Method for preparing vanadyl sulfate electrolyte by using waste residue oil hydrogenation catalyst

Abstract

The present invention belongs to the field of recovery of waste residue oil hydrogenation catalysts, and particularly relates to a method for preparing vanadyl sulfate electrolyte by using waste residue oil hydrogenation catalysts. The method uses waste residue oil hydrogenation catalysts as raw materials, and prepares high-purity vanadyl sulfate solution through the preparation process of "calcination - leaching - impurity removal - reduction - extraction - back extraction". On the one hand, it solves the problem of solid waste treatment. On the other hand, by using the solvent extraction method, vanadium is selectively recovered from high-concentration vanadium-containing solutions, greatly reducing the production cost. The obtained vanadyl sulfate solution has high purity, few impurities and high production efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of recovery of waste residue oil hydrogenation catalysts, and particularly relates to a method for preparing vanadyl sulfate electrolyte by using waste residue oil hydrogenation catalysts. Background Art

[0002] The preparation methods of vanadyl sulfate solution mainly include chemical synthesis method, electrolysis method, solvent extraction method, etc.: (1) The chemical synthesis method uses vanadium oxide or vanadium salt as raw materials, dissolves them in sulfuric acid solution, adds a reducing agent, and reduces them by high-temperature heating to prepare vanadium electrolytes with different concentrations and valence states. (2) The electrolysis method uses V2O5 or metavanadate as raw materials, adds vanadium-containing raw materials to the sulfuric acid solution in the negative electrode electrolytic cell, adds H2SO4 with the same concentration to the positive electrode electrolytic cell, connects the two poles of the battery to a DC power supply, and V2O5 or metavanadate is reduced on the surface of the negative electrode to obtain a low-valence vanadium solution. (3) The solvent extraction method uses a vanadium-containing solution as the extraction stock solution, such as stone coal leaching solution, vanadium-titanium magnetite leaching solution, vanadium-containing wastewater, etc. According to the extraction selectivity of different extractants for different metals, high-purity and high-concentration vanadium electrolytes are prepared under comprehensive conditions such as extraction, washing, and back-extraction.

[0003] The above-mentioned common preparation methods have the following disadvantages. For example, in the chemical reduction method, the solid dissolution rate is slow, the production volume per time is small, it is difficult to eradicate the addition of reducing agents such as oxalic acid, and polluting gases such as CO2, SO2, and Cl2 will also be generated. The electrolysis method has high requirements for the purity of raw materials and the performance of electrodes, low production efficiency, high cost, and huge energy consumption, and currently cannot meet the requirements of industrial large-scale production. The solvent extraction method requires multi-stage extraction, the process is complex, the volume ratio of the organic phase to the aqueous phase is high during extraction, and the volume ratio of the organic phase to the aqueous phase is low during back-extraction, resulting in low production efficiency. Summary of the Invention

[0004] Based on the above technical background, the main purpose of the present invention is to provide a method for preparing vanadyl sulfate electrolyte by using waste residue oil hydrogenation catalysts to overcome the deficiencies in the prior art.

[0005] To achieve the foregoing invention purpose, the technical solutions adopted by the present invention include:

[0006] The present invention provides a method for preparing vanadyl sulfate electrolyte by using waste residue oil hydrogenation catalysts, and the method includes the following steps:

[0007] Step 1: Oxidatively roast the waste residue oil hydrogenation catalyst, then mix it with soda ash and dry it, then carry out sodium roasting, add water to leach the sodium roasted material to obtain a vanadium-molybdenum-containing leaching solution;

[0008] Step 2: Filter and wash the vanadium-molybdenum-containing leaching solution, then adjust the pH with acid, then carry out saponification with alkali, and extract the saponified leaching solution to obtain an organic phase and an aqueous phase;

[0009] Step 3: Wash the organic phase, and then add a sulfuric acid solution and a reducing agent for back extraction to obtain a vanadyl sulfate solution.

[0010] Step 4: Wash the organic phase after back extraction, and then add an alkali for back extraction of molybdenum to obtain a molybdenum-containing solution.

[0011] In Step 1,

[0012] Preferably, the conditions for the oxidative roasting are: the oxidative roasting temperature is 400 - 800 °C, and the oxidative roasting time is 3 - 8 h.

[0013] Preferably, the molar ratio of soda ash to the spent residue hydrotreating catalyst after oxidative roasting is (1.05 - 4):1, and the molar number of the spent residue hydrotreating catalyst after oxidative roasting is calculated based on the sum of the molar numbers of V2O5 and MoO3.

