Metal recovery method of waste hydrodesulfurization catalyst containing vanadium and molybdenum

Abstract

The invention discloses a metal recovery method of a waste hydrodesulfurization catalyst containing vanadium and molybdenum, which comprises the following steps: grading ball milling activation: mixing the waste hydrodesulfurization catalyst and an inorganic salt auxiliary agent according to a preset mass ratio, adding the mixture into a ball milling tank, and carrying out ball milling on the mixed material by adopting grinding balls with different diameters according to different grading ratios, meanwhile, the ball-to-material ratio is controlled, and activated ball-milled powder is obtained; oxygen-enriched roasting: putting the activated ball-milled powder into a roasting furnace, and introducing oxidizing gas into the roasting furnace for roasting to obtain an oxygen-enriched roasted material; and low-temperature alkaline leaching is conducted, specifically, the oxygen-enriched roasting material is placed in an alkaline leaching medium according to the preset solid-to-liquid ratio, solid-liquid separation is conducted after the reaction is completed, and vanadium-molybdenum metal enrichment liquid is obtained. According to the method, grading ball milling and oxygen-enriched roasting enhanced oxidation processes are innovatively coupled, so that valence bonds of V-S-O or Mo-S-O in the waste HDS catalyst are broken, sufficient oxidation of low-valence V / Mo is realized, and efficient recovery of vanadium and molybdenum is realized at low temperature and normal pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery of waste catalysts, and particularly to a method for metal recovery of waste hydrodesulfurization catalysts containing vanadium and molybdenum. Background Art

[0002] Hydrodesulfurization (HDS) catalysts, as the core materials in the petroleum refining industry, efficiently remove sulfur, nitrogen, and metal impurities (such as vanadium and nickel) in raw materials through catalytic hydrogenation reactions. However, as the reaction progresses, the catalyst surface gradually deactivates due to the deposition of sulfur, carbon, and metals, forming hazardous solid waste mainly composed of molybdenum (4% - 12%), aluminum (15% - 30%), nickel (1% - 5%), cobalt (0% - 4%), sulfur (5% - 10%), silicon (1% - 5%), and carbon (about 5%). Such waste catalysts are both environmentally harmful and resource valuable, especially rich in high-value metals such as vanadium and molybdenum. There is an urgent need to develop efficient recovery technologies to balance environmental protection and resource recycling.

[0003] However, due to the formation of sulfide composite mineral phases (such as MoS2, CoMoS, VS4) of metals such as V, Mo, and Co in waste HDS catalysts, traditional recovery processes face multiple challenges: the vanadium-sulfur-metal complex is difficult to be fully dissociated by single ball milling due to its dense structure, resulting in low metal leaching rates (the vanadium leaching rate is less than 80%); during the subsequent oxidation process, the low-valent vanadium mineral phase is difficult to be exposed due to surface coating and requires external high temperature (>800°C) to decompose the composite phase, which not only has high energy consumption but also easily generates insoluble vanadates (such as FeVO4); in addition, the occurrence of multiple valence states of vanadium (V 3+ / V 4+ / V 5+ ) leads to the inability of traditional processes to directionally control the oxidation path, and the products are mixed with inert phases (such as V3O7), seriously restricting the separation efficiency. In existing processes, the multi-stage microbubble method proposed in CN117660767A focuses on the recovery of sodium vanadate from nickel-aluminum slag, but its technical scope is limited to the vanadium-aluminum extraction from leaching tailings and does not cover the pretreatment of waste HDS raw materials and the recovery of main metals; CN119913373A realizes separation based on the difference in the volatility characteristics of vanadium and molybdenum oxides, which requires a super-high temperature environment (>1000°C), has high energy consumption, and cannot solve the problems of raw material crushing and mineral phase regulation; although CN116417591A uses graded ball milling to optimize the uniformity of the cathode slurry, its technical core lies in material mixing and does not involve the crushing of sulfides and the mechanism of directional oxidation of vanadium mineral phases. None of these methods can systematically break through the technical bottleneck of the resource utilization of waste HDS catalysts. Summary of the Invention

[0004] (I) Object of the Invention The object of the present invention is to provide a method for metal recovery from spent hydrodesulfurization catalysts containing vanadium and molybdenum. The present invention couples a mechanical ball milling activation process with a semi-self-heating oxygen-enriched roasting technology, precisely regulates the particle size distribution of the mixture of the spent HDS catalyst material and the inorganic salt additive through multi-stage mechanical ball milling to strengthen the subsequent roasting reaction kinetics, and combines the synergistic activation effect of the inorganic salt in an oxygen-enriched atmosphere to significantly improve the leaching rate of vanadium and molybdenum metals.

