Process for gold leaching by low eutectic solvent system membrane electrolysis

Abstract

The application provides a method for gold leaching by means of a deep eutectic solvent system diaphragm electrolysis, and belongs to the field of electrochemical metallurgy. The method comprises the following steps: mixing and stirring choline chloride and ethylene glycol, adding halide and water to obtain a deep eutectic solvent electrolyte; mixing gold-containing materials with the deep eutectic solvent electrolyte, placing the mixture in an anode chamber of a diaphragm electrolytic cell, adding the deep eutectic solvent electrolyte in a cathode chamber of the diaphragm electrolytic cell, and applying direct current electrolysis; after the electrolysis is completed, performing solid-liquid separation on the materials in the anode chamber to obtain a gold-containing leaching solution. The deep eutectic solvent formed by choline chloride and ethylene glycol is used as a basic electrolyte, halide is added to provide active halogen ions for coordination, the viscosity is reduced and mass transfer is optimized by adjusting the water content, halogen oxidants are generated by anodic electrochemical oxidation in the diaphragm electrolytic cell, efficient leaching of gold in the gold-containing materials is realized, and effective isolation of anodic leaching and cathodic recovery is realized through the diaphragm.

Description

Technical Field

[0001] This invention relates to the field of electrochemical metallurgy, specifically to a diaphragm electrolytic gold leaching method using a eutectic solvent system. Background Technology

[0002] Traditional halide gold leaching processes have three main drawbacks: First, they require the addition of strong oxidants such as liquid bromine, iodine, or chlorine, which are volatile, corrosive, and toxic, posing high operational risks and imposing stringent requirements on equipment corrosion protection. Second, the recovery of gold complex anions from the leaching solution and reagent regeneration involve independent electrolysis or chemical precipitation processes, which are lengthy and consume large amounts of reagents. Third, in aqueous solutions, the gases generated by the oxidation of halide ions are easily dispersed due to their low solubility, resulting in the loss of effective components.

[0003] Existing electrochemical gold leaching technology based on eutectic solvents has the following technical bottlenecks: the viscosity of eutectic solvents is much higher than that of aqueous solutions, resulting in low mass transfer rates and limited gold dissolution rates; at the same time, in existing studies, halogens generated at the anode and reducing species generated at the cathode are mixed in the same electrolyte, resulting in low current efficiency and many side reactions; furthermore, in existing studies, the coordination dissolution of gold mainly depends on Cl in choline chloride (ChCl), resulting in limited leaching rates and selectivity.

[0004] In view of this, it is necessary to design a diaphragm electrolytic gold leaching method using a eutectic solvent system to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a diaphragm electrolytic gold leaching method in a eutectic solvent system. The method uses a eutectic solvent formed by choline chloride and ethylene glycol as the base electrolyte, adds halides to provide coordinating active halide ions, reduces viscosity and optimizes mass transfer by adjusting water content, and generates halogen oxidants in situ through anodic electrochemical oxidation in a diaphragm electrolytic cell, thereby achieving efficient leaching of gold from gold-containing materials. At the same time, the diaphragm effectively isolates anodic leaching from cathode recovery.

[0006] To achieve the above objectives, embodiments of the present invention provide a method for electrolytic gold immersion in a eutectic solvent system using a diaphragm, comprising: Choline chloride was mixed with ethylene glycol and stirred, and then a halide and water were added to obtain a eutectic solvent electrolyte. The gold-containing material is mixed with the eutectic solvent electrolyte and placed in the anode chamber of the diaphragm electrolytic cell. The eutectic solvent electrolyte is then added to the cathode chamber of the diaphragm electrolytic cell, and direct current electrolysis is applied. After electrolysis, the material in the anode chamber is subjected to solid-liquid separation to obtain a gold-containing leachate.

[0007] As a further improvement of the present invention, the molar ratio of choline chloride to ethylene glycol is 1:2 to 1:4; and / or, The stirring temperature is 60℃-80℃; and / or, The concentration of the halide in the eutectic solvent electrolyte is 0.15 mol / L–1.6 mol / L; and / or, Water accounts for 5%-30% of the total volume of the eutectic solvent electrolyte.

[0008] As a further improvement of the present invention, the halide is selected from at least one of sodium halide salts and potassium halide salts.

[0009] As a further improvement of the present invention, the gold-bearing material includes at least one of gold ore, gold concentrate, gold-bearing tailings, waste electronic circuit board fragments, and gold-bearing waste catalysts; and / or, The anode material in the anode chamber is a graphite, titanium-based coated electrode, or boron-doped diamond electrode; and / or, The cathode material in the cathode chamber is stainless steel, titanium plate, graphite or carbon felt.

[0010] As a further improvement of the present invention, the diaphragm in the diaphragm electrolyzer is a porous α-Al₂O₃ ceramic diaphragm or a cation exchange membrane; wherein... The porosity of porous α-Al2O3 ceramic membranes is 30%-45%; The cation exchange membrane is a perfluorosulfonic acid type cation exchange membrane, a sulfonated polyether ether ketone membrane, or a polybenzimidazole modified composite membrane.

[0011] As a further improvement of the present invention, the pore size of the porous α-Al₂O₃ ceramic membrane is 0.1 μm-5 μm; and / or, The wall thickness of the porous α-Al2O3 ceramic membrane is 3mm-7mm.

[0012] As a further improvement of the present invention, the electrolysis temperature is 50℃-70℃; and / or, The current density for electrolysis is 22 mA / cm² - 50 mA / cm²; and / or, The electrolysis time is 2-8 hours; and / or, The solid-liquid mass-volume ratio of the gold-containing material to the eutectic solvent electrolyte is 1:5 g / mL to 1:50 g / mL.

[0013] As a further improvement of the present invention, after obtaining the gold-containing leachate, the following steps are also included: Gold is recovered from the gold-containing leachate to obtain gold-containing products and electrolyte to be recovered.

