Process for the recovery of a nickel-containing metal catalyst

Abstract

The application relates to the field of electrochemistry and hydrometallurgy, and particularly relates to a recycling method of a nickel-containing metal catalyst. The recycling method of the nickel-containing metal catalyst comprises the following steps: placing the nickel-containing metal catalyst and a first acid liquid in an anode chamber of an electrolysis device, placing a copper ion-containing acid solution in a cathode chamber of the electrolysis device, performing an electrochemical reaction, forming a metal ion-containing solution one and a solid one in the anode chamber, and forming a solution two and a solid two in the cathode chamber; performing first precipitation on the solution one by using a first alkali to prepare a nickel ion-containing solution three and a solid three; performing second precipitation on the solution three by using a second alkali to prepare a solution four and nickel hydroxide; the anode chamber and the cathode chamber are separated by a diaphragm bag; or the anode chamber and the cathode chamber are separated by an insulating material, and a flow circulating state is realized by an auxiliary pump. The recycling method of the nickel-containing metal catalyst is high in nickel recovery rate, environment-friendly and economical, and simple in process.

Description

Technical Field

[0001] This application relates to the fields of electrochemistry and hydrometallurgy, and in particular to a method for recycling nickel-containing metal catalysts. Background Technology

[0002] Metal catalysts are a class of solid catalysts with metals as the main active component. They primarily achieve catalytic action through noble metals (such as platinum, palladium, and rhodium) or transition metals (such as iron, cobalt, and nickel), and are widely used in the petrochemical industry, environmental protection, and new energy materials. Nickel-containing metal catalysts, in particular, have a wide range of applications, which also brings enormous recycling pressure. Nickel-containing metal catalysts have high organic content, slow leaching rates, and high impurity content, making it impossible to recover nickel using mainstream hydrometallurgical systems, resulting in low recovery rates (less than 40%). Traditional recovery methods for nickel-containing metal catalysts suffer from low recovery efficiency, complex processes, and high costs. Summary of the Invention

[0003] Therefore, the main objective of this application is to provide a method for recycling nickel-containing metal catalysts that has a high nickel recovery rate, is environmentally friendly and economical, and has a simple process.

[0004] This application provides a method for recycling nickel-containing metal catalysts, comprising the following steps:

[0005] A nickel-containing metal catalyst and a first acid solution are placed in the anode chamber of an electrolysis device, and an acidic solution containing copper ions is placed in the cathode chamber of the electrolysis device to carry out an electrochemical reaction. Solution 1 and solid 1 containing metal ions are formed in the anode chamber, and solution 2 and solid 2 are formed in the cathode chamber.

[0006] Solution 1 was subjected to a first precipitate by using a first alkali to prepare solution 3 and solid 3 containing nickel ions;

[0007] A second alkali was used to induce a second precipitation in solution three, thus preparing solution four and nickel hydroxide.

[0008] The anode chamber and the cathode chamber are separated by a diaphragm bag; or the anode chamber and the cathode chamber are separated by an insulating material and a flow vortex state is achieved by an auxiliary pump.

[0009] In some embodiments, one or more of the following features are satisfied:

[0010] (1) The first acid solution includes sulfuric acid solution and / or hydrochloric acid solution;

[0011] (2) In the first acid solution, the mass fraction of acid is 6%-12%;

[0012] (3) The mass-volume ratio of the nickel-containing metal catalyst to the first acid solution is 1g:(3-20)mL.

[0013] In some embodiments, after the step of preparing solution four and nickel hydroxide, the method further includes a step of neutralizing solution two, solid one, solid three, and solution four with a second acid to prepare solution five and solid waste.

[0014] Optionally, the pH for the neutralization reaction is 6.5-7.5.

[0015] In some embodiments, one or more of the following features are satisfied:

[0016] (1) After the steps of preparing solution five and solid waste, the method also includes filtering solution five and passing it into a bipolar membrane to produce acid and alkali.

