Method for electrochemical ultrasonic intensification of vanadium and molybdenum metal leaching from spent residue hydrotreating catalysts

Abstract

The application discloses a method for electrochemical ultrasonic intensification of vanadium and molybdenum metal leaching of failed residue oil hydrogenation catalyst, and the catalyst comprises 10-70% of Al2O3, 3-25% of V, 2-15% of Mo and 1-10% of Ni in percentage by mass, and the method comprises the following steps: S1, grinding and drying the failed residue oil hydrogenation catalyst, mixing the catalyst with a leaching agent according to a preset liquid-solid ratio to form leaching slurry; S2, adding a leaching aid to the leaching slurry and inserting at least one pair of electrodes, and meanwhile, applying ultrasonic waves to the leaching slurry to perform electrochemical ultrasonic intensification leaching; and S3, performing solid-liquid separation on the leaching slurry after the intensification leaching to obtain vanadium and molybdenum enriched leaching liquid and leaching residue. Through the synergistic effect of the electrochemical field, the ultrasonic field and the leaching aid on the leaching process of the failed catalyst, efficient leaching and recovery of vanadium and molybdenum metals are realized under low temperature and normal pressure, and the technical problems of low leaching efficiency, high energy consumption and large pollution in the traditional process are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrometallurgy, and particularly relates to a method for electrochemically and ultrasonically strengthening vanadium and molybdenum metal leaching of failed residue oil hydrogenation catalyst. BACKGROUND

[0002] Residue oil hydrogenation catalyst is a core material in the petroleum refining industry and is widely used in the purification and purification of petroleum products. It can efficiently remove sulfur, nitrogen and metal impurities (such as vanadium and nickel) in the raw material through catalytic hydrogenation reaction. However, as the reaction proceeds, the catalyst surface will gradually deactivate due to the deposition of sulfur, carbon and metal, forming waste catalyst. Such waste catalyst is listed as hazardous solid waste by many countries, but at the same time contains a large amount of valuable metal resources, such as vanadium (1%~15%), molybdenum (2%~8%), aluminum (12%~35%), nickel (0.5%~5.5%), and cobalt, sulfur, silicon, carbon, etc., which have significant environmental hazards and resource recycling value, especially rich in vanadium, molybdenum and other high-value metals. Therefore, it is urgent to develop an efficient recovery technology to achieve the dual goals of environmental protection and resource recycling.

[0003] Because vanadium, molybdenum, nickel and other metals in the failed residue oil hydrogenation catalyst often exist in the form of complex sulfide complex mineral phases (such as MoS2, NiMoS, V2S3), the traditional recovery process faces multiple challenges. Although sodium roasting process can convert vanadium and molybdenum into soluble salts, the process requires extremely high roasting temperature (>800℃), and a large amount of industrial waste gas such as SO2, CO2 and secondary solid waste difficult to leach will be generated during the process. Although the hydrometallurgical process can avoid high temperature and harmful gas emission, it can extract metals by directly converting sulfides into soluble salts, but because the target metals are often wrapped in carbon or closely associated with other elements, the traditional leaching method is inefficient. In the prior art, although there are schemes such as ultrasonic strengthening alkaline leaching, high-temperature separation based on the difference in volatility characteristics, etc., but all have obvious limitations: for example, the method described in CN118458744A is only for the recovery of fluorine and lithium in waste cathode carbon blocks, and does not cover the recovery of vanadium and molybdenum metals in failed residue oil hydrogenation catalyst; CN119913373A needs to rely on ultra-high temperature environment (>1000℃), which is energy-intensive and cannot solve the problems of raw material crushing and mineral phase regulation; CN108996547A involves ultrasonic-assisted alkali leaching of vanadium, but its technical core is to treat titanium tetrachloride refining tailings, and does not involve effective crushing and directional oxidation mechanism of vanadium / molybdenum sulfides. Therefore, the existing technology has not been able to systematically break through the technical bottleneck of resource utilization of failed residue oil hydrogenation catalyst, and the industry urgently needs a new leaching technology that can integrate the advantages of multiple technologies, produce a super strong synergistic effect under mild conditions, and achieve a high metal recovery rate. SUMMARY

[0004] The embodiment of the present application aims to provide a method for electrochemical ultrasonic enhanced vanadium and molybdenum metal leaching of failed residue oil hydrogenation catalyst, which realizes efficient leaching and recovery of vanadium and molybdenum metals at low temperature and normal pressure by synergistic effect of electrochemical field, ultrasonic field and leaching aid on the leaching process of the failed catalyst, and solves the technical problems of low leaching efficiency, high energy consumption and serious pollution caused by serious metal sulfide wrapping and harsh reaction conditions in the traditional process.

[0005] To solve the above technical problems, the embodiment of the present application provides a method for electrochemical ultrasonic enhanced vanadium and molybdenum metal leaching of failed residue oil hydrogenation catalyst, wherein the failed residue oil hydrogenation catalyst comprises 10-70% of Al2O3, 3-25% of V, 2-15% of Mo and 1-10% of Ni in terms of mass percentage, and the method comprises the following steps:

[0006] S1: grinding and drying the failed residue oil hydrogenation catalyst, mixing the failed residue oil hydrogenation catalyst with a leaching agent according to a preset liquid-solid ratio, and forming leaching slurry;

[0007] S2: adding a leaching aid to the leaching slurry and inserting at least one pair of electrodes, and applying ultrasonic waves to the leaching slurry to perform electrochemical ultrasonic enhanced leaching;

[0008] S3: performing solid-liquid separation on the leaching slurry after the enhanced leaching to obtain vanadium and molybdenum enriched leaching solution and leaching residue.

[0009] Further, the electrochemical ultrasonic enhanced leaching further comprises:

[0010] detecting the oxidation-reduction potential value of the leaching slurry through the oxidation-reduction potential sensor integrated in the reaction system;

[0011] based on the oxidation-reduction potential value, dynamically adjusting at least one of the current density applied to the electrodes, the ultrasonic power value applied and the addition rate of the leaching aid through a closed-loop feedback control system, so that the oxidation-reduction potential value of the leaching slurry is maintained within a preset potential range.

[0012] Further, the preset potential range is +0.3 V to +1.2 V.

[0013] Further, at least one of the electrode pair is a three-dimensional structure electrode.

[0014] The three-dimensional structure electrode is one or more of foamed nickel, foamed copper, foamed silver and foamed titanium, the pore size is 0.1 mm to 5 mm, the porosity is 60% to 95%, the thickness is 5 mm to 50 mm, and the specific surface area is not less than 200 m 2 / m 3 .

[0015] Further, the extension direction of the porous channel inside the three-dimensional electrode is 45°-90° with the propagation direction of the ultrasonic wave.

