Method for recovering waste molybdenum-cobalt catalyst by wet process

Abstract

This invention discloses a wet recycling method for waste molybdenum-cobalt catalysts, comprising the following steps: (1) fine grinding and slurry preparation; (2) mechanical emulsification-air flotation; (3) liquid-solid separation; (4) oxygen pressure leaching; and (5) acid leaching. This invention adds a detergent to the slurry of waste Co-Mo catalysts and combines it with emulsification-air flotation technology to effectively remove oil from the surface and internal pores of the waste catalysts, achieving an oil removal rate of over 99.5%. The method of this invention involves degreasing under aqueous conditions, without introducing organic solvents, thus requiring less stringent plant conditions, eliminating the need for high-temperature treatment, reducing energy consumption, and simplifying the process for industrialization. The wet residue of the waste Co-Mo catalyst after degreasing treatment has high surface activity. Using oxygen pressure leaching combined with heated acid leaching, selective leaching and graded enrichment of molybdenum and cobalt in the waste catalyst can be achieved, with high leaching rates of both molybdenum and cobalt, exceeding 98%.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a method for the hydrometallurgical recovery of waste molybdenum-cobalt catalysts. Background Technology

[0002] Currently, increasingly stringent limits on sulfur and nitrogen content in gasoline and diesel fuel have led to increased use of Co-Mo catalysts. Simultaneously, coal liquefaction processes are also increasing the demand for Co-Mo catalysts. The activity of Co-Mo catalysts gradually deteriorates over time, eventually losing catalytic activity and becoming unusable. Improper landfill disposal of spent Co-Mo catalysts easily causes environmental pollution and wastes metal resources. To reduce environmental pollution, spent cobalt-molybdenum catalysts are generally treated to render them harmless. However, the surface of spent Co-Mo catalysts is typically coated with 10-20 wt% oil. If this oil is not thoroughly removed, it will directly affect the catalyst's reactivity during the leaching process, thus negatively impacting the recovery of cobalt and molybdenum metals. Therefore, oil removal before recovery is crucial. Currently, to recover cobalt and molybdenum metals, spent Co-Mo catalysts require deoiling treatment; the main deoiling methods include roasting deoiling and wet deoiling. High-temperature roasting leads to higher costs and energy consumption for valuable metal recovery. Furthermore, the sintered material is prone to agglomeration, reducing its leaching activity in subsequent leaching processes. Roasting also generates large amounts of harmful gases such as sulfur dioxide and nitrogen oxides. Since the catalyst surface is largely coated with heavy oil, wet deoiling typically requires organic solvents (such as ethyl acetate or ethanol) as a medium. However, organic solvents generally have irritating odors and are highly volatile, negatively impacting the working environment and health of workers. Moreover, the introduction of organic solvents places higher demands on the plant and increases investment costs. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a method for the wet recovery of waste molybdenum-cobalt catalysts.

[0004] This invention provides a method for the wet recovery of waste molybdenum-cobalt catalysts, comprising the following steps:

[0005] (1) Fine grinding and slurry preparation: The Co-Mo waste catalyst is crushed and finely ground to obtain finely ground waste catalyst; water and detergent are added to the finely ground waste catalyst to mix and slurry to obtain slurry;

[0006] (2) Mechanical emulsification-air flotation: After heating the slurry in step (1) to the set temperature, shear emulsification is performed at the set temperature. During the shear emulsification process, gas is continuously introduced for air flotation to obtain the emulsified-air flotation slurry.

[0007] (3) Liquid-solid separation: The slurry after emulsification-air flotation in step (2) is subjected to solid-liquid separation to obtain deoiled waste catalyst and waste liquid;

[0008] (4) Oxygen pressure leaching: Add leaching agent and water to the deoiled waste catalyst in step (3) to make slurry and obtain secondary slurry; pass oxygen-containing gas into the secondary slurry to perform oxygen pressure leaching and obtain oxygen pressure leaching solution and leaching residue.

[0009] (5) Acid leaching: Add concentrated sulfuric acid and water to the leaching residue in step (4) to obtain the leaching solution to be leached. Heat the leaching solution to obtain a cobalt-containing solution and acid leaching residue. The cobalt-containing solution is used to recover cobalt.

