Recovery method of homogeneous catalyst for hydrogenated butadiene-acrylonitrile rubber synthesis

Abstract

The invention relates to the technical field of platinum group metal catalyst recovery, in particular to a recovery method of a homogeneous catalyst for hydrogenated butadiene-acrylonitrile rubber synthesis. A recovery method of a homogeneous catalyst for hydrogenated butadiene-acrylonitrile rubber synthesis adopts a complexing extraction agent and an alkaline aqueous solution for continuous extraction, the catalyst is separated from a hydrogenation reaction solution through a multistage counter-current extraction process, a large amount of complexing extraction agent can coordinate with platinum group metal ions in the catalyst, original ligands are promoted to fall off, and the homogeneous catalyst is recovered. The method comprises the following steps: performing ligand exchange, extracting the catalyst to a new phase, and finally performing incineration treatment after distillation to obtain the pure platinum group metal catalyst. And meanwhile, the extraction solvent which is collected and purified through simple distillation is used mechanically and circularly, so that the overall recovery cost can be reduced. The recovery method has the advantages of low cost, high recovery rate and high efficiency, solves the problem of catalyst recovery, and is a catalyst recovery technology with wide application prospects.

Description

Technical Field

[0001] The present application relates to the technical field of platinum group metal catalyst recovery, and in particular to a method for recovering a homogeneous catalyst used in hydrogenated nitrile rubber synthesis. Background Art

[0002] Hydrogenated nitrile rubber is a highly saturated high-performance synthetic rubber obtained by catalytic hydrogenation of nitrile rubber. It not only inherits the good oil resistance of nitrile rubber, but also has excellent heat resistance, pressure difference resistance, acid and alkali resistance, and ozone resistance. It is widely used in petrochemical, automotive industry, aerospace and other fields.

[0003] The production process of hydrogenated nitrile rubber mainly includes solution hydrogenation, emulsion hydrogenation and ethylene-acrylonitrile copolymerization. The most widely used industrial process is solution hydrogenation, and the relevant process is described in detail in Chinese patent CN 104610471A. This method is to first crush the nitrile rubber, then dissolve it in a solvent, and use triphenylphosphine rhodium chloride as a catalyst and hydrogen reaction to obtain hydrogenated nitrile rubber under high temperature and high pressure. The advantage of the homogeneous solution hydrogenation process is that the catalyst and the reactant are dissolved in the same solvent, and the molecules of the two are fully contacted, which avoids the problem of diffusion and mass transfer, and thus does not require higher reaction pressure and temperature. However, the biggest defect of the homogeneous catalyst is that it is difficult to recycle or reuse, and the recovery rate is very low, which makes the preparation cost of hydrogenated nitrile rubber very high and causes metal pollution, hindering its large-scale development.

[0004] Chinese patent CN103588911A describes a method of using triaminosilane added to a solution, reacting triaminosilane with rhodium ions in the solution, absorbing 75%-85% of the residual rhodium in the solution, and then filtering and recovering it. However, silane is unstable when it comes into contact with water and easily reacts with the surface of the reactor. Chinese patent CN101704926A describes a method of removing precious metal catalysts from hydrogenated copolymer solutions by extracting stannous chloride (SnCl2) aqueous solution. However, it is very difficult for stannous chloride to separate from precious metals, and the amount used is very large. Sinopec applied for a patent entitled "Functional magnetic composite microspheres, preparation methods and applications thereof, and methods for removing precious metal catalysts from hydrogenated nitrile rubber glue", publication number CN119140057A, which uses functional magnetic composite microspheres, preparation methods and applications thereof, and removes precious metal catalysts from hydrogenated nitrile rubber glue. However, the cost of magnetic composite microspheres is very high and it is difficult to industrialize, so a new high-efficiency and low-cost technical solution is needed to solve the above problems. Summary of the invention

