A method for wet oil removal of spent catalyst

Abstract

The application discloses a method for removing oil from waste catalyst by wet method, which comprises the following steps: (1) fine grinding and slurry adjustment; (2) mechanical emulsification-air flotation; (3) liquid-solid separation; and (4) deep oil removal and slurry preparation. Through the fine grinding-slurry adjustment-mechanical emulsification-air flotation-deep oil removal treatment, the oil on the surface of the waste catalyst and the internal pore blockage can be effectively removed, and the oil removal rate of the waste catalyst reaches more than 99.5%.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and comprehensive resource recycling technology, specifically relating to a wet oil removal method for waste catalysts. Background Technology

[0002] Waste catalysts originate from industries such as petroleum product refining, basic chemical raw material manufacturing, pesticide production, and environmental remediation. These waste catalysts pose a significant threat to the ecological environment and human health. Improper disposal of waste catalysts can lead to the destruction of water bodies, soil, vegetation, and other organisms by their toxic and harmful components, ultimately endangering human health. Furthermore, waste catalysts are valuable secondary resources rich in metals such as molybdenum, cobalt, and nickel, possessing high recycling value.

[0003] The surface of spent catalysts is coated with 10-20 wt% oil, making it difficult to recover valuable metals such as molybdenum and cobalt using subsequent processes such as oxidative roasting and sodium roasting. Therefore, it is necessary to remove the oil from the surface of the spent catalysts before effective recovery of valuable metal elements can be achieved. Currently, the main methods for degreasing spent catalysts include high-temperature degreasing and wet degreasing. For example, CN107915256A discloses a method for preparing high-purity molybdic acid from spent catalysts, in which the residual oil hydrogenation catalyst is degreased using a degreasing furnace (1250-1375℃). However, this process has high energy consumption, long processing time, low efficiency, and is prone to generating harmful gases such as sulfur dioxide and nitrogen oxides. Furthermore, the material is prone to sublimation and agglomeration under high-temperature conditions. For example, CN117654995A discloses an ultrasonic pretreatment method for molybdenum-based waste catalysts. This method uses an aqueous solution of ethyl acetate as a degreasing agent to clean and remove oil from the molybdenum-based waste catalysts under ultrasonic field enhancement. However, ethyl acetate is an organic liquid with an irritating odor and is easily volatile, which will have an adverse effect on the working environment and health of workers. Moreover, the introduction of organic solvents will require higher requirements for the plant and higher investment costs. Furthermore, ultrasonic equipment is not suitable for industrialization. Summary of the Invention

[0004] Therefore, the purpose of this invention is to provide a method for wet oil removal from waste catalysts.

[0005] This invention provides a method for wet oil removal from spent catalysts, comprising the following steps: (1) Fine grinding and slurry preparation: The waste catalyst is crushed and finely ground in sequence to obtain finely ground waste catalyst; water is added to the finely ground waste catalyst to make slurry; (2) Mechanical emulsification-air flotation: After heating the slurry in step (1) to a set temperature, mechanical emulsification is carried out at the set temperature. During mechanical emulsification, gas is continuously introduced into the slurry for air flotation to obtain the emulsified-air flotation slurry. (3) Liquid-solid separation: The slurry after emulsification-air flotation in step (2) is subjected to liquid-solid separation to obtain preliminary de-oiled waste catalyst and oil emulsion; (4) Deep degreasing and pulping: Water and deep degreasing agent are added to the waste catalyst that was initially degreased in step (3) to make pulp and obtain secondary pulp; the secondary pulp is mechanically stirred and washed, and then solid-liquid separation is carried out to obtain the degreased waste catalyst and pulp washing wastewater.

[0006] Preferably, in step (1), the waste catalyst is finely ground until the particle size of -200 mesh is ≥95%; the mass ratio of the finely ground waste catalyst to water is 1:(5~10).

[0007] Preferably, in step (2), the temperature is set to 75~95℃, the mechanical emulsification speed is 1000~6000rpm, the gas is one or more of air, nitrogen, oxygen, and argon, and the gas introduction speed is 50~160m. 3 / (h·t), where m 3 The volume of the gas is represented by h, the time is represented by t, and the mass of the spent catalyst is represented by tons. The time for mechanical emulsification is 30-60 minutes.