[0014] As a further improvement of the present invention, when recovering gold from gold-containing leachate, the recovery method is either desorption recovery after adsorption by activated carbon or reduction precipitation recovery after solvent extraction.

[0015] As a further improvement to the present invention, it also includes: After adding sodium halide salt to the electrolyte to be recycled, a recovered eutectic solvent electrolyte is obtained, which is then recycled for reuse. The recycled eutectic solvent electrolyte can be recycled 9 to 15 times.

[0016] The beneficial technical effects of this invention are as follows: In terms of safety, this method eliminates the need for external strong oxidants such as liquid bromine or chlorine. Instead, it generates halogens in situ through anodic electrochemical oxidation, avoiding the storage, transportation, and addition of hazardous reagents. Furthermore, precise control of the current density and the type and concentration of halogens effectively suppresses gas escape. The diaphragm electrolytic cell design physically isolates the anodic leaching zone from the cathode recovery zone, preventing halogens from reacting with cathode products and ensuring current efficiency. Secondly, regarding efficiency and energy consumption, adding 5%-30% water to the eutectic solvent reduces the system viscosity from 36 mPa·s for pure DES to 5-15 mPa·s, significantly improving mass transfer conditions and increasing the gold dissolution rate. Simultaneously, the addition of NaBr, NaI, or NaCl provides a high concentration of active halide ions. Utilizing the lower standard redox potentials of the bromine and iodine systems, gold dissolution can be achieved at lower anodic potentials, reducing energy consumption. Furthermore, the eutectic solvent of this invention only requires a small amount of sodium halide salt to be added after gold recovery and can be recycled. It maintains high gold leaching efficiency even after 9-15 cycles, significantly reducing reagent costs and waste discharge. Finally, this method has wide applicability, applicable not only to gold ores and gold-bearing electronic waste, but also showing excellent adaptability to difficult-to-process gold ores containing sulfur and arsenic. This is due to the high-temperature stability and wide electrochemical window of the eutectic solvent, allowing for flexible operation over a relatively high temperature and wide potential range.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Detailed Implementation

[0018] The embodiments of the technical solution of this application will be described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.

[0019] 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 pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the description and claims of this application are intended to cover non-exclusive inclusion.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0023] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0024] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0025] Unless otherwise specified, the terms "comprising" and "including" as used in this application are open-ended. For example, "comprising" and "including" may mean that other components not listed may also be included or contained.

[0026] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0027] The embodiments of this application will be described in further detail below with reference to the examples. The detailed description of the following embodiments is used to illustrate the principles of this application, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0028] Traditional halide leaching gold processes require the addition of strong oxidizing agents such as liquid bromine, iodine, or chlorine. These reagents are volatile, corrosive, and toxic. Furthermore, the recovery of gold complex anions from the leaching solution and the regeneration of reagents are lengthy processes. In addition, in aqueous solutions, the gases generated by the oxidation of halide ions are easily released due to their low solubility. Furthermore, in existing electrochemical leaching gold technologies based on eutectic solvents, the viscosity of the eutectic solvent is much higher than that of aqueous solutions, resulting in low mass transfer rates and limited gold dissolution rates. The products from the anode and cathode are mixed in the same electrolyte, leading to low current efficiency and numerous side reactions. The coordination dissolution of gold mainly depends on Cl in choline chloride (ChCl), resulting in limited leaching rates and selectivity.

[0029] In view of this, it is necessary to design a diaphragm electrolytic gold leaching method using a eutectic solvent system to solve the above problems.

[0030] This invention provides a method for electrolytic gold leaching with a diaphragm in a eutectic solvent system, comprising: Choline chloride was mixed with ethylene glycol and stirred, and then a halide and water were added to obtain a eutectic solvent electrolyte. The gold-containing material is mixed with the eutectic solvent electrolyte and placed in the anode chamber of the diaphragm electrolytic cell. The eutectic solvent electrolyte is added to the cathode chamber of the diaphragm electrolytic cell, and direct current electrolysis is applied. After electrolysis, the material in the anode chamber is subjected to solid-liquid separation to obtain a gold-containing leachate.

[0031] In terms of safety, this method eliminates the need for external strong oxidants such as liquid bromine or chlorine. Instead, it generates halogens in situ through anodic electrochemical oxidation, avoiding the storage, transportation, and addition of hazardous reagents. Furthermore, the type and concentration of halogens can be precisely controlled by adjusting the current density, effectively suppressing gas escape. The diaphragm electrolytic cell design physically isolates the anodic leaching zone from the cathode recovery zone, preventing halogens from reacting with cathode products and ensuring current efficiency. Secondly, regarding efficiency and energy consumption, adding water to the eutectic solvent reduces the system viscosity, significantly improving mass transfer conditions and increasing the gold dissolution rate. Simultaneously, the addition of high-concentration active halide ions, utilizing their lower standard redox potential, allows gold dissolution at a lower anodic potential, reducing energy consumption. Moreover, the eutectic solvent of this invention only requires a small amount of sodium halide salt to be replenished after gold recovery for recycling, maintaining high gold leaching efficiency even after multiple cycles, significantly reducing reagent costs and wastewater discharge. Finally, this method has wide applicability, not only for gold ores and gold-bearing electronic waste, but also for difficult-to-process gold ores containing sulfur and arsenic. This is due to the high-temperature stability and wide electrochemical window of the low eutectic solvent, which allows it to operate flexibly over a wide range of temperatures and potentials.

[0032] It should be noted that this method uses a eutectic solvent of choline chloride and ethylene glycol as the basic electrolyte. Halides are added to provide coordinating active halide ions. The viscosity is reduced and the mass transfer efficiency is optimized by adjusting the water content. Then, in an electrolytic cell with a diaphragm, the gold-containing material is mixed with the eutectic solvent electrolyte to form a slurry, which is placed in the anode chamber of the electrolytic cell. The eutectic solvent electrolyte is placed in the cathode chamber, which causes the halide ions at the anode to oxidize. This allows the gold to react with the halide ions in the anode chamber and the generated halogen to form a complex, allowing the gold to leach out. The gold can then be recovered and the electrolyte can be recycled.