[0005] In view of the problems of difficulty and high cost in catalyst recovery in the prior art, the present application provides a recovery method for a homogeneous catalyst for hydrogenated nitrile rubber synthesis, and a preparation process for hydrogenated nitrile rubber. The present application adopts a complexing extractant and an alkaline aqueous solution for continuous extraction, and separates the catalyst from the hydrogenation reaction liquid through a multi-stage countercurrent extraction process. A large amount of complexing extractant can coordinate with the platinum group metal ions in the catalyst, promote the original ligand to fall off, realize ligand exchange, extract the catalyst to a new phase, and finally obtain a pure platinum group metal catalyst by distillation and incineration treatment; at the same time, the extraction solvent after simple distillation collection and purification is used for recycling, which can reduce the overall recovery cost. The recovery method of the present application has the advantages of low cost, high recovery rate and high efficiency, solves the problem of catalyst recovery, and is suitable for industrial production.

[0006] In a first aspect, the present application provides a method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis, using the following technical solution: A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis comprises the following steps: S1, the hydrogenation reaction liquid after the hydrogenation reaction of the nitrile rubber containing the platinum group metal compound homogeneous catalyst is collected into a temporary storage tank, and then introduced into the heavy phase inlet of the extraction centrifuge, mixed with the complexing extractant and the alkaline aqueous solution entering from the light phase inlet in the extraction centrifuge cavity, and the phase transfer of the catalyst occurs at a suitable extraction temperature and centrifugal speed; the hydrogenation reaction liquid after extraction is introduced from the heavy phase outlet into the heavy phase inlet of the next stage extraction centrifuge or exported to the temporary storage tank of the reaction liquid after extraction; at the same time, the complexing extractant and the alkaline aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then introduced from the light phase outlet into the light phase inlet of the next stage extraction centrifuge or exported to the temporary storage tank of the extraction liquid containing the platinum group metal compound homogeneous catalyst; S2, neutralizing the solution in the temporary storage tank of the extract containing the platinum group metal compound homogeneous catalyst, sending it into a distillation tower for atmospheric or reduced pressure distillation, and after draining the water, collecting the purified extraction solvent for application; S3. The concentrated liquid containing the complex of the platinum group metal in the distillation tower kettle is distilled and then incinerated to obtain a pure platinum group metal catalyst.

[0007] By adopting the above technical scheme, the recovery and separation of the catalyst (step S1): This step mainly realizes the effective separation of the catalyst by reacting the complexing extractant and the alkaline aqueous solution with the homogeneous catalyst of the platinum group metal compound in the hydrogenation reaction liquid. The complexing extractant promotes the transfer of the catalyst from the reaction liquid to the extractant phase by forming a stable complex with the platinum group metal ions. At the same time, the alkaline aqueous solution helps to stabilize the formation of the complex and may participate in the further precipitation or conversion process of the metal ions. The multi-stage countercurrent extraction process ensures the efficient recovery of the platinum group metal catalyst. Through the continuous extraction process, the loss of the catalyst can be minimized, while the extraction efficiency and the recovery rate of the catalyst can be improved. The role of the alkaline aqueous solution is to increase the solubility of the platinum group metal compound in the complexing extractant. Purification of the catalyst (step S2): The extract containing the platinum group metal catalyst is further purified through the neutralization and distillation process. The neutralization process may involve adjusting the pH value of the solution to promote the precipitation or conversion of metal ions. The distillation process is used to separate the solvent and water to ensure the purity of the subsequent treatment process. The neutralization and distillation steps work together to ensure the removal of impurities and unreacted substances in the extract while retaining effective platinum group metal catalyst components. In addition, the extraction solvent is recovered by simple distillation, which reduces solvent consumption and processing costs. Final treatment of the catalyst (step S3): The concentrated liquid in the distillation tower kettle is further distilled and incinerated to obtain a pure platinum group metal catalyst. This step ensures the high purity of the catalyst and the quality of the recovered product. The distillation and incineration steps work together to completely remove all non-platinum group metal impurities while ensuring a high recovery rate of platinum group metals. The incineration process ensures that any organic extractants and impurities that may remain are completely removed. Overall, the present application achieves efficient recovery and purification of platinum group metal catalysts through carefully designed extraction, purification and incineration steps. This method not only improves the recovery rate and purity of the catalyst, but also significantly reduces the processing cost, and has important industrial application value.

