Method for removing vanadium from petroleum coke

Abstract

The application relates to a method for removing vanadium from petroleum coke, which can effectively remove vanadium in petroleum coke by activating and leaching a mixture obtained by mixing petroleum coke and an alkali metal salt; the method for removing vanadium is mainly based on the following mechanism: on the one hand, the stable ring structure of vanadium porphyrin is cracked through activation treatment, so that the ring is opened and the bond is broken; on the other hand, oxidation and alkalization reactions occur between the alkali metal salt and inert vanadium oxide under the activation condition, so that the inert low-valence vanadium is efficiently converted into soluble high-valence vanadium species. Subsequently, through alkaline leaching treatment, the high-valence vanadium can react with the alkaline solution to generate stable vanadate ions and transfer to the liquid phase, so that the efficient removal of vanadium in the petroleum coke is realized.

Description

Technical Field

[0001] This application relates to the field of petroleum coke purification and treatment technology, and in particular to a method for removing vanadium from petroleum coke. Background Technology

[0002] Petroleum coke is a byproduct of petroleum refining and is widely used in carbon products, metallurgy, and chemical industries. In recent years, with the increasing deterioration and heavier nature of global crude oil resources, the content of metallic impurities such as vanadium (V) in petroleum coke has significantly increased, severely impacting its subsequent processing and utilization performance. Studies show that vanadium in petroleum coke mainly exists in two forms: firstly, organometallic chelates, especially vanadium porphyrins with complex coordination structures and extremely high stability; and secondly, insoluble low-valence vanadium oxides (such as V₂O₃ and VO₂). Both forms of vanadium are difficult to remove effectively under conventional treatment conditions. High vanadium content significantly increases the air reactivity of petroleum coke, leading to severe oxidation and slag shedding during aluminum electrolysis. Simultaneously, when high-vanadium petroleum coke is used as raw material to prepare prebaked anodes for use in the aluminum electrolysis industry, vanadium gradually accumulates in the electrolyte system, causing a decrease in current efficiency, anode structural instability, and even premature anode damage, significantly increasing production energy consumption and costs.

[0003] To remove vanadium from petroleum coke, the following methods are currently mainly used: (1) High-temperature and high-pressure catalytic cracking method; This method has stringent requirements for the pressure resistance and corrosion resistance of the reaction equipment, and the equipment investment and operating costs are high, making it difficult to achieve large-scale industrial promotion; (2) Oxidation-wet chemical leaching method; This method relies on strong oxidants such as hydrogen peroxide, hypochlorite, and ozone, which pose significant safety hazards (such as equipment corrosion and explosion risks), and the process is complex and the processing cost is high; (3) Biological vanadium removal method; This method uses the adsorption or reduction of vanadium by specific microorganisms to achieve removal, but the cultivation conditions of the strains are stringent, the processing cycle is long, and the adaptability to the complex component system of petroleum coke is poor. At present, it is still in the laboratory research stage and cannot meet the actual needs of rapid industrial processing. In summary, the existing petroleum coke vanadium removal methods generally have problems such as large equipment investment, high operating costs, prominent safety risks, or poor industrial feasibility.

[0004] In view of this, it is necessary to design a method for removing vanadium from petroleum coke in order to solve the above problems. Summary of the Invention

[0005] This application provides a method for removing vanadium from petroleum coke, which solves the problems of difficult and costly removal of vanadium in traditional vanadium removal processes due to the complex occurrence of vanadium in petroleum coke and its tendency to form thermodynamically stable compounds at high temperatures.

[0006] In a first aspect, this application provides a method for removing vanadium from petroleum coke, comprising the following steps: Petroleum coke is mixed with alkali metal salts to obtain a mixture; The mixture is activated to obtain activated petroleum coke; The activated petroleum coke is subjected to leaching treatment to obtain a leachate; The leachate is subjected to filtration to obtain a first solid phase and a first liquid phase; and, The first solid phase was subjected to washing and drying processes in sequence to obtain vanadium-free petroleum coke.

[0007] In some embodiments, the heating rate of the activation treatment is 3°C / min to 8°C / min; and / or, The activation temperature for the activation treatment is 200℃~500℃; and / or, The activation time for the activation treatment is 2 hours to 8 hours; and / or, The activation atmosphere for the activation treatment includes either an air atmosphere or an oxygen atmosphere; and / or, During the activation process, the flow rate of the activation atmosphere is 2 L / min to 10 L / min.

[0008] In some embodiments, the alkali metal salt includes any one or more of potassium salts and sodium salts; The potassium salt includes any one or more of potassium chloride and potassium carbonate. The sodium salt includes any one or more of sodium chloride and sodium carbonate.

[0009] In some embodiments, the mass ratio of the petroleum coke to the alkali metal salt is 100:(5~40).