[0033] As a further improvement of the present invention, the molar ratio of choline chloride to ethylene glycol is 1:2 to 1:4.

[0034] In this embodiment, the molar ratio of choline chloride to ethylene glycol is set to 1:2-1:4. This 1:2-1:4 molar ratio of choline chloride to ethylene glycol is a classic eutectic solvent system (Ethaline). At this ratio, 1:2 represents a stoichiometric ratio with strong hydrogen bonding, resulting in high chloride ion concentration and strong coordination solubility. As the proportion of ethylene glycol increases, the hydrogen bond network of the system is gradually diluted, leading to a gradual decrease in viscosity and a continuous increase in conductivity, thus enhancing mass transfer and ion conduction efficiency. At this ratio, the eutectic solvent is suitable for balanced applications such as electrochemical deposition and electrolytes, as well as low-viscosity, high-conductivity applications such as flow batteries and fast reactions, exhibiting good overall performance.

[0035] For example, the molar ratio of choline chloride to ethylene glycol can be (1:2), (1:2.5), (1:3), (1:3.5), or (1:4).

[0036] As a further improvement of the present invention, the stirring temperature is 60℃-80℃.

[0037] In this embodiment, the stirring temperature is controlled between 60℃ and 80℃. Heating at 60℃-80℃ can increase the rate of molecular thermal motion, accelerate the dissolution of solid raw materials, and shorten the preparation time. At the same time, heating can accelerate the association and rearrangement of hydrogen bonds, allowing the system to quickly reach a thermodynamically stable eutectic state. Moreover, increasing the temperature can reduce the viscosity of the system, enhance the mass transfer effect, and allow choline chloride and ethylene glycol to fully contact and mix at the molecular scale. It is important to avoid trace volatilization of ethylene glycol at high temperatures, which could cause the molar ratio to deviate from the design value, and to avoid slower dissolution and hydrogen bond reconstruction rates at lower temperatures, which would significantly lengthen the preparation cycle, easily lead to solid residues, and compromise the homogeneity of the system.

[0038] For example, the stirring temperature can be 60°C, 62°C, 65°C, 67°C, 69°C, 71°C, 75°C, 77°C or 80°C.

[0039] As a further improvement of the present invention, the concentration of the halide in the eutectic solvent electrolyte is 0.15 mol / L-1.6 mol / L.

[0040] In this embodiment, the concentration of the halide in the eutectic solvent electrolyte is controlled at 0.15 mol / L-1.6 mol / L to achieve a better balance between leaching efficiency, system stability, reaction selectivity, current efficiency, and overall cost. If the concentration is too low, there will be insufficient in-situ halogen-producing material at the anode and a lack of gold ion coordination sites, leading to a slow gold leaching rate and low leaching percentage. It will also exacerbate the oxygen evolution side reaction, reducing current efficiency. If the concentration is too high, it may exceed the dissolution threshold of the eutectic solvent, destroying the homogeneous hydrogen bond structure and precipitating solids. Simultaneously, it will significantly increase the system viscosity, hindering mass transfer, and exacerbate the self-discharge loss from halogen diffusion to the cathode and the corrosion of the anode material.

[0041] For example, the concentration of the halide in the eutectic solvent electrolyte can be 0.15 mol / L, 0.25 mol / L, 0.32 mol / L, 0.38 mol / L, 0.46 mol / L, 0.56 mol / L, 0.67 mol / L, 0.87 mol / L, 0.94 mol / L, 1.05 mol / L, 1.15 mol / L, 1.24 mol / L, 1.34 mol / L, 1.45 mol / L, or 1.6 mol / L.

[0042] As a further improvement of the present invention, water accounts for 5%-30% of the total volume of the eutectic solvent electrolyte.

[0043] In this embodiment, water accounts for 5%-30% of the total volume of the eutectic solvent electrolyte. Adding an appropriate amount of water can weaken the association degree of the hydrogen bond network in the system, significantly reduce viscosity, increase ionic conductivity and mass transfer rate, accelerate the reaction rate of in-situ anodic halide production and gold leaching, and at the same time moderately improve the dispersion stability of gold halide complexes.

[0044] For example, water may account for 5%, 8%, 13%, 16%, 19%, 23%, 28%, or 30% of the total volume of the eutectic solvent electrolyte.

[0045] Specifically, in some embodiments of the present invention, the gold leaching rate is optimal when water accounts for 10%-25% of the total volume of the eutectic solvent electrolyte, reaching approximately 90% or higher. When the water content is low, the viscosity of the eutectic solvent electrolyte is too high, which limits mass transfer and results in slower electrolysis efficiency, thus affecting gold leaching and leading to a lower leaching rate. When the water content is too high, although the viscosity and cell voltage are further reduced, the Br ion concentration is diluted and the nanostructure of the eutectic solvent is destroyed, resulting in a decrease in the coordination dissolution efficiency of gold and reducing the gold leaching rate.

[0046] As a further improvement of the present invention, the halide is selected from at least one of sodium halide salts and potassium halide salts.

[0047] In this embodiment, at least one of sodium halide and potassium halide is selected as the halide. Sodium and potassium alkali metal cations are highly inert electrochemically, with extremely negative standard reduction potentials. Within the conventional electrolysis potential range, they will not undergo reduction precipitation at the cathode, ensuring the purity of the recovered gold and avoiding unnecessary current loss due to cathode power consumption, thus improving the current efficiency of in-situ halide production. Utilizing the lower standard redox potential of the halogen system, gold dissolution can be achieved at a lower anode potential, reducing energy consumption. This reduction in electrolysis energy consumption, coupled with the enhanced alkali metal ions that dissociate, also strengthens ion migration in the solution, alleviates concentration polarization of halide ions on the anode surface, accelerates the gold leaching reaction rate, and, due to their stable properties, do not disrupt the hydrogen bond network of the eutectic solvent, minimizing interference with the long-term cyclic operation of the electrolysis system.