[0008] Preferably, in step S1, the amount of the complexing extractant is 25-300%, preferably 50-100%, of the volume of the hydrogenation reaction liquid.

[0009] Preferably, in step S1, the complexing extractant is at least one of triethylamine, tripropylamine, triethanolamine and pyridine.

[0010] Preferably, the complexing extractant is triethylamine.

[0011] By adopting the above technical scheme, triethylamine plays an important role in the recovery method of the homogeneous catalyst for hydrogenated nitrile rubber synthesis. As a complexing extractant, triethylamine and platinum group metal ions undergo coordination reaction, which causes the original ligand to fall off, realizes ligand exchange, and thus extracts the catalyst into a new phase. This process helps to improve the recovery rate and purity of the catalyst. The interaction between triethylamine and alkaline aqueous solution. During the extraction process, triethylamine and alkaline aqueous solution work together to help improve the extraction efficiency. Specifically, triethylamine can better form a complex with platinum group metal ions in an alkaline environment, thereby promoting the phase transfer of the catalyst. In general, triethylamine plays an important role in the recovery method of the homogeneous catalyst for hydrogenated nitrile rubber synthesis, which not only reduces the recovery cost, but also improves the recovery efficiency and the quality of the catalyst.

[0012] Preferably, in step S1, the alkaline aqueous solution is one of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution; the mass concentration of the alkaline aqueous solution can be 5 to 20%, preferably 10 to 15%; the amount of the alkaline aqueous solution is 0-100% of the volume of the hydrogenation reaction liquid, preferably 10-20%; the function of the alkaline aqueous solution is to increase the solubility of the platinum group metal compound in the complexing extractant.

[0013] By adopting the above technical scheme, the role of the alkaline aqueous solution is to increase the solubility of the platinum group metal compound in the complexing extractant. Specifically, the hydroxide ions in the alkaline aqueous solution react with the platinum group metal ions to form a water-soluble complex. In this way, when the complexing extractant is mixed with the hydrogenation reaction solution, the platinum group metal ions can be more effectively extracted from the reaction solution. In addition, the amount and concentration of the alkaline aqueous solution also need to be properly controlled. If the amount is too much, the reaction solution may be too alkaline, affecting the activity and stability of the catalyst. If the concentration is too high, the complex may be too stable and difficult to separate and recover by methods such as distillation. Therefore, in step S1, it is necessary to select a suitable alkaline aqueous solution according to the specific circumstances, and strictly control its amount and concentration to ensure the recovery effect and purity of the catalyst.

[0014] Preferably, in step S1, the extraction temperature is 20 to 180°C, preferably 80 to 120°C; the centrifugal speed is 1400 to 2800 rpm, preferably 2400 to 2800 rpm.

[0015] Preferably, in step S1, the platinum group metal in the platinum group metal compound is one of ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably ruthenium or palladium.

[0016] Preferably, in step S1, the extraction centrifuge is connected in a multi-stage countercurrent manner for continuous extraction, and the number of stages is specifically 3 to 10, preferably 5 to 6.