[0008] Preferably, in step (3), during solid-liquid separation, the temperature of the slurry after emulsification-air flotation is controlled to be greater than 60°C and less than the set temperature in step (2).

[0009] Preferably, in step (3), after the oil emulsion is cooled to room temperature, it undergoes natural sedimentation and phase separation to obtain an oil phase and water.

[0010] More preferably, the natural settling time is 2-4 hours.

[0011] More preferably, the oil phase is sold externally or sent to the pyrometallurgical system as fuel, and the aqueous phase is returned to the pulping process in step (1).

[0012] Preferably, in step (4), the mass ratio of the initial deoiling waste catalyst to water is 1:(2~5); the deep deoiling agent is Na2CO3 and / or laundry detergent; the mass of the deep deoiling agent is 0.3~1.3% of the mass of the initial deoiling waste catalyst.

[0013] More preferably, the deep degreasing agent is a combination of Na2CO3 and laundry detergent, with a mass ratio of Na2CO3 to laundry detergent of (0.2~1):(0.1~0.3).

[0014] Preferably, in step (4), the mechanical stirring and washing speed is 100 rpm to 500 rpm, and the mechanical stirring and washing time is 20 to 60 min.

[0015] Preferably, in step (4), the washing wastewater is sent to wastewater treatment; and the deoiled catalyst is sent to metal recovery.

[0016] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: 1. This invention effectively removes oil from the surface and internal pores of waste catalysts by fine grinding, slurry preparation, mechanical emulsification flotation, and deep oil removal, achieving an oil removal rate of over 99.5%.

[0017] 2. The method of the present invention is carried out under aqueous conditions, which avoids the generation of harmful gases, does not introduce organic solvents, has lower requirements for the plant, is simple and easy to industrialize, and is environmentally friendly.

[0018] 3. The wet residue of the spent catalyst after deoiling treatment according to the present invention has high surface activity, does not require drying, reduces energy consumption, and can be directly used as raw material for subsequent wet extraction of valuable metals such as Mo, Ni, Co, and V, with high recovery efficiency. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the method of the present invention. Detailed Implementation

[0020] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. As mentioned above, the present invention provides a method for wet oil removal from spent catalyst, comprising the following steps: (1) Fine grinding and slurry preparation: The waste catalyst is crushed and finely ground in sequence to obtain finely ground waste catalyst; water is added to the finely ground waste catalyst to make slurry; (2) Mechanical emulsification-air flotation: After heating the slurry in step (1) to a set temperature, mechanical emulsification is carried out at the set temperature. During mechanical emulsification, gas is continuously introduced into the slurry for air flotation to obtain the emulsified-air flotation slurry. (3) Liquid-solid separation: The slurry after emulsification-air flotation in step (2) is subjected to liquid-solid separation to obtain preliminary de-oiled waste catalyst and oil emulsion; (4) Deep degreasing and pulping: Water and deep degreasing agent are added to the waste catalyst that was initially degreased in step (3) to make pulp and obtain secondary pulp; the secondary pulp is mechanically stirred and washed, and then solid-liquid separation is carried out to obtain the degreased waste catalyst and pulp washing wastewater.

[0021] This invention effectively removes oil from the surface and internal pores of waste catalysts by fine grinding, slurry preparation, mechanical high-power emulsification flotation, and deep oil removal. The oily substances in the waste catalysts are thoroughly removed, with an oil removal rate of over 99.5%.

[0022] In the method of this invention, firstly, mechanical emulsification-air flotation is used for oil removal. This combined mechanical emulsification and air flotation process, under aqueous conditions, allows a large amount of oil to detach from the spent catalyst. Air bubbles carry the oil from the catalyst surface into the aqueous solution. Under emulsification conditions, the detached oil forms an emulsion with water, thus achieving preliminary deoiling of the spent catalyst. In subsequent processes, further deep deoiling is performed. After the preliminary deoiling, the binding capacity between the oil and the catalyst is greatly reduced. Therefore, in the deep deoiling process, a small amount of deoiling reagent is used, and the oil can be almost completely removed through slurry washing.