[0048] As a further improvement of the present invention, the gold-bearing material includes at least one of gold ore, gold concentrate, gold-bearing tailings, waste electronic circuit board fragments, and gold-bearing waste catalysts.

[0049] In this embodiment, the types of gold-bearing materials include at least one of gold ore, gold concentrate, gold-bearing tailings, waste electronic circuit board fragments, and gold-bearing waste catalysts. The wide variety of gold-bearing materials indicates the broad applicability of this method. It is not only applicable to conventional gold-bearing materials, but also has good applicability to some gold ores containing other impurities that are difficult to process.

[0050] As a further improvement of the present invention, the anode material in the anode chamber is graphite, titanium-based coated electrode, or boron-doped diamond electrode.

[0051] In this embodiment, the anode material in the anode chamber is selected as graphite, titanium-based coated electrode, or boron-doped diamond electrode. All three materials have good compatibility and advantages. Specifically, graphite is inexpensive, easy to process and shape, and has good conductivity and chemical inertness, and has basic corrosion resistance in low-to-medium potential halogenation leaching systems. Titanium-based coated electrodes (such as ruthenium-iridium or iridium-tantalum DSA electrodes) have excellent electrocatalytic activity for halide ion oxidation due to their surface active coating, which can significantly reduce the halide evolution overpotential and improve the current efficiency of in-situ halide production. At the same time, the titanium matrix and functional coating have strong resistance to halide corrosion and long electrode life, and can stably adapt to high current and long-term continuous production. Boron-doped diamond electrodes have an extremely wide electrochemical stability window and an extremely high oxygen evolution overpotential, which can suppress oxygen evolution side reactions to the greatest extent, so that almost all of the anode current is used for active halogen generation. They have good current efficiency and reaction selectivity, and the material itself has strong chemical stability, is resistant to halogen corrosion, and has almost no leaching pollution. They are suitable for high-potential, high-precision fine gold leaching scenarios and have the best long-term cycle stability.

[0052] As a further improvement of the present invention, the cathode material in the cathode chamber is stainless steel, titanium plate, graphite or carbon felt.

[0053] In this embodiment, the cathode material selected in the cathode chamber is stainless steel, titanium plate, graphite, or carbon felt. All of these materials can be used for electrolytic gold leaching and have good results. Specifically, stainless steel is inexpensive, has high mechanical strength, and is easy to process and form. It has a balance between conductivity and corrosion resistance in mild corrosive environments, making it suitable for low-cost electrolysis scenarios with conventional current densities. Titanium plates have excellent chemical stability and outstanding resistance to halogen media corrosion. They do not show significant metal leaching during long-term operation and will not contaminate the gold products being deposited and recovered, making them suitable for processes with high halogen concentrations and long-term continuous operation. Graphite cathodes have strong chemical inertness and no risk of introducing metal impurities. They have a moderate overpotential for hydrogen evolution reactions and can balance gold deposition purity with cathode process stability, making them suitable for scenarios with high product purity requirements. Carbon felt has a well-developed porous structure and extremely high specific surface area, which can significantly reduce the effective current density of gold deposition, improve gold adhesion capacity and mass transfer efficiency, and is especially suitable for deep recovery of low-concentration gold-containing systems and high-load electrolysis conditions.

[0054] As a further improvement of the present invention, the diaphragm in the diaphragm electrolyzer is a porous α-Al₂O₃ ceramic diaphragm or a cation exchange membrane; wherein... The porosity of porous α-Al2O3 ceramic membranes is 30%-45%.

[0055] In this embodiment, the porosity of the porous α-Al2O3 ceramic membrane is controlled to be 30%-45%, which enables ion conduction, reduces cathode self-discharge and ineffective gold deposition losses, and improves the current efficiency of in-situ halide production and gold recovery.

[0056] For example, the porosity of the porous α-Al2O3 ceramic membrane can be 30%, 32%, 35%, 37%, 39%, 41%, 44% or 45%.

[0057] As a further improvement of the present invention, the cation exchange membrane is a perfluorosulfonic acid type cation exchange membrane, a sulfonated polyether ether ketone membrane, or a polybenzimidazole modified composite membrane.

[0058] In this embodiment, the cation exchange membrane is selected as a perfluorosulfonic acid type cation exchange membrane, a sulfonated polyether ether ketone membrane, or a polybenzimidazole modified composite membrane. All three are suitable for the electrolytic gold leaching process and have good effects. Specifically, the perfluorosulfonic acid type cation exchange membrane has excellent chemical stability and resistance to halogen oxidation, high cation conductivity and strong anion barrier properties, which can effectively block the diffusion of gold halide complexes and active halogens across the membrane and ensure high current efficiency. The sulfonated polyether ether ketone membrane has outstanding resistance to organic solvents, low swelling rate and good dimensional stability in eutectic organic media, and the degree of sulfonation can be flexibly adjusted to balance conductivity and barrier effect. It has lower raw material and preparation costs, is resistant to pollution and easy to regenerate, and has both performance and economic advantages. The polybenzimidazole modified composite membrane has strong resistance to strong oxidation, high temperature and corrosion due to its rigid imidazole ring backbone. It has excellent structural stability under high concentration of active halogens and temperature conditions, extremely low membrane swelling rate and outstanding mechanical strength, and can withstand harsh electrolytic environments for a long time.

[0059] As a further improvement of the present invention, the pore size of the porous α-Al2O3 ceramic membrane is 0.1μm-5μm.

[0060] In this embodiment, the pore size of the porous α-Al2O3 ceramic membrane is controlled to be 0.1μm-5μm. Under the premise that small-volume ions such as halide ions and alkali metal ions can pass freely to maintain conductivity, it effectively blocks the diffusion of large-volume gold halide complexes and active halogens to the counter electrode, thereby improving the gold recovery efficiency.