[0017] (2) The first acid solution and the second acid solution are bipolar membrane acid preparation solutions;

[0018] (3) The first alkali and the second alkali are bipolar membrane alkali solutions.

[0019] In some embodiments, one or more of the following features are satisfied:

[0020] (1) The second acid includes sulfuric acid and / or hydrochloric acid;

[0021] (2) The first base and the second base each independently include sodium hydroxide;

[0022] (3) The second acid is provided in the form of an acid solution; the mass fraction of the acid in the acid solution is 6%-12%;

[0023] (4) The first base and the second base are provided in the form of an alkaline solution; the mass fraction of the base in the alkaline solution is 5%-10%.

[0024] In some embodiments, one or more of the following features are satisfied:

[0025] (1) The pH of the first precipitate is 3.5-5.2;

[0026] (2) The pH of the second precipitate is 7.5-9.0.

[0027] In some embodiments, the cathode and anode of the electrolysis device are made of graphite or titanium;

[0028] And / or, the reaction conditions in the anode chamber include: the redox potential of the anolyte from the point of energization to the point of anolyte reaction is 0.5V-5V; and the total organic carbon (TOC) in the reaction solution at the reaction endpoint is ≤400ppm.

[0029] In some embodiments, the electrolysis equipment includes at least two identical swirl electrolysis chamber skids;

[0030] The same-polarity swirl electrolysis chamber skids are connected in parallel or in series.

[0031] In some embodiments, the nickel-containing metal catalyst contains 60wt%-80wt% nickel, 0.1wt%-2wt% iron, 1wt%-20wt% aluminum, 1wt%-12wt% organic matter, and the balance is water and oxygen.

[0032] In some embodiments, the copper ion content in the acidic solution containing copper ions is 20 g / L-100 g / L, H... + The concentration is 0.2 mol / L-2 mol / L.

[0033] Studies have found that nickel-containing metal catalysts have high organic content, slow leaching rates, and high impurity content, making it impossible to recover nickel using mainstream hydrometallurgical systems, resulting in low recovery rates. Traditional methods for recovering nickel-containing metal catalysts involve processes such as high-temperature roasting and high-temperature acid leaching, which are complex, costly, environmentally unfriendly, and have low recovery efficiency, failing to meet industrial needs.

[0034] Based on this, the method for recycling nickel-containing metal catalysts provided in this application involves reacting the nickel-containing metal catalyst and a first acid solution in the anode chamber of an electrolysis device. This process effectively removes organic matter and leaches nickel ions and impurity metal ions through electrochemical oxidation-reduction. The first solution obtained after solid-liquid separation undergoes stepwise precipitation to remove impurity metals, yielding high-purity nickel hydroxide. Simultaneously, a diaphragm bag or insulating material is used to separate the anode and cathode chambers of the electrolysis device, preventing nickel ions from the anode chamber from entering the cathode chamber, thereby improving the nickel recovery rate. Furthermore, the acidic solution containing copper ions can react in the cathode chamber to achieve copper recovery.

[0035] Furthermore, the method for recycling nickel-containing metal catalysts in this application has the following advantages:

[0036] The process is simple, with low processing costs, and can recover waste nickel catalysts with different nickel contents in stages, adapting to a wide range of raw materials. The size of the electrolysis equipment can be flexibly customized, and it can be flexibly assembled and used with skid-mount devices, etc., with low equipment requirements. The electrochemical oxidation-reduction method can stably provide continuous oxidation-reduction capacity, with high reaction efficiency, high nickel recovery rate, and high purity. In short, this application provides a method for the recovery and utilization of nickel-containing metal catalysts with high nickel recovery rate, environmental friendliness, economy, and simple process, which can meet the needs of industrial nickel recovery. Attached Figure Description

[0037] To better describe and illustrate the embodiments or examples provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments or examples, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0038] Figure 1 This is a schematic diagram of the method for recycling the nickel-containing metal catalyst of this application. Detailed Implementation

[0039] The method for recycling nickel-containing metal catalysts according to this application is further described in detail below with reference to specific embodiments. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0041] In this article, "one or more" refers to any one, two or more of the listed items.