[0010] Preferably, in step (1), the spent catalyst is finely ground until the particle size of -200 mesh is ≥95%.

[0011] Preferably, in step (1), the detergent is Na2CO3 and / or laundry powder; the amount of detergent added is 0.3~1.2% of the mass of the finely ground waste catalyst; the mass ratio of the finely ground waste catalyst to water is 1:(5~10).

[0012] More preferably, the detergent is composed of Na2CO3 and laundry powder, and the mass ratio of sodium carbonate to laundry powder is (0.2~1):(0.1~0.3).

[0013] Preferably, in step (2), the temperature is set to 75~95℃; the shear emulsification speed is 1000~6000 rpm; the shear emulsification time is 30~60 min; the gas is one or more of air, nitrogen, oxygen, and argon; and 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.

[0014] Preferably, in step (3), during solid-liquid separation, the temperature of the slurry after emulsification-air flotation is controlled to be no less than 60°C and less than the set temperature in step (2).

[0015] Preferably, in step (4), the leaching agent is a combination of NaOH and Na2CO3, with a mass ratio of NaOH to Na2CO3 of 1:(2~4); the amount of leaching agent added is 10~25% of the mass of the deoiled waste catalyst; and the mass ratio of water to the deoiled waste catalyst is (2~5):1.

[0016] Preferably, in step (4), the oxygen-containing gas is air or oxygen; the oxygen pressure leaching pressure is 2.7~5MPa, the oxygen pressure leaching temperature is 180~220℃, and the oxygen pressure leaching time is 1.5~3h.

[0017] Preferably, in step (4), the oxygen pressure leachate is used to recover molybdenum.

[0018] Preferably, in step (5), the mass ratio of concentrated sulfuric acid to water is 1:(2~5); the liquid-solid mass ratio of the leaching solution is (1~2):1.

[0019] Preferably, in step (5), the temperature of the acid leaching is 100~104℃ and the time of the acid leaching is 10~40min.

[0020] Preferably, in step (5), the cobalt-containing solution is used to recover cobalt.

[0021] Preferably, in step (5), the main component of the acid leaching residue is unreacted carrier material Al2O3.

[0022] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects:

[0023] 1. This invention adds a detergent to the slurry of waste Co-Mo catalyst and combines it with emulsification-air flotation technology, which can effectively remove oil from the surface and internal pores of the waste catalyst, and the oil removal rate of the waste catalyst is over 99.5%.

[0024] 2. The method of the present invention is carried out under aqueous conditions without the introduction of organic solvents, which reduces the requirements for the plant, eliminates the need for high-temperature treatment, reduces energy consumption, and makes the process relatively simple and easy to industrialize.

[0025] 3. The wet residue of the waste Co-Mo catalyst after deoiling treatment of the present invention has high surface activity. By using oxygen pressure leaching combined with heated acid leaching, the selective leaching and stepwise enrichment of molybdenum and cobalt in the waste catalyst can be achieved, with high leaching rates of molybdenum and cobalt, both greater than 98%. Attached Figure Description

[0026] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] The concentrated sulfuric acid used in this invention has a mass concentration of 98 wt%.

[0030] As mentioned above, this invention provides a method for the wet recovery of waste molybdenum-cobalt catalysts, comprising the following steps:

[0031] (1) Fine grinding and slurry preparation: The Co-Mo waste catalyst is crushed and finely ground to obtain finely ground waste catalyst; water and detergent are added to the finely ground waste catalyst to mix and slurry to obtain slurry;

[0032] (2) Mechanical emulsification-air flotation: After heating the slurry in step (1) to the set temperature, shear emulsification is performed at the set temperature. During the shear emulsification process, air flotation is performed continuously to obtain the emulsified-air flotation slurry.

[0033] (3) Liquid-solid separation: The slurry after emulsification-air flotation in step (2) is subjected to solid-liquid separation to obtain deoiled waste catalyst and waste liquid;

[0034] (4) Oxygen pressure leaching: Add leaching agent and water to the deoiled waste catalyst in step (3) to make slurry and obtain secondary slurry; leach the secondary slurry with oxygen-containing gas, and after leaching, separate the solid and liquid to obtain oxygen pressure leaching solution and leaching residue.

