Recovery method for active metal of waste hydrogenation catalyst

Abstract

The invention provides a method for recovering active metals from a waste hydrogenation catalyst. The method comprises the following steps: step 1, roasting and grinding the waste hydrogenation catalyst; step 2, mixing and leaching ammonia water, a complexing agent and the waste hydrogenation catalyst obtained in the step 1; and step 3, carrying out solid-liquid separation on the mixture obtained in the step 2, wherein the obtained liquid is an alkaline complexing solution containing active metal. According to the waste hydrogenation catalyst active metal recovery method, substances such as strong acid and strong alkali are not used, the influence on equipment and the environment is small, and through the synergistic effect of the ammonia water and the complexing agent, the leaching time is short, and the metal leaching rate is high.

Description

Technical Field

[0001] The present invention relates to a method for recovering active metals from spent hydrogenation catalysts. Background Art

[0002] With the continuous improvement of global refining capacity, the consumption of hydrogenation catalysts has been growing steadily. Commonly used hydrogenation catalysts include Mo-Ni, Mo-Co, W-Ni, Mo-Ni-Co systems, etc. Under the action of hydrogenation catalysts, desulfurization, denitrogenation, deoxidation, demetallization and conversion of heavy oil into light fractions are achieved, and the quality and output of oil products are improved. Catalysts cannot be used permanently. As the use time increases, the properties of the catalysts will change due to chemical poisoning, loss of active metals, heavy metal deposition, etc., and the activity will gradually decrease, and in severe cases, the activity will be lost. This permanent deactivation is difficult to restore activity through regeneration treatment. About 750,000 tons of waste hydrogenation catalysts are produced worldwide each year. Waste hydrogenation catalysts are hazardous wastes (HW50 category), and heavy metals and other substances will cause harm to the environment. However, the strategic metals such as Mo, W, Ni, Co, and V in waste hydrogenation catalysts are much higher in grade than the original ore and are important secondary resources. How to recover the valuable metals of waste catalysts in a green and economical way is a hot topic and difficulty in current research.

[0003] In the prior art, the methods for recovering spent hydrogenation catalysts mainly include wet leaching, roasting-leaching and pyrometallurgical enrichment.

[0004] Patent CN114231733A discloses a metal recovery process based on a hydrogenation catalyst, which includes oxidative roasting followed by the use of NaOH or Na 2 CO 3 Molybdenum and vanadium are leached out, the filter residue solid is leached with sulfuric acid, and nickel and cobalt are recovered from the liquid.

[0005] Patent CN109652649B discloses a method for improving the recovery rate of cobalt and molybdenum from spent catalysts, wherein the cobalt and molybdenum are recovered by leaching the spent cobalt-molybdenum-based hydroprocessing catalyst with an acid solution, wherein the acid solution contains hydrofluoric acid.

[0006] Patent CN102041388B discloses a method for recovering metals from waste catalysts containing molybdenum and nickel. The waste catalyst is calcined, then mixed with an alkaline substance and calcined. It is then leached with a mixed acid (acid solution containing sulfuric acid, nitric acid and citric acid), and ammonium molybdate is precipitated by adding ammonia water. Alkaline substances are added to obtain aluminum hydroxide, which is filtered and separated. Alkaline substances are added to obtain nickel precipitates, which are dissolved in sulfuric acid and concentrated and crystallized to obtain nickel sulfate.

[0007] Patent CN100347318C discloses a method for separating and recovering cobalt and molybdenum from waste cobalt-molybdenum catalysts. The waste cobalt and molybdenum catalyst powders that have been calcined and crushed are first dissolved with concentrated hydrochloric acid, and then the molybdenum and cobalt phases are extracted respectively with an extractant. Concentrated hydrochloric acid is also used in the washing and stripping processes.