[0005] (II) Technical Solution To solve the above problems, the present invention provides a method for metal recovery from spent hydrodesulfurization catalysts containing vanadium and molybdenum. The spent hydrodesulfurization catalyst includes 10-70% by mass of Al2O3, 3-25% of V, 2-15% of Mo, and 1-10% of Ni. The method includes: S1, staged ball milling activation: Mix the spent hydrodesulfurization catalyst and the inorganic salt additive in a preset mass ratio and add them to a ball milling tank to obtain a mixed material. Use grinding balls with different diameters to perform ball milling on the mixed material according to different staged ratios, and at the same time control the ball-to-material ratio to obtain an activated ball mill powder. Adding the inorganic salt additive in step S1 can destroy the inert mineral phase of the spent HDS catalyst during ball milling, making the material contact more uniform, and the mineral phase is more likely to be reconstructed during oxygen-enriched enhanced oxidation, which is more conducive to subsequent vanadium and molybdenum metal recovery.

[0006] S2, oxygen-enriched roasting: Place the activated ball mill powder in a roasting furnace, and introduce an oxidizing gas into the roasting furnace for roasting to obtain an oxygen-enriched roasted material; S3, low-temperature alkali leaching: Place the oxygen-enriched roasted material in an alkaline leaching medium according to a preset solid-liquid ratio, perform solid-liquid separation after the reaction ends to obtain a vanadium and molybdenum metal enrichment solution.

[0007] Further, the diameter of the grinding balls is 2 mm to 30 mm, and the preferred grinding ball diameters are 30 mm, 25 mm, 20 mm, 15 mm, 12 mm, 10 mm, 8 mm, 6 mm, 4 mm, 2 mm. Further, the grinding balls are proportioned according to any one of the first-stage to tenth-stage ratios, and are specifically set as: First-stage ratio φ20 = 100%, second-stage ratio φ20:φ8 = 70%:30%, Third-stage ratio φ20:φ12:φ8 = 40%:40%:20%, Fourth-stage ratio φ20:φ15:φ12:φ10 = 25%:35%:25%:15%, Fifth-stage ratio φ20:φ15:φ12:φ10:φ8 = 20%:25%:30%:15%:10%, Sixth-stage ratio φ20:φ15:φ12:φ10:φ8:φ6 = 15%:25%:25%:20%:10%:5%, Seven - stage gradation: φ20:φ15:φ12:φ10:φ8:φ6:φ4 = 15%:25%:25%:15%:10%:5%:5%, Eight - stage gradation: φ25:φ20:φ15:φ12:φ10:φ8:φ6:φ4 = 15%:15%:15%:20%:15%:10%:5%:5%, Nine - stage gradation: φ30:φ25:φ20:φ15:φ12:φ10:φ8:φ6:φ4 = 15%:15%:15%:15%:10%:10%:10%:5%:5%, Ten - stage gradation: φ30:φ25:φ20:φ15:φ12:φ10:φ8:φ6:φ4:φ2 = 15%:15%:15%:15%:10%:10%:5%:5%:5%:5%, where φ is the diameter. Preferably, the mass ratio of the powder particle size within 50 - 260μm after graded ball - milling activation is taken as the target. During these multi - stage graded ball - milling processes, during the four - stage graded ball - milling, the proportion of the powder particle size within 50 - 260μm is the highest. Subsequently, the grinding balls are proportioned according to the four - stage gradation.

[0008] Furthermore, the mass ratio of the waste hydrodesulfurization catalyst to the grinding balls is 2:1 - 12, and the preferred ratios are 2:1, 2:2, 2:4, 2:6, 2:8, 2:10, 2:12. Controlling the mass ratio between the two can convert mechanical energy into chemical energy to the greatest extent, activate the waste HDS catalyst material, make the particles more uniform in the shortest time, have a better activation degree, ensure that the particle size of the material is in a better particle range, balance the impact force during the mechanical activation process, reduce energy consumption and equipment loss, and improve the grinding efficiency. Among these combinations, the best mass ratio is 2:10.

[0009] Furthermore, in step S1, the ball - milling time is 10 - 360 min and the ball - milling speed is 100 - 600 r / min. The ball - milling time (ball - milling impact time) affects the activation degree of the material. The activation of the material and the degree of particle size uniformity show a trend of first increasing and then stabilizing with time. When the impact time is 90 min, the activation degree of the material is the best. Thus, the particle size of the waste HDS catalyst powder can be controlled within 50 - 260μm.