[0035] (5) Acid leaching: Add concentrated sulfuric acid and water to the leaching residue in step (4) to obtain the leaching solution to be leached. Heat the leaching solution to be leached with acid. After acid leaching, separate the solid and liquid to obtain a cobalt-containing solution and acid leaching residue.

[0036] The oil adsorbed on the surface of spent Co-Mo catalysts is mostly heavy oil. If water is used as the medium for washing and degreasing, a large amount of detergent is usually required, and the degreasing effect is poor. In the method of this invention, detergent is added to the slurry of spent Co-Mo catalysts, followed by mechanical emulsification and air flotation for oil removal. Under aqueous conditions, mechanical emulsification combined with air flotation 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 the conditions of detergent and emulsification stirring, the detached oil forms an oil-in-water emulsion, dispersed in the water, and completely detaches from the catalyst, thus achieving highly efficient oil removal.

[0037] In this invention, a detergent is added to the slurry of waste Co-Mo catalyst. After mechanical emulsification and air flotation, the surface of the waste catalyst is activated, which helps to increase the surface energy of the de-oiled waste Co-Mo catalyst and thus improve the subsequent leaching effect.

[0038] Preferably, in step (1), the spent catalyst is finely ground until the particle size of -200 mesh is ≥95%.

[0039] Preferably, in step (1), the detergent is Na2CO3 and / or laundry powder; the amount of detergent added is 0.3~1.2% of the mass of the finely ground 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%, etc.; 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.

[0040] The amount of detergent added in this invention is very small, mainly because of the mechanical emulsification-flotation effect. Only a small amount of detergent is needed to achieve efficient separation of oil and waste catalyst.

[0041] More preferably, the detergent is composed of Na2CO3 and laundry powder, and the mass ratio of sodium carbonate to laundry powder is (0.2~1):(0.1~0.3), including but not limited to 0.2:0.1, 0.2:0.2, 0.2:0.3, 0.5:0.1, 0.5:0.3, 0.8:0.1, 0.8:0.3, 1:0.1, 1:0.3, etc.

[0042] In this invention, the detergent uses a combination of Na2CO3 and laundry powder, which can achieve a better degreasing effect.

[0043] Preferably, in step (2), the set temperature is 75~95℃, including but not limited to 75℃, 80℃, 90℃, 95℃, etc.; the shear emulsification speed is 1000~6000rpm, including but not limited to 1000rpm, 2000rpm, 3000rpm, 4000rpm, 5000rpm, 6000rpm, etc.; the shear emulsification time is 30~60min, including 30min, 35min, 40min, 45min, 50min, 55min, 60min, etc.; the gas is one or more of air, nitrogen, oxygen, and argon; and the gas introduction rate is 50~160m. 3 / (h·t), where m 3 The volume of the gas is represented by h, 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.

[0044] This invention improves oil removal efficiency by controlling the process parameters of the heating, mechanical emulsification, and air flotation treatment process.

[0045] Preferably, in step (3), during solid-liquid separation, the temperature of the slurry after emulsification-air flotation is controlled to be no less than 60°C and less than the set temperature in step (2).

[0046] In the solid-liquid separation process of this 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 from being re-adsorbed onto the catalyst.

[0047] Preferably, in step (4), the leaching agent is a combination of NaOH and Na2CO3, and the mass ratio of NaOH to Na2CO3 is 1:(2~4), including but not limited to 1:2, 1:2.5, 1:3, 1:3.5, 1:4, etc.; the amount of leaching agent added is 10~25% of the mass of the deoiling waste catalyst, including but not limited to 10%, 15%, 20%, 25%, etc.; the mass ratio of water to the deoiling waste catalyst is (2~5):1, including but not limited to 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0048] Preferably, in step (4), the oxygen pressure leachate is used to recover molybdenum.