[0008] Patent CN102050492B discloses a method for recovering metals from molybdenum-containing waste catalysts, including sodium calcination of the waste catalysts, water leaching to obtain a sodium molybdate solution, adding sulfuric acid to adjust the pH to 0.5 (sulfuric acid solution), then using an organic extractant to obtain an ammonium molybdate solution, and adjusting the pH to 1 to 4 (nitric acid solution) with nitric acid, and separating to obtain an ammonium molybdate precipitate. The above sulfuric acid solution and nitric acid solution are added with a mixed acid solution of an organic acid to leaching the solid phase filter residue after water leaching, and finally precipitating with ammonia water to obtain ammonium molybdate.

[0009] In the above-mentioned waste catalyst recovery method, in order to achieve a better metal recovery rate, it is inevitable to use strong acid / strong alkali to increase the leaching rate, or use strong acid for pH adjustment to achieve a better target precipitation effect. However, the use of strong acid / strong alkali brings many problems and influences to the production process. For example, the use of strong acid has a higher degree of harshness on production equipment. For key equipment and pipelines, enterprises must use more expensive corrosion-resistant materials. The strong corrosiveness, irritation and danger of dangerous chemicals such as strong acids and strong alkalis bring more risks to the health and safety of production personnel, and the difficulty of operation and preventive measures are increased at the same time. The discharge and treatment of a large amount of waste acid and waste alkali bring a certain economic burden to the enterprise. In addition, the use of strong acid also brings about the dissolution of part of the alumina carrier. In order to purify the active component compounds in the subsequent process, extraction and stripping, repeated dissolution and precipitation steps are added, which makes the waste catalyst recovery process more time-consuming and complicated, and the processing cost is high, which brings inconvenience to the industrial recovery process. If weak bases such as ammonia, ammonium carbonate, sodium carbonate, or weak acid-strong base salts are used instead, the leaching time will be as long as 3 to 4 hours, and the leaching rate will be low. A small amount of Mo will enter the filter residue, affecting the recovery of alumina and increasing the separation cost.

[0010] How to recycle spent hydrogenation catalysts in a greener, lower-cost and more efficient way is of great significance. Summary of the invention

[0011] The main purpose of the present invention is to provide a method for recovering active metals from spent hydrogenation catalysts, so as to overcome the problems of using strong acids and alkalis and low metal recovery rates in the prior art process for recovering active metals from spent hydrogenation catalysts.

[0012] In order to achieve the above object, the present invention provides a method for recovering active metals from spent hydrogenation catalysts, comprising the following steps:

[0013] Step 1, calcining and grinding the spent hydrogenation catalyst;

[0014] Step 2, mixing ammonia water and a complexing agent to leach the waste hydrogenation catalyst obtained in step 1;

[0015] Step 3, separating the mixture obtained in step 2 into solid and liquid, and the obtained liquid is an alkaline complex solution containing active metals.

[0016] The method for recovering active metals from waste hydrogenation catalysts of the present invention further comprises:

[0017] Step 4: impregnating a fresh carrier with the alkaline complex solution containing active metals, and then aging, drying and calcining to obtain a fresh hydrogenation catalyst.

[0018] The method for recovering active metals from waste hydrogenation catalysts of the present invention comprises the following steps: the calcination temperature in step 1 is 500-600° C. and the calcination time is 2-4 hours; the particle size of the waste hydrogenation catalyst after grinding is 60-100 meshes, and a smaller particle size is conducive to the leaching of active metals.

[0019] In the method for recovering active metals from waste hydrogenation catalysts of the present invention, the complexing agent is at least one of ethylenediaminetetraacetic acid (EDTA), aminotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol ditetraacetic acid (EGTA), ethylenediaminediacetic acid (EDDHA), cyclohexanediaminetetraacetic acid (CDTA), and citric acid (CA).

[0020] The method for recovering active metals from waste hydrogenation catalysts of the present invention comprises the following steps: the mass ratio of the aqueous ammonia to the waste hydrogenation catalyst is 5:1 to 1:1; the mass ratio of the complexing agent to the waste hydrogenation catalyst is 0.3:1 to 1:1; and the concentration of the aqueous ammonia is 25-28wt%.

[0021] In the method for recovering active metals from spent hydrogenation catalysts of the present invention, the leaching temperature in step 2 is 50-80° C., and the leaching time is 1-5 hours.