[0023] Preferably, in step (1), the waste catalyst is finely ground until the particle size of -200 mesh is ≥95%; the mass ratio of the finely ground waste catalyst to water is 1:(5~10), including but not limited to 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.

[0024] Preferably, in step (2), the set temperature is 75~95℃, including but not limited to 75℃, 80℃, 85℃, 90℃, 95℃, etc.; the mechanical emulsification speed is 1000~6000rpm, including but not limited to 1000rpm, 2000rpm, 3000rpm, 4000rpm, 5000rpm, 6000rpm, etc.; the gas is one or more of air, nitrogen, oxygen, and argon; and the gas introduction speed is 50~160m. 3 / (h·t), where m 3 The volume of the gas is represented by h, the time by t, and the mass of the spent catalyst is represented by tons, including but not limited to 50m³. 3 / (h·t), 60m 3 / (h·t), 70m 3 / (h·t), 80m³ / (h·t), 90m 3 / (h·t), 100m 3 / (h·t), 110m 3 / (h·t), 120m 3 / (h·t), 130m 3 / (h·t), 140m 3 / (h·t), 150m 3 / (h·t), 160m 3 / (h·t) etc.; the mechanical emulsification time is 30~60min, including but not limited to 30min, 35min, 40min, 45min, 50min, 55min, 60min etc.

[0025] This invention improves the efficiency of preliminary oil removal by controlling the process parameters of the heating, mechanical emulsification, and air flotation treatment process.

[0026] Preferably, in step (3), during solid-liquid separation, the temperature of the slurry after emulsification-air flotation is controlled to be greater than 60°C and less than the set temperature in step (2).

[0027] In the solid-liquid separation process of the present invention, controlling the temperature of the slurry to be greater than 60°C can increase the compatibility between oil and water and prevent the oil that has detached from the catalyst surface from being re-adsorbed onto the catalyst due to excessively low temperature.

[0028] Preferably, in step (3), after the oil emulsion is cooled to room temperature, it undergoes natural sedimentation and phase separation to obtain an oil phase and water.

[0029] The surface of the spent catalyst is mostly heavy oil. In this invention, the oil phase and the water phase can be separated by cooling and settling through oil emulsion. This method has low energy consumption, is simple to operate, and the oil can be further recycled and reused.

[0030] More preferably, the natural settling time is 2 to 4 hours, including but not limited to 2 hours, 2.5 hours, 3 hours, 3.5 hours, and 4 hours.

[0031] More preferably, the oil phase is sold or sent to the pyrometallurgical system as fuel, and the aqueous phase is returned to the pulping process in step (1) or (4).

[0032] The separated oil phase in this invention can be reused, thus improving resource utilization.

[0033] Preferably, in step (4), the mass ratio of the initial deoiling waste catalyst to water is 1:(2~5), including but not limited to 1:2, 1:3, 1:4, 1:5, etc.; the deep deoiling agent is Na2CO3 and / or laundry detergent; the mass of the deep deoiling agent is 0.3~1.3% of the mass of the initial deoiling waste catalyst, including but not limited to 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, etc.

[0034] More preferably, the deep degreasing agent is a combination of Na2CO3 and laundry detergent, with a mass ratio of Na2CO3 to laundry detergent of (0.2~1):(0.1~0.3), including but not limited to 0.2:0.1, 0.2:0.3, 0.5:0.1, 0.5:0.2, 0.5:0.3, 0.8:0.1, 0.8:0.2, 0.8:0.3, 1.0:0.1, 1.0:0.2, 1.0:0.3, etc.

[0035] Preferably, in step (4), the rotation speed of the mechanical stirring and washing is 100 rpm to 500 rpm, including but not limited to 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, etc.; the mechanical stirring and washing time is 20 to 60 min, including but not limited to 20 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0036] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0037] The process flow diagram of a wet oil removal method for spent catalysts in this invention is as follows: Figure 1 As shown, the specific steps can be found in the embodiments.

[0038] Example 1 In this embodiment, the spent catalyst is a Mo-Co spent catalyst containing 16.2% oil, 8.2% Mo, and 2.1% Co.

[0039] (1) 800g of waste catalyst is crushed and finely ground to -200 mesh ≥95%; the finely ground waste catalyst is mixed with water at a mass ratio of 1:8 to make slurry.