[0049] Preferably, in step (4), the oxygen-containing gas is air and / or oxygen; the oxygen pressure leaching pressure is 2.7~5MPa, including but not limited to 2.7MPa, 3MPa, 3.2MPa, 3.5MPa, 3.7MPa, 4MPa, 4.2MPa, 4.5MPa, 4.7MPa, 5MPa, etc.; the oxygen pressure leaching temperature is 180~220℃, including but not limited to 180℃, 190℃, 200℃, 210℃, 220℃, etc.; the oxygen pressure leaching time is 1.5~3h, including but not limited to 1.5h, 2.0h, 2.5h, 3.0h, etc.

[0050] Preferably, in step (5), the mass ratio of concentrated sulfuric acid to water is 1:(2~5), including but not limited to 1:2, 1:3, 1:4, 1:5, etc.; the liquid-solid ratio of the leaching solution is (1~2):1, including but not limited to 1:1, 1.5:1, 2:1, etc.

[0051] Preferably, in step (5), the temperature of the acid leaching is 100~104℃, including but not limited to 100℃, 101℃, 102℃, 103℃, 104℃, etc.; the time of the acid leaching is 10~40min, including but not limited to 10min, 15min, 20min, 25min, 30min, 35min, 40min, etc.; the acid leaching is carried out under normal pressure.

[0052] Preferably, in step (5), the cobalt-containing solution is used to recover cobalt.

[0053] Preferably, in step (5), the main component of the acid leaching residue is unreacted carrier material Al2O3.

[0054] 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.

[0055] Example 1

[0056] In this embodiment, the waste Mo-Co catalyst contains 16.2% oil, 8.2% Mo, and 2.1% Co.

[0057] (1) 800g of waste Mo-Co catalyst was crushed and finely ground to -200 mesh ≥95% to obtain finely ground waste catalyst; 4.5L of water and 4g of Na2CO3 were added to the finely ground waste catalyst to mix and slurry to obtain slurry.

[0058] (2) Heat the slurry in step (1) to 85°C and mechanically emulsify it at this temperature using a high shear homogenizing emulsifier. Control the rotation speed of mechanical emulsification to 3000 rpm. During shear emulsification, continuously blow air into the slurry (the air flow rate is 60 L / h) for air flotation. After mechanical emulsification for 40 min, mechanically emulsified-air flotation slurry is obtained.

[0059] (3) The mechanical emulsification-air flotation slurry in step (2) is rapidly separated into solid and liquid while hot (the temperature of the slurry is controlled to be no less than 70°C) to obtain the de-oiled waste Mo-Co catalyst and waste liquid, wherein the de-oiling rate of the de-oiled waste Mo-Co catalyst is 99.6%.

[0060] (4) 500g of the de-oiled Mo-Co catalyst from step (3), 25g of NaOH, 75g of Na2CO3 and 1.5L of water are slurried to obtain a slurry. The slurry is added to a high-pressure reactor, the total air pressure is controlled at 4.2MPa, the temperature is controlled at 200℃, and oxygen pressure leaching is performed for 2.5h. After solid-liquid separation, oxygen pressure leaching solution and leaching residue are obtained. The volume of oxygen pressure leaching solution is 1.5L, the concentration of Mo in oxygen pressure leaching solution is 32g / L, and the leaching rate of Mo is 98.16%.

[0061] (5) Mix 200g of the leaching residue from step (4) with 300g of sulfuric acid solution (the sulfuric acid solution is prepared by 75g of concentrated sulfuric acid (98wt%) and 225g of water) to obtain the leaching solution; heat the leaching solution for acid leaching for 30min (wherein: the heating and acid leaching temperature is 102℃), and then separate the liquid and solid to obtain a cobalt-containing solution and acid leaching residue; wherein the volume of the cobalt-containing solution is 230mL, the concentration of cobalt in the cobalt-containing solution is 30.8g / L, and the cobalt leaching rate is 98.1%; the acid leaching residue is 172g, and the cobalt content in the acid leaching residue is 0.08%.

[0062] Comparative Example 1

[0063] This is basically the same as Example 1, except that no detergent is added during the slurry preparation process in step (1). Specifically:

[0064] (1) 800g of waste Mo-Co catalyst was crushed and finely ground to -200 mesh ≥95% to obtain finely ground waste catalyst; 4.5L of water was added to the finely ground waste catalyst for mixing and slurry preparation to obtain slurry.

