Method for recycling valuable metals and cyanides in cyanidation tail liquid based on pulse current diaphragm electrolysis

Abstract

The invention provides a method for recycling valuable metal and cyanide in cyanidation tail liquid based on pulse current diaphragm electrolysis, and belongs to the field of wastewater treatment.The method comprises the steps that a diaphragm electrolysis device is assembled, and an anode chamber and a cathode chamber are separated through an ion exchange membrane; an alkaline electrolyte solution is added into the anode chamber, and cyanidation tail liquid to be treated is added into the cathode chamber; carrying out electrolytic reaction by adopting single pulse current, and continuously aerating the cathode chamber; and after the reaction is completed, measuring the catholyte, and calculating the cyanide recovery rate and the valuable metal recovery rate. According to the method, the valuable metal in the cyanidation tail liquid can be efficiently and selectively recycled with low energy consumption under the alkaline condition, meanwhile, cyanide is effectively recycled, the limitation of a traditional electrolytic method is overcome, and the method has important economic and environmental significance.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis. Background Art

[0002] Cyanide is the most widely used gold extraction method in gold hydrometallurgy, but the cyanide tail liquid produced by this method usually contains highly toxic cyanide and heavy metal complexes. If these tail liquids are discharged directly, they will cause serious harm to the environment and ecosystem. The current methods for treating cyanide tail liquid mainly include: chemical oxidation, adsorption, DC electrolysis, etc. Chemical oxidation can effectively destroy cyanide, but it is usually unable to effectively recover valuable metals, and may cause secondary pollution or consume a large amount of chemical agents, and the treatment cost is high; adsorption is mainly used to recover precious metals such as gold, but the treatment effect on other metals and cyanide is limited, and the adsorbent regeneration or subsequent treatment is complicated; DC electrolysis is to recover metals and destroy cyanide at the same time by applying a certain amount of direct current. However, traditional DC electrolysis has the following problems: for low-concentration tail liquid, the current efficiency is low, the energy consumption is high, and electrode passivation is prone to occur, affecting the treatment effect and electrode life; the cathode hydrogen evolution side reaction is serious, reducing the metal recovery efficiency; the anode and cathode products may mix, reverse reaction or generate unwanted byproducts, such as cyanate (CNO produced by anodic oxidation - ) may migrate to the cathode region and affect metal deposition, or the cyanide ions produced at the cathode may migrate to the anode and be over-oxidized.

[0003] In view of this, it is necessary to design a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis to solve the above problems. Summary of the Invention

[0004] In view of the technical problems existing in the background technology, the present application provides a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis, aiming to solve the technical problems existing in the existing cyanide tail liquid treatment technology, such as low recovery rate of valuable metals under alkaline conditions, inability to recover cyanide at the same time, high energy consumption, and easy passivation of electrodes.

[0005] The present application provides a method for recovering valuable metals and cyanide from cyanide tail liquid based on pulse current diaphragm electrolysis, comprising the following steps: S1. Assemble a diaphragm electrolysis device with an ion exchange membrane separating the anode chamber and the cathode chamber; S2. adding an alkaline electrolyte solution to the anode chamber and adding the cyanide tail liquid to be treated to the cathode chamber; S3. Electrolysis reaction is carried out using a single pulse current, and continuous aeration is provided to the cathode chamber; S4. After the reaction is completed, the cathode electrolyte is measured to calculate the cyanide recovery rate and the valuable metal recovery rate.

[0006] As a further improvement of the present application, the cathode of the diaphragm electrolysis device is one of graphite felt electrode, carbon felt electrode, stainless steel electrode, nickel foam electrode, and copper foam electrode.

[0007] As a further improvement of the present application, the anode of the diaphragm electrolysis device is one of titanium iridium tantalum electrode, platinum gold titanium electrode, ruthenium iridium titanium electrode, and tin antimony titanium electrode.

[0008] As a further improvement of the present application, the parameters of the electrolysis reaction include: voltage 1-7V, current 0.4-2A, pulse frequency 50Hz-1kHz, duty cycle range 30-70%, and pulse width range 500-5000μs.

[0009] As a further improvement of the present application, the electrolysis reaction time is 1-8h.

[0010] As a further improvement of the present application, the flow rate of the aeration is 1-4mL / min.

[0011] As a further improvement of the present application, the ion exchange membrane is one of cation exchange membrane, anion exchange membrane, and bipolar membrane.

[0012] As a further improvement of the present application, the valuable metal concentration in the cyanide tail liquid is 1000-5000ppm, and the cyanide concentration is 1000-10000ppm.

[0013] As a further improvement of the present application, the diaphragm electrolysis device comprises a pulse power supply, a diaphragm electrolysis cell, and an aeration device.