[0010] Furthermore, the mixed material includes: 50 - 95% by mass of the waste hydrodesulfurization catalyst and 5 - 50% of the inorganic salt auxiliary agent.

[0011] Furthermore, in step S2, an oxidizing gas with an oxygen volume concentration of 25 - 100% is introduced, the calcination temperature is 400 - 900 °C, and the calcination time is 1 - 6 h. Within this parameter range, the mineral phase transformation in the waste HDS catalyst is more complete.

[0012] Further, the inorganic salt assistant is at least one of calcium carbonate, calcium oxide, calcium hydroxide, sodium chloride, anhydrous sodium carbonate and sodium hydroxide.

[0013] Further, the alkaline leaching medium includes one or more of sodium hydroxide, potassium hydroxide and sodium carbonate solutions with a mass fraction of 0.01 - 10%.

[0014] Further, the preset solid-liquid ratio in the S3 step is 6 - 20 g / mL.

[0015] Further, the leaching time in the S3 step is 0.5 - 6 h, and the temperature of the leaching medium is 50 - 100 °C.

[0016] (III) Beneficial effects The above technical solution of the present invention has the following beneficial technical effects: The present invention provides a method for metal recovery from spent hydrodesulfurization catalysts containing vanadium and molybdenum. This method innovatively couples the graded ball milling and oxygen-enriched roasting enhanced oxidation processes. First, different diameters of grinding balls are used to ball mill the mixed materials according to different grading ratios. By adjusting the grading quantity and ratio, the valence bonds of V-S-O or Mo-S-O in the spent HDS catalyst are broken, and the partial grease and residual carbon contained therein are homogenized, and activated ball mill powder within the range of 50 μm - 260 μm can be accurately obtained. The process of graded grinding can activate the mineral phase, ensuring that oxygen can fully penetrate into the interior of the particles during roasting, reducing energy consumption. Then, oxygen-enriched semi-autothermal roasting is used, which can make the mineral phase transformation more complete and is more conducive to the roasting transformation of valuable metals. By using the heat value of the activated material itself for roasting, the material phase reconstruction is realized, which is convenient for subsequent better leaching and is beneficial for subsequent metal extraction. The preparation process of the present invention is simple, has a narrow particle size distribution, controllable particle size, can achieve the full oxidation of low-valence V / Mo, and can realize the efficient recovery of vanadium and molybdenum under low temperature and normal pressure. Description of the drawings

[0017] Figure 1 It is the preparation flow chart of the method for metal recovery from spent hydrodesulfurization catalysts containing vanadium and molybdenum of the present invention; Figure 2 It is the comparison chart of the particle size distribution intervals of the spent catalysts after graded ball milling in Examples 1 - 3 of the present invention; Figure 3 It is the XRD spectrum of the spent catalyst before and after roasting in Example 3 of the present invention. Detailed implementation manners

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0019] In the spent hydrodesulfurization catalyst (spent HDS catalyst) of the present invention, it includes 10 - 70% by mass of Al2O3, 3 - 25% of V, 2 - 15% of Mo, and 1 - 10% of Ni. Figure 1 This is the preparation flow chart of the present invention.

[0020] The present invention couples the mechanical ball milling activation process with the semi-self-heating oxygen-enriched roasting technology. By precisely regulating the particle size distribution of the mixture of the spent HDS catalyst material and the inorganic salt additive through multi-stage mechanical ball milling to strengthen the subsequent roasting reaction kinetics, combined with the synergistic activation effect of the inorganic salt under an oxygen-enriched atmosphere, the leaching rate of vanadium and molybdenum metals is significantly improved. Among them, the semi-self-heating oxygen-enriched roasting technology means that the spent HDS catalyst contains valuable metals such as vanadium and molybdenum, and there is also residual carbon accumulated during operation on its surface. The meaning of semi-self-heating is to utilize the calorific value of the carbon accumulated in the spent HDS catalyst to achieve a semi-self-heating roasting purpose by burning under an oxygen-enriched state, thereby reducing a part of the energy consumption. Finally, the synergistic activation effect of the inorganic salt under an oxygen-enriched atmosphere means that when regulating by multi-stage mechanical ball milling, the spent HDS catalyst and the inorganic salt are mixed, and during the subsequent oxygen-enriched atmosphere roasting, the inorganic salt will be synergistically transformed with the spent HDS catalyst, which is beneficial to the subsequent leaching of vanadium and molybdenum metals.