[0022] The method for recovering active metals from spent hydrogenation catalysts of the present invention, wherein the active metal of the spent hydrogenation catalyst is at least one of molybdenum, cobalt and nickel.

[0023] The method for recovering active metals from spent hydrogenation catalysts of the present invention comprises the following steps: before impregnating a fresh carrier with the alkaline complex solution containing active metals, a molybdenum precursor, a cobalt precursor and / or a nickel precursor and / or ammonia water are added to the alkaline complex solution.

[0024] The method for recovering active metals from waste hydrogenation catalysts of the present invention, wherein in step 4, the aging time is 1-24 hours, the drying temperature is 100-150° C., the drying time is 2-6 hours, the roasting temperature is 400-600° C., and the roasting time is 2-6 hours.

[0025] The method for recovering active metals from spent hydrogenation catalysts of the present invention comprises the following steps: the alkaline complex solution containing active metals is concentrated or diluted before impregnating a fresh carrier.

[0026] Beneficial effects of the present invention:

[0027] The present invention uses ammonia water and a complexing agent to work synergistically. Ammonia water can promote and accelerate the stripping and dissolution of the target metal from the carrier to form metal ions; the complexing agent has molecules, atoms or ionic compounds that can be used to coordinate lone electron pairs, and can form coordination bonds with metal ions with empty orbitals. In addition, under the combined action of the complexing agent and the composite leaching agent formed by the complexing agent and the ammonia water, the ammonia water provides solvent conditions for the diffusion and liberation of the complex. The metal that is difficult to leach using ammonia water alone is surrounded by the lone pair of electrons of the complex in this alkaline solution. The alkaline environment accelerates the complexing action, realizes the chelation / coordination of more metal ions, and then realizes the effect of efficient metal leaching. In addition, the stable alkaline complexing solution formed by the composite of the ammonia water and the complexing agent of the present invention can effectively improve the stability of the metal leaching solution and avoid the precipitation, precipitation and other solution re-condensation phenomena of the leaching solution.

[0028] Furthermore, the cobalt and molybdenum complex solution obtained by the present invention is not separated, thereby reducing the cumbersome processes such as extraction and multiple precipitation, and is directly used for the preparation of fresh hydrogenation catalyst, which greatly reduces and simplifies the treatment process of heavy metal-containing waste liquid. At the same time, it is connected with the preparation process of fresh hydrogenation catalyst, eliminating the process of dissolving and preparing the solution with the precursor, and has the advantages of reasonable technical route, operability, strong economy, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure is a schematic diagram of the process flow for recovering active metals from spent hydrogenation catalysts according to one embodiment of the present invention.

[0030] Figure 2 The XRD diagrams of the fresh hydrogenation catalyst A and the fresh hydrodesulfurization catalyst E obtained in Example 1 of the present invention are shown. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following implementation modes. The structures or experimental methods of specific conditions are not specified in the following implementation modes, and generally conventional conditions are followed.

[0032] The present invention provides a method for recovering active metals from spent hydrogenation catalysts. Figure 1 As shown, the following steps are included:

[0033] Step 1, calcining and grinding the spent hydrogenation catalyst;

[0034] Step 2, mixing ammonia water and a complexing agent to leach the waste hydrogenation catalyst obtained in step 1;

[0035] Step 3, separating the mixture obtained in step 2 into solid and liquid, and the obtained liquid is an alkaline complex solution containing active metals.

[0036] The present invention uses ammonia water and a complexing agent to work synergistically. Ammonia water can promote and accelerate the stripping and dissolution of the target metal from the carrier to form metal ions; the complexing agent has molecules, atoms or ionic compounds that can be used to coordinate lone electron pairs, and can form coordination bonds with metal ions with empty orbitals. In addition, under the combined action of the complexing agent and the composite leaching agent formed by the complexing agent and the ammonia water, the ammonia water provides solvent conditions for the diffusion and liberation of the complex. The metal that is difficult to leach using ammonia water alone is surrounded by the lone pair of electrons of the complex in this alkaline solution. The alkaline environment accelerates the complexing action, realizes the chelation / coordination of more metal ions, and then realizes the effect of efficient metal leaching. Furthermore, the stable complexing solution formed by the composite of the ammonia water and the complexing agent of the present invention can effectively improve the stability of the metal leaching solution and avoid the precipitation, precipitation and other solution re-condensation phenomena of the leaching solution.

