Method for rapidly dissolving high-temperature alloy, synchronously and efficiently separating hafnium and recycling nickel and cobalt through electrolytic method

Abstract

The invention relates to a method for rapidly dissolving a high-temperature alloy, synchronously and efficiently separating hafnium and recovering nickel and cobalt by using an electrolytic method, in particular to a method for promoting electrochemical dissolution of the high-temperature alloy, and a method for recovering nickel and cobalt products and hafnium-containing enrichment by controlling an ion competitive reduction sequence according to reduction potential differences of different metals. The invention provides a method for rapidly dissolving high-temperature alloy waste to recover nickel and cobalt resources and synchronously and efficiently separating hafnium-containing enriched substances, and mainly aims at solving the problems that valuable metal resources are difficult to recover due to the fact that high-temperature alloy is difficult to dissolve in an acid solution, and the process for treating the high-temperature alloy waste is complex and causes secondary pollution to the environment. According to the method, a traditional long-process recovery method is broken through, a unique alkaline region of a cathode / solution interface in the acid solution is regulated and controlled by utilizing metal reduction potential difference, the nickel-cobalt product is generated, meanwhile, the hafnium-containing enrichment is recovered, and the process flow is shortened. The method comprises the following steps: 1, respectively taking a high-temperature alloy and a titanium sheet as an anode and a cathode of electrolysis equipment, adjusting the pH value of an electrolyte to a certain value, turning on a direct-current power supply, and regulating and controlling electrolysis parameters to carry out electrochemical dissolution; 2, performing solid-liquid separation on a product in the electrolytic bath, and filtering to obtain a hafnium-containing enriched product; 3, separating the cathode product from the cathode to obtain a nickel-cobalt product; and 4, washing the hafnium-containing enriched product and a cathode nickel-cobalt product.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically a method for rapidly dissolving high-temperature alloys to recover nickel and cobalt resources using an electrochemical method and simultaneously and efficiently separating hafnium-containing concentrates. Background Technology

[0002] The development of modern aerospace technology has presented unprecedented challenges to high-temperature materials. These aerospace components need to operate stably for extended periods under harsh conditions such as extreme temperatures, high stress, oxidizing or corrosive atmospheres, and complex thermal cycles. Therefore, high-temperature alloys have emerged and become irreplaceable key materials. High-temperature alloys are advanced alloys that use nickel and cobalt as a matrix, fusing aluminum, chromium, molybdenum, tantalum, tungsten, hafnium, and other metallic elements through solid solution strengthening, second-phase strengthening, or special alloying methods. These alloys significantly improve creep strength, high-temperature stability, and resistance to heat corrosion, making them the preferred materials for hot-end components of modern aero-engines, such as turbine disks, blades, and other parts. With the rapid development of my country's aerospace, aviation, gas turbine, and nuclear energy sectors, the demand for high-temperature alloys is increasing, while the amount of high-temperature alloy waste generated is also enormous, necessitating comprehensive recycling and utilization.

[0003] Methods for preparing high-temperature alloy materials have been extensively studied, but methods for recycling high-temperature alloys are relatively limited. Currently, methods for extracting valuable elements from high-temperature alloy waste are divided into pyrometallurgical and hydrometallurgical processes. Pyrometallurgical processes utilize high-temperature redox reactions to separate and enrich valuable components in the alloy, typically requiring a molten state. The advantages of pyrometallurgical smelting are high production efficiency and a short process flow; its disadvantages include high energy consumption, difficulty in achieving full-component recovery of metals such as hafnium and molybdenum, and unstable product quality. Hydrometallurgical processes offer the advantages of effectively separating and recovering multiple metal elements, high resource utilization, and low energy consumption. Among hydrometallurgical processes, electrochemical methods for treating high-temperature alloys and recovering precious metals such as hafnium have become a highly attractive and valuable new research direction due to their core advantages such as high ion selectivity, simple process, good environmental performance, and high energy-saving potential. Wang Zhijun's patent, "A Method for Enriching Tungsten, Tantalum, and Hafnium from High-Temperature Alloy Waste" (Patent Publication No.: CN108359804A), employs an electrochemical method to recover tungsten, tantalum, and hafnium metals from high-temperature alloy waste. This method improves upon existing wet recycling techniques, using titanium baskets as anodes and cathodes to effectively enrich tungsten, tantalum, and hafnium. However, it cannot simultaneously recover nickel and cobalt. Li Jie's patent, "A Method and Apparatus for Promoting Electrochemical Dissolution of High-Temperature Alloys" (Patent Publication No.: CN119265590A), places waste high-temperature alloys in a vibrating basket and accelerates electrolysis under stirring and vibration conditions to obtain electrolyte and anode mud. This method has the advantage of highly efficient metal dissolution, but it cannot simultaneously extract valuable nickel and cobalt. Therefore, the processing technology in this study improves the dissolution efficiency of hafnium and other precious metals in high-temperature alloys while simultaneously separating and extracting nickel and cobalt products by utilizing the unique alkaline region at the cathode / solution interface in acidic solutions. The prepared nickel and cobalt products can be used as precursors in the catalytic field, achieving efficient utilization of metal resources, which has significant value and importance. Summary of the Invention