[0040] (2) Heat the slurry to 85°C and at this temperature, use a high shear homogenizing emulsifier to mechanically emulsify the slurry for 40 minutes. During the mechanical emulsification process, air is continuously introduced for air flotation (the mechanical emulsification speed is 3000 rpm and the air flow rate is 20 L / h) to obtain the mechanically emulsified and air-flotated slurry.

[0041] (3) The slurry after mechanical emulsification and air flotation is rapidly separated into liquid and solid, and the temperature of liquid-solid separation is controlled at 65℃~75℃ to obtain preliminary de-oiled waste catalyst and oil emulsion.

[0042] (4) The oil emulsion is rapidly cooled in ice water and allowed to settle naturally for 3 hours. The oil and water phases are separated to obtain the oil phase and water phase. The oil phase can be sold or sent to the pyrometallurgical system as fuel, while the water phase is returned to the slurry preparation process in step (1) or (5).

[0043] (5) The pre-de-oiled waste catalyst is mixed with water (return water from step (4)) at a mass ratio of 1:3, and then 0.3% Na2CO3 and 0.2% laundry detergent are added by mass of the pre-de-oiled waste catalyst. After mixing and slurry preparation, a slurry is obtained. The slurry is mechanically washed in a slurry washing tank for 30 minutes, with the rotation speed controlled at 150 rpm. After mechanical washing, the slurry is separated into washing liquid and de-oiled waste catalyst by liquid-solid separation. The washing liquid is sent to wastewater treatment, and the wet residue of the de-oiled waste catalyst is used as raw material for the recovery of valuable metals such as Mo, Ni, Co, and V.

[0044] In this embodiment, the oil recovery rate was 85.6% and the deoiling rate was 99.8%. Mo, Ni, Co, and V in the waste catalyst were still present in the deoiling waste catalyst.

[0045] Comparative Example 1 In this comparative example, a deoiling agent was directly used for deoiling. The specific steps are as follows: Waste catalyst was mixed with water at a mass ratio of 1:3, and then 1.0% Na₂CO₃ and 1.0% laundry detergent were added by mass. After mixing and pulping, a slurry was obtained. The slurry was mechanically washed in a washing tank for 30 minutes at a speed of 150 rpm. After mechanical washing, the slurry was subjected to liquid-solid separation to obtain washing liquid and de-oiled waste catalyst. The washing liquid was sent to wastewater treatment, and the wet residue of the de-oiled waste catalyst was used as raw material for the recovery of valuable metals such as Mo, Ni, Co, and V.

[0046] The oil removal rate in this comparative example was 15.8%.

[0047] Compared to Example 1, Comparative Example 1 only used a higher proportion of detergent to remove oil from the waste catalyst. The oil could not be recovered and the oil removal effect was poor. This may be because the oil was mainly heavy oil and had a high binding strength with the catalyst. Therefore, it was difficult to remove the oil by directly using an oil remover.

[0048] Comparative Example 2 It is basically the same as Example 1, except that step (2) is different, as follows: (2) Heat the slurry to 85°C and at this temperature, use a high shear homogenizing emulsifier to mechanically emulsify the slurry for 40 minutes (the mechanical emulsification speed is 3000 rpm) to obtain the mechanically emulsified slurry.

[0049] In this embodiment, the oil recovery rate was 42.6% and the deoiling rate was 59.5%. Mo, Ni, Co, and V in the waste catalyst were still present in the deoiled waste catalyst.

[0050] Compared to Example 1, Comparative Example 2 did not undergo air flotation, which may result in incomplete separation of some oil from the surface of the spent catalyst, leading to a decrease in oil removal efficiency and a reduction in oil recovery rate.

[0051] Comparative Example 3 It is basically the same as Example 1, except that step (2) is different, as follows: (2) Heat the slurry to 85°C and at this temperature, use a mixer to mechanically stir the slurry for 40 minutes. During the mechanical stirring process, air is continuously introduced for air flotation (the mechanical stirring speed is 500 rpm and the air flow rate is 60 L / h) to obtain the slurry after mechanical stirring and air flotation.

[0052] In this embodiment, the oil recovery rate was 28.2% and the deoiling rate was 39.6%. Mo, Ni, Co, and V in the waste catalyst were still present in the deoiled waste catalyst.