[0016] Further, the electric field applied to the electrode is a pulse electric field.

[0017] The pulse current frequency of the pulse electric field is 150 Hz-1000 Hz.

[0018] Further, the calculation formula between the pulse current frequency of the pulse electric field and the frequency of the ultrasonic wave is:

[0019] f u = N × f p ;

[0020] Wherein, f u is the pulse current frequency of the pulse electric field, f p is the frequency of the ultrasonic wave, and N is a positive integer of 10-200.

[0021] Further, the leaching aid is one or more of hydrogen peroxide, sodium persulfate and sodium thiosulfate.

[0022] Further, when the leaching aid is hydrogen peroxide or sodium persulfate, the ratio of the molar amount of effective oxygen in the leaching aid to the total molar amount of vanadium and molybdenum is 1.0-3.0, based on the total mass of vanadium and molybdenum in the spent residue oil hydrogenation catalyst.

[0023] Further, the temperature of the leaching slurry in the electrochemical ultrasonic intensification leaching process is 50℃-80℃.

[0024] The above technical solutions of the embodiments of the present application have the following beneficial technical effects:

[0025] 1. By using a three-dimensional electrode with a specific pore size, porosity and high specific surface area, and making the extension direction of the internal porous channel of the electrode 45°-90° with the propagation direction of the ultrasonic wave, a spatially coupled intensified reaction field is constructed; the ultrasonic wave produces strong cavitation effect and micro-flow disturbance in the complex pores inside the electrode, greatly enhancing the mass transfer efficiency and reactant renewal rate of the solid-liquid interface; at the same time, the three-dimensional electrode provides a large electrochemical active surface, making the electric field distribution more uniform; this synergistic design in space configuration effectively breaks down the mass transfer barrier caused by the carbonaceous and sulfide wrapping in the spent catalyst, enabling the reaction reagent and active radicals to efficiently contact and attack the target mineral phase, achieving efficient oxidation leaching of low-valence vanadium and molybdenum under mild conditions, with vanadium and molybdenum leaching rate >98%;

[0026] 2. By integrating the redox potential sensor with the closed-loop feedback control system, taking the real-time redox potential value of the reaction system as the core control index, dynamically linking and adjusting the current density, ultrasonic power and leaching additive addition rate, the precise optimization and adaptive control of the leaching process are realized; it can ensure that the reaction always maintains in the optimal oxidation potential interval of +0.3~+1.2V, so that the low-valence vanadium and molybdenum sulfide is continuously oxidized to the easily soluble high-valence state, while avoiding the invalid decomposition or side reaction caused by excessive addition of oxidizing agent; based on the intelligent control of the key chemical parameters of the reaction process, not only the utilization efficiency of reagents and energy is significantly improved, but also the efficiency and stability of the leaching process are ensured, avoiding the problems of large recovery rate fluctuation and high cost caused by extensive process control in the traditional leaching process;

[0027] 3. By adopting pulse electric field and cooperatively designing its frequency with the ultrasonic frequency (for example, matching the excitation period of pulse current with the transient period of local high temperature and high pressure generated by ultrasonic cavitation), the precise superposition and release of electrochemical energy and acoustic energy on the microscale are realized; the time-frequency coupling mechanism makes the pulse electric field provide high-intensity electrochemical impact at the moment when the ultrasonic cavitation effect is most significant and the strongest oxidation environment is most needed, thereby greatly promoting the in-situ generation and utilization of active species such as hydroxyl radicals; the synergy of the two physical fields in energy release produces a reinforcement effect of "1+1>2", realizes the efficient breaking of the stubborn V-S-O-V or Mo-S-O-V valence bond in the catalyst and the sufficient oxidation of low-valence vanadium and molybdenum metal, and achieves a breakthrough effect of nearly 99% leaching of vanadium and molybdenum without harsh conditions of high temperature and high pressure. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the process flow chart of the method for electrochemical ultrasonic enhanced leaching of vanadium and molybdenum metals of failed residue oil hydrogenation catalyst provided by the embodiment of the present application;

[0029] Figure 2 is the process schematic diagram of the electrochemical ultrasonic enhancement provided by the embodiment of the present application;

[0030] Figure 3 is the EPR peak spectrum of hydroxyl radicals detected during the electrochemical ultrasonic enhanced leaching. DETAILED DESCRIPTION

[0031] To make the purpose, technical scheme and advantages of the present application more clear and explicit, the present application is further described in detail below with reference to the specific embodiments and the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0032] Please refer to Figure 1The embodiment of the present application provides a method for electrochemical ultrasonic enhanced vanadium and molybdenum leaching from failed residue oil hydrogenation catalyst, the failed residue oil hydrogenation catalyst comprises 10-70% of Al2O3, 3-25% of V, 2-15% of Mo and 1-10% of Ni in terms of mass percentage, and the method comprises the following steps:

[0033] S1: grinding and drying the failed residue oil hydrogenation catalyst, mixing with a leaching agent according to a preset liquid-solid ratio to form leaching slurry.

[0034] Firstly, the failed residue oil hydrogenation catalyst is pretreated. Typical components of the catalyst include (mass percentage): 10-70% of Al2O3, 3-25% of V, 2-15% of Mo and 1-10% of Ni, wherein vanadium and molybdenum mainly exist in the form of insoluble vanadium oxide (VO2), vanadium sulfide (V2S3), molybdenum oxide (MoO2), molybdenum sulfide (MoS2) and carbonaceous inclusions. The pretreatment comprises grinding and drying: using mechanical ball milling to grind the raw material to a particle size of less than 70 μm, and more than 90% of the particles are greater than 70 μm; then drying at a temperature of 60-300 ℃ for 60-240 minutes. The catalyst powder after drying is mixed with a leaching agent according to a liquid-solid ratio of 5-50 mL / g to form leaching slurry. The leaching agent is one or more of NaOH solution or KOH solution, and the concentration is 10-400 g / L.

[0035] S2: adding a leaching aid to the leaching slurry and inserting at least one pair of electrodes, while applying ultrasonic waves to the leaching slurry, to perform electrochemical ultrasonic enhanced leaching.