[0010] In some embodiments, the leaching treatment temperature is 30°C to 95°C; and / or, The leaching time for the leaching treatment is 2h to 8h.

[0011] In some embodiments, the leaching treatment includes the step of mixing the activated petroleum coke with an alkaline solution.

[0012] In some embodiments, the solid-liquid ratio of the activated petroleum coke to the alkaline solution is 1 g:(1~5) mL; and / or, The alkaline solution includes any one or more of sodium hydroxide solution and potassium hydroxide solution; and / or, The concentration of the alkaline solution is 0.5 mol / L to 5 mol / L.

[0013] In some embodiments, the washing treatment reagent includes deionized water; and / or, The washing process includes 3 to 5 washing cycles; and / or, The drying process is performed at a temperature of 60℃~100℃; and / or, The drying process takes 6 to 12 hours.

[0014] In some embodiments, the particle size of the petroleum coke is ≤6 mm; and / or, The vanadium content in the petroleum coke is 400ppm to 1000ppm.

[0015] In some embodiments, the vanadium removal rate in the vanadium-degraded petroleum coke is ≥65.3%.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art: The method for removing vanadium from petroleum coke provided in this application involves activating and leaching a mixture of petroleum coke and alkali metal salts to effectively remove vanadium. The method is based on the following mechanism: firstly, activation treatment breaks down the stable cyclic structure of vanadium porphyrin and oxidizes and decomposes the coordination structure; secondly, under activation conditions, the alkali metal salt reacts with vanadium oxide through oxidation and alkalization reactions, efficiently converting inert low-valence vanadium into soluble high-valence vanadium species. Subsequent alkaline leaching allows the high-valence vanadium to react with the alkaline solution to generate stable vanadate ions, which are then transferred to the liquid phase, ultimately achieving efficient removal of vanadium from the petroleum coke. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] Various embodiments of this application may exist in the form of a range. It should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of this application. Therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this application, it means including any referenced number (fraction or integer) within the indicated range. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this application can be purchased commercially or prepared by existing methods. In this application, the terms "comprising," "including," etc., mean "including but not limited to." In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any actual relationship or order between these entities or operations. In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0019] This application provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix petroleum coke with alkali metal salts to obtain a mixture; Step 2: Activate the mixture to obtain activated petroleum coke; Step 3: Leach the activated petroleum coke to obtain a leachate; Step 4: The leachate is filtered to obtain a first solid phase and a first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke.

[0020] This application provides a method for removing vanadium from petroleum coke. By performing activation treatment and leaching on a mixture obtained from petroleum coke and alkali metal salt, vanadium can be effectively removed from the petroleum coke.

[0021] Vanadium in petroleum coke mainly exists in two forms, which are difficult to remove effectively by conventional processes: one is organometallic chelates mainly composed of vanadium porphyrin. These substances have stable molecular structures and complex coordination structures, and conventional treatment methods are unable to destroy their stable structures; the other is insoluble low-valence vanadium compounds such as V2O3 and VO2, which have low chemical activity and are difficult to dissolve.

[0022] The vanadium removal method provided in this application is mainly based on the following mechanism: On the one hand, the stable cyclic structure of vanadium porphyrin is broken down by activation treatment, and the coordination structure is decomposed by oxidation. On the other hand, alkali metal salts react with vanadium oxide under activation conditions to undergo oxidation and alkalization reactions, promoting the efficient conversion of inert low-valence vanadium into soluble high-valence vanadium species. Subsequently, after alkaline leaching treatment, the high-valence vanadium reacts with the alkaline solution to generate stable vanadate ions, which are then transferred to the liquid phase, ultimately achieving efficient removal of vanadium from petroleum coke.

[0023] The method provided in this application completes the ring-opening of vanadium porphyrin and the valence state conversion of low-valent vanadium under mild reaction conditions. The entire process requires no high-pressure equipment or strong oxidants, completely overcoming the shortcomings of existing vanadium removal technologies, such as high equipment requirements, harsh operating conditions, significant safety risks, and high processing costs. This technology effectively solves the technical pain points of traditional petroleum coke vanadium removal processes, including low removal efficiency, high environmental pollution risks, and difficulty in industrial implementation, possessing significant cost advantages and broad prospects for industrial application.

[0024] As an optional implementation, in this embodiment of the application, the activation treatment includes: heating the mixture to 200℃~500℃ at a heating rate of 3℃ / min~8℃ / min, and activating it at a constant temperature of 200℃~500℃ for 2h~8h.

[0025] This process features mild activation conditions and lower overall energy consumption: the activation temperature is controlled at 200℃~500℃, which is much lower than that of traditional high-temperature pyrolysis processes; the entire process does not require high-pressure supporting equipment, which greatly reduces equipment investment and production and operation costs, making it easy to promote and apply on a large scale in industrial applications.