[0042] In this application, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0043] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0044] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0045] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0046] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0047] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows for temperature fluctuations within the precision range controlled by the instrument.

[0048] In this application, the nickel recovery rate is the mass yield of nickel, calculated as follows: mass of nickel in nickel hydroxide / mass of nickel in the nickel-containing metal catalyst × 100%; the nickel content in the nickel-containing metal catalyst is tested as follows: the nickel-containing metal catalyst is dried and ground until all particles pass through a 200-mesh sieve, then digested in an ultrasonic digester using a hydrochloric acid-nitric acid system or aqua regia, so that elements such as nickel enter the solution as ions, and then the nickel in the sample solution is determined by inductively coupled plasma optical emission spectrometry (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS); the content of organic matter in the nickel-containing metal catalyst is determined by a TOC analyzer.

[0049] In this application, the copper ion content in the acidic solution containing copper ions is determined by inductively coupled plasma optical emission spectrometry (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS).

[0050] In this application, the mass fraction of acid in the bipolar membrane acid-producing solution and the mass fraction of alkali in the bipolar membrane alkali-producing solution are determined by potentiometric titration.

[0051] Some embodiments of this application provide a method for recycling nickel-containing metal catalysts, comprising the following steps:

[0052] A nickel-containing metal catalyst and a first acid solution are placed in the anode chamber of an electrolysis device, and an acidic solution containing copper ions is placed in the cathode chamber of the electrolysis device to carry out an electrochemical reaction. Solution 1 and solid 1 containing metal ions are formed in the anode chamber, and solution 2 and solid 2 are formed in the cathode chamber.

[0053] Solution 1 was subjected to a first precipitate by using a first alkali to prepare solution 3 and solid 3 containing nickel ions;

[0054] A second alkali was used to induce a second precipitation in solution three, thus preparing solution four and nickel hydroxide.

[0055] The anode chamber and the cathode chamber are separated by a diaphragm bag; or the anode chamber and the cathode chamber are separated by an insulating material and a flow vortex state is achieved by an auxiliary pump.

[0056] The method for recycling nickel-containing metal catalysts provided in this application involves reacting the nickel-containing metal catalyst and a first acid solution in the anode chamber of an electrolysis device. Through electrochemical oxidation-reduction, organic matter is effectively removed and nickel ions and impurity metal ions are leached out. The first solution obtained after solid-liquid separation undergoes stepwise precipitation to remove impurity metals, yielding high-purity nickel hydroxide. Simultaneously, a diaphragm bag or insulating material is used to separate the anode and cathode chambers of the electrolysis device, preventing nickel ions from the anode chamber from entering the cathode chamber, thereby improving the nickel recovery rate. Furthermore, the acidic solution containing copper ions can react in the cathode chamber to achieve copper recovery.

[0057] In some embodiments, the reaction conditions in the anode chamber include: the redox potential from the start of the electrolysis process to the anode electrolysis chamber is 0.5V-5V; and the total organic carbon (TOC) in the reaction solution at the reaction endpoint is ≤400ppm. Understandably, the aforementioned redox potential falls within the range of high electrolysis efficiency, which is beneficial for improving electrolysis efficiency and controlling the total organic carbon content in the reaction solution at the reaction endpoint to a low range. Optionally, the redox potential can be 0.5V, 1V, 2V, 3V, 4V, 5V, etc.

[0058] In some embodiments, the first acid solution includes a sulfuric acid solution and / or a hydrochloric acid solution. It is understood that sulfuric acid and hydrochloric acid solutions are common acids that are beneficial for stabilizing the electrode reaction and improving reaction efficiency, safety, and environmental friendliness. Hydrochloric acid is more conducive to nickel leaching than sulfuric acid, thus improving recovery efficiency.