[0036] In the formed leaching slurry, at least one pair of electrodes (anode and cathode) is inserted to apply an electric field, while ultrasonic waves are applied to the slurry, and a leaching aid is added, to perform electrochemical ultrasonic enhanced leaching. At least one of the electrodes can be preferably a three-dimensional electrode with a pore size of 0.1-5 mm, a porosity of 60%-95%, a thickness of 5-50 mm, and a specific surface area of not less than 200 m 2 / m 3 ; the direction of the porous channel inside the three-dimensional electrode is preferably at an angle of 45°-90° with the propagation direction of the ultrasonic waves to enhance the synergistic effect. The electric field can be provided by a pulse or a direct current power supply, when a pulse is used, the frequency is 150-1000 Hz, and the current density of the system is controlled at 1-500 mA / cm 2The ultrasound is generated by a probe ultrasound probe with a frequency of 20-28 kHz and a power intensity of 100-1600 W / L, and the sound field direction of the probe is arranged non-parallel to the surface of the electrode. The leaching aid is one or more of 30% hydrogen peroxide, sodium persulfate and sodium thiosulfate; when hydrogen peroxide or sodium persulfate is used, the addition amount is 1.0-3.0 times the molar ratio of the effective oxygen in the leaching aid to the total moles of vanadium and molybdenum based on the total mass of vanadium and molybdenum in the catalyst. The temperature of the entire leaching reaction system is controlled at 50-80°C, and the oxidation-reduction potential (ORP) sensor integrated in the system can be used to monitor the oxidation-reduction potential in real time. The oxidation-reduction potential is used as the core index, and the current density, ultrasonic power or leaching aid addition rate is dynamically adjusted through a closed-loop feedback system to maintain the oxidation-reduction potential value of the system in the target range of +0.3 to +1.2 V (vs. Ag / AgCl), ensuring that vanadium and molybdenum are fully oxidized to high valence states (V(V) and Mo(VI)) and stably dissolved. The electrochemical ultrasonic enhanced leaching time is 5-180 minutes.

[0037] S3: solid-liquid separation is performed on the leaching slurry after the completion of the enhanced leaching to obtain a vanadium-molybdenum enriched leaching solution and a leaching residue.

[0038] After the completion of the electrochemical ultrasonic enhanced leaching, solid-liquid separation is performed on the leaching slurry after the reaction. Two products are obtained after separation: one is a leaching solution rich in high-valence vanadium and molybdenum, i.e., a vanadium-molybdenum enriched solution, which can be used in subsequent separation and purification processes to produce ammonium metavanadate and ammonium molybdate products; the other is a solid residue, i.e., a leaching residue, which can be used as a raw material for the recovery of other valuable metals (such as nickel) after drying.

[0039] Further, the electrochemical ultrasonic enhanced leaching in step S2 further includes:

[0040] S21: detecting the oxidation-reduction potential value of the leaching slurry by the oxidation-reduction potential sensor integrated in the reaction system.

[0041] In the electrochemical ultrasonic intensified leaching process, the redox potential value in the leaching slurry is continuously monitored in real time by a redox potential sensor integrated in the reaction vessel. The sensor uses a three-electrode system with a silver chloride electrode as the reference electrode. The measurement probe is directly immersed in the slurry. By detecting the potential difference between the working electrode and the reference electrode, the redox state of the entire reaction system is accurately reflected. In the alkaline leaching system of the failed residue oil hydrogenation catalyst, the redox potential value directly represents the concentration of active oxidizing substances in the leaching medium and its oxidation ability to vanadium and molybdenum. When vanadium and molybdenum exist in the form of low-valence oxides or sulfides, the oxidation of the system is weak, and the potential value is low. With the generation of hydroxyl radicals by electrochemistry and ultrasonic and the decomposition of leaching aids, the oxidation of the system is enhanced, vanadium and molybdenum are gradually oxidized to high-valence state, and the potential value is correspondingly increased. The monitoring data is transmitted in real time to the control system through a signal converter, forming a continuous trend curve, which provides a direct and quantitative chemical basis for the judgment and control of the reaction process. For example, in actual operation, when the sensor detects that the potential value reaches +1.0V or above, it usually indicates that vanadium and molybdenum have been basically oxidized to soluble vanadate and molybdate ions.

[0042] S22: Based on the redox potential value, at least one of the current density applied to the electrode, the ultrasonic power value applied, and the addition rate of leaching aids is dynamically adjusted by a closed-loop feedback control system to maintain the redox potential value of the leaching slurry within a preset potential range.

[0043] Based on the real-time obtained oxidation-reduction potential value, the closed-loop feedback control system dynamically adjusts at least one of the current density applied to the electrode, the output power of the ultrasonic wave, and the addition rate of the leaching aid, to stabilize the oxidation-reduction potential of the reaction system in the preset target range (usually +0.3 V to +1.2 V). The control system takes a programmable logic controller as the core, receives the potential signal from the sensor, compares it with the preset value, and calculates the required adjustment amount through the internal proportional-integral-derivative algorithm, and then issues instructions to the actuator. When the monitored potential is lower than the lower limit of the set range, it means that the oxidation capacity of the system is insufficient, and the controller may instruct the direct current or pulse power to increase the output current density to strengthen the anode oxidation reaction, or instruct the ultrasonic generator to increase the output power to enhance the cavitation effect to generate more active oxygen free radicals, or instruct the metering pump to increase the feeding rate of the leaching aid to directly supplement the oxidant. Conversely, if the potential value exceeds the upper limit, the above parameters are adjusted accordingly to prevent the invalid decomposition of the oxidant and energy waste. This dynamic adjustment ensures that the reaction is always in the optimal oxidation environment, both fully ensuring the oxidation dissolution efficiency of vanadium and molybdenum, and achieving precise quantitative control of reagents and energy consumption. In specific implementation, for example, under the conditions of using 1 mol / L sodium hydroxide solution, liquid-solid ratio of 10:1, and temperature of 80°C, through the closed-loop system linkage adjustment, the current density can be stabilized at 400-500 mA / cm 3 interval, the ultrasonic power density is maintained at the level of 400-600 W / L, and the addition rate of 30% hydrogen peroxide is controlled within 0.2 grams per minute per gram of catalyst.

[0044] By implementing the closed-loop feedback control based on the real-time monitoring of oxidation-reduction potential, the present application realizes the accurate real-time perception and self-adaptive regulation of the chemical state of the electrochemical ultrasonic enhanced leaching process. The core chemical indicators of the reaction process are directly linked to the key operation parameters, forming a complete control loop from state perception, intelligent decision-making to precise execution, ensuring that the reaction system always maintains within the target oxidation potential interval, creating a stable and controllable chemical environment for efficient and sufficient oxidation of vanadium and molybdenum. At the same time, this method effectively overcomes the problems of excessive reagent addition, energy invalid dissipation, or insufficient oxidation caused by fixed parameters in traditional open-loop control, significantly improving the utilization efficiency of oxidants and the energy efficiency of the process, and ultimately maximizing the leaching rate of vanadium and molybdenum and optimizing the process stability under mild process conditions.

[0045] Further, the preset potential range is +0.3 V ~ +1.2 V.