[0026] However, if the activation temperature is below 200℃, the kinetic rate of the ring-opening oxidation reaction of vanadium porphyrin is low, and the material activation reaction is incomplete; if the activation temperature is above 500℃, the petroleum coke skeleton will undergo violent pyrolysis and oxidation ablation, resulting in a decrease in the actual yield of petroleum coke. The system is also prone to generating insoluble inert vanadium phases such as vanadium aluminum spinel, which is not conducive to subsequent vanadium leaching and removal.

[0027] The activation and holding time was set to 2-8 hours. Within this activation time range, alkali metal salts can fully react with petroleum coke in an oxidizing atmosphere, which can not only fully drive the oxidative cracking of the vanadium porphyrin ring structure, but also realize the directional conversion of low-valent vanadium to soluble high-valent vanadium.

[0028] As an optional implementation, in this embodiment of the application, the activation atmosphere of the activation treatment includes either an air atmosphere or an oxygen atmosphere.

[0029] Heating the material in an oxidizing atmosphere composed of air or oxygen is the core driving force for breaking the stable cyclic structure of vanadium porphyrin. The macrocyclic skeleton of vanadium porphyrin consists of four pyrrole rings connected by methylene bridges, with vanadium ions coordinated and chelated at the center of the ring. In an oxidizing atmosphere and at a low temperature range of 200℃ to 500℃, oxygen molecules can undergo an oxidation reaction with the aromatic conjugated system of the porphyrin ring; oxygen preferentially attacks the methylene bridge (-CH=) and the α-carbon atom of the pyrrole ring, initiating the breaking of carbon-carbon and carbon-nitrogen bonds within the ring, thus achieving ring-opening and decomposition of the vanadium porphyrin macrocycle. This process relies on low-temperature oxidation to complete the ring-opening and decomposition of vanadium porphyrin. At the same time, alkali metal salts in the system can react with insoluble low-valence vanadium to produce soluble high-valence vanadium species under an oxidizing atmosphere; subsequently, after alkaline leaching treatment, the high-valence vanadium reacts with the alkali to generate stable vanadate ions, which dissolve in the liquid phase, ultimately achieving efficient removal of vanadium from petroleum coke at a relatively low cost.

[0030] As an optional implementation, in this embodiment of the application, the flow rate of the activation atmosphere during the activation process is 2L / min to 10L / min.

[0031] Using an activation atmosphere with a flow rate of 2 L / min to 10 L / min ensures sufficient oxygen supply within the system, maintaining a stable and adequate oxidation environment. Sufficient oxygen can fully participate in the oxidative cracking reaction of the vanadium porphyrin macrocycle, promoting the breakage of C-C and CN bonds in the ring structure, completing the ring opening of porphyrin, and simultaneously oxidizing the insoluble low-valent vanadium into soluble high-valent vanadium species.

[0032] In the embodiments of this application, when activating the mixture, the mixture may be placed in a tube furnace or an atmosphere furnace (silicon molybdenum furnace).

[0033] As an optional implementation, in the embodiments of this application, the alkali metal salt includes any one or more of potassium salts and sodium salts.

[0034] As an optional implementation, in the embodiments of this application, the potassium salt includes any one or more of potassium chloride and potassium carbonate.

[0035] In the embodiments of this application, the sodium salt includes any one or more of sodium chloride and sodium carbonate.

[0036] The efficiency of ring-opening cracking of vanadium porphyrin by oxidative heating alone is limited and cannot achieve efficient vanadium removal. It must be coupled with alkali metal salts to achieve excellent vanadium removal effect.

[0037] In low-temperature roasting activation systems, the added alkali metal salts play a crucial role in activation enhancement. Under air or oxygen oxidizing atmospheres, alkali metal salts can react with low-valence vanadium oxide to form water-soluble vanadates, significantly improving vanadium removal efficiency. The specific mechanism is as follows: Alkali metal salts can react with insoluble low-valent vanadium oxides in petroleum coke to convert them into soluble high-valent vanadates MVO3 (where M refers to either sodium or potassium). The core conversion reaction is shown below: V₂O₃ + M₂CO₃ + O₂ → 2MVO₃ + CO₂ 2VO2 + M2CO3 + 1 / 2O2 → 2MVO3 + CO2 2MCl + V2O5+ 1 / 2 O2→ 2MVO3+ Cl2 This demonstrates a significant synergistic effect between the oxidizing atmosphere, alkali metal salts, and heating conditions. The introduced air or oxygen, under heating conditions, creates a strong oxidizing environment, promoting the oxidative decomposition of stable vanadium-containing coordination structures to generate oxides such as VO2 or V2O5. Alkali metal salts react with inert vanadium oxides under the oxidizing atmosphere to form soluble high-valent vanadates.