[0053] Compared to Example 1, in Comparative Example 3, where mechanical stirring alone failed to achieve emulsification, the oil removal effect decreased and the oil recovery rate also decreased.

[0054] Example 2 The process is basically the same as in Example 1, except that the deep degreasing agent in step 5 is different. Specifically, 0.5% Na2CO3 (by mass of the waste catalyst from the initial degreasing process) is added. 3。

[0055] In this embodiment, the oil recovery rate was 85.6% and the oil removal rate was 99.7%.

[0056] Example 3 The process is basically the same as in Example 1, except that the deep degreasing agent in step 5 is different. Specifically, 0.5% of the mass of the waste catalyst used for initial degreasing is added as laundry detergent. 。

[0057] In this embodiment, the oil recovery rate was 85.6% and the oil removal rate was 99.6%.

[0058] Example 4 In this embodiment, the spent catalyst Mo-Ni spent catalyst contains 15.8% oil, 15.22% Mo, and 6.2% Ni.

[0059] (1) 800g of waste catalyst is crushed and finely ground to -200 mesh ≥95%; the finely ground waste catalyst is mixed with water at a mass ratio of 1:5 to make slurry.

[0060] (2) Heat the slurry to 75°C and at this temperature, use a high shear homogenizing emulsifier to mechanically emulsify the slurry for 30 minutes. During the mechanical emulsification process, nitrogen is continuously introduced for air flotation (the mechanical emulsification speed is 6000 rpm and the nitrogen flow rate is 80 L / h) to obtain the mechanically emulsified air-flotated slurry.

[0061] (3) The slurry after mechanical emulsification and air flotation is rapidly separated into liquid and solid, and the temperature of liquid-solid separation is controlled at 65℃~70℃ to obtain preliminary de-oiled waste catalyst and oil emulsion.

[0062] (4) The oil emulsion is rapidly cooled in ice water and allowed to settle naturally for 2 hours. The oil and water phases are separated to obtain the oil phase and water phase. The oil phase can be sold or sent to the pyrometallurgical system as supplementary fuel, while the water phase is returned to the slurry preparation process in step (1) or (5).

[0063] (5) The pre-de-oiled waste catalyst and water (return water from step (4)) are mixed at a mass ratio of 1:5, and then 0.3% Na2CO3 (by mass of the pre-de-oiled waste catalyst) is added. After mixing and slurry preparation, a slurry is obtained. The slurry is mechanically washed in a slurry washing tank for 60 minutes at a speed of 500 rpm. After mechanical washing, the slurry is separated into washing liquid and de-oiled waste catalyst by liquid-solid separation. The washing liquid is sent to wastewater treatment, and the wet residue of the de-oiled waste catalyst is used as a raw material for the recovery of valuable metals such as Mo, Ni, Co, and V.

[0064] In this embodiment, the oil recovery rate was 88.2% and the oil removal rate was 99.9%.

[0065] Example 5 In this embodiment, the spent catalyst Mo-Ni spent catalyst contains 15.8% oil, 15.22% Mo, and 6.2% Ni.

[0066] (1) 800g of waste catalyst is crushed and finely ground to -200 mesh ≥95%; the finely ground waste catalyst is mixed with water at a mass ratio of 1:10 to make slurry.

[0067] (2) Heat the slurry to 95°C and at this temperature, use a high shear homogenizing emulsifier to mechanically emulsify the slurry for 60 minutes. During the mechanical emulsification process, oxygen is continuously introduced for air flotation (the mechanical emulsification speed is 1000 rpm and the oxygen flow rate is 50 L / h) to obtain the mechanically emulsified air-flotated slurry.

[0068] (3) The slurry after mechanical emulsification and air flotation is rapidly separated into liquid and solid, and the temperature of liquid-solid separation is controlled at 75℃~80℃ to obtain preliminary de-oiled waste catalyst and oil emulsion.

[0069] (4) The oil emulsion is rapidly cooled in ice water and allowed to settle naturally for 4 hours. The oil and water phases are separated to obtain the oil phase and water phase. The oil phase can be sold or sent to the pyrometallurgical system as supplementary fuel, while the water phase is returned to the slurry preparation process in step (1) or (5).