[0046] In the alkaline solution of sodium hydroxide or potassium hydroxide, vanadium and molybdenum need to be fully oxidized from the low valence state (such as V(IV), Mo(IV)) in the raw material to the soluble high valence state, i.e. pentavalent vanadium (V(V) in the form of vanadate) and hexavalent molybdenum (Mo(VI) in the form of molybdate), which requires the system to have a high enough oxidation potential. When the redox potential is lower than +0.3 V, it indicates that the system has insufficient oxidation capacity, and the oxidation reaction of vanadium and molybdenum has weak driving force, which cannot effectively destroy the stable structure of its sulfide or low-valence oxide, resulting in low leaching rate. As the potential rises and enters the interval of +0.3 V to +1.2 V, the system has strong oxidizing ability under the combined action of electrochemical anodic oxidation, hydroxyl radicals generated by ultrasonic cavitation and external oxidizing agents (such as hydrogen peroxide and persulfate), which is enough to break the stubborn chemical bonds of V-S and Mo-S and oxidize the metal ions to the target high valence state, thereby realizing efficient dissolution. However, the potential should not be increased unlimitedly, and the upper limit is set to +1.2 V to prevent the adverse effects of excessive oxidation: on the one hand, too high a potential may promote the catalytic decomposition of leaching aids (such as hydrogen peroxide) without effect, reducing their utilization rate and possibly generating a large amount of gas; on the other hand, under extremely high potential, some dissolved high-valence metal complexes may undergo disproportionation or other side reactions, affecting subsequent separation and purification, and extremely strong electrochemical conditions may also exacerbate electrode side reactions and equipment corrosion.

[0047] Further, at least one of the electrodes in the pair is a three-dimensional electrode; the three-dimensional electrode is one or more of foamed nickel, foamed copper, foamed silver, foamed titanium, the pore size is 0.1 mm to 5 mm, the porosity is 60% to 95%, the thickness is 5 mm to 50 mm, and the specific surface area is not less than 200 m 2 / m 3 .

[0048] Such a three-dimensional porous electrode, unlike traditional flat electrodes, has a network of interconnected and controllable size channels inside. The pore size is in the range of 0.1 to 5 mm, which can ensure that the solid catalyst particles and gas bubbles in the leaching slurry can pass through or escape smoothly, avoiding blockage, and can form significant turbulent flow and boundary layer effects inside the channels, strengthening mass transfer. A porosity of up to 60% to 95% means that most of the electrode volume is pore space, which greatly reduces the resistance of the fluid passing through and provides a large three-phase (solid-liquid-gas) interface area for electrochemical reactions, ultrasonic cavitation effects, and chemical reactions. The electrode thickness is designed to be 5 mm to 50 mm, which ensures that the electrode has sufficient mechanical strength and electrical conductivity, and provides sufficient depth diffusion and reaction space for the reactants, so that the electric field and ultrasonic field can be fully extended in the three-dimensional direction. The specific surface area is not less than 200 m 2 / m 3The volume specific surface area of the three-dimensional electrode is improved by orders of magnitude compared with the flat plate electrode, which directly translates into a dramatic increase in the electrochemically active surface area, so that at the same apparent current density, the real current density is significantly reduced, thereby reducing electrode polarization, improving current efficiency, and facilitating uniform and efficient production of active species such as hydroxyl radicals. In actual operation, for example, using a three-dimensional electrode with a pore size of about 1 mm, a porosity of about 85%, a thickness of about 20 mm, made of foamed nickel, foamed copper, foamed silver, foamed titanium or carbon felt material, in alkaline leaching slurry, the huge internal surface becomes a dense occurrence area for electrochemical reaction and ultrasonic cavitation, effectively promoting the solid-liquid interface renewal and the oxidation and dissolution process of the target metal.

[0049] Further, the direction of the porous channel inside the three-dimensional electrode is at an angle of 45°-90° with the propagation direction of the ultrasonic wave.

[0050] The ultrasonic wave propagates in the liquid medium in the form of a longitudinal wave, and the energy transmission and cavitation effect have obvious directionality. When the propagation direction of the sound wave is close to parallel with the direction of the through-hole inside the electrode (smaller angle), the sound wave can pass through the hole more smoothly, but the shear effect on the inner wall of the hole and the secondary effects such as vortex and microjet formed inside the hole are weaker. When the angle between the two directions increases to 45° or more until perpendicular (90°), the propagation direction of the sound wave deviates significantly from the axial direction of the hole. At this time, the sound wave will encounter a large number of irregular solid-liquid interfaces when entering the porous electrode, resulting in strong scattering, refraction and interference phenomena. This interaction leads to more efficient dispersion, absorption and conversion of sound field energy inside the three-dimensional electrode, on the one hand, generating stronger periodic fluid shear force near the inner wall of the hole, which is beneficial to the stripping of the passivation layer or solid particles attached to the surface of the electrode, and promoting the interface renewal; on the other hand, it is easier to induce strong cavitation bubble collapse at the intersection or local narrow area of the hole, generating local high temperature, high pressure and high-speed microjet. These microjets can penetrate deep into the hole and disturb the boundary layer, thereby greatly enhancing the mass transfer and diffusion process of reactants and products inside the electrode pores. In actual implementation, for example, the sound emitting surface of the ultrasonic probe is perpendicular (i.e. 90° angle) to the side of the three-dimensional electrode composed of foamed metal, so that the sound wave is perpendicular to the main hole direction inside the electrode, and the circulation flow of the leaching slurry in the electrode pores is observed to be significantly intensified, the bubbles on the electrode surface are detached faster, and the overall leaching kinetics is effectively improved.

[0051] Further, the electric field applied to the electrode is a pulse electric field; the pulse current frequency of the pulse electric field is 150 Hz-1000 Hz.

[0052] Unlike direct current field, pulsed electric field forms a high current density transient excitation in each pulse cycle and then enters a zero or low current intermittent period through periodic on and off. When the frequency is between 150 Hz and 1000 Hz, the corresponding single pulse cycle time is between about 6.67 milliseconds and 1 millisecond. This time scale has specific advantages: on the one hand, it is much shorter than the time for the concentration difference polarization to be established by the conventional diffusion process, so that in the high current density stage of pulse conduction, a high concentration of active species (such as hydroxyl radicals) can be quickly generated on the electrode surface, and in the subsequent intermittent period, the reactants are replenished and the products are removed in time through liquid phase diffusion and ultrasonic disturbance, thereby effectively relieving the concentration difference polarization and maintaining a high electrochemical reaction efficiency; on the other hand, there is a reasonable multiple relationship between this frequency range and the ultrasonic frequency (usually 20 kHz to 28 kHz) used in the system, which creates conditions for the coupling of the two physical fields in time. For example, when the ultrasonic frequency is 20 kHz, its single acoustic cycle is 50 microseconds, and a 200 Hz pulse cycle (5 milliseconds) can contain about 100 ultrasonic cycles, which makes it possible to synchronize the on period of pulsed current with the key transient of ultrasonic cavitation bubble collapse to produce local high temperature, high pressure and strong microjet, thereby concentrating energy in space and time and strengthening the interface reaction. In actual operation, for example, in a system using 1 mol / L NaOH leaching agent, liquid-solid ratio 10:1, temperature 80℃, setting the pulse frequency to 200 Hz, duty cycle 50%, peak current density 500 mA / cm 2 , and cooperating with 20 kHz, 600 W / L ultrasonic waves, stable high leaching efficiency can be observed.