[0004] This invention addresses the challenges of high-temperature alloys being poorly soluble in acidic solutions, hindering the recovery of valuable metal resources, and the complex and environmentally polluting processes involved in processing high-temperature alloy waste. It provides a short-process method for rapidly dissolving high-temperature alloy waste, simultaneously extracting nickel and cobalt resources, and efficiently separating hafnium-containing concentrates. This method breaks away from traditional long-process recycling methods, utilizing differences in metal reduction potential to control the preparation of nickel and cobalt products while simultaneously recovering hafnium-containing concentrates, thus shortening the process flow.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for rapidly dissolving high-temperature alloys and simultaneously and efficiently separating hafnium to recover nickel and cobalt using electrolysis, characterized in that the method includes the following steps:

[0006] Step 1: One-step electrochemical dissolution simultaneously yields nickel-cobalt products and hafnium-containing concentrates.

[0007] High-temperature alloy and titanium sheet were used as the anode and cathode of the electrolysis device, respectively. Sulfuric acid was added to the electrolytic cell and adjusted to a certain pH value. The DC power supply was turned on and the parameters were adjusted to carry out the electrolysis reaction. The inner wall of the electrolytic cell was equipped with a heater. The electrolysis device consisted of (1) a high-temperature alloy electrode, (2) a Ti electrode, (3) a first wire, (4) a second wire, (5) a DC power supply, (6) an electrolytic cell, (7) an electrolyte, (8) a heater, and (9) a thermometer. When the DC power supply (5) was turned on, the current density on the cathode surface was 100-1000 A / m2, the electrolyte temperature was set to 20-50℃, and after electrolysis for 1-6 hours, nickel-cobalt products and hafnium-containing enrichment were obtained.

[0008] Step 2: Solid-liquid separation to collect hafnium-containing concentrates

[0009] The product in the electrolytic cell is subjected to solid-liquid separation. The electrolyte obtained in step one is poured into a vacuum filter. After vacuum filtration, the electrolyte and hafnium-containing concentrate are obtained. The filtered electrolyte can be recycled.

[0010] Step 3: Separate and collect nickel-cobalt products

[0011] After the electrochemical dissolution process is completed, nickel and cobalt elements are deposited on the cathode, and finally a nickel-cobalt-containing product is obtained on the cathode titanium sheet;

[0012] Step 4: Washing hafnium-containing concentrates and nickel-cobalt products

[0013] The hafnium-containing concentrate and nickel-cobalt product obtained in steps two and three are washed with deionized water 3 to 5 times and then washed with anhydrous ethanol 3 to 5 times. The washed hafnium-containing concentrate and nickel-cobalt product are dried at 50 to 70°C for 2 to 3 hours to obtain the hafnium-containing concentrate and nickel-cobalt product.

[0014] Principle of this invention

[0015] During electrolysis, the high-temperature alloy, acting as the anode, is electrolyzed at an appropriate current density. Metal ions enter the electrolyte, and Ni in the electrolyte... 2+ Co 2+ Cations migrate towards the Ti cathode and compete for electrons, resulting in selective deposition. Simultaneously, a hydrogen evolution reaction occurs at the Ti cathode, leading to a localized increase in pH and Ni. 2+ Co 2+ Cations combine to form hydroxides. The discharge sequence is OH. - (H2O)>SO4 2- Therefore, H2O preferentially undergoes a hydrogen evolution reaction on the Ti cathode surface to produce H2 and OH. - The generated OH - and Ni 2+ Co 2+ Reaction: 2OH - +Ni 2+=Ni(OH)2,2OH - +Co 2+ =Co(OH)2. Electrolysis products are generated at the cathode / solution interface, that is, only in the alkaline electroreduction micro-region near the cathode, avoiding the dissolution of Co(OH)2 in an acidic environment, and realizing the generation of nickel cobalt hydroxide in an acidic environment.