[0061] For example, the pore size of the porous α-Al2O3 ceramic membrane can be 0.1μm, 0.29μm, 0.54μm, 0.87μm, 1.27μm, 1.84μm, 2.39μm, 3.43μm, 3.97μm, 4.37μm or 5μm.

[0062] As a further improvement of the present invention, the wall thickness of the porous α-Al2O3 ceramic membrane is 3mm-7mm.

[0063] In this embodiment, the wall thickness of the porous α-Al2O3 ceramic membrane is set to 3mm-7mm. The appropriate wall thickness can form longer tortuous pore channels, enhance the size sieving effect, further block the diffusion of large-volume gold halide complexes and active halogens across the membrane, reduce cathode self-discharge loss, and improve the current efficiency of in-situ halogen production and gold recovery. At the same time, the sufficient substrate thickness also enhances the membrane's long-term corrosion resistance and deformation resistance to halide ions, active halogens and organic media.

[0064] For example, the wall thickness of the porous α-Al2O3 ceramic membrane can be 3 mm, 4 mm, 5 mm, 6 mm or 7 mm.

[0065] As a further improvement of the present invention, the electrolysis temperature is 50℃-70℃.

[0066] In this embodiment, by controlling the electrolysis temperature between 50°C and 70°C, the viscosity of the eutectic solvent of choline chloride and ethylene glycol is reduced, thereby increasing the ionic conductivity and mass transfer rate, accelerating the in-situ halogen production at the anode and the oxidation complexation rate of gold, and shortening the leaching cycle. At the same time, this temperature is much lower than the boiling point of ethylene glycol, which can avoid component volatilization causing deviation in the ratio, and will not excessively damage the hydrogen bond network structure of the system. It can also suppress the large-scale release of active halogens and the aggravation of hydrogen evolution and oxygen evolution side reactions, thus ensuring leaching efficiency while maintaining high current efficiency and system stability.

[0067] For example, the electrolysis temperature can be 50°C, 54°C, 57°C, 59°C, 61°C, 63°C, 66°C, 68°C, or 70°C.

[0068] As a further improvement of the present invention, the current density for electrolysis is 22 mA / cm²-50 mA / cm².

[0069] In this embodiment, the current density of electrolysis is controlled at 22mA / cm²-50mA / cm² to ensure that the anode stably and continuously generates sufficient active halogens, providing ample oxidant for gold oxidation, ensuring a stable leaching rate, effectively avoiding the problems of significantly aggravated oxygen evolution side reactions and deteriorated concentration polarization of halide ions on the anode surface under high current, while reducing self-discharge losses caused by the diffusion of excessive active halogens to the cathode, delaying the corrosion and aging of electrode materials and diaphragms, and concentrating the anode current for halogen leaching of gold, maintaining a high current utilization rate, and reducing the electrolysis energy consumption per unit leaching amount.

[0070] For example, the current density for electrolysis can be 22 mA / cm², 27 mA / cm², 31 mA / cm², 34 mA / cm², 37 mA / cm², 41 mA / cm², 45 mA / cm², 47 mA / cm², or 50 mA / cm².

[0071] As a further improvement of the present invention, the electrolysis time is 2h-8h.

[0072] In this embodiment, the electrolysis time is controlled to be 2h-8h, so that the halogen generated in situ can fully contact and react with the gold-containing material, allowing the gold to be fully oxidized and form a stable gold halide complex that enters the liquid phase, resulting in a high gold leaching rate.

[0073] For example, the electrolysis time can be 2h, 3h, 4h, 5h, 6h, 7h or 8h.

[0074] As a further improvement of the present invention, the solid-liquid mass-volume ratio of the gold-containing material to the eutectic solvent electrolyte is 1:5g / mL to 1:50g / mL.

[0075] In this embodiment, the solid-liquid mass-volume ratio of the gold-containing material to the eutectic solvent electrolyte is controlled at 1:5 g / mL to 1:50 g / mL. This ensures the material processing capacity per unit volume of electrolyte, allowing the leaching solution to have sufficient gold concentration to reduce the pressure of subsequent recovery, while also enabling the material to be fully dispersed, ensuring smooth mass transfer and gold leaching rate, reducing wear and blockage of electrodes and diaphragms by solid particles, and maintaining stable operation of the electrolysis process.

[0076] For example, the solid-liquid mass-volume ratio of the gold-containing material to the eutectic solvent electrolyte can be 1:5 g / mL, 1:9 g / mL, 1:13 g / mL, 1:15 g / mL, 1:19 g / mL, 1:24 g / mL, 1:28 g / mL, 1:33 g / mL, 1:37 g / mL, 1:41 g / mL, 1:46 g / mL, or 1:50 g / mL.

[0077] Specifically, in some embodiments of the present invention, when the solid-liquid mass-volume ratio of the gold-containing material to the eutectic solvent electrolyte is 1:10 g / mL to 1:30 g / mL, the gold leaching effect is better. This mass-volume ratio range effectively avoids the problems of excessive system viscosity, incomplete leaching and increased equipment wear caused by an excessively high solid-liquid ratio, while also reducing the disadvantages of solvent waste, low gold concentration in the leaching solution and increased subsequent recycling costs caused by an excessively low solid-liquid ratio.

[0078] As a further improvement of the present invention, after obtaining the gold-containing leachate, the following steps are also included: Gold is recovered from the gold-containing leachate to obtain gold-containing products and electrolyte to be recovered.

[0079] In this embodiment, gold is leached in the anode chamber and dissolved in the solution. After the leaching step is completed, the gold needs to be recovered through a series of processes so that the leached gold can be reused. At the same time, the electrolyte obtained after recovery can also be reused, which greatly reduces reagent costs and waste discharge.

[0080] As a further improvement of the present invention, when recovering gold from gold-containing leachate, the recovery method is either desorption recovery after adsorption by activated carbon or reduction precipitation recovery after solvent extraction.