[0021] Example 1 Take a 100 g mixture of the spent HDS catalyst and 40 g of granular sodium carbonate according to a mass ratio of 10:4 and place it in a ball milling tank body. According to M 球 :M 料 = 5:1, weigh 500 g of ball milling beads, satisfying a three-stage gradation: the mass ratio of φ20:φ12:φ8 is 2:2:1, and perform the particle size gradation of the ball milling beads. After mixing the above ball milling beads with the spent catalyst, perform graded ball milling centrifugal impact at a speed of 550 rpm for 60 min; after the ball milling impact is completed, collect the graded ball milling powder to obtain the activated powder of the spent HDS catalyst (activated ball milling powder), where 67.41% of the powder particle size is in the range of 74 - 250 μm, as the raw material for the next roasting. Roast the obtained spent HDS catalyst powder at 800 °C for 4 h, and control the O2 volume concentration to be 80% during the period. After the reaction ends, obtain the oxygen-enriched roasted material. Place the above oxygen-enriched roasted material in a 5 wt% NaOH leaching medium at a liquid-solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium and molybdenum enriched solution. After calculation, the leaching rate of V in the spent catalyst is 86.7%, and the leaching rate of Mo is 91.29%.

[0022] Example 2 Take 100 g of waste HDS catalyst and 40 g of granular sodium carbonate mixture in a mass ratio of 10:4 and place them in a ball milling tank. According to M 球 :M 料 =5:1, weigh 500 g of ball milling beads, which meet the four - stage gradation with a mass ratio of φ20:φ15:φ12:φ10 of 5:7:5:3, and perform the particle size gradation of the ball milling beads. After mixing the above - mentioned ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball milling powder to obtain waste HDS catalyst powder, among which 83.08% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the volume concentration of O2 to be 80% during the period. After the reaction, obtain the oxygen - rich roasted material. Place the above - mentioned oxygen - rich roasted material in a 5 wt% NaOH leaching medium with a liquid - to - solid ratio of 10 ml / g, the leaching temperature is 95 °C, and after 2 h, perform solid - liquid separation to obtain a vanadium - molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 94.7%, and the leaching rate of Mo is 98.29%.

[0023] Example 3 Take 100 g of waste HDS catalyst and 40 g of granular sodium carbonate mixture in a mass ratio of 10:4 and place them in a ball milling tank. According to M 球 :M 料 =5:1, weigh 500 g of ball milling beads, which meet the six - stage gradation: the mass ratio of φ20:φ15:φ12:φ10:φ8:φ6 is 3:5:5:4:2:1, and perform the particle size gradation of the ball milling beads. After mixing the above - mentioned ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball milling powder to obtain waste HDS catalyst powder, among which 50.88% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the volume concentration of O2 to be 80% during the period. After the reaction, obtain the oxygen - rich roasted material. Place the above - mentioned oxygen - rich roasted material in a 5 wt% NaOH leaching medium with a liquid - to - solid ratio of 10 ml / g, the leaching temperature is 95 °C, and after 2 h, perform solid - liquid separation to obtain a vanadium - molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 84.03%, and the leaching rate of Mo is 89.26%. Figure 2 It is a comparison chart of the particle size distribution intervals after graded ball milling of the waste catalysts in Examples 1 - 3 Figure 3 It is the XRD spectrum of the waste catalyst in Example 3 of the present invention before and after roasting. From the comparison in the figure, it can be seen that roasting makes the mineral phase transformation of the waste HDS catalyst more complete, converting vanadium and molybdenum into soluble salts, making them more easily leached

[0024] Example 4 Take 100 g of waste HDS catalyst and 40 g of granular sodium carbonate mixture in a mass ratio of 10:4 and place them in a ball milling tank body. According to M 球 :M 料 =4:1, weigh 400 g of ball milling beads, which meet the four - stage gradation with a mass ratio of φ20:φ15:φ12:φ10 of 5:7:5:3, and carry out the particle size gradation of the ball milling beads. After mixing the above - mentioned ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball - milled powder to obtain waste HDS catalyst powder. Among them, 78.39% of the powder particle size is in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Bake the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the O2 volume concentration to be 80% during the process. After the reaction ends, obtain the oxygen - rich roasted material. Place the above - mentioned oxygen - rich roasted material in a 5 wt.% NaOH leaching medium with a liquid - to - solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, carry out solid - liquid separation to obtain the vanadium - molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 89.73%, and the leaching rate of Mo is 92.26%.