[0065] In step (3), the deoiling rate of the deoiled waste Mo-Co catalyst was 80.2%.

[0066] In step (4), the concentration of Mo in the oxygen pressure leachate is 26.2 g / L, and the leaching rate of Mo is 80.32%.

[0067] In step (5), the concentration of cobalt in the cobalt-containing solution is 22.4 g / L, and the leaching rate of cobalt is 71.34%.

[0068] Based on the data from Comparative Example 1, the oil removal effect was significantly reduced compared to Example 1 when no detergent was added during the slurry preparation process, and the corresponding leaching effect also showed a significant decrease.

[0069] Comparative Example 2

[0070] This is essentially the same as Example 1, except that air flotation is not performed during the mechanical emulsification process in step (2). Specifically:

[0071] (2) Heat the slurry in step (1) to 85°C and mechanically emulsify it for 40 minutes at this temperature using a high-shear homogenizing emulsifier. Control the rotation speed of mechanical emulsification to 3000 rpm to obtain mechanically emulsified slurry.

[0072] In step (3), the deoiling rate of the deoiled waste Mo-Co catalyst was 76.5%;

[0073] In step (4), the concentration of Mo in the oxygen pressure leachate is 24.7 g / L, and the leaching rate of Mo is 75.73%.

[0074] In step (5), the concentration of cobalt in the cobalt-containing solution is 21.5 g / L, and the leaching rate of cobalt is 68.47%.

[0075] Based on the data from Comparative Example 2, the oil removal effect was significantly reduced compared to Example 1 when air flotation was not performed during the oil removal process, and the corresponding leaching effect also showed a significant decrease.

[0076] Comparative Example 3

[0077] This is basically the same as Example 1, except that step (2) of mechanical emulsification is replaced by mechanical stirring. Specifically:

[0078] (2) Heat the slurry in step (1) to 85°C and mechanically stir it at this temperature using a mixer. Control the speed of the mechanical mixer to 500 rpm. During stirring, continuously blow air into the slurry (the flow rate of the blown air is 60 L / h) to perform air flotation. After mechanical stirring for 40 min, mechanical emulsification-air flotation slurry is obtained.

[0079] In step (3), the deoiling rate of the deoiled waste Mo-Co catalyst is 42%.

[0080] In step (4), the concentration of Mo in the oxygen pressure leachate is 18.7 g / L, and the leaching rate of Mo is 57.33%.

[0081] In step (5), the concentration of cobalt in the cobalt-containing solution is 19.2 g / L, and the leaching rate of cobalt is 61.14%.

[0082] Based on the data from Comparative Example 3, the oil removal effect was significantly reduced compared to Example 1 when emulsification was not performed during the oil removal process, and the corresponding leaching effect also showed a significant decrease.

[0083] Example 2

[0084] The process is basically the same as in Example 1, except that in step 1), the detergent is a combination of Na2CO3 and laundry powder, that is, in step 1), 2g of Na2CO3 and 2g of laundry powder are added.

[0085] The oil removal rate in step (3) is 99.7%;

[0086] In step (4), the concentration of Mo in the oxygen pressure leachate is 32.1 g / L, and the leaching rate of Mo is 98.17%.

[0087] In step (5), the concentration of cobalt in the cobalt-containing solution is 30.83 g / L, and the leaching rate of cobalt is 98.2%.

[0088] Example 3

[0089] The process is basically the same as in Example 1, except that in step 1), the detergent is laundry powder, that is, an equal mass of laundry detergent is used instead of Na2CO3.

[0090] The oil removal rate in step (3) is 99.6%;

[0091] In step (4), the concentration of Mo in the oxygen pressure leachate is 32 g / L, and the leaching rate of Mo is 98.1%.

[0092] In step (5), the concentration of cobalt in the cobalt-containing solution is 30.79 g / L, and the leaching rate of cobalt is 98.07%.

[0093] Example 4

[0094] In this embodiment, the waste Mo-Co catalyst contains 16.2% oil, 8.2% Mo, and 2.1% Co.