[0059] In some embodiments, the mass fraction of acid in the first acid solution is 6%-12%. Understandably, the aforementioned first acid solution has a suitable concentration, which is beneficial for balancing reaction stability and reaction efficiency. Optionally, the mass fraction of acid can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0060] In some embodiments, the mass-to-volume ratio of the nickel-containing metal catalyst to the first acid solution is 1 g:(3-20) mL. Understandably, this ratio promotes complete electrolysis. Optionally, the mass-to-volume ratio of the nickel-containing metal catalyst to the first acid solution can be 1 g:3 mL, 1 g:5 mL, 1 g:10 mL, 1 g:15 mL, 1 g:20 mL, etc.

[0061] In some embodiments, after the steps of preparing solution four and nickel hydroxide, a further step is included: neutralizing solution two, solid one, solid three, and solution four with a second acid to prepare solution five and solid waste. It is understood that the above neutralization reaction enables comprehensive treatment of the solution and solid waste generated from the reaction, which is beneficial to environmental protection. Specifically, a neutralization reaction with a pH of 6.5-7.5 yields a neutral product, which is beneficial for subsequent processing.

[0062] In some embodiments, after the steps of preparing solution five and solid waste, the method further includes filtering solution five and then passing it through a bipolar membrane to produce acid or alkali. Understandably, filtering solution five and passing it through a bipolar membrane allows for the reuse of the salt solution and avoids secondary pollution to the environment.

[0063] In some embodiments, the first acid and the second acid are bipolar membrane acid solutions; the first alkali and the second alkali are bipolar membrane alkali solutions. Understandably, bipolar membrane acid and alkali solutions, compared to conventional acids and alkalis, can be prepared from waste salt solutions via a bipolar membrane, resulting in lower costs and reducing process costs. In particular, by combining the step of filtering solution five before it enters the bipolar membrane acid / alkali solution, the recycling of solution five, the bipolar membrane acid solution, and the bipolar membrane alkali solution can be achieved. Coupled bipolar membrane acid / alkali production with electrochemical oxidation-reduction for the recovery of nickel-containing metal catalysts, this approach helps to further reduce process costs while maintaining high nickel recovery rates, and also reduces the amount of byproducts generated and the processing burden, thus improving economic and environmental efficiency.

[0064] In some embodiments, the second acid includes sulfuric acid and / or hydrochloric acid; the first base and the second base each independently include sodium hydroxide. It is understood that the above acids and bases are common acids and bases, with readily available raw materials, which helps to reduce costs.

[0065] In some embodiments, the second acid is provided in the form of an acid solution; the acid solution has a mass fraction of 6%-12%. This second acid is beneficial for improving reaction stability while also maintaining reaction efficiency. Specifically, the mass fraction of the acid in the acid solution can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0066] In some embodiments, the first and second bases are provided in the form of an alkaline solution; the mass fraction of the base in the alkaline solution is 5%-10%. Understandably, the aforementioned first and second bases facilitate precise pH adjustment and control of the precipitation reaction. Specifically, the mass fraction of the base in the alkaline solution can be 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0067] In some embodiments, the pH of the first precipitate is 3.5-5.2. Understandably, controlling the pH of the first precipitate within this range is beneficial for precipitating impurity metal ions while preventing the precipitation of nickel ions, thereby improving the recovery rate and purity of nickel. Specifically, the pH of the first precipitate can be 3.5, 4, 4.5, 5, 5.1, 5.2, etc.

[0068] In some embodiments, the pH of the second precipitate is 7.5-9.0. Understandably, controlling the pH of the second precipitate within this range is beneficial for the complete precipitation of nickel ions and improves the nickel ion yield. Specifically, the pH of the second precipitate can be 7.5, 8, 8.5, 9, etc.