[0037] The method for recovering active metals from waste hydrogenation catalysts does not use substances such as strong acids and strong bases, has little impact on equipment and the environment, and has a short leaching time and a high metal leaching rate through the synergistic effect of ammonia water and a complexing agent.

[0038] In one embodiment, if Figure 1 As shown, the method for recovering active metals from spent hydrogenation catalysts of the present invention further comprises: step 4, impregnating a fresh carrier with the alkaline complex solution containing active metals, and then aging, drying and roasting to obtain a fresh hydrogenation catalyst.

[0039] In this way, the present invention directly uses the alkaline complex solution containing active metals for the preparation of fresh hydrogenation catalysts, eliminating the subsequent complex purification process, and can achieve separation of carriers and metals at low cost to obtain efficient fresh hydrogenation catalysts, greatly improving the economy and ease of operation of the industrial recovery process.

[0040] The present invention does not specifically limit the spent hydrogenation catalyst, which is generally a supported catalyst. The active metal is, for example, molybdenum, cobalt, nickel and the like, and the carrier is, for example, alumina. The active metal is generally supported on the carrier in the form of a stable metal oxide or metal sulfide oxide. The present invention does not specifically limit the oil product previously treated by the spent hydrogenation catalyst, for example, it was used for gasoline hydrogenation treatment.

[0041] The waste hydrogenation catalyst of the present invention is first roasted to remove sulfur, carbon, etc. In one embodiment, the roasting temperature is 500-600°C, the roasting time is 2-4 hours, and the roasting is carried out in air. The roasting treatment realizes the removal of a large amount of carbon and sulfur compounds in the waste hydrogenation catalyst. The spent hydrogenation catalyst after roasting is crushed and ground. In one embodiment, the particle size of the ground spent hydrogenation catalyst is 60-100 mesh, and a smaller particle size is conducive to metal leaching.

[0042] Step 2 of the present invention is: mixing ammonia water and a complexing agent to leach the waste hydrogenation catalyst obtained in step 1.

[0043] In one embodiment, the complexing agent is at least one of citric acid (CA), ethylenediaminetetraacetic acid (EDTA), aminotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol ditetraacetic acid (EGTA), ethylenediaminediacetic acid (EDDHA), and cyclohexanediaminetetraacetic acid (CDTA). The mass ratio of ammonia water to the spent hydrogenation catalyst is 5:1 to 1:1; the mass ratio of the complexing agent to the spent hydrogenation catalyst is 0.3:1 to 1:1. Preferably, the concentration of ammonia water is 25-28wt%.

[0044] In another embodiment, the present invention first mixes ammonia water and a complexing agent to form a stable complexing solution, and then leaches the spent hydrogenation catalyst. Preferably, the pH value of the solution obtained after mixing ammonia water and a complexing agent is 10-12.

[0045] In the present invention, "leaching" refers to mixing a complex solution formed by ammonia water and a complexing agent with the spent hydrogenation catalyst to leach active metals on the spent hydrogenation catalyst. In one embodiment, the leaching temperature is 50-80° C., and the leaching time is 1-5 hours, for example, 3 hours. Stirring is performed continuously during the leaching process.

[0046] Step 3 of the present invention is: subjecting the mixture obtained in step 2 to solid-liquid separation, and the obtained liquid is an alkaline complex solution containing active metals.

[0047] The present invention does not particularly limit the method of solid-liquid separation of the mixture obtained in step 2, for example, filtering. After solid-liquid separation, the obtained solid is mainly a carrier of the spent hydrogenation catalyst, and the obtained liquid is an alkaline complex solution containing active metals, which can be recycled.

[0048] In one embodiment, the solid obtained in step 3 of the present invention can be leached again, that is, the solid is mixed with ammonia water and a complexing agent for leaching again to improve the leaching rate of active metals. The present invention does not particularly limit the number of times the solid is leached again, for example, 0, 1, 2, 3, or 4 times.

