractant are contacted in a container, and the contact container includes a tower, a kettle, and a tank.

19. The preparation method according to claim 3, characterized in that: In step 7), the mass ratio of the bromide ion-containing aqueous phase to the organic extractant is 1:(0.1-1); and the contact temperature is 20-100°C.

20. The preparation method according to claim 3, characterized in that In step 7), the entire bromide ion-containing aqueous phase is contacted with an organic extractant.

21. The preparation method according to claim 1 or 2, characterized in that: The organic extractant is an organic solvent in which a brominated polymer is dissolved, and the organic solvent contains 0-5 wt % of the brominated polymer.

22. The preparation method according to claim 1 or 2, characterized in that: In step 6), the remaining portion of the bromine-containing wastewater is divided into two parts, 0-30 wt% is used as washing water in step 2'), and 70-100% is reused as hot water in step 2').

23. The preparation method according to claim 1 or 2, characterized in that: In step 6), the mass of the remaining bromine-containing wastewater is 70 to 97 wt % of the total mass of the bromine-containing wastewater.