[0038] In summary, oxidative heating achieves the basic disruption of the vanadium porphyrin macrocycle, while alkali metal salts form soluble high-valence vanadates with vanadium through a dual mechanism of oxidation and sodium conversion. The two work together to fully activate the vanadium component in the material.

[0039] As an optional implementation, in this embodiment of the application, the mass ratio of the petroleum coke to the alkali metal salt is 100:(5~40).

[0040] Thus, further limiting the mass ratio of petroleum coke to alkali metal salt to 100:(5~40) ensures sufficient reaction. However, if the content of alkali metal salt is too high, the vanadium removal rate is close to saturation, and further increasing the salt content will only significantly increase the cost of vanadium removal and waste raw materials; if the content of alkali metal salt is too low, the material activation reaction will not be complete, the conversion of low-valent vanadium to soluble high-valent vanadium will be incomplete, and the vanadium removal effect will be significantly reduced. Therefore, taking all factors into consideration, this application sets the mass ratio of petroleum coke to alkali metal salt in the range of 100:(5~40).

[0041] As an optional implementation, in this embodiment of the application, the leaching temperature is 30°C to 95°C.

[0042] This leaching temperature range can fully guarantee the solubility of vanadates in the system; if the leaching temperature is too high, it will not only significantly increase the energy consumption of the process, but also easily cause the alkali solution to volatilize more rapidly, further aggravating the corrosion and wear of the production equipment.

[0043] In this embodiment of the application, the leaching time of the leaching treatment is 2h to 8h.

[0044] Within this leaching time range, the vanadates in the system can be fully dissolved.

[0045] As an optional implementation, in this embodiment of the application, the leaching treatment includes the following steps: mixing the activated petroleum coke with an alkaline solution.

[0046] Petroleum coke contains impurities such as silicon, calcium, and iron. During the low-temperature roasting and activation stage, vanadium readily reacts with these impurities to generate various water-insoluble vanadates and complex metal oxides. Typical products include calcium vanadate (Ca3(VO4)2) and iron vanadate (FeVO4), which are insoluble in water, as well as silicate vanadate glass phases with complex structures and extremely poor solubility.

[0047] For these types of sparingly soluble vanadates, as well as low-valent vanadium species that are not fully oxidized and transformed during activation, this process is followed by an alkaline leaching step. Various sparingly soluble vanadium components in the system can react with the alkaline solution to transform into water-soluble, stable vanadates, which then fully dissolve in the liquid phase. Simultaneously, the petroleum coke matrix carbon skeleton remains chemically stable under the low-temperature leaching environment and does not react with the alkaline solution.

[0048] Based on the above characteristics, this process can achieve highly selective removal of vanadium components while ensuring a high yield of petroleum coke products.

[0049] In this embodiment of the application, the solid-liquid ratio of the activated petroleum coke to the alkaline solution is 1g:(1~5)mL.

[0050] For example, the solid-liquid ratio of the activated petroleum coke to the alkaline solution is 1g:1mL, 1g:2mL, 1g:3mL, 1g:4mL, or 1g:5mL.

[0051] The solid-liquid ratio of activated petroleum coke to alkaline solution is further limited to 1 g:(1~5) mL. This solid-liquid ratio range provides sufficient alkaline solution to ensure that all vanadates in the system react fully and dissolve completely. If the amount of alkaline solution is too high, the vanadium removal rate will only increase slightly, but it will significantly increase the consumption of alkaline reagents and the subsequent waste liquid treatment load, increasing the overall production cost. If the amount of alkaline solution is insufficient, the alkalinity of the system will be insufficient, and the sparingly soluble vanadates cannot be completely converted into soluble vanadates, resulting in insufficient vanadium dissolution and a significant decrease in the vanadium removal effect. Considering multiple factors such as vanadium removal efficiency, reagent consumption, and waste liquid treatment cost, this application sets the solid-liquid ratio of activated petroleum coke to alkaline solution in the range of 1 g:(1~5) mL.

[0052] In this embodiment, the alkaline solution includes any one or more of sodium hydroxide solution and potassium hydroxide solution.

[0053] After the material is roasted and activated, vanadium mainly exists in the form of vanadates (such as NaVO3, Ca3(VO4)2, etc.), while a small amount of incompletely converted low-valent vanadium oxides remain. The strong alkaline solution with sodium hydroxide and potassium hydroxide as the core has a triple action mechanism: (1) it undergoes a metathesis reaction with water-insoluble vanadates such as calcium vanadate, converting them into water-soluble orthovanadates (such as Na3VO4); (2) it dissolves the residual low-valent vanadium oxides in the system. V2O3 and VO2 can dissolve in a strong alkaline environment and undergo disproportionation or oxidation reactions simultaneously; (3) it corrodes and breaks the silicate passivation film on the surface of petroleum coke, so that the vanadates wrapped inside are fully exposed, which facilitates the dissolution of vanadium components.