[0017] By adopting the above technical scheme, multi-stage countercurrent extraction can make the extractant and the extracted material have more contact opportunities, thereby improving the extraction efficiency. Each stage of extraction can transfer part of the catalyst from the heavy phase to the light phase, and the concentration of the catalyst gradually decreases as the extraction process proceeds. Due to the continuity and high efficiency of multi-stage countercurrent extraction, the amount of extractant used can be reduced while ensuring the extraction effect. This can reduce costs and reduce potential impacts on the environment. Multi-stage countercurrent extraction can more effectively separate and recover platinum group metal catalysts. Each stage of extraction can improve the recovery rate of the catalyst, and ultimately obtain a platinum group metal catalyst of higher purity. Multi-stage countercurrent extraction allows for fine control of the extraction conditions of each stage, including the type, concentration, pH value, etc. of the extractant, thereby optimizing the extraction process and improving the extraction effect. The use of a multi-stage countercurrent extraction centrifuge can simplify the process flow, reduce the subsequent processing steps and equipment requirements, and thus reduce the complexity and cost of the overall process. Each stage of extraction in the multi-stage countercurrent extraction centrifuge can complement and synergize with each other to ensure that the catalyst is efficiently and evenly separated from the reaction solution. This synergy helps to improve the stability and reliability of the entire extraction process. In summary, the application of the multi-stage countercurrent extraction centrifuge in step S1 not only improves the extraction efficiency and the catalyst recovery rate, but also reduces the cost and environmental impact. It is an efficient and economical catalyst recovery method.

[0018] Preferably, in step S3, the incineration temperature is 550 to 600°C, and the incineration time is 5 to 7 hours.

[0019] In summary, the beneficial technical effects of this application are: 1. Cost-effectiveness: Using low-cost complexing extractants (such as triethylamine, triethanolamine, etc.) for extraction and recovering these extractants by simple distillation methods significantly reduces the overall cost of catalyst recovery.

[0020] 2. Environmentally friendly: The complex formed by the complexing extractant and the platinum group metal ions can be removed by incineration, avoiding pollution to the environment while ensuring a high recovery rate of platinum group metals.

[0021] 3. High efficiency: The continuous countercurrent multi-stage extraction process is adopted to improve the extraction efficiency and catalyst recovery rate. This process design can ensure the effective separation of the catalyst from the hydrogenation reaction liquid.

[0022] 4. Industrial applicability: This recovery method solves the problem of difficult catalyst recovery and is suitable for industrial production processes, which helps to improve the overall efficiency and economic benefits of hydrogenated nitrile rubber production.

[0023] 5. Safety: By incinerating the complex, the handling and emission of harmful substances can be effectively reduced, thus improving the safety of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings used in the embodiments: Figure 1 is a schematic diagram of the metal ligand formed in Example 1; Figure 2 is a schematic diagram of the metal ligand formed in Example 2; Figure 3 Schematic diagram of the extraction step of the homogeneous catalyst for hydrogenated nitrile rubber synthesis in Example 1. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0026] Example 1 A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis comprises the following steps: S1, the hydrogenation reaction liquid after the hydrogenation reaction of 100L of nitrile rubber containing 5ppm palladium homogeneous catalyst is collected in a temporary storage tank, and then introduced into the heavy phase inlet of the extraction centrifuge, and mixed with 60L triethylamine and 10L sodium hydroxide aqueous solution with a mass concentration of 20% entering the light phase inlet in the extraction centrifuge cavity, and the phase transfer of the catalyst occurs at an extraction temperature of 100°C and a centrifugal speed of 2400rpm; the hydrogenation reaction liquid after extraction is introduced from the heavy phase outlet into the heavy phase inlet of the next-stage extraction centrifuge; at the same time, triethylamine and sodium hydroxide aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then introduced from the light phase outlet into the light phase inlet of the next-stage extraction centrifuge; the extraction stage is 5; finally, the hydrogenation reaction liquid after extraction is exported from the heavy phase outlet to the reaction liquid temporary storage tank after extraction; at the same time, triethylamine and sodium hydroxide aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then exported from the light phase outlet to the extraction liquid temporary storage tank containing the platinum group metal compound homogeneous catalyst; S2, neutralizing the solution in the temporary storage tank of the extract containing the platinum group metal compound homogeneous catalyst, sending it into a distillation tower for atmospheric distillation, and collecting the purified extraction solvent for application after draining the water; S3. The concentrated liquid containing the complex of platinum group metals in the bottom of the distillation tower is distilled and then incinerated at a temperature of 550° C. for 7 hours to obtain a pure platinum group metal catalyst, which is then sent to the catalyst manufacturer for recovery and reuse.