[0049] In one embodiment, the method for recovering active metals from spent hydrogenation catalysts of the present invention further comprises step 4, impregnating a fresh carrier with the alkaline complex solution containing active metals, and then aging, drying and calcining to obtain a fresh hydrogenation catalyst.

[0050] The present invention does not particularly limit the method of impregnating the fresh carrier with the alkaline complex solution containing active metals, and it can be equal volume impregnation, excessive impregnation, etc. In another embodiment, the alkaline complex solution containing active metals is supplemented with active metal precursors such as molybdenum precursor, cobalt precursor, nickel precursor, etc., and then the fresh carrier is impregnated. In another embodiment, the alkaline complex solution containing active metals is supplemented with ammonia water as needed. In another embodiment, the alkaline complex solution containing active metals of the present invention is concentrated or diluted, and then the fresh carrier is impregnated to meet the water absorption rate requirement of the fresh carrier.

[0051] In one embodiment, the alkaline complex solution containing active metals obtained in step 3 of the present invention and the liquid obtained by re-leaching the solid are used to impregnate a fresh support together, or the fresh support is impregnated in steps.

[0052] The present invention does not particularly limit the aging, drying and calcination processes in the process of preparing fresh hydrogenation catalyst. In one embodiment, the aging time is 1-24 hours, the aging temperature is, for example, room temperature 20-30°C, the drying temperature is 100-150°C, the drying time is 2-6 hours, the calcination temperature is 400-600°C, and the calcination time is 2-6 hours.

[0053] The present invention uses ammonia water and a complexing agent as a compound leaching agent to leach catalyst metals such as molybdenum and cobalt, thereby avoiding the use of strong acids and strong bases, thereby lowering the material requirements for equipment, and equipment of general materials can be used without the need for corrosion protection.

[0054] The alkaline complex solution containing active metals obtained by the present invention does not separate cobalt and molybdenum metals, but directly impregnates a fresh carrier, thereby reducing cumbersome processes such as extraction and multiple precipitations, and omitting the process of dissolving a precursor and preparing an impregnation solution, making the process simpler and more time-saving, while saving processing costs.

[0055] The process of the present invention has good economic efficiency and recyclability, and realizes the recovery and reuse of metal resources. Catalyst production enterprises save the cost of waste catalyst treatment, and at the same time greatly reduce the purchase cost of active metal precursors, thereby greatly reducing the production cost of catalysts.

[0056] In summary, the metal components of the waste hydrogenation catalyst have been calcined to form stable metal oxides or metal sulfide oxides, which are difficult to react directly with the complexing agent. The present invention uses ammonia water and a complexing agent to act synergistically. Ammonia water can promote the stripping and dissolution of metal oxides from the carrier to form metal ions; the complexing agent contains a ligand with two or more coordinated atoms, which reacts with metal ions to generate a complex with a ring structure. The complexing agent is easily soluble in ammonia water and the coordination reaction is relatively rapid in the alkaline environment provided by ammonia water. It can form divalent and trivalent metal chelates with alkaline earth metals, rare earth elements and transition metal ions, and the stability of the complex is high. Therefore, the present invention uses ammonia water and a complexing agent to recover the active metals of the hydrogenation catalyst, with a short leaching time and a high leaching rate.

[0057] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0058] Example 1

[0059] 150g of waste gasoline hydrodesulfurization catalyst was roasted at 550℃ for 2h to remove sulfur and carbon, and then crushed to 20-40 mesh. The cobalt and molybdenum contents (by weight of oxides) were analyzed to be 1.7% and 12.2% respectively, and the weight content of carrier alumina was about 86.1%. Take 100g of crushed waste catalyst sample and place it in a reactor. Take 500ml of ammonia water with a concentration of 25-28wt% (the ammonia concentration used in the following examples is the same as that in this example) and 100g of ethylenediaminetetraacetic acid (EDTA), mix and stir to dissolve, and measure the pH value to be 12, and add them to the above reactor. Turn on stirring, heat the reactor to 80℃, stir for 5h, and then stop stirring. The mixture in the reactor was filtered and separated, and the filtrate was an alkaline complex solution of cobalt and molybdenum. After the catalyst residue was dried at 120℃, the cobalt and molybdenum contents were analyzed, and the cobalt and molybdenum metal recovery rates were 86% and 93% respectively.