[0095] (1) 800g of waste Mo-Co catalyst was crushed and finely ground to -200 mesh ≥95% to obtain finely ground waste catalyst; 4L of water, 1.2g of Na2CO3 and 1.2g of laundry detergent were added to the finely ground waste catalyst to mix and slurry to obtain slurry.

[0096] (2) Heat the slurry in step (1) to 75°C and mechanically emulsify it using a high shear homogenizer at this temperature. Control the rotation speed of mechanical emulsification to 6000 rpm. During shear emulsification, continuously blow air into the slurry (the air flow rate is 50 L / h) to perform air flotation. After mechanical emulsification for 30 min, mechanically emulsified-air flotation slurry is obtained.

[0097] (3) The mechanical emulsification-air flotation slurry in step (2) is rapidly separated into solid and liquid while hot (the temperature of the slurry is controlled to be no less than 60°C) to obtain the de-oiled waste Mo-Co catalyst and waste liquid, wherein the de-oiling rate of the de-oiled waste Mo-Co catalyst is 99.8%.

[0098] (4) 500g of the de-oiled Mo-Co catalyst from step (3), 17g of NaOH, 34g of Na2CO3 and 1.0L of water are slurried to obtain a slurry. The slurry is added to a high-pressure reactor, the total air pressure is controlled at 5MPa, the temperature is controlled at 220℃, and oxygen pressure leaching is performed for 1.5h. After solid-liquid separation, oxygen pressure leaching solution and leaching residue are obtained. The volume of oxygen pressure leaching solution is 1.0L, the concentration of Mo in oxygen pressure leaching solution is 48g / L, and the leaching rate of Mo is 98.13%.

[0099] (5) Mix 200g of the leaching residue from step (4) with 210g of sulfuric acid solution (the sulfuric acid solution is prepared by 35g of concentrated sulfuric acid (98wt%) and 175g of water) to obtain the leaching solution; after heating and acid leaching the leaching solution for 30min (the acid leaching temperature is 103℃), the liquid and solid are separated to obtain a cobalt-containing solution and acid leaching residue; the volume of the cobalt-containing solution is 180mL, the concentration of cobalt in the cobalt-containing solution is 38.77g / L, and the cobalt leaching rate is 98.04%; the acid leaching residue is 174g, and the cobalt content in the acid leaching residue is 0.08%.

[0100] Example 5

[0101] In this embodiment, the waste Mo-Co catalyst contains 16.2% oil, 8.2% Mo, and 2.1% Co.

[0102] (1) 800g of waste Mo-Co catalyst was crushed and finely ground to -200 mesh ≥95% to obtain finely ground waste catalyst; 8L of water, 8.6g of Na2CO3 and 1.0g of laundry detergent were added to the finely ground waste catalyst to mix and slurry to obtain slurry.

[0103] (2) Heat the slurry in step (1) to 95°C and mechanically emulsify it using a high shear homogenizer at this temperature. Control the rotation speed of mechanical emulsification to 1000 rpm. During shear emulsification, continuously blow air into the slurry (the air flow rate is 80 L / h) to perform air flotation. After mechanical emulsification for 60 min, mechanically emulsified-air flotation slurry is obtained.

[0104] (3) The mechanical emulsification-air flotation slurry in step (2) is rapidly separated into solid and liquid while hot (the temperature of the slurry is controlled to be no less than 80°C) to obtain the de-oiled waste Mo-Co catalyst and waste liquid, wherein the de-oiling rate of the de-oiled waste Mo-Co catalyst is 99.7%.

[0105] (4) 500g of the de-oiled Mo-Co catalyst from step (3), 25g of NaOH, 100g of Na2CO3 and 2.5L of water are slurried to obtain a slurry. The slurry is added to a high-pressure reactor, the total air pressure is controlled at 2.7MPa, the temperature is controlled at 180℃, and oxygen pressure leaching is performed for 3 hours. After solid-liquid separation, oxygen pressure leaching solution and leaching residue are obtained. The volume of oxygen pressure leaching solution is 2.5L, the concentration of Mo in oxygen pressure leaching solution is 19.27g / L, and the leaching rate of Mo is 98.49%.