[0027] Example 2 A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis comprises the following steps: S1, collect 100L of hydrogenation reaction liquid containing 3ppm rhodium homogeneous catalyst after the hydrogenation reaction of nitrile rubber into a temporary storage tank, and then introduce it into the heavy phase inlet of the extraction centrifuge, and mix it with 100L pyridine and 10L potassium hydroxide aqueous solution with a mass concentration of 15% entering from the light phase inlet in the extraction centrifuge cavity, and phase transfer of the catalyst occurs at an extraction temperature of 120°C and a centrifugal speed of 2800rpm; the hydrogenation reaction liquid after extraction is introduced from the heavy phase outlet into the heavy phase inlet of the next-stage extraction centrifuge; at the same time, pyridine and potassium hydroxide aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then introduced from the light phase outlet into the light phase inlet of the next-stage extraction centrifuge; the extraction stage is 6; finally, the hydrogenation reaction liquid after extraction is exported from the heavy phase outlet to the reaction liquid temporary storage tank after extraction; at the same time, pyridine and potassium hydroxide aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then exported from the light phase outlet to the extraction liquid temporary storage tank containing the platinum group metal compound homogeneous catalyst; S2, neutralizing the solution in the temporary storage tank of the extract containing the platinum group metal compound homogeneous catalyst, sending it into a distillation tower for atmospheric distillation, and collecting the purified extraction solvent for application after draining the water; S3. The concentrated liquid containing the complex of platinum group metals in the distillation tower kettle is distilled and then incinerated at a temperature of 600°C for 5 hours to obtain a pure platinum group metal catalyst, which is then sent to the catalyst manufacturer for recovery and reuse.

[0028] Example 3 A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis comprises the following steps: S1. Collect 100L of hydrogenation reaction liquid containing 4ppm ruthenium homogeneous catalyst after the hydrogenation reaction of nitrile rubber into a temporary storage tank, and then introduce it into the heavy phase inlet of the extraction centrifuge, and mix it with 80L tripropylamine and 15L sodium hydroxide aqueous solution with a mass concentration of 12% entering from the light phase inlet in the extraction centrifuge cavity, and phase transfer of the catalyst occurs at an extraction temperature of 80°C and a centrifugal speed of 2600rpm; the hydrogenation reaction liquid after extraction is introduced from the heavy phase outlet into the heavy phase inlet of the next-stage extraction centrifuge; at the same time, tripropylamine and sodium hydroxide aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then introduced from the light phase outlet into the light phase inlet of the next-stage extraction centrifuge; the number of extraction stages is 5; finally, the hydrogenation reaction liquid after extraction is exported from the heavy phase outlet to the temporary storage tank for the reaction liquid after extraction; at the same time, tripropylamine and sodium hydroxide aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then exported from the light phase outlet to the temporary storage tank for the extraction liquid containing the homogeneous catalyst of the platinum group metal compound; S2, neutralizing the solution in the temporary storage tank of the extract containing the platinum group metal compound homogeneous catalyst, sending it into a distillation tower for vacuum distillation, and collecting the purified extraction solvent for application after draining the water; S3. The concentrated liquid containing the complex of platinum group metals in the bottom of the distillation tower is distilled and then incinerated at a temperature of 580° C. for 6 hours to obtain a pure platinum group metal catalyst, which is then sent to the catalyst manufacturer for recovery and reuse.

[0029] Example 4 The same as Example 1, except that the amount of triethylamine added was changed from 60 L to 80 L.

[0030] Example 5 The same as Example 1, except that the amount of triethylamine added was changed from 60L to 100L.

[0031] Performance Testing The metal content and metal removal rate in the extraction complexing agent phase in Examples 1 to 5 were tested respectively; the metal content in the extraction complexing agent phase in Examples 1, 4 and 5 refers to the content of palladium after palladium is extracted and complexed with palladium by triethylamine; the metal content in the extraction complexing agent phase in Example 2 refers to the content of rhodium after rhodium is extracted and complexed with rhodium by pyridine; the metal content in the extraction complexing agent phase in Example 3 refers to the content of ruthenium after ruthenium is extracted and complexed with tripropylamine; the results are shown in Table 1.