[0060] 87.2 g of fresh alumina carrier was taken, and the water absorption was measured to be 70%. The metal complex liquid was evaporated and concentrated to 61.0 ml, and the fresh alumina carrier was impregnated. After aging for 1 hour, drying at 100°C for 6 hours, and calcining in a muffle furnace at 550°C for 2 hours, a fresh hydrogenation catalyst A was obtained. The composition thereof was analyzed, and the cobalt and molybdenum contents (by weight of oxides) were 1.5% and 11.3% respectively.

[0061] Example 2

[0062] 150g of waste gasoline hydrodesulfurization catalyst was roasted at 600℃ for 3h to remove sulfur and carbon, and then crushed to 20-40 mesh. The cobalt and molybdenum contents (by weight of oxides) were analyzed to be 1.9% and 12.5% ​​respectively, and the weight content of carrier alumina was about 85.6%. Take 100g of crushed waste catalyst sample and place it in a reactor. Take 300ml of ammonia water and 70g of ethylenediaminetetraacetic acid (EDTA), mix and stir to dissolve, and measure the pH value to be 11, and add it to the above reactor. Turn on the stirring, heat the reactor to 60℃, stir for 4h, and then stop stirring. The mixed solution in the reactor is filtered and separated, and the filtrate is "cobalt and molybdenum alkaline complex solution one", completing the first leaching. Put the filter residue into the reactor again, put into a mixed solution of 300ml of ammonia water and 70g of diethylenetriamine pentatriacetic acid (DTPA), heat the reactor to 80℃, stir for 5h, and then filter and separate the solution in the reactor, and the filtrate is "cobalt and molybdenum alkaline complex solution two". After the catalyst residue was dried at 120°C, the cobalt and molybdenum contents were analyzed, and the cobalt and molybdenum metal recoveries were 96% and 98% respectively.

[0063] Take 85.9g of fresh alumina carrier, and measure the water absorption rate to be 70%. Evaporate and concentrate "cobalt and molybdenum alkaline complex solution 1" to 60.1ml, perform one impregnation, age for 12h, dry at 120℃ for 4h, and roast at 600℃ for 4h to obtain a fresh gasoline hydrodesulfurization catalyst semi-finished product. The water absorption rate of the catalyst semi-finished product is 60%, evaporate and concentrate "cobalt and molybdenum alkaline complex solution 2", perform two impregnations, age for 12h, dry at 120℃ for 4h, and roast at 600℃ for 4h to obtain a fresh gasoline hydrodesulfurization catalyst B, and analyze its cobalt and molybdenum contents to be 1.8% and 12.3% respectively.

[0064] Example 3

[0065] 150g of waste gasoline hydrodesulfurization catalyst was roasted at 500℃ for 4h to remove sulfur and carbon, and then crushed to 20-40 mesh. The cobalt and molybdenum contents (by weight of oxides) were analyzed to be 1.3% and 11.8% respectively, and the weight content of carrier alumina was about 86.9%. Take 100g of crushed waste catalyst sample and place it in a reactor. Take 100ml of ammonia water and 30g of ethylenediaminediacetic acid (EDDHA), mix and stir to dissolve, and measure the pH value to be 10, and add it to the above reactor. Turn on stirring, heat the reactor to 50℃, stir for 3h, and then stop stirring. The mixed liquid in the reactor was filtered and separated, and the filtrate was an alkaline complex solution of cobalt and molybdenum. After the catalyst residue was dried at 120℃, the cobalt and molybdenum contents were analyzed, and the cobalt and molybdenum metal recovery rates were 84% and 90% respectively.