[0016] Cathode reaction:

[0017] H2O+e – =H ● +OH – (1)

[0018] H ● +H ● =H2 (2)

[0019] Chemical reaction:

[0020] 2OH – +Co 2+ =Co(OH)2 (3)

[0021] 3Co(OH)2=Co3O4+2H2O+H2 (disproportionation reaction, T≈50℃) (4)

[0022] According to the standard electrode potential, Ni 2+ Co 2+ The reduction reaction is more efficient than (H2O)H + The reduction reaction is difficult to occur, therefore H2O preferentially undergoes the hydrogen evolution reaction at the cathode, producing H2 and OH. - OH - It can react with the large amount of Ni enriched near the cathode. 2+ Co 2+ The reaction generates Ni(OH)2 and Co(OH)2 through chemical reactions (3) to (4), and the hydrogen evolution reaction produces a large amount of OH. - The presence of ions leads to the formation of a locally highly alkaline (high pH) microregion near the Ti cathode surface. In this environment, especially with the possible combined effects of temperature or electrochemical fields, Co(OH)₂ can undergo a solid-phase transformation (disproportionation reaction) to generate Co₃O₄ without the participation of anhydrous substances or in the presence of an external oxidant. This part of the reaction is essentially a partial reaction of Co… 2+ Oxidized to Co 3+ Another part Co 2+ Maintaining the same valence state, it eventually forms a Co-containing compound. 2+ and Co 3+The mixed-valence oxide Co3O4, while Ni(OH)2 is extremely stable in alkaline environments and does not readily undergo disproportionation reactions. This invention employs an electrochemical method that eliminates the need to add alkaline substances to adjust the pH of the solution; instead, it utilizes the hydrogen evolution reaction to generate OH-. - A special alkaline electroreduction microregion is created near the cathode, and by controlling the properties of the microregion, nickel-cobalt products can be prepared at the cathode. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a diagram of the electrolytic apparatus used in Example 1 of the present invention to simultaneously prepare hafnium-enriched products and nickel-cobalt products;

[0025] Figure 2 This is a process flow diagram for the simultaneous preparation of hafnium-containing enrichment and nickel-cobalt products in Example 1 of the present invention;

[0026] Figure 3 This is a scanning electron microscope image of the tunable pore size nickel-cobalt product prepared in Example 1 of the present invention;

[0027] Figure 4 XRD patterns of hafnium-enriched compounds prepared in Example 1 of this invention;

[0028] Figure 5 The XRD pattern of the nickel-cobalt product prepared in Example 1 of this invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0031] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0033] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0034] Example 1

[0035] A cobalt-based superalloy was used as the anode. A solution containing 1 mol / L concentrated sulfuric acid was added to deionized water and the pH was adjusted to 4. This solution was then poured into the electrolysis apparatus, and electrolysis was performed by turning on a DC power supply. The current density was set to 200 A / m³. 2 The heater temperature was 25℃, and the nickel-cobalt product was separated after electrolysis for 2 hours. The product in the electrolytic cell underwent solid-liquid separation, and the electrolyte containing trace alloying elements and anode mud were obtained by filtration. The collected electrolyte was adjusted by adding H2SO4 to participate in the electrolysis reaction. After filtration, the anode mud was washed 5 times each with deionized water and anhydrous ethanol. The washed material was dried at 65℃ for 4 hours to obtain a dried hafnium-containing concentrate. The obtained nickel-cobalt alloy product was washed 5 times each with deionized water and anhydrous ethanol. The washed material was dried at 65℃ for 4 hours to obtain a dried nickel-cobalt product.