[0025] Example 5 Take 100 g of waste HDS catalyst and 40 g of granular sodium carbonate mixture in a mass ratio of 10:4 and place them in a ball milling tank body. According to M 球 :M 料 =3:1, weigh 300 g of ball milling beads, which meet the four - stage gradation with a mass ratio of φ20:φ15:φ12:φ10 of 5:7:5:3, and carry out the particle size gradation of the ball milling beads. After mixing the above - mentioned ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball - milled powder to obtain waste HDS catalyst powder. Among them, 59.39% of the powder particle size is in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Bake the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the O2 volume concentration to be 80% during the process. After the reaction ends, obtain the oxygen - rich roasted material. Place the above - mentioned oxygen - rich roasted material in a 5 wt.% NaOH leaching medium with a liquid - to - solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, carry out solid - liquid separation to obtain the vanadium - molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 87.62%, and the leaching rate of Mo is 90.35%.

[0026] Example 6 Take 100 g of waste HDS catalyst and 40 g of granular sodium carbonate mixture in a mass ratio of 10:4 and place them in a ball milling tank body. According to M 球 :M 料=5:1 Weigh 500 g of ball-milling beads to meet the four-stage gradation with a mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3 for the ball-milling bead particle size gradation. After mixing the above ball-milling beads with the waste catalyst, conduct gradation ball-milling centrifugal impact at a speed of 500 rpm for 10 min; after the ball-milling impact is completed, collect the gradation ball-milling powder to obtain waste HDS catalyst powder. Among them, 23.28% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next calcination. Calcinate the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, while controlling the O2 volume concentration to be 80% during the process. After the reaction ends, obtain the oxygen-rich calcined material. Place the above oxygen-rich calcined material in a 5 wt.% NaOH leaching medium with a liquid-solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 75.26%, and the leaching rate of Mo is 81.34%.

[0027] Example 7 Take a 100 g waste HDS catalyst and a 40 g granular sodium carbonate mixture in a mass ratio of 10:4 and place them in the ball-milling tank body, according to M 球 :M 料 =5:1 Weigh 500 g of ball-milling beads to meet the four-stage gradation with a mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3 for the ball-milling bead particle size gradation. After mixing the above ball-milling beads with the waste catalyst, conduct gradation ball-milling centrifugal impact at a speed of 500 rpm for 150 min; after the ball-milling impact is completed, collect the gradation ball-milling powder to obtain waste HDS catalyst powder. Among them, 85.32% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next calcination. Calcinate the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, while controlling the O2 volume concentration to be 80% during the process. After the reaction ends, obtain the oxygen-rich calcined material. Place the above oxygen-rich calcined material in a 5 wt.% NaOH leaching medium with a liquid-solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 91.26%, and the leaching rate of Mo is 94.34%.

[0028] Example 8 Take a 100 g waste HDS catalyst and a 40 g granular sodium carbonate mixture in a mass ratio of 10:4 and place them in the ball-milling tank body, according to M 球 :M 料=5:1 Weigh 500 g of ball milling beads to meet the four - stage particle size distribution with a mass ratio of φ20:φ15:φ12:φ10 of 5:7:5:3 for the particle size grading of ball milling beads. After mixing the above - mentioned ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 360 min; after the ball milling impact is completed, collect the graded ball - milled powder to obtain waste HDS catalyst powder. Among them, 86.21% of the powder particle size is in the range of 74 - 250 μm, which is used as the raw material for the next - step roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the O2 volume concentration to be 80% during the period. After the reaction, obtain the oxygen - rich roasted material. Place the above - mentioned oxygen - rich roasted material in a 5 wt.% NaOH leaching medium with a liquid - to - solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, carry out solid - liquid separation to obtain a vanadium - molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 95.26%, and the leaching rate of Mo is 98.34%.

[0029] Example 9 Take a 100 g waste HDS catalyst and 40 g of granular sodium hydroxide mixture in a mass ratio of 10:4 and place them in a ball - milling tank body, according to M 球 :M 料 =5:1 Weigh 500 g of ball milling beads to meet the mass ratio of φ20:φ15:φ12:φ10 of 5:7:5:3 for the particle size grading of ball milling beads. After mixing the above - mentioned ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball - milled powder to obtain waste HDS catalyst powder. Among them, 82.98% of the powder particle size is in the range of 74 - 250 μm, which is used as the raw material for the next - step roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the O2 volume concentration to be 80% during the period. After the reaction, obtain the oxygen - rich roasted material. Place the above - mentioned oxygen - rich roasted material in a 1 wt% NaOH leaching medium with a liquid - to - solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, carry out solid - liquid separation to obtain a vanadium - molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 93.26%, and the leaching rate of Mo is 95.34%.