[0054] Petroleum coke feedstock contains impurities such as silicon, calcium, and iron. During the roasting and activation stage, vanadium readily combines with these impurities to form water-insoluble vanadates and complex metal oxides. Typical products include calcium vanadate (Ca3(VO4)2), iron vanadate (FeVO4), and a complex, poorly soluble silicate-vanadate glass phase. To address these insoluble vanadium compounds and insufficiently oxidized low-valence vanadium species, this process incorporates a strong alkali leaching step. Various insoluble vanadium components react with the alkali solution to form stable, water-soluble vanadates, which are then transferred to the liquid phase. For example, these vanadates react with NaOH to form a stable vanadium-containing solution (such as Na3VO4), thus entering the liquid phase. Simultaneously, the petroleum coke carbon skeleton remains chemically stable under low-temperature leaching conditions and does not react with strong alkalis, thereby achieving highly selective removal of vanadium components and maintaining a high yield of petroleum coke products.

[0055] In the embodiments of this application, the concentration of the alkaline solution is 0.5 mol / L to 5 mol / L.

[0056] The alkaline solution concentration is sufficient to achieve the conversion reaction of insoluble vanadates; if the alkaline solution concentration is too high, the vanadium removal rate will not be significantly improved, and the consumption of reagents will increase, while increasing the cost pressure of subsequent waste liquid treatment.

[0057] As an optional implementation, in this embodiment of the application, the washing reagent includes any one of deionized water, ultrapure water, and dilute acid solution; the dilute acid solution includes dilute hydrochloric acid with a concentration of 0.5 mol / L to 1 mol / L.

[0058] Preferably, the washing process includes washing with dilute hydrochloric acid and deionized water in sequence.

[0059] Pre-washing with dilute hydrochloric acid serves two main purposes: first, it neutralizes residual alkaline solution adhering to the surface of the petroleum coke, preventing side reactions between the strong alkali and the carbon skeleton of the petroleum coke during the drying stage, thus avoiding raw material loss; second, it dissolves insoluble precipitates formed by the reaction of small amounts of calcium and magnesium impurities in the system, reducing impurity residue. After washing with dilute hydrochloric acid, it is washed again with deionized water 2-3 times to thoroughly remove residual hydrochloric acid and soluble salt impurities from the surface of the material, effectively ensuring the purity of the final petroleum coke product.

[0060] In this embodiment of the application, the number of washing cycles in the washing process includes 3 to 5 times.

[0061] Preferably, the number of washing cycles in the washing process includes: washing with dilute hydrochloric acid once and washing with deionized water two to four times.

[0062] If the number of washing cycles is too low, the residual salts and alkali components on the surface of the material cannot be completely removed, which will cause the ash content of the finished petroleum coke to increase and the conductivity to deteriorate, seriously affecting its subsequent application quality. If the number of washing cycles is too high, it will significantly increase the process water consumption, prolong the overall operation time, and easily cause the loss of petroleum coke fine powder, reducing the product yield.

[0063] In this embodiment of the application, the drying temperature is 60℃~100℃.

[0064] If the drying temperature is too low, the internal moisture of the material cannot be completely removed, and the finished product is prone to clumping, which is not conducive to subsequent weighing and performance characterization tests. If the drying temperature exceeds 100℃, it is easy to cause slight oxidation of the surface of the petroleum coke, and at the same time cause the loss of volatile matter in the material, reducing the actual yield of petroleum coke products.

[0065] As an optional implementation, in this embodiment of the application, the drying time is 6h to 12h; the drying instrument used includes any one of a vacuum drying oven and a forced-air drying oven.

[0066] As an optional implementation, in this embodiment of the application, the particle size of the petroleum coke after crushing and screening is ≤6mm; the vanadium content in the petroleum coke is 400ppm~1000ppm.

[0067] As an optional implementation, in this embodiment of the application, the vanadium removal rate in the vanadium-degraded petroleum coke is ≥65.3%.

[0068] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0069] Example 1 Example 1 provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix 100g of petroleum coke with 20g of alkali metal salt (a mixture of 5g of anhydrous sodium carbonate and 15g of sodium chloride) at a mass ratio of 100:20 to obtain a mixture. Among them, the particle size of petroleum coke is ≤6mm; the vanadium content in petroleum coke is 980ppm.

[0070] Step 2: Place the mixture in a silicon-molybdenum furnace for activation treatment to obtain activated petroleum coke; The activation atmosphere for the activation treatment is air. During the activation process, the flow rate of the activation atmosphere is 5 L / min; The heating rate for activation treatment was 5℃ / min; the activation temperature for activation treatment was 400℃; and the activation time for activation treatment was 8h.