[0053] Further, the calculation formula between the pulse current frequency of pulsed electric field and the frequency of ultrasonic waves is:

[0054] f u = N × f p ;

[0055] Wherein, f u is the pulse current frequency of pulsed electric field, f p is the frequency of ultrasonic waves, and N is a positive integer between 10 and 200.

[0056] When the ultrasonic wave propagates in the leaching slurry, it produces periodic compression and rarefaction at a specific frequency (usually in the range of 20 kHz to 28 kHz), each cycle of which is accompanied by the nucleation, growth and violent collapse of cavitation bubbles, and at the moment of collapse, it produces local extreme high temperature, high pressure and strong impact microjet. The pulsed electric field is periodically applied to the electrode at another specific frequency (in the range of 150 Hz to 1000 Hz) to produce high concentration of electrically generated free radicals (such as hydroxyl radicals) and to intensify the electrochemical oxidation reaction on the electrode surface and in the liquid layer near the electrode during the conduction phase of each pulse. When the ultrasonic frequency is an integer multiple of the pulse frequency (i.e. formula f u = N × f p where N is a positive integer) of the pulse frequency, the system will experience an integer number of complete ultrasonic cavitation cycles within each pulse cycle. Through synchronous control technology, the starting conduction time of the pulsed current can be accurately set to repeatedly align with the specific phase point in the ultrasonic wave cycle where the cavitation effect is most significant and the strong oxidation environment is most needed (for example, the moment of cavitation bubble collapse); ensuring that in the micro regions and moments created by ultrasonic waves with strong local mixing and extreme physical and chemical conditions, the strong electrochemical oxidation energy provided by the pulsed electric field can be most concentrated and most effectively utilized, thereby achieving precise coupling and synergistic amplification of the two energy forms in time and space.

[0057] N is limited to between 10 and 200, which is a feasible and effective matching interval calculated based on the commonly used ultrasonic frequency range and pulse frequency range of the system. For example, when using ultrasonic waves with a frequency of 20 kHz, if N = 100, the corresponding pulse frequency is 200 Hz; if N = 50, the pulse frequency is 400 Hz, which all fall within the effective working range of 150 Hz to 1000 Hz.

[0058] Optionally, the leaching aid is one or more of hydrogen peroxide, sodium persulfate and sodium thiosulfate. Both hydrogen peroxide and sodium persulfate are strong oxidants with high standard electrode potentials, which can provide active oxygen in alkaline environment to directly participate in or promote the oxidation process of vanadium and molybdenum from low valence to high valence. More importantly, under the local high temperature and high pressure environment generated by ultrasonic cavitation effect, the decomposition kinetics of these oxidants is significantly accelerated, and strong oxidizing species such as hydroxyl radicals are more likely to be generated; at the same time, the electrochemical anode process can also directly or indirectly catalyze its decomposition, further improving the oxidation efficiency. The mechanism of sodium thiosulfate is different. In an alkaline system, it can act as a mild reducing agent to adjust the local oxidation-reduction environment and prevent some metals from being excessively oxidized and precipitated. Its thiosulfate ions can also form soluble complexes with some metal ions, thereby promoting the dissolution and mass transfer of metal ions. When electrochemistry and ultrasonic waves are used in combination, the cavitation and stirring effect of ultrasonic waves can greatly improve the dispersion uniformity of these leaching aids in the slurry, prevent the decomposition of the leaching aids due to the local high concentration, and the presence of an electric field can change the adsorption and reaction path of the aid molecules on the electrode surface, thereby optimizing the utilization efficiency. In actual implementation, for example, under the process conditions of 1 mol / L NaOH solution, liquid-solid ratio of 10:1, and temperature of 80°C, hydrogen peroxide with a mass concentration of 30% can be added alone, and the amount of addition is accurately calculated according to the effective oxygen molar ratio based on the total content of vanadium and molybdenum in the catalyst; or they can be used in combination, such as adding sodium persulfate at the beginning to provide a strong oxidizing atmosphere, and then adding a small amount of sodium thiosulfate to stabilize the leaching solution system.

[0059] Further, when the leaching aid is hydrogen peroxide or sodium persulfate, the ratio of the molar amount of effective oxygen in the leaching aid to the total molar amount of vanadium and molybdenum is 1.0-3.0, based on the total mass of vanadium and molybdenum in the spent hydroprocessing catalyst.

[0060] When hydrogen peroxide or sodium persulfate is used as leaching aid, the control of its addition amount is not based on simple mass ratio, but an accurate metering method based on reaction stoichiometry is adopted, which is specifically specified as follows: the ratio of the effective oxygen provided by the leaching aid (hydrogen peroxide or sodium persulfate) to the total molar amount of vanadium and molybdenum (converted from the total mass of vanadium and molybdenum in the spent oil hydroprocessing catalyst) should be controlled within the range of 1.0 to 3.0. The oxidation of vanadium and molybdenum from low valence state (such as V(IV), Mo(IV)) to soluble high valence state (V(V), Mo(VI)) in the raw material is the key step of leaching, and this process requires a certain amount of active oxygen. In theory, 0.5 moles of O (or equivalent oxidizing agent) are required to oxidize 1 mole of V(IV) to V(V), and 1 mole of O is required to oxidize 1 mole of Mo(IV) to Mo(VI). However, the actual system is more complex: vanadium and molybdenum in the raw material often exist in the form of sulfides or complex oxides, and the process of their oxidation and dissolution may be accompanied by side reactions such as desulfurization, which requires additional oxygen; the electrochemical anode process and ultrasonic cavitation effect in the system can produce hydroxyl radicals and other active oxygen species, which can share part of the oxidation function; the additional oxidizing agent has the risk of ineffective decomposition under the conditions of strong alkalinity, high temperature and multi-field coupling. Therefore, the lower limit of the ratio of effective oxygen to total metal molar amount is set to 1.0, which aims to ensure that enough basic stoichiometric oxygen is provided to meet the theoretical needs of complete oxidation of all target metals to the target valence state, and to provide the necessary margin to overcome mass transfer limitations and competing reactions, thereby ensuring high leaching rate.