[0030] Example 10 Take a 100 g waste HDS catalyst and 40 g of powdered calcium carbonate mixture in a mass ratio of 10:4 and place them in a ball - milling tank body, according to M 球 :M 料=5:1 Weigh 500 g of ball milling beads, with the mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3, and perform particle size grading of the ball milling beads. After mixing the above ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball milling powder to obtain waste HDS catalyst powder. Among them, 84.21% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next calcination. Calcinate the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, controlling the volume concentration of O2 to be 80% during the period. After the reaction, obtain the oxygen-rich calcined material. Place the above oxygen-rich calcined material in a 5 wt% NaOH leaching medium with a liquid-solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 93.45%, and the leaching rate of Mo is 96.27%.

[0031] Example 11 Take a mixture of 100 g of waste HDS catalyst and 40 g of powdered calcium carbonate in a mass ratio of 10:4 and place it in the ball milling tank body, according to M 球 :M 料 =5:1 Weigh 500 g of ball milling beads, with the mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3, and perform particle size grading of the ball milling beads. After mixing the above ball milling beads with the waste catalyst, carry out graded ball milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball milling impact is completed, collect the graded ball milling powder to obtain waste HDS catalyst powder. Among them, 84.21% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next calcination. Calcinate the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, controlling the volume concentration of O2 to be 80% during the period. After the reaction, obtain the oxygen-rich calcined material. Place the above oxygen-rich calcined material in a 5 wt% NaOH leaching medium with a liquid-solid ratio of 10 ml / g, and the leaching temperature is 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 94.45%, and the leaching rate of Mo is 97.35%.

[0032] Example 12 Take a mixture of 100 g of waste HDS catalyst and 40 g of granular sodium carbonate in a mass ratio of 10:4 and place it in the ball milling tank body, according to M 球 :M 料Weigh 500 g of ball-milling beads in a ratio of 5:1, with the mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3, and perform particle size grading of the ball-milling beads. After mixing the above ball-milling beads with the waste catalyst, carry out graded ball-milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball-milling impact is completed, collect the graded ball-milling powder to obtain waste HDS catalyst powder, where 83.08% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the volume concentration of O2 to be 80% during this period. After the reaction ends, obtain the oxygen-enriched roasting material. Place the above oxygen-enriched roasting material in a 5 wt% Na2CO3 leaching medium at a liquid-solid ratio of 10 ml / g, with a leaching temperature of 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 94.78%, and the leaching rate of Mo is 98.36%.

[0033] Example 13 Take a mixture of 100 g of waste HDS catalyst and 40 g of granular sodium carbonate in a mass ratio of 10:4 and place it in a ball-milling tank body according to M 球 :M 料 Weigh 500 g of ball-milling beads in a ratio of 5:1, with the mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3, and perform particle size grading of the ball-milling beads. After mixing the above ball-milling beads with the waste catalyst, carry out graded ball-milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball-milling impact is completed, collect the graded ball-milling powder to obtain waste HDS catalyst powder, where 83.08% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the volume concentration of O2 to be 25% during this period. After the reaction ends, obtain the oxygen-enriched roasting material. Place the above oxygen-enriched roasting material in a 5 wt% NaOH leaching medium at a liquid-solid ratio of 10 ml / g, with a leaching temperature of 95 °C. After 2 h, perform solid-liquid separation to obtain a vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 90.28%, and the leaching rate of Mo is 95.34%.

[0034] Example 14: Take a mixture of 100 g of waste HDS catalyst and 40 g of granular sodium carbonate in a mass ratio of 10:4 and place it in a ball-milling tank body according to M 球 :M 料Weigh 500 g of ball-milling beads at a ratio of 5:1, with the mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3, to conduct the particle size grading of the ball-milling beads. After mixing the above ball-milling beads with the waste catalyst, carry out graded ball-milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball-milling impact is completed, collect the graded ball-milled powder to obtain the waste HDS catalyst powder. Among them, 83.08% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Roast the obtained waste HDS catalyst powder mixture at 400 °C for 4 h, and control the volume concentration of O2 to be 80% during this period. After the reaction ends, obtain the oxygen-rich roasted material. Place the above oxygen-rich roasted material in a 5 wt.% NaOH leaching medium at a liquid-solid ratio of 10 ml / g, with the leaching temperature being 95 °C. After 2 h, perform solid-liquid separation to obtain the vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 79.38%, and the leaching rate of Mo is 82.49%.