[0070] (5) The pre-de-oiled waste catalyst is mixed with water (return water from step (4)) at a mass ratio of 1:2, and then 1.0% Na2CO3 and 0.3% laundry detergent are added by mass of the pre-de-oiled waste catalyst. After mixing and slurry preparation, a slurry is obtained. The slurry is mechanically washed in a slurry washing tank for 20 minutes, with the rotation speed controlled at 100 rpm. After mechanical washing, the slurry is separated into washing liquid and de-oiled waste catalyst by liquid-solid separation. The washing liquid is sent to wastewater treatment, and the wet residue of the de-oiled waste catalyst is used as raw material for the recovery of valuable metals such as Mo, Ni, Co, and V.

[0071] In this embodiment, the oil recovery rate was 86.3% and the oil removal rate was 99.7%.

[0072] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for wet oil removal from spent catalyst, characterized in that, Includes the following steps: (1) Fine grinding and slurry preparation: The waste catalyst is crushed and finely ground in sequence to obtain finely ground waste catalyst; water is added to the finely ground waste catalyst to make slurry; (2) Mechanical emulsification-air flotation: After heating the slurry in step (1) to a set temperature, mechanical emulsification is performed at the set temperature. During mechanical emulsification, gas is continuously introduced into the slurry for air flotation to obtain the emulsified-air flotation slurry. The rotation speed of mechanical emulsification is 1000~6000 rpm; the gas introduction speed is 50~160 m / s. 3 / (h·t), where m 3 The volume of the gas is represented by h, the time is represented by t, and the mass of the spent catalyst is represented by tons. (3) Liquid-solid separation: The slurry after emulsification-air flotation in step (2) is subjected to liquid-solid separation to obtain preliminary de-oiled waste catalyst and oil emulsion; (4) Deep degreasing and pulping: Water and deep degreasing agent are added to the waste catalyst that was initially degreased in step (3) to make pulp and obtain secondary pulp; the secondary pulp is mechanically stirred and washed, and then solid-liquid separation is carried out to obtain the degreased waste catalyst and pulp washing wastewater.

2. The method for wet oil removal from spent catalyst according to claim 1, characterized in that, In step (1), the waste catalyst is finely ground until the particle size of -200 mesh is ≥95%; the mass ratio of the finely ground waste catalyst to water is 1:(5~10).

3. The method for wet oil removal from spent catalyst according to claim 1, characterized in that, In step (2), the temperature is set to 75~95℃; the gas is one or more of air, nitrogen, oxygen, and argon; and the mechanical emulsification time is 30~60min.

4. The method for wet oil removal from spent catalyst according to claim 1, characterized in that, In step (3), during solid-liquid separation, the temperature of the slurry after emulsification-air flotation is controlled to be greater than 60°C and less than the set temperature in step (2).

5. The method for wet oil removal from spent catalysts according to claim 1 or 4, characterized in that, In step (3), after the oil emulsion is cooled to room temperature, it undergoes natural sedimentation and phase separation to obtain an oil phase and water.

6. The method for wet oil removal from spent catalyst according to claim 5, characterized in that, The natural settling time is 2-4 hours.

7. The method for wet oil removal from spent catalyst according to claim 5, characterized in that, The oil phase is sold externally or sent to the pyrometallurgical system as fuel, and the aqueous phase is returned to step (1) pulping process.

8. The method for wet oil removal from spent catalyst according to claim 1, characterized in that, In step (4), the mass ratio of the initial deoiling waste catalyst to water is 1:(2~5); the deep deoiling agent is Na2CO3 and / or laundry detergent; the mass of the deep deoiling agent is 0.3~1.3% of the mass of the initial deoiling waste catalyst.

9. The method for wet oil removal from spent catalyst according to claim 8, characterized in that, The deep degreasing agent is a combination of Na2CO3 and laundry detergent, with a mass ratio of Na2CO3 to laundry detergent of (0.2~1):(0.1~0.3).

10. The method for wet oil removal from spent catalyst according to claim 1 or 8, characterized in that, In step (4), the mechanical stirring and washing speed is 100 rpm to 500 rpm, and the mechanical stirring and washing time is 20 to 60 min.

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