[0081] In this embodiment, both gold recovery methods demonstrate good recovery results. Specifically, the activated carbon adsorption followed by desorption recovery process is mature and reliable, with low operating costs and simple operation, and the activated carbon can be regenerated and recycled. The solvent extraction followed by reduction precipitation recovery and separation exhibits strong selectivity, effectively removing base metal impurities such as copper and iron, resulting in a high gold enrichment factor, high purity of the final product, and suitability for leaching solutions with complex compositions.

[0082] As a further improvement to the present invention, it also includes: After adding sodium halide salt to the electrolyte to be recycled, a recovered eutectic solvent electrolyte is obtained, which is then recycled for reuse. The recycled eutectic solvent electrolyte can be recycled 9 to 15 times.

[0083] In this embodiment, the anodic reaction leaches gold by combining halide ions with the electrolyte, consuming the halides in the electrolyte. Other components are largely unconsumed or undamaged. Therefore, adding sodium halide salts to the electrolyte to be recycled allows for its reuse, enabling the recycled eutectic solvent electrolyte to be recycled. Furthermore, the recycling frequency is 9-15 times, fully utilizing the eutectic solvent electrolyte, significantly reducing reagent costs and waste discharge, and achieving a high gold leaching rate, resulting in excellent final performance.

[0084] It should be noted that there are many options for adding halides to the electrolyte to be recycled. In addition to sodium halides, potassium halides can also be used, such as KCl, KBr, or KI.

[0085] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0086] I. Preparation Method Example 1 NaBr-DES system membrane electrolytic gold immersion (ceramic membrane) Choline chloride and ethylene glycol were mixed at a molar ratio of 1:2 and magnetically stirred at 80°C for 1 hour until a homogeneous and transparent liquid was formed, yielding 300 mL of eutectic solvent (DES) of the ethylene chloride type. 150 mL of this solution was taken, and 0.5 g of sodium bromide was added, stirring until completely dissolved. Then, 25 g of deionized water (approximately 10% of the total system volume) was added and mixed thoroughly to obtain the NaBr-DES electrolyte.

[0087] A tubular porous α-Al₂O₃ ceramic membrane was used (pore size 0.5 μm, porosity 35%, wall thickness 5 mm, effective membrane area 20 cm²). 2 The electrolytic cell is an H-type diaphragm cell with a diaphragm structure. 150 mL of NaBr-DES electrolyte and 10 g of gold concentrate (gold grade 13.6 g / t, 90% particle size 0.074 mm) are added to the anode chamber. 150 mL of DES electrolyte with the same composition is added to the cathode chamber. Graphite electrodes are used for the anode, and stainless steel plates are used for the cathode.

[0088] A constant current of 1.0A was applied for electrolysis, with a cell voltage of 3.5V-5.0V. The electrolysis temperature was 50℃. The electrolysis time was 6 hours. The magnetic stirrer in the anode chamber rotated at 300 rpm.

[0089] After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0090] Example 2 NaBr-DES system membrane electrolytic leaching of gold (cation exchange membrane) Choline chloride and ethylene glycol were mixed at a molar ratio of 1:2 and magnetically stirred at 80°C for 1 hour until a homogeneous and transparent liquid was formed, yielding 300 mL of eutectic solvent (DES) of the ethylene chloride type. 150 mL of this solution was taken, and 0.5 g of sodium bromide was added, stirring until completely dissolved. Then, 25 g of deionized water (approximately 10% of the total system volume) was added and mixed thoroughly to obtain the NaBr-DES electrolyte.

[0091] An H-type membrane electrolyzer with Nafion 117 cation exchange membranes (183 μm thick) was used. 150 mL of NaBr-DES electrolyte and 10 g of raw gold ore (gold grade 1.31 g / t, 88% particle size 0.074 mm) were added to the anode chamber. 150 mL of DES electrolyte with the same composition was added to the cathode chamber. An IrO2 / Ti coated electrode was used for the anode, and a titanium plate was used for the cathode.

[0092] A constant current of 0.7A was applied for electrolysis, with a cell voltage of 3.1V-4.0V. The electrolysis temperature was 60℃, and the electrolysis time was 2 hours. The magnetic stirrer in the anode chamber operated at 300 rpm.

[0093] After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0094] Example 3 NaBr-DES system membrane electrolytic leaching of gold (cation exchange membrane) Choline chloride and ethylene glycol were mixed at a molar ratio of 1:2 and magnetically stirred at 80°C for 1 hour until a homogeneous and transparent liquid was formed, yielding 300 mL of eutectic solvent (DES) of the ethylene chloride type. 150 mL of this solution was taken, and 45 g of sodium bromide was added, stirring until completely dissolved. Then, 25 g of deionized water (approximately 10% of the total system volume) was added and mixed thoroughly to obtain the NaBr-DES electrolyte.

[0095] An H-type membrane electrolyzer with Nafion 117 cation exchange membrane (183 μm thick) was used. 150 mL of NaBr-DES electrolyte and 10 g of waste circuit board (already acid-leached to dissolve base metals, gold grade 120.8 g / t, 78% of particles 0.074 mm in diameter) were added to the anode chamber. 150 mL of DES electrolyte with the same composition was added to the cathode chamber. An IrO2 / Ti coated electrode was used for the anode, and a titanium plate was used for the cathode.

[0096] A constant current of 1.1A was applied for electrolysis, with a cell voltage of 5.1V-7.0V. The electrolysis temperature was 60℃, and the electrolysis time was 4 hours. The magnetic stirrer in the anode chamber rotated at 300 rpm.

[0097] After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0098] Example 4 NaCl-DES system membrane electrolytic gold leaching (cation exchange membrane) Choline chloride and ethylene glycol were mixed at a molar ratio of 1:2 and magnetically stirred at 80°C for 1 hour until a homogeneous and transparent liquid was formed, yielding 300 mL of eutectic solvent (DES) of the ethyl ether type. 150 mL of this solution was taken, and 0.5 g of sodium chloride was added, stirring until completely dissolved. Then, 25 g of deionized water (approximately 10% of the total mass of the system) was added and mixed thoroughly to obtain the NaCl-DES electrolyte.