[0014] The beneficial effects of the present application are: The present application provides a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis, which assembles a diaphragm electrolysis device to separate the anode chamber and the cathode chamber by an ion exchange membrane; adds an alkaline electrolyte solution to the anode chamber and adds the cyanide tail liquid to be treated to the cathode chamber; performs electrolysis reaction by using single pulse current and continuously aerates the cathode chamber; and measures the cathode electrolyte after the reaction is completed to calculate the cyanide recovery rate and the valuable metal recovery rate. The present application develops a technology for efficiently, lowly, and selectively recovering valuable metals in cyanide tail liquid under alkaline conditions and effectively recovering cyanide at the same time, which can overcome the limitations of traditional electrolysis method and has important economic and environmental significance.

[0015] Pulse electrolysis technology uses a specific device to control the current, causing it to cycle through a preset pattern of "on-off-on-off" cycles. This offers advantages such as improved mass transfer, increased current efficiency, and enhanced deposit quality. Diaphragm electrolysis effectively separates the anode and cathode regions, preventing product mixing and improving reaction selectivity and efficiency. Combining pulse current with diaphragm electrolysis for cyanide tail liquor treatment overcomes the shortcomings of existing technologies, enabling the simultaneous recovery of valuable metals and cyanide while reducing energy consumption, costs, and efficiency.

[0016] The present application uses a diaphragm material to effectively physically isolate the cathode and anode regions. The anode is an electrolyte solution for conductivity, and the cathode is the cyanide tail liquid to be treated. This prevents the mixing of products in the cathode and anode regions, prevents the re-oxidation and dissolution of the deposited valuable metals, inhibits the oxidation of cyanide ions, and improves the net yield and purity of the target product. By applying a single pulse current, the ion concentration near the electrode interface is restored during the "power-off" period of the pulse power supply, thereby reducing concentration polarization, significantly improving the mass transfer process, and increasing the reaction efficiency at low concentrations, thereby improving the recovery efficiency of valuable metals and cyanide. At the same time, pulse electrodeposition can make the metal deposited layer grains finer and have better adhesion, which is conducive to subsequent stripping and collection from the cathode, thereby improving the purity and value of the recovered metal and avoiding the loose powder or sponge-like deposition often seen in DC electrolysis. Moreover, by optimizing the pulse parameters (frequency, duty cycle, pulse width, etc.), the electrode potential and interfacial reaction environment can be more finely controlled, the occurrence of side reactions such as cathode hydrogen evolution, the passivation of the electrode surface, and the significant reduction of overall energy consumption, saving electricity costs.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0019] Figure 1 This is a diagram of a diaphragm electrolysis device in an embodiment of the present application; Figure 2 This is a schematic diagram of a single pulse current waveform in an embodiment of the present application; Figure 3 This is the ICP diagram of the cyanide tail liquid to be treated in Example 1 of the present application; Figure 4 This is a SEM-EDS image of the precipitated product on the cathode plate in Example 1 of the present application; Figure 5 This is a physical picture of the cathode plate after the reaction in Example 1 of this application. DETAILED DESCRIPTION

[0020] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0022] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0024] The highly toxic cyanide tail liquid produced by the cyanidation method for gold extraction needs to be strictly treated. The existing methods have their own limitations: chemical oxidation destroys cyanide but it is difficult to recover metals; adsorption focuses on the recovery of precious metals, but is insufficient in cyanide treatment; direct current electrolysis can simultaneously treat cyanide and recover metals, but there are problems such as low current efficiency, electrode passivation, hydrogen evolution side reaction, and mixing of anode and cathode products leading to reverse reaction, which affect the treatment effect and energy consumption.

[0025] In order to solve the technical problems existing in the existing cyanide tail liquid treatment technology, such as low recovery rate of valuable metals under alkaline conditions, inability to simultaneously recover cyanide, high energy consumption, and easy passivation of electrodes, the present application provides a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis, wherein, by combining pulse current with diaphragm electrolysis and applying it to cyanide tail liquid treatment, it is possible to achieve the technical effect of efficiently, low-consumption, and selectively recovering valuable metals in cyanide tail liquid under alkaline conditions, and simultaneously effectively recovering cyanide.

[0026] The present invention provides a method for recovering valuable metals and cyanide from cyanide tail liquid based on pulse current diaphragm electrolysis, comprising the following steps: S1. Assemble a diaphragm electrolysis device with an ion exchange membrane separating the anode chamber and the cathode chamber; S2. An alkaline electrolyte solution is added to the anode chamber and the cyanide tail liquid to be treated is added to the cathode chamber; S3. Electrolysis reaction is carried out using a single pulse current, and continuous aeration is provided to the cathode chamber; S4. After the reaction is completed, the cathode electrolyte is measured to calculate the cyanide recovery rate and the valuable metal recovery rate.