[0066] To prepare a fresh catalyst for gasoline hydrodesulfurization with a cobalt oxide content of 3wt% and a molybdenum oxide content of 15wt%, 82g of fresh alumina carrier was taken, and the water absorption rate was measured to be 70%. The cobalt and molybdenum alkaline complex solution was evaporated and concentrated to 57.4ml. 6.84g of chemically pure cobalt nitrate hexahydrate and 4.70g of ammonium molybdate tetrahydrate were added to the above complex solution, stirred and dissolved, and then impregnated with the above fresh alumina carrier, aged for 24h, dried at 150℃ for 2h, and calcined in a muffle furnace at 500℃ for 6h to obtain a fresh catalyst C for gasoline hydrodesulfurization. The cobalt and molybdenum contents were 3.1% and 15.0% respectively.

[0067] Example 4

[0068] The same as Example 1, except that the waste gasoline hydrodesulfurization catalyst is a nickel and molybdenum catalyst. The nickel and molybdenum contents (by weight of oxides) are analyzed to be 1.7% and 12.2% respectively. The nickel and molybdenum metal recovery rates are 85% and 93%. A fresh hydrogenation catalyst D is obtained and its composition is analyzed. The nickel and molybdenum contents (by weight of oxides) are 1.4% and 11.3%.

[0069] Comparative Example 1

[0070] 150g of waste gasoline hydrodesulfurization catalyst was roasted at 550℃ for 4h to remove sulfur and carbon, and then crushed to 20-40 mesh. The cobalt and molybdenum contents (by weight of oxides) were analyzed to be 1.7% and 12.2% respectively, and the weight content of carrier alumina was about 86.1%. Take 100g of crushed waste catalyst sample and place it in a reactor. Take 500ml of ammonia water with a concentration of 25-28wt% and add it to the above reactor. Turn on stirring, heat the reactor to 80℃, stir for 5h, and then stop stirring. The mixed liquid in the reactor was filtered and separated, and the filtrate was a cobalt and molybdenum solution. After the catalyst residue was dried at 120℃, the cobalt and molybdenum contents were analyzed, and the cobalt and molybdenum metal recovery rates were 56.4% and 74.3% respectively.

[0071] Comparative Example 2

[0072] 150g of waste gasoline hydrodesulfurization catalyst was roasted at 550℃ for 4h to remove sulfur and carbon, and then crushed to 20-40 mesh. The cobalt and molybdenum contents (by weight of oxides) were analyzed to be 1.7% and 12.2% respectively, and the weight content of carrier alumina was about 86.1%. Take 100g of crushed waste catalyst sample and place it in a reactor. Take 100g of EDTA and dissolve it in 500ml of water, stir and dissolve it, and then add it to the above reactor. Turn on the stirring, heat the reactor to 80℃, stir for 5h, and then stop stirring. The mixed liquid in the reactor was filtered and separated, and the filtrate was a cobalt and molybdenum solution. After the catalyst residue was dried at 120℃, the cobalt and molybdenum contents were analyzed, and the cobalt and molybdenum metal recovery rates were 61.5% and 63.2% respectively.

[0073] Figure 2The XRD diagrams of the fresh hydrogenation catalyst A and the fresh hydrodesulfurization catalyst E obtained in Example 1 of the present invention are shown. Figure 2 The XRD diffraction peaks (220), (311), (222), (400), (511), and (400) shown are all attributed to the characteristic peaks of alumina. The characteristic peaks of active metals cobalt and molybdenum are not detected in the fresh hydrogenation catalyst A and the fresh hydrodesulfurization catalyst E, indicating that the active metals are highly dispersed on the carrier, and the catalyst prepared by the complex solution obtained by the active metal recovery method of the present invention has structural characteristics comparable to those of the fresh hydrogenation catalyst.

[0074] Among them, the fresh hydrodesulfurization catalyst E is a fresh hydrodesulfurization catalyst prepared in a conventional manner, and the cobalt and molybdenum contents are 1.5% and 11.0% by weight of oxides, that is, it is obtained by impregnating a fresh carrier with fresh cobalt and molybdenum precursors, and the active metals are not recovered.