[0035] Example 15 Take a 100 g waste HDS catalyst and a 40 g granular sodium carbonate mixture in a mass ratio of 10:4 and place them in a ball-milling tank body, according to M 球 :M 料 Weigh 500 g of ball-milling beads at a ratio of 5:1, with the mass ratio of φ20:φ15:φ12:φ10 being 5:7:5:3, to conduct the particle size grading of the ball-milling beads. After mixing the above ball-milling beads with the waste catalyst, carry out graded ball-milling centrifugal impact at a speed of 500 rpm for 90 min; after the ball-milling impact is completed, collect the graded ball-milled powder to obtain the waste HDS catalyst powder. Among them, 83.08% of the powder has a particle size in the range of 74 - 250 μm, which is used as the raw material for the next roasting. Roast the obtained waste HDS catalyst powder mixture at 800 °C for 4 h, and control the volume concentration of O2 to be 80% during this period. After the reaction ends, obtain the oxygen-rich roasted material. Place the above oxygen-rich roasted material in a 5 wt% NaOH leaching medium at a liquid-solid ratio of 10 ml / g, with the leaching temperature being 50 °C. After 2 h, perform solid-liquid separation to obtain the vanadium-molybdenum enriched solution. After calculation, the leaching rate of V in the waste catalyst is 82.68%, and the leaching rate of Mo is 86.27%.

[0036] Comparative Example 1 The difference between this comparative example and Example 2 is that no graded ball-milling is carried out. Instead, directly mix the waste catalyst, the inorganic salt auxiliary Na2CO3 with ball-milling beads with a diameter of 10 mm, and carry out ball-milling at a speed of 500 rpm. The proportion of the waste catalyst powder with a particle size in the range of 74 - 250 μm is 20.15%. Subsequently, carry out oxygen-rich roasting and low-temperature alkali leaching. After calculation, the leaching rate of V in the waste catalyst is 36.50%, and the leaching rate of Mo is 42.04%.

[0037] Comparative Example 2 The difference between this comparative example and Example 2 is that no oxygen-enriched roasting is carried out, that is, nitrogen is introduced during the roasting stage to exclude oxygen. After calculation, the leaching rate of V in the waste catalyst is 5.93%, and the leaching rate of Mo is 6.01%.

[0038] Comparative Example 3 The difference between this comparative example and Example 2 is that no inorganic salt additive is added during the staged ball milling process. The powder after ball milling is directly mixed with the inorganic salt additive, and then oxygen-enriched roasting and low-temperature alkali leaching are carried out. After calculation, the leaching rate of V in the waste catalyst is 48.5%, and the leaching rate of Mo is 52.6%.

[0039] Table 1 Process and detection results of each example It can be seen from the detection results in Table 1 that: (1) The present invention sets ten-stage grading, and the fourth-stage grading is the optimal one, which can efficiently process the waste HDS catalyst material, with high energy conversion rate, achieving the purpose of crushing in a short time, reducing ineffective energy consumption and over-grinding phenomena. It can be seen from the comparison between Examples 1-3 and Comparative Example 1 that by precisely controlling the quality of the ball milling beads and the number of grading during the staged ball milling process, the particle size of the waste HDS catalyst can be regulated, which is beneficial to the entry of oxygen into the interior of the waste catalyst during the subsequent roasting process, promoting the oxidation reaction of low-valence vanadium and molybdenum ore phases, and finally achieving a high vanadium and molybdenum leaching efficiency.

[0040] (2) It can be seen from the comparison between Examples 1-3 and Comparative Example 2 that oxygen-enriched roasting promotes the rapid oxidation of V2S3 / MoS2 in the waste HDS catalyst to generate soluble vanadate (NaVO3) and molybdate (Na2MoO4), improving the conversion efficiency of low-valence vanadium and molybdenum; at the same time, by increasing the oxygen concentration during the roasting process, the metal sulfide can be oxidized layer by layer, avoiding particle sintering caused by local over-burning, and providing a favorable leaching channel for the subsequent leaching process.

[0041] (3) It can be known from the comparison of Examples 2, 4, and 5 that changing the ball-to-material ratio will affect the degree of material crushing. When the ball-to-material ratio is 5:1 and ball milling is carried out for 90 min, the material crushing degree is better, and 83.08% of the waste HDS catalyst can be controlled within the range of 74-250 μm.