[0014] Preferably, the conditions for the sodium roasting are: the sodium roasting temperature is 400 - 800 °C, and the sodium roasting time is 3 - 8 h.

[0015] Preferably, the conditions for the water leaching are: the mass ratio of the sodium roasted material to water is 1:(2.5 - 5), the leaching temperature is 40 - 90 °C, and the leaching time is 1 - 4 h.

[0016] In Step 2,

[0017] Preferably, after filtration and washing with water, sulfuric acid is added to adjust the pH of the vanadium- and molybdenum-containing leaching solution to 1.5 - 2.2;

[0018] Preferably, the saponification conditions are: at 20 - 30 °C, add a soda ash solution or ammonia water for saponification, and the saponification rate is 0 - 80%.

[0019] Preferably, the extraction conditions are: add an extractant, a modifier, and a diluent, and perform multi-stage countercurrent extraction at 20 - 30 °C. The extraction time is 3 - 10 min, and the extraction O / A = 1:(1 - 10).

[0020] In Step 3,

[0021] Preferably, the reducing agent is selected from one or more of SO2, H2, sodium sulfite, sodium bisulfite, sodium thiosulfate, and sodium metabisulfite;

[0022] Preferably, the addition amount of the reducing agent is 0.5% - 5% of the mass of the organic phase.

[0023] Preferably, the back extraction conditions are: perform multi-stage countercurrent back extraction at 20 - 30 °C. The back extraction time is 3 - 10 min, and the back extraction O / A = (10 - 1):1.

[0024] In Step 4,

[0025] Preferably, the conditions for molybdenum back-extraction are as follows: at 20 - 30°C, add sodium carbonate solution or ammonia water for molybdenum back-extraction, the back-extraction time is 3 - 10 min, and the back-extraction O / A = (20 - 1):1.

[0026] The beneficial effects of the present invention are as follows:

[0027] (1) The method of the present invention uses waste residue oil hydrogenation catalyst as the main raw material to prepare vanadyl sulfate solution from the waste residue oil hydrogenation catalyst. On the one hand, it solves the problem of solid waste treatment, and on the other hand, it uses the solvent extraction method to selectively recover vanadium from the high-concentration vanadium-containing solution, greatly reducing the production cost.

[0028] (2) The method of the present invention uses waste residue oil hydrogenation catalyst as the raw material to prepare high-purity vanadyl sulfate solution through the preparation process of "calcination - leaching - impurity removal - reduction - extraction - back-extraction" to meet the raw material requirements of the vanadium battery industry.

[0029] The present invention controls the calcination and leaching conditions of the waste residue oil hydrogenation catalyst to control the impurity content and vanadium concentration in the leaching solution;

[0030] The present invention removes impurities by chemical precipitation method, which can further reduce the impurity content in the leaching solution;

[0031] The present invention preferably uses gas reductants such as SO2, which can avoid introducing impurities brought by the reductant into the vanadyl sulfate solution, and the obtained vanadyl sulfate solution has high purity and high production efficiency;

[0032] The present invention uses the solvent extraction method to selectively separate vanadium and molybdenum. By regulating the back-extraction process conditions, a vanadyl sulfate solution can be directly obtained after back-extraction, omitting the post-treatment process, which is more convenient.

[0033] The method of the present invention has good application prospects in both the field of waste residue oil hydrogenation catalyst recovery and the field of preparing vanadyl sulfate solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The schematic diagram of the preparation process showing the method of preparing vanadyl sulfate electrolyte using the waste residue oil hydrogenation catalyst according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present invention will be described in detail below, and its features and advantages will become clearer and more definite with these descriptions.

[0036] The waste residue oil hydrogenation catalyst has been included in the hazardous waste list (HW50), contains relatively more rare metals, generally with a V content of 1% - 20% (mass fraction, the same below), an Mo content of 3% - 20%, and an Al2O3 content of about 40%. Its grade is much higher than that of the original ore. It is an important secondary resource and has a relatively high recycling value.