[0075] In a 20 mL micro-reactor, the desulfurization activity of fresh hydrogenation catalysts AD prepared in Examples 1-4 and fresh hydrodesulfurization catalyst E prepared by a conventional method (cobalt and molybdenum contents were 1.5% and 11.0% by weight of oxides) was evaluated. The hydrogenation temperature was 270°C, the pressure was 2.0 MPa, and the space velocity was 3.0 h -1 , hydrogen to oil ratio is 300, sulfurized oil contains 2wt% CS 2 The raw material oil is catalytic heavy gasoline from a petrochemical company. The raw material properties are shown in Table 1. The evaluation conditions are shown in Table 2. The evaluation results are shown in Table 3.

[0076] Table 1 Properties of Catalytic Heavy Gasoline Raw Materials of a Petrochemical Company

[0077]

[0078]

[0079] Table 2 Catalyst evaluation conditions

[0080]

[0081] Table 3 Hydrodesulfurization activity evaluation results

[0082]

[0083] As shown in Table 3, the fresh hydrogenation catalysts AD prepared by recovering the active metals of the waste hydrogenation catalysts in Examples 1-4 of the present invention have a comparable hydrogenation effect to the fresh catalysts prepared by using fresh carriers and fresh active metal precursors, and the small amount of impurities doped in the recovered active metals of the waste catalysts has almost no effect on the hydrogenation effect of the catalysts.

[0084] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for recovering active metals from spent hydrogenation catalysts, characterized in that: The steps include: Step 1, calcining and grinding the spent hydrogenation catalyst; Step 2, mixing ammonia water and a complexing agent to leach the waste hydrogenation catalyst obtained in step 1; Step 3, separating the mixture obtained in step 2 into solid and liquid, and the obtained liquid is an alkaline complex solution containing active metals.

2. The method for recovering active metals from spent hydrogenation catalysts according to claim 1, characterized in that: Also includes: Step 4: impregnating a fresh carrier with the alkaline complex solution containing active metals, and then aging, drying and calcining to obtain a fresh hydrogenation catalyst.

3. The method for recovering active metals from spent hydrogenation catalysts according to claim 1, characterized in that: The calcination temperature of step 1 is 500-600° C., and the calcination time is 2-4 hours; the particle size of the spent hydrogenation catalyst after grinding is 60-100 mesh.

4. The method for recovering active metals from spent hydrogenation catalysts according to claim 1, characterized in that: The complexing agent is at least one of citric acid (CA), ethylenediaminetetraacetic acid (EDTA), aminotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol ditetraacetic acid (EGTA), ethylenediaminediacetic acid (EDDHA), and cyclohexanediaminetetraacetic acid (CDTA).

5. The method for recovering active metals from spent hydrogenation catalysts according to claim 1, characterized in that: The mass ratio of the aqueous ammonia to the spent hydrogenation catalyst is 5:1 to 1:1; the mass ratio of the complexing agent to the spent hydrogenation catalyst is 0.3:1 to 1:1; and the concentration of the aqueous ammonia is 25-28 wt%.

6. The method for recovering active metals from spent hydrogenation catalysts according to claim 1, characterized in that: The leaching temperature in step 2 is 50-80° C., and the leaching time is 1-5 hours. In step 2, the pH value of the solution obtained after mixing the ammonia water and the complexing agent is 10-12.

7. The method for recovering active metals from spent hydrogenation catalysts according to claim 1, characterized in that: The active metal of the spent hydrogenation catalyst is at least one of molybdenum, cobalt and nickel.

8. The method for recovering active metals from spent hydrogenation catalysts according to claim 2, characterized in that: Before the fresh carrier is impregnated with the alkaline complex solution containing the active metal, a molybdenum precursor, a cobalt precursor and / or a nickel precursor is added, and / or ammonia water is added.

9. The method for recovering active metals from spent hydrogenation catalysts according to claim 2, characterized in that: In step 4, the aging time is 1-24 hours, the drying temperature is 100-150° C., the drying time is 2-6 hours, the calcination temperature is 400-600° C., and the calcination time is 2-6 hours.

10. The method for recovering active metals from spent hydrogenation catalysts according to claim 2, characterized in that: The alkaline complex solution containing the active metal is concentrated or diluted before impregnating the fresh support.

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