[0106] (6) Mix 200g of the leaching residue from step (4) with 390g of sulfuric acid solution (the sulfuric acid solution is prepared by 130g of concentrated sulfuric acid (98wt%) and 260g of water) to obtain the leaching solution; after heating and acid leaching the leaching solution for 10min (the acid leaching temperature is 104℃), the liquid and solid are separated to obtain a cobalt-containing solution and acid leaching residue; the volume of the cobalt-containing solution is 270mL, the concentration of cobalt in the cobalt-containing solution is 25.9g / L, and the cobalt leaching rate is 98.30%; the acid leaching residue is 173g, and the cobalt content in the acid leaching residue is 0.07%.

[0107] 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 recovery of waste molybdenum-cobalt catalyst, characterized in that, Includes the following steps: (1) Fine grinding and slurry preparation: The Co-Mo waste catalyst is crushed and finely ground to obtain finely ground waste catalyst; water and detergent are added to the finely ground waste catalyst to mix and slurry to obtain slurry; (2) Mechanical emulsification-air flotation: After heating the slurry in step (1) to a set temperature, shear emulsification is performed at the set temperature. During the shear emulsification process, gas is continuously introduced for air flotation to obtain the emulsified-air flotation slurry; wherein: the rotation speed of shear 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 solid-liquid separation to obtain de-oiled waste catalyst and waste liquid; (4) Oxygen pressure leaching: Add leaching agent and water to the deoiled waste catalyst in step (3) to make slurry and obtain secondary slurry; pass oxygen-containing gas into the secondary slurry to perform oxygen pressure leaching and obtain oxygen pressure leaching solution and leaching residue. (5) Acid leaching: Add concentrated sulfuric acid and water to the leaching residue in step (4) to obtain the leaching solution to be leached. Heat the leaching solution to obtain a cobalt-containing solution and acid leaching residue.

2. The method for wet recovery of waste molybdenum-cobalt catalyst according to claim 1, characterized in that, In step (1), the detergent is Na2CO3 and / or laundry powder; the amount of detergent added is 0.3~1.2% of the mass of the finely ground waste catalyst; the mass ratio of the finely ground waste catalyst to water is 1:(5~10).

3. The method for wet recovery of waste molybdenum-cobalt catalyst according to claim 2, characterized in that, The detergent is composed of Na2CO3 and laundry powder, with a mass ratio of sodium carbonate to laundry powder of (0.2~1):(0.1~0.3).

4. The method for wet recovery of spent molybdenum-cobalt catalyst according to any one of claims 1 and 2, characterized in that, In step (2), the temperature is set to 75~95℃; the shearing emulsification time is 30~60min; and the gas is one or more of air, nitrogen, oxygen, and argon.

5. The method for wet recovery of waste molybdenum-cobalt 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 no less than 60°C and less than the set temperature in step (2).

6. The method for wet recovery of waste molybdenum-cobalt catalyst according to claim 1, characterized in that, In step (4), the leaching agent is a combination of NaOH and Na2CO3, with a mass ratio of NaOH to Na2CO3 of 1:(2~4); the amount of leaching agent added is 10~30% of the mass of the deoiled waste catalyst; the mass ratio of water to the deoiled waste catalyst is (2~5):1; the oxygen pressure leaching solution is used to recover molybdenum.

7. The method for wet recovery of spent molybdenum-cobalt catalyst according to any one of claims 1 and 6, characterized in that, In step (4), the oxygen-containing gas is air or oxygen; the oxygen pressure leaching pressure is 2.7~5MPa, the oxygen pressure leaching temperature is 180~220℃, and the oxygen pressure leaching time is 1.5~3h.

8. The method for wet recovery of waste molybdenum-cobalt catalyst according to claim 1, characterized in that, In step (5), the mass ratio of concentrated sulfuric acid to water is 1:(2~5); the liquid-solid mass ratio of the leaching solution is (1~2):1; and the cobalt-containing solution is used to recover cobalt.

9. The method for wet recovery of spent molybdenum-cobalt catalyst according to any one of claims 1 and 8, characterized in that, In step (5), the temperature of the acid leaching is 100~104℃; the time of the acid leaching is 10~40min.

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