[0036] Example 2

[0037] A nickel-based superalloy was used as the anode. A solution containing 2 mol / L concentrated sulfuric acid was added to deionized water, and the pH was adjusted to 3. This solution was then poured into the electrolysis apparatus, and electrolysis was performed by turning on a DC power supply. The current density was set to 300 A / m³. 2 The heater temperature was 40℃, and the nickel-cobalt product was separated after electrolysis for 3 hours. The product in the electrolytic cell underwent solid-liquid separation, and the electrolyte containing trace alloying elements and anode mud were obtained by filtration. The collected electrolyte was adjusted by adding H2SO4 to participate in the electrolysis reaction. After filtration, the anode mud was washed 5 times each with deionized water and anhydrous ethanol. The washed material was dried at 65℃ for 4 hours to obtain a dried hafnium-containing concentrate. The obtained nickel-cobalt product was washed 5 times each with deionized water and anhydrous ethanol. The washed material was dried at 65℃ for 4 hours to obtain a dried nickel-cobalt product.

[0038] Example 3

[0039] A high-temperature alloy based on iron was used as the anode. A solution containing 3 mol / L concentrated sulfuric acid was added to deionized water, and the pH was adjusted to 2. This solution was then poured into the electrolysis apparatus, and electrolysis was performed by turning on a DC power supply. The current density was set to 400 A / m³. 2 The heater temperature was 50℃, and the nickel-cobalt product was separated after electrolysis for 4 hours. The product in the electrolytic cell underwent solid-liquid separation, and the electrolyte containing trace alloying elements and anode mud were obtained by filtration. The collected electrolyte was circulated to participate in the electrolysis reaction by adding H2SO4 to adjust the pH. After filtration, the anode mud was washed 5 times each with deionized water and anhydrous ethanol. The washed material was dried at 65℃ for 4 hours to obtain a dried hafnium-containing concentrate. The obtained nickel-cobalt product was washed 5 times each with deionized water and anhydrous ethanol. The washed material was dried at 65℃ for 4 hours to obtain a dried nickel-cobalt product.

[0040] The present invention has the following beneficial effects:

[0041] I. This invention utilizes the high-density, highly oxidizing intermediate products at the anode / solution interface during the electrolysis process to significantly increase the dissolution rate of high-temperature alloys and expand the methods for recycling high-temperature alloys.

[0042] Second, this invention utilizes an electrolysis process to achieve rapid dissolution of high-temperature alloys, extraction of nickel and cobalt elements, and separation of hafnium-containing enrichments in one step, with a short process and simple process route.

[0043] Third, the nickel and cobalt elements extracted by this invention can be used as catalysts for batteries and water electrolysis to produce hydrogen, and can be applied in the field of new energy.

[0044] Fourth, this invention uses membrane-free and additive-free electrolysis, which is low in cost, simple in equipment and process, has no secondary pollution to the environment, and is easy to industrialize.

[0045] Fifth, this invention does not use the surfactants found in existing methods, which reduces the introduction of new impurities and allows for the preparation of nickel-cobalt products with higher purity.

[0046] VI. Compared with other electrolytic methods for the resource utilization of high-temperature alloys, this invention does not require the addition of alkaline substances such as NaOH or Ca(OH)2 solution to adjust the pH value of the solution, and the process is shorter.

[0047] This invention provides a method for rapidly dissolving high-temperature alloys using electrolysis while simultaneously and efficiently separating hafnium to recover nickel and cobalt.