[0071] Step 3: Add the activated petroleum coke to an alkaline solution (sodium hydroxide solution) for leaching treatment to obtain a leachate; The leaching temperature was 95℃; the leaching time was 6 hours. The solid-liquid ratio of activated petroleum coke to sodium hydroxide solution is 1 g: 5 mL; the concentration of sodium hydroxide solution is 2 mol / L.

[0072] Step 4: Filter the leachate to obtain the first solid phase and the first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke with a vanadium content of 212.66 ppm. The washing reagents include deionized water; the washing process involves 5 washes. The drying temperature was 85℃; the drying time was 6 hours.

[0073] Example 2 Example 2 provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix petroleum coke with 20g of alkali metal salt (anhydrous sodium carbonate) at a mass ratio of 100:20 to obtain a mixture; Among them, the particle size of petroleum coke is ≤6mm; the vanadium content in petroleum coke is 980ppm.

[0074] Step 2: Place the mixture in a silicon-molybdenum furnace for activation treatment to obtain activated petroleum coke; The activation atmosphere for the activation treatment is air. During the activation process, the flow rate of the activation atmosphere is 5 L / min; The heating rate for activation treatment was 5℃ / min; the activation temperature for activation treatment was 500℃; and the activation time for activation treatment was 2h.

[0075] Step 3: Add the activated petroleum coke to an alkaline solution (potassium hydroxide solution) for leaching treatment to obtain a leachate; The leaching temperature was 80℃; the leaching time was 8 hours. The solid-liquid ratio of activated petroleum coke to potassium hydroxide solution is 1 g: 5 mL; the concentration of potassium hydroxide solution is 4 mol / L.

[0076] Step 4: Filter the leachate to obtain the first solid phase and the first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke; The washing reagents include deionized water; the washing process involves 5 washes. The drying temperature was 85℃; the drying time was 6 hours.

[0077] Example 3 Example 3 provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix 100g of petroleum coke with 5g of alkali metal salt (a mixture of 2g of anhydrous sodium carbonate and 3g of sodium chloride) at a mass ratio of 100:5 to obtain a mixture. Among them, the particle size of petroleum coke is ≤6mm; the vanadium content in petroleum coke is 980ppm.

[0078] Step 2: Place the mixture in a silicon-molybdenum furnace for activation treatment to obtain activated petroleum coke; The activation atmosphere for the activation treatment is an oxygen atmosphere; During the activation process, the flow rate of the activation atmosphere is 2 L / min; The heating rate for activation treatment was 5℃ / min; the activation temperature for activation treatment was 300℃; and the activation time for activation treatment was 6h.

[0079] Step 3: Add the activated petroleum coke to an alkaline solution (sodium hydroxide solution) for leaching treatment to obtain a leachate; The leaching temperature was 95℃; the leaching time was 6 hours. The solid-liquid ratio of activated petroleum coke to sodium hydroxide solution is 1 g: 5 mL; the concentration of sodium hydroxide solution is 2 mol / L.

[0080] Step 4: Filter the leachate to obtain the first solid phase and the first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke; The washing process involves five washes, and the reagents used include deionized water. The drying temperature was 85℃; the drying time was 6 hours.

[0081] Example 4 Example 4 provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix petroleum coke with an alkali metal salt (a mixture of 20g anhydrous sodium carbonate and 20g sodium chloride) at a mass ratio of 100:40 to obtain a mixture. Among them, the particle size of petroleum coke is ≤6mm; the vanadium content in petroleum coke is 700ppm.

[0082] Step 2: Place the mixture in a silicon-molybdenum furnace for activation treatment to obtain activated petroleum coke; The activation atmosphere for the activation treatment is air. During the activation process, the flow rate of the activation atmosphere is 5 L / min; The heating rate for activation treatment was 5℃ / min; the activation temperature for activation treatment was 400℃; and the activation time for activation treatment was 8h.

[0083] Step 3: Add the activated petroleum coke to an alkaline solution (potassium hydroxide solution) to leach the activated petroleum coke and obtain a leachate. The leaching temperature was 95℃; the leaching time was 6 hours. The solid-liquid ratio of activated petroleum coke to potassium hydroxide solution is 1 g: 5 mL; the concentration of potassium hydroxide solution is 5 mol / L.

[0084] Step 4: Filter the leachate to obtain the first solid phase and the first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke; The washing reagents include deionized water; the washing process involves 5 washes. The drying temperature was 85℃; the drying time was 6 hours.

[0085] Example 5 Example 5 provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix 100g of petroleum coke with 20g of alkali metal salt (a mixture of 5g of anhydrous sodium carbonate and 15g of sodium chloride) at a mass ratio of 100:20 to obtain a mixture. Among them, the particle size of petroleum coke is ≤6mm; the vanadium content in petroleum coke is 400ppm.