[0037] The present invention aims to provide a method for preparing vanadyl sulfate electrolyte using the waste residue oil hydrogenation catalyst, as Figure 1 shown. The method includes the following steps:

[0038] Step 1: Oxidatively roast the waste residue oil hydrogenation catalyst, then add soda ash and mix, followed by drying, and then perform sodium roasting. Add water to leach the sodium roasted material to obtain a vanadium and molybdenum containing leaching solution;

[0039] Step 2: Filter and wash the vanadium and molybdenum containing leaching solution, then adjust the pH with acid, then saponify with alkali, and extract the saponified leaching solution to obtain an organic phase and an aqueous phase;

[0040] Step 3: Wash the organic phase, then add a sulfuric acid solution and a reducing agent for back extraction to obtain a vanadyl sulfate solution;

[0041] Step 4: Wash the back extracted organic phase, then add alkali for back extraction of molybdenum to obtain a molybdenum containing solution.

[0042] The above steps are specifically described below.

[0043] In Step 1, the conditions for the oxidative roasting are: the oxidative roasting temperature is 400 - 800 °C, and the oxidative roasting time is 3 - 8 h.

[0044] Preferably, the conditions for the oxidative roasting are: the oxidative roasting temperature is 550 °C, and the oxidative roasting time is 5 h.

[0045] The molar ratio of soda ash to the waste residue oil hydrogenation catalyst after oxidative roasting is (1.05 - 4):1. The molar number of the waste residue oil hydrogenation catalyst after oxidative roasting is calculated based on the sum of the molar numbers of V2O5 and MoO3.

[0046] Preferably, the molar ratio of soda ash to the waste residue oil hydrogenation catalyst after oxidative roasting is 2.5:1. The molar number of the waste residue oil hydrogenation catalyst after oxidative roasting is calculated based on the sum of the molar numbers of V2O5 and MoO3.

[0047] The drying conditions are: drying at 110 - 130 °C for 1 - 2 h. Preferably, drying at 120 °C for 1.5 h.

[0048] The conditions for the sodium roasting are: the sodium roasting temperature is 400 - 800 °C, and the sodium roasting time is 3 - 8 h.

[0049] Preferably, the conditions for sodium roasting are as follows: the sodium roasting temperature is 550 °C, and the sodium roasting time is 6 h.

[0050] The conditions for water leaching are as follows: the mass ratio of the sodium roasted material to water is 1:(2.5 - 5), the leaching temperature is 40 - 90 °C, and the leaching time is 1 - 4 h.

[0051] Preferably, the conditions for water leaching are as follows: the mass ratio of the sodium roasted material to water is 1:4, the leaching temperature is 75 °C, and the leaching time is 2.5 h.

[0052] The vanadium- and molybdenum-containing leaching solution mainly contains sodium vanadate, sodium molybdate and sodium carbonate, with a pH of 9 - 11. In the vanadium- and molybdenum-containing leaching solution, the vanadium concentration is 10 - 40 g / L, and the molybdenum concentration is 10 - 40 g / L.

[0053] In step 2, after filtration and washing with water, sulfuric acid is added to adjust the pH of the vanadium- and molybdenum-containing leaching solution to 1.5 - 2.2.

[0054] The saponification conditions are as follows: at 20 - 30 °C, soda ash solution or ammonia water is added for saponification, and the saponification rate is 0 - 80%.

[0055] Preferably, the saponification conditions are as follows: at 25 °C, ammonia water is added for saponification, and the saponification rate is 70%.

[0056] The extraction conditions are as follows: multi-stage countercurrent extraction is carried out at 20 - 30 °C, the extraction time is 3 - 10 min, and the extraction O / A (volume ratio of organic phase to aqueous phase) = 1:(1 - 10).

[0057] Preferably, the extraction conditions are as follows: an extractant, a modifier and a diluent are added, multi-stage countercurrent extraction is carried out at 25 °C, the extraction time is 5 min, and after extraction, O / A (volume ratio of organic phase to aqueous phase) = 1:3.

[0058] The volume ratio of the extractant, the modifier and the diluent is 10 - 30:0 - 10:60 - 80.

[0059] Preferably, the volume ratio of the extractant, the modifier and the diluent is 20:5:70.

[0060] The extractant is selected from one or more of TOA (trioctylamine), N235 (trialkyl tertiary amine), N263 (methyltrialkylammonium chloride) and TBP (tributyl phosphate), preferably TOA.

[0061] The modifier is sec-octanol or isooctanol. The modifier can avoid the formation of the third phase.

[0062] The diluent is kerosene or DT-100.

[0063] In Step 3, the reducing agent is selected from one or more of SO2, H2, sodium sulfite, sodium bisulfite, sodium thiosulfate, and sodium metabisulfite.

[0064] Preferably, the reducing agent is SO2 and sodium thiosulfate.