[0032] Table 1 Test results Analyzing the data in Table 1, we can see that: 1) Example 1-Example 5 A method for recovering a homogeneous catalyst for hydrogenating nitrile rubber synthesis is provided, wherein a complexing extractant and an alkaline aqueous solution are used for continuous extraction, and the catalyst is separated from the hydrogenation reaction liquid by a multi-stage countercurrent extraction process. A large amount of complexing extractant can coordinate with the platinum group metal ions in the catalyst, causing the original ligand to fall off, achieving ligand exchange, extracting the catalyst to a new phase, and finally distilling and then incinerating to obtain a pure platinum group metal catalyst. The metal removal rate is ≥95%.

[0033] 2) The performance comparison analysis of the recovery method of the homogeneous catalyst for hydrogenated nitrile rubber synthesis of Example 1 and Example 4-Example 5 shows that increasing the amount of the complexing extractant can effectively improve the metal removal efficiency. This method not only has a high catalyst recovery rate, but also can be recycled by collecting the purified extraction solvent through simple distillation, significantly reducing the overall production cost.

[0034] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the protection scope of the present application.

Claims

1. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis, characterized in that: The following steps are involved: S1, the hydrogenation reaction liquid after the hydrogenation reaction of the nitrile rubber containing the platinum group metal compound homogeneous catalyst is collected into a temporary storage tank, and then introduced into the heavy phase inlet of the extraction centrifuge, mixed with the complexing extractant and the alkaline aqueous solution entering from the light phase inlet in the extraction centrifuge cavity, and the phase transfer of the catalyst occurs at a suitable extraction temperature and centrifugal speed; the hydrogenation reaction liquid after extraction is introduced from the heavy phase outlet into the heavy phase inlet of the next stage extraction centrifuge or exported to the temporary storage tank of the reaction liquid after extraction; at the same time, the complexing extractant and the alkaline aqueous solution are introduced into the light phase outlet of the extraction centrifuge, and then introduced from the light phase outlet into the light phase inlet of the next stage extraction centrifuge or exported to the temporary storage tank of the extraction liquid containing the platinum group metal compound homogeneous catalyst; S2, neutralizing the solution in the temporary storage tank of the extract containing the platinum group metal compound homogeneous catalyst, sending it into a distillation tower for atmospheric or reduced pressure distillation, and after draining the water, collecting the purified extraction solvent for application; S3. The concentrated liquid containing the complex of the platinum group metal in the distillation tower kettle is distilled and then incinerated to obtain a pure platinum group metal catalyst.

2. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S1, the amount of the complexing extractant is 25-300% of the volume of the hydrogenation reaction liquid.

3. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S1, the complexing extractant is at least one of triethylamine, tripropylamine, triethanolamine and pyridine.

4. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 3, characterized in that: The complexing extractant is triethylamine.

5. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S1, the alkaline aqueous solution is one of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution; the mass concentration of the alkaline aqueous solution can be 5 to 20%; and the amount of the alkaline aqueous solution used is 0-100% of the volume of the hydrogenation reaction liquid.

6. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S1, the extraction temperature is 20 to 180°C; the centrifugal speed is 1400 to 2800 rpm.

7. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S1, the platinum group metal in the platinum group metal compound is one of ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably ruthenium or palladium.

8. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S1, the extraction centrifuge is connected in a multi-stage countercurrent manner for continuous extraction, and the number of stages is specifically 3 to 10, preferably 5 to 6.

9. A method for recovering a homogeneous catalyst for hydrogenated nitrile rubber synthesis according to claim 1, characterized in that: In step S3, the incineration temperature is 550 to 600°C and the incineration time is 5 to 7 hours.

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