[0086] Step 2: Place the mixture in a silicon-molybdenum furnace for activation treatment to obtain activated petroleum coke; The activation atmosphere for the activation treatment is air. During the activation process, the flow rate of the activation atmosphere is 10 L / min; The heating rate for activation treatment was 5℃ / min; the activation temperature for activation treatment was 200℃; and the activation time for activation treatment was 8h.

[0087] Step 3: Add the activated petroleum coke to an alkaline solution (sodium hydroxide solution) to leach the activated petroleum coke and obtain a leachate. The leaching temperature was 30℃; the leaching time was 6 hours. The solid-liquid ratio of activated petroleum coke to sodium hydroxide solution is 1 g: 5 mL; the concentration of sodium hydroxide solution is 2 mol / L.

[0088] Step 4: Filter the leachate to obtain the first solid phase and the first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke; The washing reagents include deionized water; the washing process involves 5 washes. The drying temperature was 85℃; the drying time was 6 hours.

[0089] Example 6 Example 6 provides a method for removing vanadium from petroleum coke, comprising the following steps: Step 1: Mix 100g of petroleum coke with 20g of alkali metal salt (a mixture of 5g of anhydrous potassium carbonate and 15g of potassium chloride) at a mass ratio of 100:20 to obtain a mixture. Among them, the particle size of petroleum coke is ≤6mm; the vanadium content in petroleum coke is 980ppm.

[0090] Step 2: Place the mixture in a silicon-molybdenum furnace for activation treatment to obtain activated petroleum coke; The activation atmosphere for the activation treatment is air. During the activation process, the flow rate of the activation atmosphere is 5 L / min; The heating rate for activation treatment was 5℃ / min; the activation temperature for activation treatment was 400℃; and the activation time for activation treatment was 8h.

[0091] Step 3: Add the activated petroleum coke to an alkaline solution (sodium hydroxide solution) for leaching treatment to obtain a leachate; The leaching temperature was 95℃; the leaching time was 6 hours. The solid-liquid ratio of activated petroleum coke to sodium hydroxide solution is 1 g: 5 mL; the concentration of sodium hydroxide solution is 2 mol / L.

[0092] Step 4: Filter the leachate to obtain the first solid phase and the first liquid phase; Step 5: The first solid phase is washed and dried sequentially to obtain vanadium-free petroleum coke with a vanadium content of 212.66 ppm. The washing reagents include deionized water; the washing process involves 5 washes. The drying temperature was 85℃; the drying time was 6 hours.

[0093] Comparative Example 1 Comparative Example 1 provides a method for removing vanadium from petroleum coke, which differs from Example 1 in that the activation atmosphere of the activation treatment is different. In Comparative Example 1, the activation atmosphere of the activation treatment is an argon atmosphere.

[0094] The remaining steps and parameters are the same as in Example 1, and will not be repeated here.

[0095] Comparative Example 2 Comparative Example 2 provides a method for removing vanadium from petroleum coke, which differs from Example 1 in that no activation treatment was performed in Comparative Example 2.

[0096] The remaining steps and parameters are the same as in Example 1, and will not be repeated here.

[0097] Comparative Example 3 Comparative Example 3 provides a method for removing vanadium from petroleum coke, which differs from Example 1 in that the composition of the mixture is different. The mixture in Comparative Example 3 consists of petroleum coke and sodium thiosulfate.

[0098] The remaining steps and parameters are the same as in Example 1, and will not be repeated here.

[0099] Comparative Example 4 Comparative Example 4 provides a method for removing vanadium from petroleum coke, which differs from Example 1 in that the composition of the mixture is different. The mixture in Comparative Example 4 consists of 100g of petroleum coke and 3g of alkali metal salt (a mixture of 1g of anhydrous sodium carbonate and 2g of sodium chloride).

[0100] The remaining steps and parameters are the same as in Example 1, and will not be repeated here.

[0101] The vanadium removal rates in the methods provided in the various embodiments and comparative examples are shown in Table 1.

[0102] Table 1. Vanadium removal efficiency achieved by the process parameters and corresponding methods used in the examples and comparative examples.

[0103] Analysis of experimental results: According to the results in Table 1, it can be seen that the results of Examples 1 to 5 confirm that by using a process of low-temperature oxygen or air activation atmosphere coupled with alkaline leaching to pre-activate petroleum coke and carry out subsequent leaching treatment, the vanadium removal rate can be stably higher than 65%.

[0104] Comparing Example 1 with Comparative Example 1, it can be seen that air or oxygen must be introduced during the activation stage to create an oxidizing atmosphere. If an inert atmosphere is used, vanadium porphyrin in petroleum coke is difficult to undergo ring-opening oxidation reaction, and low-valent vanadium cannot be oxidized into high-valent soluble vanadate, ultimately resulting in a significant deterioration in the vanadium removal effect.