[0065] The addition amount of the reducing agent is 0.5% - 5% of the mass of the organic phase. Preferably, the addition amount of the reducing agent is 3% of the mass of the organic phase.

[0066] Dosage of sulfuric acid solution: It depends on the stripping A / O. When stripping vanadium, the dosage of the reducing agent is based on the weight of the oil phase, or it can also be expressed according to the excess coefficient of the theoretical dosage. The dosage of sulfuric acid is determined according to the sulfuric acid concentration and the stripping A / O ratio.

[0067] The concentration of the sulfuric acid solution is 0.1 - 6M. Preferably, the concentration of the sulfuric acid solution is 3M.

[0068] The stripping conditions are as follows: multi-stage countercurrent stripping is carried out at 20 - 30°C, the stripping time is 3 - 10 min, and the stripping O / A = (10 - 1):1.

[0069] Preferably, the stripping conditions are as follows: multi-stage countercurrent stripping is carried out at 25°C, the stripping time is 5 min, and the O / A after stripping is 3:1.

[0070] In Step 4, the conditions for stripping molybdenum are as follows: at 20 - 30°C, sodium carbonate solution or ammonia water is added for molybdenum stripping, the stripping time is 3 - 10 min, and the stripping O / A = (20 - 1):1.

[0071] Preferably, the conditions for stripping molybdenum are as follows: at 25°C, sodium carbonate solution is added for molybdenum stripping, the stripping time is 5 min, and the O / A after stripping is 3:1.

[0072] The stripping agent obtained after stripping can also be recycled to Step 2 for extraction, which can save energy, reduce emissions, and is environmentally friendly.

[0073] Examples

[0074] The present invention will be further illustrated by the following specific examples. These examples are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0075] Example 1

[0076] Step 1: Conduct a primary oxidative roasting on the waste residue oil hydrogenation catalyst at a roasting temperature of 550°C for 5 hours; then mix it with a 30 wt% sodium carbonate (Na2CO3) solution to form a loose gravel-like state. The molar ratio of sodium carbonate to (V2O5 + MoO3) in the waste residue oil hydrogenation catalyst after oxidative roasting is 2.5:1. Subsequently, dry it at 120°C for 1.5 hours, and then conduct a secondary sodium roasting at a temperature of 550°C for 6 hours; add purified water to the sodium roasted material, and the mass ratio of the sodium roasted material to water is 1:4. The leaching temperature is 75°C, and the leaching time is 2.5 hours to obtain a vanadium- and molybdenum-containing leaching solution. The vanadium- and molybdenum-containing leaching solution mainly contains sodium vanadate, sodium molybdate, and sodium carbonate, with a pH of 10.

[0077] Step 2: Use a vacuum filter to filter and wash the vanadium- and molybdenum-containing leaching solution obtained in Step 1, and then adjust the pH value of the solution to 2.0 with sulfuric acid.

[0078] Under the condition of 25°C, saponify the extraction system with a 32 wt% sodium carbonate solution, and the saponification rate is 70%; while stirring, add the saponified extraction system, and at the same time add an extractant, a modifier, and a diluent, stir evenly, and conduct extraction at room temperature (25°C), and conduct multi-stage countercurrent extraction for 5 minutes to obtain an organic phase and an aqueous phase, with O / A (volume ratio of organic phase / aqueous phase) = 1:3. Among them, the volume ratio of the extractant TOA, the modifier sec-octanol, and the diluent kerosene is 20:5:70.

[0079] Step 3: Wash the extracted organic phase, and after washing, use a 2.0 mol / L sulfuric acid solution + reducing agent to strip vanadium. The addition amount of the reducing agent is 3% of the mass of the organic phase. Conduct multi-stage countercurrent stripping at room temperature (25°C) for 5 minutes. The reducing agent is SO2. After stripping, O / A = 3:1, and a vanadyl sulfate solution is obtained by stripping.

[0080] Step 4: Wash the organic phase after vanadium stripping, and after washing, use a 2 mol / L sodium carbonate solution to strip molybdenum. O / A = 3:1, and conduct multi-stage countercurrent stripping at room temperature (25°C) for 5 minutes to obtain a molybdenum-containing solution.