[0099] An H-type membrane electrolyzer with Nafion 117 cation exchange membranes (183 μm thick) was used. 150 mL of NaCl-DES electrolyte and 10 g of raw gold ore (gold grade 1.31 g / t, 88% particle size 0.074 mm) were added to the anode chamber. 150 mL of DES electrolyte with the same composition was added to the cathode chamber. An IrO2 / Ti coated electrode was used for the anode, and a titanium plate was used for the cathode.

[0100] A constant current of 0.7A was applied for electrolysis, with a cell voltage of 2.9V-3.8V. The electrolysis temperature was 50℃, and the electrolysis time was 4 hours. The magnetic stirrer in the anode chamber operated at 300 rpm.

[0101] After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0102] Example 5 KI-DES system membrane electrolytic leaching with gold (cation exchange membrane) Choline chloride and ethylene glycol were mixed at a molar ratio of 1:2 and magnetically stirred at 80°C for 1 hour until a homogeneous and transparent liquid was formed, yielding 300 mL of eutectic solvent (DES) of the ethyl ether type. 150 mL of this solution was taken, and 0.9 g of potassium iodide was added, stirring until completely dissolved. Then, 25 g of deionized water (approximately 10% of the total mass of the system) was added and mixed thoroughly to obtain the KI-DES electrolyte.

[0103] An H-type membrane electrolyzer with Nafion 117 cation exchange membranes (183 μm thick) was used. 150 mL of KI-DES electrolyte and 10 g of raw gold ore (gold grade 1.31 g / t, 88% particle size 0.074 mm) were added to the anode chamber. 150 mL of DES electrolyte with the same composition was added to the cathode chamber. An IrO2 / Ti coated electrode was used for the anode, and a titanium plate was used for the cathode.

[0104] A constant current of 0.9A was applied for electrolysis, with a cell voltage of 4.2V-5.7V. The electrolysis temperature was 50℃, and the electrolysis time was 8 hours. The magnetic stirrer in the anode chamber operated at 300 rpm.

[0105] After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0106] Example 6 Based on the conditions of Example 2 (with 0 cycles in Example 2), the recycling performance of the NaBr-DES electrolyte was investigated. After each leaching cycle, the leachate was adsorbed by activated carbon to recover gold, and then NaBr was added to the filtrate to 0.16 mol / L (to replenish Br lost due to adsorption and chemical consumption), without replacing the eutectic solvent. Nine consecutive cycles were performed, each using 10 g of the same gold ore, and the gold leaching rate for each cycle was calculated. The results are shown in Table 2.

[0107] Example 7 Based on the NaBr-DES system of Example 2, with the NaBr concentration fixed at 0.16 mol / L, gold ore at 10 g, current at 0.7 V, temperature at 60 °C, and electrolysis at 2 h, the effect of water content on gold leaching rate was investigated by only changing the water content. The results are shown in Table 3.

[0108] Example 8 Based on the conditions of Example 2 (Nafion 117 membrane, water content 10%, NaBr concentration 0.16 mol / L, temperature 60°C, electrolysis for 2 h, effective electrode area 30 cm²), 2 The effects of different current densities on gold leaching rate and current efficiency were investigated, and the results are shown in Table 4.

[0109] Comparative Example 1 Compared to Example 2, the difference is that a diaphragm is not used, and the anode and cathode are placed in the same electrolytic cell (diaphragm-free single chamber). The current is 0.7V, the temperature is 60°C, and the electrolysis time is 2 hours. The remaining steps are roughly the same as in Example 2, and will not be repeated here. After electrolysis, the material in the electrolytic cell is vacuum filtered to separate the solid and liquid phases.

[0110] Comparative Example 2 Compared to Example 2, the difference is that pure water is used instead of the eutectic solvent (i.e., an aqueous NaBr system without choline chloride and ethylene glycol). The remaining steps are largely the same as in Example 2 and will not be repeated here. After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0111] Comparative Example 3 Compared to Example 2, the difference is that NaBr is not added, and gold leaching is achieved solely based on the DES system. The remaining steps are largely the same as in Example 2 and will not be repeated here. After electrolysis, the slurry in the anode chamber is vacuum filtered to separate the solid and liquid phases.

[0112] II. Testing Methods The gold grade of the separated leaching residue was determined by fire assay, and the gold leaching rate was calculated.

[0113] III. Analysis of Test Results for Each Embodiment and Comparative Example Table 1. Gold leaching rate results for Examples 1-5 and Comparative Examples 1-2 Table 2, Results of Cycle Count Test in Eutectic Solvent of Example 6 Table 3. Test results of the effect of water content on gold immersion efficiency in Example 7 Table 4. Test results of the effect of current density on immersion gold efficiency in Example 8. Conclusion: As can be seen from Table 1, the gold leaching rate of Examples 1-5 is all above 84%, showing a high leaching rate and good gold leaching effect. Among them, the leaching rate of Examples 1 and 3 is about 92%, with the best leaching effect, which can best achieve the purpose of gold leaching.

[0114] As shown in Table 2, the gold leaching rate of the eutectic solvent electrolyte in Example 6 remained above 85% after 7 cycles, but decreased to 80.3% after 9 cycles. This indicates that the electrolyte can be recycled and reused. The main reasons for the decrease in leaching rate are: the electrolyte viscosity slowly increased with the number of cycles, and the mass transfer conditions gradually deteriorated; a small amount of organic components underwent slow degradation during anodizing; and the accumulation of impurity ions brought in by the slurry interfered with the electrochemical process.