[0061] Further, the temperature value of the leaching slurry in the electrochemical ultrasonic enhanced leaching process is 50 ℃ to 80 ℃.

[0062] Controlling the temperature of the leaching slurry within the range of 50℃ to 80℃ during the reaction process is an optimized operating range determined after comprehensively considering multiple factors such as reaction kinetics, reagent stability, energy consumption, and process controllability. From a reaction kinetics perspective, increasing the temperature can generally significantly increase the chemical reaction rate constant. Within the 50℃ to 80℃ range, the rates of vanadium and molybdenum sulfide oxidation and dissolution reactions, as well as related interfacial mass transfer processes, are effectively enhanced, thereby accelerating the overall leaching kinetics. However, higher temperatures are not always better; the upper limit of 80℃ is mainly based on protecting the stability of the leaching agent and leaching aids. The alkaline leaching agent used in this system (such as NaOH solution) becomes more corrosive to the equipment at high temperatures, and the thermal decomposition rate of leaching aids such as hydrogen peroxide or sodium persulfate is significantly accelerated in environments exceeding 80℃. This results in a large amount of ineffective loss of their effective oxygen components before reaching the target reaction interface, reducing utilization efficiency and potentially generating gases that interfere with the reaction. Meanwhile, this upper temperature limit also helps maintain the stability of dissolved high-valent vanadium (V(V)) and molybdenum (Mo(VI)) complexes in alkaline solutions, preventing hydrolysis precipitation or disproportionation reactions at high temperatures. Setting the lower limit at 50℃ ensures that the system possesses sufficient fundamental thermodynamic driving force when introducing the synergistic effect of electrochemical and ultrasonic fields, allowing the physical field enhancement effect to function at a reasonable reaction rate. This avoids the inability to achieve efficient leaching at excessively low temperatures due to the slow intrinsic reaction even with an external field. Furthermore, this mid-temperature range (50-80℃) has good compatibility with the electrochemical process, helping to maintain appropriate electrolyte conductivity and electrode reactivity, while also relatively lowering the cavitation threshold of ultrasound, making the cavitation effect easier to generate and maintain. In practical operation, for example, in a system using 1 mol / L NaOH solution with a liquid-to-solid ratio of 10:1, the temperature is stably controlled at 80℃, and a 200 Hz pulsed current (500 mA / cm²) is applied. 2 Using 20 kHz ultrasound (600 W / L), a vanadium and molybdenum leaching rate of nearly 99% can be achieved, and the process is stable with economical reagent consumption.

[0063] In the experiments of Example 1 and Comparative Example 1, reactive oxygen species in the leaching system were detected using EPR, and the detection results are as follows: Figure 3 As shown, during ultrasonic and electrochemical field-enhanced leaching, typical hydroxyl radical characteristic peaks appeared in the liquid phase. The presence of highly oxidizing hydroxyl radicals significantly enhanced the oxidative leaching of low-valent vanadium and molybdenum in the system, increasing the leaching rates of vanadium and molybdenum from 62.28% and 54.56% in the comparative example to 99.36% and 99.18%, respectively.

[0064] The above method will be further explained and illustrated below with several comparative examples and embodiments.

[0065] Comparative Example 1

[0066] The pretreated spent residue hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, and then hydrogen peroxide (30% concentration) was added dropwise according to the mass ratio of hydrogen peroxide to spent residue hydrogenation catalyst of 0.2 g / g, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process separation and purification of raw materials to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 65.94%, and the Mo leaching rate was 53.54%.

[0067] Comparative Example 2

[0068] The pretreated spent residue hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, and then hydrogen peroxide (30% concentration) was added dropwise according to the mass ratio of hydrogen peroxide to spent residue hydrogenation catalyst of 0.2 g / g, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process separation and purification of raw materials to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 65.94%, and the Mo leaching rate was 53.54%.

[0069] Comparative Example 3

[0070] The pretreated spent residue hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, and then hydrogen peroxide (30% concentration) was added dropwise according to the mass ratio of hydrogen peroxide to spent residue hydrogenation catalyst of 0.2 g / g, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process separation and purification of raw materials to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 65.94%, and the Mo leaching rate was 53.54%.

[0071] Comparative Example 4

[0072] The pretreated spent residue hydroprocessing catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, then the electrochemical field was applied, the pulse current frequency was set to 200 Hz, the current density was set to 500 mA / cm 2 , and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried and used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process to separate and purify the raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate showed that the V leaching rate was 74.64%, and the Mo leaching rate was 72.37%.

[0073] Comparative Example 5

[0074] The pretreated spent residue hydroprocessing catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, then the electrochemical field was applied with an ultrasonic external field, the pulse current frequency was set to 200 Hz, the electrochemical field cathode and anode were stainless steel plate electrodes, the current density was set to 500 mA / cm 2 , the ultrasonic frequency was 20 kHz, the power intensity was 600 W / L, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried and used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process to separate and purify the raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate showed that the V leaching rate was 74.64%, and the Mo leaching rate was 72.37%.

[0075] Example 1

[0076] The pretreated spent residue hydroprocessing catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, then the electrochemical field was applied with an ultrasonic external field, the pulse current frequency was set to 200 Hz, the electrochemical field cathode and anode were three-dimensional structure foam nickel electrodes, the current density was set to 500 mA / cm 2, the ultrasonic frequency is 20 kHz, the power intensity is 600 W / L, the hydrogen peroxide (30% concentration) is added drop by drop according to the mass ratio of 0.2 g / g, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for the next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate shows that the V leaching rate is 99.36%, and the Mo leaching rate is 99.18%.

[0077] Example 2

[0078] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heated to 80°C, and at the same time, an electrochemical and ultrasonic external field is applied, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam nickel electrodes, the current density is set to 500 mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 400 W / L, the hydrogen peroxide (30% concentration) is added drop by drop according to the mass ratio of 0.2 g / g, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for the next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate shows that the V leaching rate is 98.67%, and the Mo leaching rate is 97.86%.

[0079] Example 3

[0080] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heated to 80°C, and at the same time, an electrochemical and ultrasonic external field is applied, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam nickel electrodes, the current density is set to 500 mA / cm 2, the ultrasonic frequency is 20 kHz, the power intensity is 400 W / L, the mass ratio of sodium persulfate to the spent residue oil hydrogenation catalyst is 2 g / g, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing leaching filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for next-step process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo contents in the leaching filtrate shows that the V leaching rate is 98.96% and the Mo leaching rate is 98.35%

[0081] Example 4

[0082] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heating to 80°C, and at the same time, an electrochemical and ultrasonic external field is applied, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam nickel electrodes, and the current density is set to 400 mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 600 W / L, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing leaching filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for next-step process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo contents in the leaching filtrate shows that the V leaching rate is 98.12% and the Mo leaching rate is 98.03%.