[0105] Comparing Example 1 and Comparative Example 2, it can be seen that when the pre-activation process is omitted, the vanadium removal rate is only 6.7%; it is difficult to achieve efficient vanadium removal by simply relying on alkaline leaching, which fully demonstrates the key role of the pre-oxidation activation process in the vanadium removal process.

[0106] Comparing Example 1 and Comparative Example 3, it can be seen that when sodium thiosulfate is added alone in the low-temperature activation system, the lack of synergistic effect of the complex salt makes it impossible to effectively promote the oxidation and activation process of vanadium, resulting in a significant decrease in the vanadium removal rate.

[0107] Comparing Example 1 and Comparative Example 4, it can be seen that in the activation system, when the alkali metal salt in the mixture is too low, it is difficult to effectively promote the oxidation and activation of vanadium, which will also result in a low vanadium removal rate.

[0108] In summary, this invention provides a method for removing vanadium from petroleum coke. By activating and leaching a mixture of petroleum coke and alkali metal salts, vanadium can be effectively removed from the petroleum coke. The vanadium removal method is mainly based on the following mechanism: on the one hand, activation treatment breaks the stable ring structure of vanadium porphyrin, achieving ring opening and bond breaking; on the other hand, alkali metal salts react with inert vanadium oxides under activation conditions to induce oxidation and alkalization reactions, promoting the efficient conversion of inert low-valence vanadium into soluble high-valence vanadium species. Subsequent alkaline leaching treatment allows the high-valence vanadium to react with the alkaline solution to generate stable vanadate ions, which are then transferred to the liquid phase, ultimately achieving efficient removal of vanadium from the petroleum coke, with an overall vanadium removal rate exceeding 65%. The reagents used in this method are inexpensive and readily available alkalis and salts such as sodium carbonate, sodium chloride, and sodium hydroxide. The process is simple, safe, and highly controllable, making it suitable for large-scale continuous industrial production.

[0109] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for removing vanadium from petroleum coke, characterized in that, Includes the following steps: Petroleum coke is mixed with alkali metal salts to obtain a mixture; The mixture is activated to obtain activated petroleum coke; The activated petroleum coke is subjected to leaching treatment to obtain a leachate; The leachate is subjected to filtration to obtain a first solid phase and a first liquid phase; as well as, The first solid phase was subjected to washing and drying processes in sequence to obtain vanadium-free petroleum coke.

2. The method for removing vanadium from petroleum coke according to claim 1, characterized in that, The heating rate of the activation treatment is 3℃ / min to 8℃ / min; and / or, The activation temperature for the activation treatment is 200℃~500℃; and / or, The activation time for the activation treatment is 2 hours to 8 hours; and / or, The activation atmosphere for the activation treatment includes either an air atmosphere or an oxygen atmosphere; and / or, During the activation process, the flow rate of the activation atmosphere is 2 L / min to 10 L / min.

3. The method for removing vanadium from petroleum coke according to claim 1, characterized in that, The alkali metal salt includes any one or more of potassium salts and sodium salts; The potassium salt includes any one or more of potassium chloride and potassium carbonate. The sodium salt includes any one or more of sodium chloride and sodium carbonate.

4. The method for removing vanadium from petroleum coke according to claim 3, characterized in that, The mass ratio of the petroleum coke to the alkali metal salt is 100:(5~40).

5. The method for removing vanadium from petroleum coke according to claim 1, characterized in that, The leaching treatment temperature is 30℃~95℃; and / or, The leaching time for the leaching treatment is 2h to 8h.

6. The method for removing vanadium from petroleum coke according to claim 5, characterized in that, The leaching process includes the following steps: mixing the activated petroleum coke with an alkaline solution.

7. The method for removing vanadium from petroleum coke according to claim 6, characterized in that, The solid-liquid ratio of the activated petroleum coke to the alkaline solution is 1 g:(1~5) mL; and / or, The alkaline solution includes any one or more of sodium hydroxide solution and potassium hydroxide solution; and / or, The concentration of the alkaline solution is 0.5 mol / L to 5 mol / L.

8. The method for removing vanadium from petroleum coke according to claim 1, characterized in that, The washing treatment reagent includes deionized water; and / or, The washing process includes 3 to 5 washing cycles; and / or, The drying process is performed at a temperature of 60℃~100℃; and / or, The drying process takes 6 to 12 hours.

9. The method for removing vanadium from petroleum coke according to claim 3, characterized in that, The particle size of the petroleum coke is ≤6mm; and / or, The vanadium content in the petroleum coke is 400ppm to 1000ppm.

10. The method for removing vanadium from petroleum coke according to any one of claims 1 to 9, characterized in that, The vanadium removal rate in the vanadium-degraded petroleum coke is ≥65.3%.

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