[0069] In some embodiments, the cathode and anode of the electrolysis apparatus are made of graphite or titanium. Understandably, using inert cathodes and anodes avoids the introduction of other impurities. Graphite, being softer and more easily worn, requires a thicker electrode plate.

[0070] In some embodiments, the electrolysis equipment includes at least two identical swirling electrolysis chamber skids; these skids are connected in parallel or in series. Understandably, the processing capacity and depth can be adjusted and the electrolysis efficiency controlled by arranging multiple identical swirling electrolysis chamber skids; wherein, parallel connection of the identical swirling electrolysis chamber skids allows for flexible increases or decreases in processing capacity; and series connection allows for flexible increases or decreases in leaching depth.

[0071] In some embodiments, the nickel-containing metal catalyst contains 60wt%-80wt% nickel, 0.1wt%-2wt% iron, 1wt%-20wt% aluminum, and 1wt%-12wt% organic matter, with the balance being water and oxygen. It is understood that the above-mentioned nickel-containing metal catalyst is rich in nickel but also contains impurities such as iron and aluminum, as well as organic matter, making recovery difficult. The recovery method for the nickel-containing metal catalyst specified in this application can achieve high-efficiency and high-purity recovery. Optionally, the nickel-containing metal catalyst may contain 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, etc.; iron may contain 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, etc.; aluminum may contain 1wt%, 5wt%, 10wt%, 15wt%, 20wt%, etc.; and organic matter may contain 1wt%, 3wt%, 6wt%, 9wt%, 12wt%, etc.

[0072] In some embodiments, the copper ion content in the acidic solution containing copper ions is 20 g / L-100 g / L, H +The concentration is 0.2 mol / L-2 mol / L. The above-mentioned acidic solution containing copper ions is beneficial to the cathode chamber reaction, enabling copper recovery and balancing the current in the anode and cathode chambers. Optionally, the copper ion concentration in the acidic solution can be 20 g / L, 40 g / L, 60 g / L, 80 g / L, or 100 g / L; H + The concentration can be 0.2 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, etc.

[0073] Understandably, a solid-liquid separation step, including but not limited to at least one of centrifugation and filtration, is required before obtaining the solution and the solid.

[0074] Understandably, the main components of nickel-containing metal catalysts are impurity metals such as nickel, iron, and aluminum, and organic ligands. When the nickel-containing metal catalyst and the first acid solution react in the anode chamber of the electrolysis equipment, the organic matter is converted into carbon dioxide and water through an electro-Fenton reaction, thus removing the organic matter. Simultaneously, impurity metals such as nickel and iron are oxidized into nickel ions and other impurity metal ions, which enter solution one. The inert, unreacted impurities remain as solid one. When the acidic solution containing copper ions reacts in the cathode chamber of the electrolysis equipment, the copper ions are reduced to sponge copper (i.e., solid two), simultaneously yielding an acidic solution two. When the first alkali is used to precipitate solution one, impurity metal ions (iron ions, aluminum ions, etc.) will precipitate first, becoming the corresponding metal hydroxides (solid three), while nickel ions remain in solution three. When the second alkali is used to precipitate solution three, the nickel ions precipitate as nickel hydroxide, forming a low-metal waste liquid (i.e., solution four). When solutions two, solid one, solid three, and solution four are neutralized with the second acid, a neutral salt solution (i.e., solution five) and solid waste (main components: aluminum hydroxide, iron hydroxide, acid-insoluble substances, etc.) are generated. By filtering solution five and feeding it into a bipolar membrane acid / alkali generator, bipolar membrane acid and alkali solutions can be prepared. The bipolar membrane acid solution can be used to provide the first and second acids, and the bipolar membrane alkali solution can provide the first and second alkalis for stepwise precipitation of impurity metal ions and nickel ions, achieving recycling. Specifically, as follows... Figure 1 As shown.

[0075] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0076] Unless otherwise specified, all raw materials and reagents used in this application can be purchased commercially. The following is an example.