[0081] Example 2

[0082] Step 1: The spent residue oil hydrogenation catalyst is subjected to primary oxidative roasting at a roasting temperature of 500 °C and a roasting time of 8 h; then it is mixed with a 30 wt% sodium carbonate (Na2CO3) solution to form a loose gravel-like shape. The molar ratio of sodium carbonate to (V2O5 + MoO3) in the spent residue oil hydrogenation catalyst after oxidative roasting is 4:1. Subsequently, it is dried at 110 °C for 2 h, and then subjected to secondary sodium roasting at a secondary sodium roasting temperature of 500 °C and a roasting time of 8 h; clean water is added to the sodium roasted material, and the mass ratio of the sodium roasted material to water is 1:2.5. The leaching temperature is 60 °C and the leaching time is 4 h to obtain a vanadium- and molybdenum-containing leaching solution. The main components in the leaching solution are sodium metavanadate, sodium molybdate, and sodium carbonate, with pH = 9.

[0083] Step 2: The vanadium- and molybdenum-containing leaching solution obtained in Step 1 is filtered and washed with a vacuum filter, and then the pH value of the solution is adjusted to 1.5 with sulfuric acid.

[0084] Under the condition of 20 °C, the extraction system is saponified with 30 wt% ammonia water, and the saponification rate is 60%; while stirring, the saponified extraction system is added, and at the same time, an extractant, a modifier, and a diluent are added, stirred evenly, and extraction is carried out at room temperature (20 °C) with multi-stage countercurrent extraction. The extraction time is 10 min to obtain an organic phase and an aqueous phase, with O / A (volume ratio of organic phase / aqueous phase) = 1:1. Among them, the volume ratio of the extractant N235, the modifier isooctanol, and the diluent kerosene is 10:10:60.

[0085] Step 3: The organic phase obtained by extraction is washed, and after washing, vanadium is back-extracted with a 1.0 mol / L sulfuric acid solution + a reducing agent. The addition amount of the reducing agent is 0.5% of the mass of the organic phase. Multi-stage countercurrent back-extraction is carried out at room temperature (20 °C), and the back-extraction time is 10 min. The reducing agent is sodium thiosulfate. After back-extraction, O / A = 4:1, and a vanadyl sulfate solution is obtained by back-extraction.

[0086] Step 4: The organic phase after vanadium back-extraction is washed, and after washing, molybdenum is back-extracted with ammonia water, with O / A = 4:1. Multi-stage countercurrent back-extraction is carried out at room temperature (20 °C), and the back-extraction time is 10 min to obtain a molybdenum-containing solution.

[0087] Example 3

[0088] Step 1: Subject the waste residue oil hydrogenation catalyst to a first oxidation roasting at a roasting temperature of 600 °C for 3 h; then mix it with a 30 wt% sodium carbonate (Na2CO3) solution to form a loose gravel-like state. The molar ratio of sodium carbonate to (V2O5 + MoO3) in the waste residue oil hydrogenation catalyst after oxidation roasting is 1.05:1. Subsequently, dry it at 130 °C for 1 h, and then conduct a second sodium roasting. The second sodium roasting temperature is 600 °C, and the roasting time is 3 h; add clean water to the sodium roasted material. The mass ratio of the sodium roasted material to water is 1:5, the leaching temperature is 90 °C, and the leaching time is 1 h to obtain a vanadium- and molybdenum-containing leaching solution. The vanadium- and molybdenum-containing leaching solution mainly contains sodium vanadate, sodium molybdate, and sodium carbonate, with a pH of 11.

[0089] Step 2: Filter and wash the vanadium- and molybdenum-containing leaching solution obtained in Step 1 using a vacuum filter, and then adjust the pH value of the solution to 2.2 with sulfuric acid.

[0090] Under the condition of 30 °C, saponify the extraction system with a 32 wt% sodium carbonate solution, and the saponification rate is 80%; while stirring, add the saponified extraction system, and at the same time add an extractant, a modifier, and a diluent, stir evenly, and conduct extraction at room temperature (30 °C). Conduct multi-stage countercurrent extraction, with an extraction time of 3 min, to obtain an organic phase and an aqueous phase, and O / A (volume ratio of organic phase to aqueous phase) = 1:4. Among them, the volume ratio of the extractant N263, the modifier sec-octanol, and the diluent kerosene is 30:10:80.

[0091] Step 3: Wash the organic phase obtained by extraction, and after washing, conduct reverse extraction of vanadium with a 3.0 mol / L sulfuric acid solution + a reducing agent. The addition amount of the reducing agent is 5% of the mass of the organic phase. Conduct multi-stage countercurrent reverse extraction at room temperature (30 °C), with a reverse extraction time of 3 min. The reducing agent is sodium metabisulfite. After reverse extraction, O / A = 1:1, and a vanadyl sulfate solution is obtained by reverse extraction.