[0083] Example 5

[0084] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heating to 80°C, and at the same time, an electrochemical and ultrasonic external field is applied, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam nickel electrodes, and the current density is set to 400 mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 600 W / L, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing leaching filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for next-step process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo contents in the leaching filtrate shows that the V leaching rate is 98.12% and the Mo leaching rate is 98.03%.

[0085] Example 6

[0086] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, and the temperature was heated to 80°C. The ultrasonic field was applied to the electrochemical field, the pulse current frequency was set to 200 Hz, the anode and cathode of the electrochemical field were three-dimensional foam copper electrodes, and the current density was set to 500 mA / cm 2 The ultrasonic frequency was 20 kHz, the power intensity was 600 W / L, the hydrogen peroxide (30% concentration) was added dropwise according to the mass ratio of hydrogen peroxide to spent residue oil hydrogenation catalyst of 0.2 g / g, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 98.54%, and the Mo leaching rate was 97.89%.

[0087] Example 7

[0088] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, and the temperature was heated to 80°C. The ultrasonic field was applied to the electrochemical field, the pulse current frequency was set to 200 Hz, the anode and cathode of the electrochemical field were three-dimensional foam copper electrodes, and the current density was set to 500 mA / cm 2 The ultrasonic frequency was 20 kHz, the power intensity was 400 W / L, the hydrogen peroxide (30% concentration) was added dropwise according to the mass ratio of hydrogen peroxide to spent residue oil hydrogenation catalyst of 0.2 g / g, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 98.54%, and the Mo leaching rate was 97.89%.

[0089] Example 8

[0090] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, while applying electrochemical and ultrasonic external field, the pulse current frequency was set to 200 Hz, the anode and cathode of the electrochemical field were three-dimensional foam copper electrodes, the current density was set to 500 mA / cm 2 , the ultrasonic frequency was 20 kHz, the power intensity was 400 W / L, the mass ratio of sodium persulfate to spent residue oil hydrogenation catalyst was 2 g / g, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 98.16%, and the Mo leaching rate was 97.42%.

[0091] Example 9

[0092] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, while applying electrochemical and ultrasonic external field, the pulse current frequency was set to 200 Hz, the anode and cathode of the electrochemical field were three-dimensional foam copper electrodes, the current density was set to 400 mA / cm 2 , the ultrasonic frequency was 20 kHz, the power intensity was 600 W / L, and the leaching time was 60 min. The slurry after reaction was subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue was dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate was used for the next step process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of V and Mo content in the leaching filtrate showed that the V leaching rate was 96.88%, and the Mo leaching rate was 96.17%.

[0093] Example 10

[0094] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent were added to three leaching tanks, the liquid-solid ratio was 10:1 mL / g, the stirring speed was 400 rpm / min, heated to 80°C, while applying electrochemical and ultrasonic external field, the pulse current frequency was set to 200 Hz, the anode and cathode of the electrochemical field were three-dimensional foam copper electrodes, the current density was set to 400 mA / cm 2, the ultrasonic frequency is 20 kHz, the power intensity is 600W / L, the mass ratio of sodium persulfate to the spent residue oil hydrogenation catalyst is 2g / g, and the leaching time is 60min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing leaching filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis is performed on the V and Mo contents in the leaching filtrate, and the results show that the V leaching rate is 95.72%, and the Mo leaching rate is 95.31%.

[0095] Example 11

[0096] The pretreated spent residue oil hydrogenation catalyst and 1mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1mL / g, the stirring speed is 400rpm / min, heating to 80°C, and then an electrochemical field and an ultrasonic field are applied, the pulse current frequency is set to 200Hz, the anode and cathode of the electrochemical field are three-dimensional foam silver electrodes, the current density is set to 500mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 600W / L, the mass ratio of sodium persulfate to the spent residue oil hydrogenation catalyst is 2g / g, and the leaching time is 60min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing leaching filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis is performed on the V and Mo contents in the leaching filtrate, and the results show that the V leaching rate is 95.72%, and the Mo leaching rate is 95.31%.

[0097] Example 12

[0098] The pretreated spent residue oil hydrogenation catalyst and 1mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1mL / g, the stirring speed is 400rpm / min, heating to 80°C, and then an electrochemical field and an ultrasonic field are applied, the pulse current frequency is set to 200Hz, the anode and cathode of the electrochemical field are three-dimensional foam silver electrodes, the current density is set to 500mA / cm 2, the ultrasonic frequency is 20 kHz, the power intensity is 400 W / L, the hydrogen peroxide (30% concentration) is added dropwise according to the mass ratio of hydrogen peroxide to failed residue oil hydrogenation catalyst of 0.2 g / g, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for the next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate shows that the V leaching rate is 97.42%, and the Mo leaching rate is 96.93%.

[0099] Example 13

[0100] The pretreated failed residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heated to 80°C, and at the same time, an electrochemical and ultrasonic external field is applied, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam silver electrodes, and the current density is set to 500 mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 400 W / L, the sodium persulfate is added dropwise according to the mass ratio of sodium persulfate to failed residue oil hydrogenation catalyst of 2 g / g, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for the next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate shows that the V leaching rate is 98.05%, and the Mo leaching rate is 97.64%.

[0101] Example 14

[0102] The pretreated failed residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heated to 80°C, and at the same time, an electrochemical and ultrasonic external field is applied, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam silver electrodes, and the current density is set to 400 mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 600 W / L, and the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue is dried to be used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for the next process separation and purification of raw material to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate shows that the V leaching rate is 98.77%, and the Mo leaching rate is 98.21%.

[0103] Example 15

[0104] The pretreated spent residue oil hydrogenation catalyst and 1 mol / L NaOH solution leaching agent are added to three leaching tanks, the liquid-solid ratio is 10:1 mL / g, the stirring speed is 400 rpm / min, heating to 80°C, while applying an electrochemical and ultrasonic external field, the pulse current frequency is set to 200 Hz, the anode and cathode of the electrochemical field are three-dimensional foam silver electrodes, the current density is set to 400 mA / cm 2 , the ultrasonic frequency is 20 kHz, the power intensity is 600 W / L, the mass ratio of sodium persulfate to spent residue oil hydrogenation catalyst is 2 g / g, the leaching time is 60 min. The slurry after reaction is subjected to solid-liquid separation to obtain leaching residue and vanadium-molybdenum-containing filtrate, and the leaching residue is dried and used as raw material for recovering other valuable metals. The vanadium-molybdenum-containing leaching filtrate is used for the next process separation and purification of raw materials to obtain ammonium metavanadate and ammonium molybdate products. Chemical analysis of the V and Mo contents in the leaching filtrate shows that the V leaching rate is 95.33%, and the Mo leaching rate is 95.12%.