[0077] Nickel-containing metal catalyst A: Ni: 61.25 wt%, organic matter content: 9.9 wt%, iron: 1.62 wt%, aluminum: 4.25 wt%, the remaining components are water and oxygen.

[0078] Nickel-containing metal catalyst B: Ni: 71.2 wt%, organic matter content: 8.2 wt%, iron: 0.32 wt%, aluminum: 0.98 wt%, the remaining components are water and oxygen.

[0079] Acidic solution containing copper ions: Cu: 45 g / L, H + The concentration is 1 mol / L.

[0080] Unless otherwise specified, all experimental instruments used in this application can be purchased commercially. The following are examples:

[0081] Electrolysis equipment: The shell of the electrolysis equipment is made of polypropylene integral casting. The anode chamber and cathode chamber are also separated by polypropylene. A flow vortex state is achieved by an auxiliary pump. The anode is a titanium mesh bag with a mesh size of <200 mesh. Electrolysis residual solids can leak out through the mesh and be sucked away by the pump. The cathode is a titanium plate.

[0082] Example 1

[0083] This embodiment provides a method for recycling nickel-containing metal catalysts, the steps of which are as follows:

[0084] 1. Weigh 20g of waste nickel metal catalyst A and 100ml of bipolar membrane acid-producing solution (sulfuric acid solution, with a mass fraction of 11.8%), add them to the anodic electrolysis chamber, and pass an acidic solution containing copper ions (Cu: 45g / L) into the cathode chamber. Perform an electrochemical reaction by passing an electric current until the redox potential in the anodic electrolysis chamber reaches 0.82V, which is the endpoint of the reaction.

[0085] In the anode chamber, organic matter is removed by electro-Fenton oxidation, and metal ions are leached to obtain a solution containing metal ions and a solid. The total organic carbon (TOC) of the initial reaction solution is 19,800 ppm, and the total organic carbon (TOC) of the final reaction solution is 296 ppm (meeting the preset process requirement of TOC≤400ppm).

[0086] The cathode chamber yielded solution 2 and solid 2 (sponge copper), with the copper ion concentration at the end of electrolysis being 0.043 g / L;

[0087] 2. Solution 1 was adjusted to pH 4.0 using a bipolar membrane alkali solution (NaOH solution, NaOH mass fraction 9.7%), and precipitated to obtain solution 3 containing nickel ions and solid 3 (hydroxide of impurity metal); solution 3 was further adjusted to pH 7.5 using the above bipolar membrane alkali solution, and precipitated to obtain solution 4 and nickel hydroxide (nickel content 11.66g).

[0088] 3. Adjust the pH of Solution 2, Solid 1, Solid 3, and Solution 4 to 6.5 with the bipolar membrane acid-generating solution (sulfuric acid solution, with a sulfuric acid mass fraction of 11.8%) and neutralize to obtain Solution 5 and solid waste (dry weight 4.26g, main components: aluminum hydroxide, iron hydroxide, acid-insoluble matter silicon dioxide and aluminum oxide, containing Ni: 13.80%).

[0089] 4. After precise filtration, the solution enters a bipolar membrane to prepare acid and alkali.

[0090] The overall recovery rate in this embodiment reached 95.2%.

[0091] Example 2

[0092] This embodiment provides a method for recycling nickel-containing metal catalysts, the steps of which are as follows:

[0093] 1. Weigh 10g of waste nickel metal catalyst A and 100ml of bipolar membrane acid-producing solution (sulfuric acid solution, with a sulfuric acid mass fraction of 11.8%), add them to the anodic electrolysis chamber, and pass an acidic solution containing copper ions (Cu: 45g / L) into the cathode chamber. Perform an electrochemical reaction by passing an electric current until the redox potential in the anodic electrolysis chamber reaches 1.62V, which is the endpoint of the reaction.