[0092] Step 4: Wash the organic phase after reverse extraction of vanadium, and after washing, conduct reverse extraction of molybdenum with a 1.0 mol / L sodium carbonate solution. O / A = 1:1, conduct multi-stage countercurrent reverse extraction at room temperature (30 °C), and the reverse extraction time is 3 min to obtain a molybdenum-containing solution.

[0093] Experimental Example

[0094] Component Test of Experimental Example 1

[0095] Conduct component tests on the roasted materials after the first oxidation roasting of Example 1, Example 2, and Example 3 respectively. The test results are shown in Table 1. Conduct a component test on the vanadium- and molybdenum-containing leaching solution of Example 1, and the test results are shown in Table 2.

[0096] Table 1 Composition Table of Waste Residue Oil Hydrogenation Catalyst after First Roasting

[0097]

[0098] Note: The "%" in Table 1 is the mass percentage.

[0099] Table 2 Composition Table of Leaching Solution

[0100]

[0101] It can be seen from Table 1 that after the first roasting, the main components of the roasted material are V2O5 and MoO3 after removing Al2O3. It can be seen from Table 2 that after water leaching, the main components of the leaching solution are Mo and V in addition to Al and Na elements, and the contents of other elements are relatively small, indicating that the leaching solution obtained by the method described in the present invention has less impurities and can be purified by chemical precipitation method, indicating that a high-purity vanadyl sulfate solution can be obtained by this method.

[0102] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims

1. A method for preparing a vanadyl sulfate electrolyte using a waste oil hydrogenation catalyst, characterized in that: The method comprises the following steps: Step 1, oxidatively roasting the waste oil hydrogenation catalyst, then adding soda ash, mixing and drying, then sodium roasting, adding water to the sodium roasted material for leaching, and obtaining a vanadium-molybdenum leaching solution; Step 2, filtering and washing the vanadium-molybdenum-containing leachate, then adding acid to adjust the pH, then adding alkali for saponification, and extracting the saponified leachate to obtain an organic phase and an aqueous phase; After filtering and washing, sulfuric acid is added to adjust the pH of the vanadium-molybdenum leaching solution to 1.5-2.2; The saponification conditions are: adding a soda solution or ammonia water for saponification at 20-30°C, with a saponification rate of 0-80%; The extraction conditions are: adding an extractant, a modifier and a diluent, performing multi-stage countercurrent extraction at 20 to 30° C., an extraction time of 3 to 10 minutes, and extraction O / A = 1: (1 to 10); The volume ratio of the extractant, the modifier and the diluent is 10-30:0-10:60-80; The extractant is selected from one or more of TOA, N235, N263 and TBP; The modifier is sec-octanol or isooctyl alcohol; The diluent is kerosene or DT-100; Step 3, washing the organic phase, and then adding a sulfuric acid solution and a reducing agent for stripping to obtain a vanadyl sulfate solution; The reducing agent is selected from one or more of SO2, sodium thiosulfate, and sodium pyrosulfite; The amount of the reducing agent added is 0.5% to 5% of the mass of the organic phase; The stripping conditions are: multi-stage countercurrent stripping at 20-30° C., stripping time of 3-10 min, stripping O / A=(10-1):1; Step 4: Wash the organic phase after stripping, then add alkali to strip molybdenum to obtain a molybdenum-containing solution.

2. The method according to claim 1, characterized in that In step 1, The oxidation roasting conditions are: the oxidation roasting temperature is 400-800° C., and the oxidation roasting time is 3-8 hours.

3. The method according to claim 1, characterized in that In step 1, The molar ratio of soda ash to the oxidatively calcined waste oil hydrogenation catalyst is (1.05-4):1, and the molar number of the oxidatively calcined waste oil hydrogenation catalyst is the sum of the molar numbers of V2O5 and MoO3.

4. The method according to claim 1, characterized in that: In step 1, The conditions of the sodium calcination are as follows: the sodium calcination temperature is 400-800° C., and the sodium calcination time is 3-8 hours.

5. The method according to claim 1, characterized in that In step 1, The water leaching conditions are as follows: the mass ratio of the sodium roasted material to water is 1:(2.5-5), the leaching temperature is 40-90° C., and the leaching time is 1-4 hours.

6. The method according to claim 1, characterized in that In step 4, The conditions for stripping molybdenum are: adding sodium carbonate solution or ammonia water to strip molybdenum at 20-30° C., the stripping time is 3-10 minutes, and the stripping O / A=(20-1):1.

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