[0115] As shown in Table 3, the immersion efficiency is optimal when the water content is in the range of 10%-25%. When the water content is too low (<5%), the viscosity is too high, leading to limited mass transfer; when the water content is too high (>30%), although the viscosity and cell voltage are further reduced, the Br ion concentration is diluted and the DES nanostructure is destroyed, resulting in a decrease in the coordination dissolution efficiency of gold. The preferred water content is 10%-25%.

[0116] Table 4 shows that the highest gold leaching rate is achieved when the current density is between 23 mA / cm² and 50 mA / cm². Too low a current density results in insufficient leaching driving force; too high a current density intensifies anodic side reactions (such as oxygen evolution from water oxidation and ethylene glycol oxidation degradation), leading to the release of reddish-brown gas (bromine). Considering both leaching rate and energy consumption, the optimal current density is 23 mA / cm²–30 mA / cm².

[0117] In Comparative Example 1, the gold leaching rate was 64.8% (significantly lower than the 89.4% in Example 2). This is because the Br2 generated at the anode diffuses into the cathode region and is reduced to Br ions, thus reducing the utilization rate of the oxidant; the gold complex [AuBr4]... － In the cathode region, the reduced Au powder remains suspended in the solution, making effective collection difficult. This demonstrates the significant advantages of diaphragm electrolyzers compared to diaphragmless systems.

[0118] In Comparative Example 2, the gold leaching rate was 87.2%, but a large amount of reddish-brown gas (bromine) was released during the leaching process. This was mainly because the solubility of bromine in aqueous solution is much lower than that in the choline chloride-ethylene glycol eutectic solvent system. This demonstrates that eutectic solvents have a significant advantage over aqueous solutions.

[0119] In Comparative Example 3, the gold leaching rate was 35.4%. Without the addition of halides, the gold leaching efficiency in the eutectic solvent system was significantly reduced. Without halides, the anodic reaction during electrolysis involved the oxidation of gold, followed by the formation of a complex with chloride ions in the eutectic solvent, resulting in a slow reaction rate. However, with the addition of halides, the anode first oxidizes the halide ions. Through the combined action of the elemental halogen and the halide ions, gold forms a complex, greatly accelerating the reaction rate and increasing the gold leaching rate.

[0120] Therefore, this method uses a eutectic solvent formed by choline chloride and ethylene glycol as the base electrolyte, adds halides to provide coordinating active halide ions, reduces viscosity and optimizes mass transfer by adjusting water content, and generates halogen oxidants in situ through anodic electrochemical oxidation in a diaphragm electrolytic cell, thereby achieving efficient leaching of gold from gold-containing materials. At the same time, the diaphragm effectively isolates anodic leaching from cathode recovery.

[0121] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing embodiments by combining some of the constituent elements, are also included in the scope of this application without departing from the spirit of this application.

[0122] Furthermore, although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for diaphragm electrolytic gold leaching in a eutectic solvent system, characterized in that, include: Choline chloride was mixed with ethylene glycol and stirred, and then a halide and water were added to obtain a eutectic solvent electrolyte. The gold-containing material is mixed with the eutectic solvent electrolyte and placed in the anode chamber of the diaphragm electrolytic cell. The eutectic solvent electrolyte is then added to the cathode chamber of the diaphragm electrolytic cell, and direct current electrolysis is applied. After electrolysis, the material in the anode chamber is subjected to solid-liquid separation to obtain a gold-containing leachate.

2. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 1, characterized in that, The molar ratio of choline chloride to ethylene glycol is 1:2 to 1:4; and / or, The stirring temperature is 60℃-80℃; and / or, The concentration of the halide in the eutectic solvent electrolyte is 0.15 mol / L to 1.6 mol / L; and / or, The water accounts for 5% to 30% of the total volume of the eutectic solvent electrolyte.

3. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 1, characterized in that, The halide is selected from at least one of sodium halides and potassium halides.

4. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 1, characterized in that, The gold-bearing materials include at least one of gold ore, gold concentrate, gold-bearing tailings, waste electronic circuit board fragments, and gold-bearing waste catalysts; and / or, The anode material in the anode chamber is a graphite, titanium-based coated electrode, or boron-doped diamond electrode; and / or, The cathode material in the cathode chamber is stainless steel, titanium plate, graphite, or carbon felt.

5. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 1, characterized in that, The diaphragm in the diaphragm electrolytic cell is a porous α-Al₂O₃ ceramic diaphragm or a cation exchange membrane; wherein... The porosity of the porous α-Al2O3 ceramic membrane is 30%~45%; The cation exchange membrane is a perfluorosulfonic acid type cation exchange membrane, a sulfonated polyether ether ketone membrane, or a polybenzimidazole modified composite membrane.

6. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 5, characterized in that, The porous α-Al₂O₃ ceramic membrane has a pore size of 0.1 μm-5 μm; and / or, The porous α-Al2O3 ceramic membrane has a wall thickness of 3mm-7mm.

7. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 1, characterized in that, The electrolysis temperature is 50℃-70℃; and / or, The current density of the electrolysis is 22 mA / cm²-50 mA / cm²; and / or, The electrolysis time is 2-8 hours; and / or, The solid-liquid mass-volume ratio of the gold-containing material to the eutectic solvent electrolyte is 1:5g / mL to 1:50g / mL.

8. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 1, characterized in that, After obtaining the gold-containing leachate, the following steps are also included: The gold in the gold-containing leachate is recovered to obtain a gold-containing product and an electrolyte to be recovered.

9. The diaphragm electrolytic gold leaching method for a eutectic solvent system according to claim 8, characterized in that, When recovering gold from the gold-containing leachate, the recovery method is either desorption recovery after adsorption by activated carbon or reduction precipitation recovery after solvent extraction.

10. The eutectic solvent system diaphragm electrolytic gold leaching method according to claim 8, characterized in that, Also includes: After adding sodium halide salt to the electrolyte to be recycled, a recovered eutectic solvent electrolyte is obtained, and the recovered eutectic solvent electrolyte is recycled; wherein, The recovered eutectic solvent electrolyte is recycled 9 to 15 times.

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