[0042] (4) It can be known from Comparative Example 3 and Examples 10-12 that more than 80% of the waste HDS catalyst can be controlled within the range of 74-250 μm after being mixed and ball milled with different inorganic salt additives. Under the same leaching conditions, the vanadium leaching rate is above 93% and the molybdenum leaching rate is above 96%.

[0043] The present invention provides a method for metal recovery from spent hydrodesulfurization catalysts containing vanadium and molybdenum, which has the following advantages: 1) The multi-stage graded grinding balls adopted in the present invention are centrifugally impacted with the material to fully dissociate the vanadium-sulfur-metal composite structure on the surface of the spent HDS catalyst, significantly increasing the reaction specific surface area and enhancing the subsequent reaction activity.

[0044] 2) The preparation process of the spent HDS catalyst powder adopted in the present invention is simple, with a narrow particle size distribution and controllable particle size. By adjusting the number and ratio of the gradation, the spent HDS catalyst powder in the range of 50 μm to 260 μm can be accurately obtained, ensuring that oxygen can fully penetrate into the interior of the particles during the roasting process, reducing energy consumption and increasing the sulfide oxidation rate.

[0045] 3) The present invention innovatively couples the graded ball milling and the oxygen-enriched roasting enhanced oxidation process, causing the valence bonds of V-S-O or Mo-S-O in the spent HDS catalyst to break, realizing the full oxidation of low-valent V / Mo, and achieving the efficient recovery of vanadium and molybdenum under low temperature and normal pressure.

Claims

1. A method for metal recovery of spent hydrodesulfurization catalyst containing vanadium and molybdenum, characterized in that, The spent hydrodesulfurization catalyst contains 10-70% by mass of Al2O3, 3-25% of V, 2-15% of Mo, and 1-10% of Ni. The method includes: S1, graded ball milling activation: Mix the spent hydrodesulfurization catalyst and the inorganic salt additive in a preset mass ratio and add them into a ball milling tank to obtain a mixed material. Use grinding balls with different diameters to perform ball milling on the mixed material according to different graded ratios, and at the same time control the ball-to-material ratio to obtain an activated ball mill powder; S2, oxygen-rich roasting: Place the activated ball mill powder in a roasting furnace, and introduce an oxidizing gas into the roasting furnace for roasting to obtain an oxygen-rich roasted material; S3, low-temperature alkali leaching: Place the oxygen-rich roasted material in an alkaline leaching medium according to a preset liquid-solid ratio. After the reaction ends, perform solid-liquid separation to obtain a vanadium and molybdenum metal enrichment solution.

2. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, characterized in that, The diameter of the grinding balls is 2 mm to 30 mm, and the grinding balls are proportioned according to any one of the first to tenth grades.

3. The method for metal recovery of the vanadium- and molybdenum-containing spent hydrodesulfurization catalyst according to claim 2, characterized in that, The grinding balls are proportioned according to the fourth grade ratio, and the fourth grade ratio includes: φ20:φ15:φ12:φ10 = 25%:35%:25%:15%, where φ is the diameter.

4. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, wherein The mass ratio of the spent hydrodesulfurization catalyst to the grinding balls is 2:1 to 12.

5. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, wherein The mixed material includes: 50-95% by mass of the spent hydrodesulfurization catalyst and 5-50% of the inorganic salt additive.

6. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, characterized in that, In the S2 step, an oxidizing gas with an oxygen volume concentration of 25-100% is introduced, the roasting temperature is 400-900 °C, and the roasting time is 1-6 h.

7. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, wherein The inorganic salt additive is at least one of calcium carbonate, calcium oxide, calcium hydroxide, sodium chloride, anhydrous sodium carbonate, and sodium hydroxide.

8. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, characterized in that, The alkaline leaching medium includes one or more of sodium hydroxide, potassium hydroxide, and sodium carbonate solutions with a mass percentage of 0.01-10 wt%.

9. The method for metal recovery of the spent hydrodesulfurization catalyst containing vanadium and molybdenum according to claim 1, characterized in that, In the S3 step, the preset liquid-solid ratio is 6-20 mL / g.

10. The method for metal recovery of the vanadium- and molybdenum-containing spent hydrodesulfurization catalyst according to claim 1, characterized in that, In the S3 step, the leaching time is 0.5-6 h, and the temperature of the leaching medium is 50-100 °C.

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