[0048] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rapidly dissolving a high-temperature alloy by electrolysis, synchronously separating hafnium and recovering nickel and cobalt with high efficiency, characterized in that According to the difference of reduction potential of different metals, the unique alkaline region of cathode / solution interface in the acid solution is regulated by ion competition reduction sequence to recover nickel-cobalt resources and hafnium-containing concentrate synchronously, and the method comprises the following steps: Step one: one-step electrochemical dissolution to obtain nickel-cobalt product and hafnium-containing concentrate High-temperature alloy and titanium sheet are respectively used as anode and cathode of electrolytic equipment, sulfuric acid is added into electrolytic cell and pH value is regulated, direct current power supply is turned on to regulate parameters for electrolysis reaction, heater is arranged on inner wall of electrolytic cell, and electrolytic device is composed of (1) high-temperature alloy electrode, (2) Ti electrode, (3) first lead wire, (4) second lead wire, (5) direct current power supply, (6) electrolytic cell, (7) electrolyte, (8) heater and (9) thermometer; direct current power supply (5) is turned on, current density on surface of cathode is 100-1000 A / m 2 , electrolyte temperature is set to 20-50 DEG C, and nickel-cobalt product and hafnium-containing concentrate are obtained after electrolysis for 1-6 h. Step two: solid-liquid separation to collect hafnium-containing concentrate The product in the electrolytic cell is subjected to solid-liquid separation, the electrolyte obtained in step one is poured into a suction filtration device, and the electrolyte and hafnium-containing concentrate are obtained by suction filtration, and the electrolyte after suction filtration can be recycled. Step three: separation and collection of nickel-cobalt product After the electrochemical dissolution process is completed, nickel-cobalt elements are deposited on the cathode, and finally a product containing nickel-cobalt is obtained on the cathode titanium sheet. Step four: washing of hafnium-containing concentrate and nickel-cobalt product The hafnium-containing concentrate and nickel-cobalt product obtained in steps two and three are washed with deionized water for 3-5 times and then washed with anhydrous ethanol for 3-5 times, and the washed hafnium-containing concentrate and nickel-cobalt product are dried at 50-70℃ for 2-3h to obtain the hafnium-containing concentrate and nickel-cobalt product.

2. The method for rapidly dissolving superalloy and synchronously separating hafnium and recovering nickel and cobalt with high efficiency by electrolysis according to claim 1, characterized in that, The electrolyte in step one is a dilute sulfuric acid solution with a certain pH value, but it is not limited to this acid solution. It is required that the ions in the electrolyte are mainly H+, and the pH range of the solution is 1-4, and the concentration of sulfuric acid used to adjust the pH is 1-5mol / L.

3. The method for rapidly dissolving superalloy and synchronously separating hafnium and recovering nickel and cobalt with high efficiency by electrolysis according to claim 1, characterized in that, The heater arranged on the inner wall of the electrolytic cell in step one adopts constant temperature heating in the electrolysis reaction, and the heating temperature is 20-50℃.

4. The method for rapidly dissolving superalloy and synchronously separating hafnium and recovering nickel and cobalt with high efficiency by electrolysis according to claim 1, characterized in that, The current density of the cathode surface of the direct current power supply in step one is 100-1000 A / m 2 , ensuring the efficient dissolution of the alloy while depositing nickel and cobalt ions.

5. The method for rapidly dissolving superalloy, synchronously separating hafnium and recovering nickel and cobalt with high efficiency by electrolysis according to claim 1, characterized in that, The high-temperature alloy waste in step one includes but is not limited to cobalt-based alloy, nickel-based alloy and iron-based alloy, and the alloy composition contains different contents of nickel, cobalt, tungsten, tantalum and hafnium.

6. The method for rapid dissolution of superalloys and simultaneous efficient separation of hafnium and recovery of nickel and cobalt by electrochemical method according to claim 1, characterized in that, In step two, the product in the electrolytic cell is subjected to solid-liquid separation, and the hafnium-containing concentrate is directly obtained by suction filtration, which avoids the complicated problem of enrichment process.

7. The method for rapidly dissolving superalloy, synchronously separating hafnium and recovering nickel and cobalt with high efficiency by electrolysis according to claim 1, characterized in that, In step two, the nickel-cobalt material is separated from the cathode, and the collected electrolyte is adjusted to a certain pH value by adding sulfuric acid and recycled, which avoids the problems of acid consumption and resource waste.

8. The method for rapidly dissolving superalloy and synchronously separating hafnium and recovering nickel and cobalt with high efficiency by using electrochemical method according to claim 1, characterized in that, In step three, the concentration of hafnium in the electrolyte is less than 0.001ppm, the content of hafnium in the hafnium-containing concentrate is not less than 7wt%, and the total content of the cathode nickel-cobalt product is not less than 99wt%.

9. The method for rapid dissolution of superalloys and simultaneous separation of hafnium and recovery of nickel and cobalt by electrochemical method according to claim 1, characterized in that, In step four, the hafnium-containing concentrate and nickel-cobalt product are washed with deionized water for not less than 3-5 times and then washed with anhydrous ethanol for not less than 3-5 times, and the washed hafnium-containing concentrate and nickel-cobalt product are dried at 50-70℃ for not less than 2h.

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