[0094] In the anode chamber, organic matter is removed by electro-Fenton oxidation, and metal ions are leached to obtain a solution containing metal ions and a solid. The total organic carbon (TOC) of the initial reaction solution is 9900 ppm, and the total organic carbon (TOC) of the final reaction solution is 56 ppm (meeting the preset process requirement of TOC≤400ppm).

[0095] The cathode chamber yielded solution 2 and solid 2 (sponge copper), and the copper ion concentration at the end of electrolysis was 0.048 g / L.

[0096] 2. Solution 1 was adjusted to pH 4.5 using a bipolar membrane alkali solution (NaOH solution, NaOH mass fraction 9.5%), and precipitation yielded Solution 3 containing nickel ions and Solid 3 (hydroxide of impurity metal); Solution 3 was further adjusted to pH 8.0 using the above bipolar membrane alkali solution, and precipitation yielded Solution 4 and nickel hydroxide (nickel content 5.936g).

[0097] 3. Adjust the pH of Solution 2, Solid 1, Solid 3, and Solution 4 to 6.5 with the bipolar membrane acid-generating solution (sulfuric acid solution, with a sulfuric acid mass fraction of 11.8%) and neutralize to obtain Solution 5 and solid waste (dry weight 1.75g, main components: aluminum hydroxide, iron hydroxide, acid-insoluble matter silicon dioxide and aluminum oxide, containing Ni: 10.78%).

[0098] 4. After precise filtration, the solution enters a bipolar membrane to prepare acid and alkali.

[0099] The overall recovery rate in this embodiment reached 96.9%.

[0100] Example 3

[0101] Except that the bipolar membrane acid production solution uses sulfuric acid solution (sulfuric acid mass fraction of 6%) and nickel-containing metal catalyst B, the rest is the same as in Example 1. The total organic carbon (TOC) of the final reaction solution in the anode chamber is 328 ppm, yielding nickel hydroxide (nickel content 13.38 g) and solid waste dry weight 5.65 g, containing Ni: 15.21%. The total recovery rate of this example reaches 94.0%.

[0102] Example 4

[0103] Except for the use of hydrochloric acid solution (hydrochloric acid mass fraction of 10%) for bipolar membrane acid production and the use of nickel-containing metal catalyst B, the rest is the same as in Example 1. The total organic carbon (TOC) of the final reaction solution in the anode chamber is 285 ppm, yielding nickel hydroxide (nickel content 13.71 g), and solid waste with a dry weight of 4.05 g, containing 13.08% Ni. The total recovery rate of this example reaches 96.28%.

[0104] Note: Hydrochloric acid is more effective at leaching minerals than sulfuric acid.

[0105] Example 5

[0106] Except for the use of sulfuric acid solution (5% by mass) for bipolar membrane acid production and the use of nickel-containing metal catalyst B, the rest is the same as in Example 1; wherein, the total organic carbon (TOC) of the final reaction solution in the anode chamber is 386 ppm, nickel hydroxide (13.11 g of nickel content) is obtained, and the dry weight of solid waste is 5.82 g, of which it contains 19.46% Ni. The total recovery rate of this example reaches 92.05%.

[0107] Example 6

[0108] Except for the use of sulfuric acid solution (hydrochloric acid mass fraction of 5%) in the bipolar membrane acid production solution and the use of nickel-containing metal catalyst B, the rest is the same as in Example 1; wherein, the total organic carbon (TOC) of the anode chamber endpoint reaction solution is 354 ppm, nickel hydroxide (nickel content 13.20 g) is obtained, and the dry weight of solid waste is 5.61 g, of which it contains 18.52% Ni. The total recovery rate of this example reaches 92.7%.