[0105] The embodiment of the present application aims to protect a method for electrochemically and ultrasonically strengthening vanadium-molybdenum metal leaching of spent residue oil hydrogenation catalyst, which has the following effects:

[0106] 1. A three-dimensional electrode with a specific pore size, porosity and high specific surface area is used, and the extension direction of the internal porous channels of the electrode is at an angle of 45°-90° with the propagation direction of the ultrasonic waves, so as to construct a spatially coupled strengthening reaction field; the ultrasonic waves produce strong cavitation effect and micro-flow disturbance in the complex channels inside the electrode, greatly enhancing the mass transfer efficiency and reactant renewal rate of the solid-liquid interface; at the same time, the three-dimensional electrode provides a large electrochemical active surface, making the electric field distribution more uniform; this synergistic design in space configuration effectively breaks down the mass transfer barrier caused by carbon and sulfide wrapping in the spent catalyst, enabling the reaction reagents and active radicals to efficiently contact and attack the target mineral phase, achieving efficient oxidation leaching of low-valence vanadium-molybdenum under mild conditions, with a vanadium-molybdenum leaching rate of >98%;

[0107] 2. By integrating the redox potential sensor with the closed-loop feedback control system, taking the real-time redox potential value of the reaction system as the core control index, dynamically linking and adjusting the current density, ultrasonic power and leaching additive addition rate, the precise optimization and adaptive control of the leaching process are realized; it can ensure that the reaction always maintains in the optimal oxidation potential interval of +0.3~+1.2V, so that the low-valence vanadium and molybdenum sulfide is continuously oxidized to the easily soluble high-valence state, while avoiding the invalid decomposition or side reaction caused by excessive addition of oxidizing agent; based on the intelligent control of the key chemical parameters of the reaction process, not only the utilization efficiency of reagents and energy is significantly improved, but also the efficiency and stability of the leaching process are ensured, avoiding the problems of large fluctuation of recovery rate and high cost caused by extensive process control in traditional leaching process;

[0108] 3. By adopting pulse electric field and coordinating its frequency with the ultrasonic frequency (for example, matching the excitation period of pulse current with the transient period of local high temperature and high pressure generated by ultrasonic cavitation), the precise superposition and release of electrochemical energy and acoustic energy on the microscale are realized; the time-frequency coupling mechanism makes the pulse electric field provide high-intensity electrochemical impact at the moment when the ultrasonic cavitation effect is most significant and the strong oxidation environment is most needed, thereby greatly promoting the in-situ generation and utilization of active species such as hydroxyl radicals; the synergy of the two physical fields in energy release produces a strengthening effect of "1+1>2", realizes the efficient breaking of the stubborn V-S-O-V or Mo-S-O-V valence bond in the catalyst and the sufficient oxidation of low-valence vanadium and molybdenum metal, without harsh conditions of high temperature and high pressure, achieving a breakthrough effect of nearly 99% leaching of vanadium and molybdenum.

[0109] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can be modified or replaced by the same, without departing from the spirit and scope of the present application, any modification or equivalent replacement, which should be covered within the protection scope of the claims of the present application.

Claims

1. A method for electrochemical ultrasound intensification of vanadium and molybdenum metal leaching from spent residue hydroprocessing catalyst failure, characterized in that, The failure residue hydrogenation catalyst comprises 10-70% of Al2O3, 3-25% of V, 2-15% of Mo and 1-10% of Ni by mass percentage, and the method comprises the following steps: S1: grinding and drying the failure residue hydrogenation catalyst, mixing with the leaching agent according to a preset liquid-solid ratio to form a leaching slurry; S2: adding a leaching aid to the leaching slurry and inserting at least one pair of electrodes, while applying ultrasonic waves to the leaching slurry to perform electrochemical ultrasonic enhanced leaching; S3: performing solid-liquid separation on the leaching slurry after the enhanced leaching to obtain a vanadium-molybdenum enriched leaching solution and a leaching residue; At least one of the electrode pair is a three-dimensional electrode, and the extension direction of the porous channel inside the three-dimensional electrode is at an angle of 45°-90° with the propagation direction of the ultrasonic waves.

2. The method of electrochemical ultrasonic intensification of vanadium and molybdenum metal leaching of spent residue hydroprocessing catalyst failure sludge according to claim 1, characterized in that, The electrochemical ultrasonic enhanced leaching further comprises: detecting the oxidation-reduction potential value of the leaching slurry through a redox potential sensor integrated in the reaction system; based on the oxidation-reduction potential value, at least one of the current density applied to the electrode, the ultrasonic power value applied and the addition rate of the leaching aid is dynamically adjusted by a closed-loop feedback control system to maintain the oxidation-reduction potential value of the leaching slurry within a preset potential range.

3. The method of claim 2, wherein the preset potential range is +0.3 V to +1.2 V.

4. The method of claim 1, wherein the leaching aid is one or more of hydrogen peroxide, sodium persulfate and sodium thiosulfate.

5. The method of claim 1, wherein the electric field applied to the electrode is a pulse electric field, and the pulse current frequency of the pulse electric field is 150 Hz to 1000 Hz. The three-dimensional structure electrode is one or more of foamed nickel, foamed copper, foamed silver and foamed titanium, the pore size is 0.1 mm to 5 mm, the porosity is 60% to 95%, the thickness is 5 mm to 50 mm, and the specific surface area is not less than 200 m 2 / m 3 .

6. The method of claim 5, wherein the calculation formula between the pulse current frequency of the pulse electric field and the frequency of the ultrasonic waves is:

7. The method of claim 1, wherein the leaching aid is one or more of hydrogen peroxide, sodium persulfate and sodium thiosulfate.

8. The method of claim 7, wherein when the leaching aid is hydrogen peroxide or sodium persulfate, the ratio of the molar amount of effective oxygen in the leaching aid to the total molar amount of vanadium and molybdenum in the failure residue hydrogenation catalyst is 1.0-3.

0.

9. The method of any one of claims 1-8, wherein the temperature of the leaching slurry during the electrochemical ultrasonic enhanced leaching is 50-80℃. ​ f u = N × f p ; wherein f u is the frequency of the pulsed electric current of the pulsed electric field, f p is the frequency of the ultrasound wave, and N is a positive integer from 10 to 200. ​ ​ ​ ​ ​ ​

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