[0109] In the method for recovering nickel-containing metal catalysts disclosed in this application, the main loss of nickel comes from solid 1: spent nickel catalyst with a particle size >100 mesh and unleached nickel coated with acid-insoluble silica and alumina. Optional measures include: sieving solid 1 to separate solids >100 mesh, grinding them, and returning them to the anolyte for nickel recovery; or treating solid 1 with an alkali to dissolve the silica and alumina on its surface before returning it to the anolyte for nickel recovery.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for recycling nickel-containing metal catalysts, characterized in that, Includes the following steps: A nickel-containing metal catalyst and a first acid solution are placed in the anode chamber of an electrolysis device, and an acidic solution containing copper ions is placed in the cathode chamber of the electrolysis device to carry out an electrochemical reaction. Solution 1 and solid 1 containing metal ions are formed in the anode chamber, and solution 2 and solid 2 are formed in the cathode chamber. Solution 1 was subjected to a first precipitate by using a first alkali to prepare solution 3 and solid 3 containing nickel ions; A second alkali was used to induce a second precipitation in solution three, thus preparing solution four and nickel hydroxide. The anode chamber and the cathode chamber are separated by a diaphragm bag; or the anode chamber and the cathode chamber are separated by an insulating material and a flow swirl state is achieved by an auxiliary pump. The pH of the first precipitate is 3.5-5.2; The nickel-containing metal catalyst is rich in nickel, and also contains iron, aluminum impurities, and organic matter.

2. The recycling method as described in claim 1, characterized in that, It meets one or more of the following characteristics: (1) The first acid solution includes sulfuric acid solution and / or hydrochloric acid solution; (2) In the first acid solution, the mass fraction of acid is 6%-12%; (3) The mass-volume ratio of the nickel-containing metal catalyst to the first acid solution is 1g:(3-20)mL.

3. The recycling method as described in claim 1 or 2, characterized in that, After the steps of preparing solution four and nickel hydroxide, the process also includes a step of neutralizing solution two, solid one, solid three, and solution four with a second acid to prepare solution five and solid waste.

4. The recycling method as described in claim 3, characterized in that, The pH for the neutralization reaction is 6.5-7.

5.

5. The recycling method as described in claim 3, characterized in that, It meets one or more of the following characteristics: (1) After the steps of preparing solution five and solid waste, the method also includes filtering solution five and passing it into a bipolar membrane to produce acid and alkali. (2) The first acid solution and the second acid solution are bipolar membrane acid preparation solutions; (3) The first alkali and the second alkali are bipolar membrane alkali solutions.

6. The recycling method as described in claim 3, characterized in that, It meets one or more of the following characteristics: (1) The second acid includes sulfuric acid and / or hydrochloric acid; (2) The first base and the second base each independently include sodium hydroxide; (3) The second acid is provided in the form of an acid solution; the mass fraction of the acid in the acid solution is 6%-12%; (4) The first base and the second base are provided in the form of an alkaline solution; the mass fraction of the base in the alkaline solution is 5%-10%.

7. The recycling method as described in claim 1 or 2, characterized in that, The pH of the second precipitate is 7.5-9.

0.

8. The recycling method as described in claim 1 or 2, characterized in that, The cathode and anode of the electrolysis equipment are made of graphite or titanium. And / or, the reaction conditions in the anode chamber include: the redox potential of the anolyte from the point of energization to the point of anolyte reaction is 0.5V-5V; and the total organic carbon (TOC) in the reaction solution at the reaction endpoint is ≤400ppm.

9. The recycling method as described in claim 1 or 2, characterized in that, The electrolysis equipment includes at least two identical swirl electrolysis chamber skids; The same-polarity swirl electrolysis chamber skids are connected in parallel or in series.

10. The recycling method as described in claim 1 or 2, characterized in that, The nickel-containing metal catalyst contains 60wt%-80wt% nickel, 0.1wt%-2wt% iron, 1wt%-20wt% aluminum, 1wt%-12wt% organic matter, and the balance is water and oxygen.

11. The recycling method as described in claim 1 or 2, characterized in that, The acidic solution containing copper ions has a copper ion content of 20 g / L-100 g / L, H + The concentration is 0.2 mol / L-2 mol / L.

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