[0027] In the technical solution of the embodiment of the present application, efficient separation of cyanide and metal is achieved through ion exchange membrane, pulse current electrolysis reduces concentration polarization, improves current efficiency, and at the same time inhibits the occurrence of side reactions such as hydrogen evolution reaction, cathode aeration synergistically promotes the dissociation of metal cyanide complexes, accelerates the reduction and deposition of metal ions, and prevents the pH in the cathode region from being too high, which leads to cyanide hydrolysis. Through the synergistic effect of electrochemical kinetic regulation and mass transfer enhancement, the problem of simultaneous and efficient recovery of metals and cyanide in traditional cyanide tail liquid treatment is solved, which has both economic and environmental benefits.

[0028] Furthermore, in some embodiments, the cathode of the diaphragm electrolysis device is one of a graphite felt electrode, a carbon felt electrode, a stainless steel electrode, a foam nickel electrode, and a foam copper electrode.

[0029] In the technical solution of the embodiment of the present application, the cathode adopts an electrode material with high cost performance, which significantly reduces the system cost while ensuring the treatment effect.

[0030] Furthermore, in some embodiments, the anode of the diaphragm electrolysis device is one of a titanium-iridium-tantalum electrode, a platinum-titanium electrode, a ruthenium-iridium-titanium electrode, and a tin-antimony-titanium electrode.

[0031] In the technical solution of the embodiment of the present application, the anode adopts a titanium-based coated electrode with good oxygen evolution performance to ensure excellent corrosion resistance in the electrolyte, thereby ensuring the long-term stable and efficient operation of the entire electrolysis process, and helping to improve the overall effect of metal recovery on the cathode side.

[0032] Furthermore, in some embodiments, the parameters of the electrolysis reaction include: voltage 1-7V, current 0.4-2A, pulse frequency 50Hz-1kHz, duty cycle range 30-70%, and pulse width range 500-5000μs.

[0033] In the technical solution of the embodiment of the present application, by optimizing the voltage and current parameter settings of the pulse current, the electrode reaction process is directly affected to improve the recovery efficiency of valuable metals and cyanide, thereby improving the overall treatment performance; by optimizing the frequency of the pulse current, the transmission efficiency of the reactants to the electrode interface and the activity and stability of the electrode surface are synchronously regulated, overcoming the mass transfer limitation and slowing down the adverse effects such as passivation, and ultimately improving the comprehensive performance of valuable metal recovery and cyanide treatment; by optimizing the duty cycle of the pulse current, the current "on" time (t on ) and the “off” time (t off ) to find the optimal balance between the effective electrochemical reaction time and the interface ion concentration / surface state recovery time, thereby synergistically optimizing the mass transfer efficiency, improving the current efficiency of the target reaction, reducing overall energy consumption, and reducing electricity costs while ensuring a certain processing rate; by optimizing the pulse width of the pulse current, the depth of the electrochemical reaction during a single pulse and the subsequent "off" time (t off ) The balance between the degree of interface recovery and the effect of the pulse width can be achieved by selecting an appropriate pulse width, which can effectively drive the deposition of valuable metals and the conversion of cyanide while avoiding severe concentration polarization caused by too long a time of action.

[0034] Furthermore, in some embodiments, the electrolysis reaction time is 1 to 8 hours.

[0035] In the technical solution of the embodiment of the present application, by optimizing the diaphragm electrolysis reaction time, an optimal reaction end point is determined according to the treatment target and the change law of current efficiency during the electrolysis process, thereby maximizing equipment utilization, shortening the batch processing cycle and reducing unit energy consumption while ensuring the treatment effect, thereby achieving the economy and efficiency of the overall process.

[0036] Furthermore, in some embodiments, the aeration flow rate is 1-4 mL / min.

[0037] In the technical solution of the present embodiment, the introduction of air or oxygen promotes ion diffusion in the solution, making it easier for ions to migrate from the bulk of the solution to the electrode surface, thereby accelerating the reaction rate. The aeration rate is controlled by a rotameter, with a set value of 1-4 mL / min. Too little aeration results in a low recovery rate for valuable metals, while too much aeration results in a decreased cyanide recovery rate.

[0038] Furthermore, in some embodiments, the ion exchange membrane is one of a cation exchange membrane, an anion exchange membrane, and a bipolar membrane.

[0039] In the technical solution of the embodiment of the present application, the presence of the ion exchange membrane avoids cross-contamination of the cathode and anode products and ensures the recovery rate of cyanide. The ion exchange membrane is preferably a bipolar membrane. The bipolar membrane has a synchronous acid-base regulation function, which can automatically maintain the pH balance between the cathode chamber and the anode chamber, prevent the deposited valuable metals from being reoxidized and dissolved, inhibit the oxidation of cyanide ions, and improve the net yield and purity of the target product. The alkaline electrolyte solution is a sodium salt or potassium salt solution, which can significantly improve the conductivity. The alkaline environment is combined with pulse electrolysis to improve the cyanide recovery rate while reducing side reactions.

[0040] Furthermore, in some embodiments, the concentration of valuable metals in the cyanide tail liquid is 1000-5000 ppm, and the concentration of cyanide is 1000-10000 ppm.

[0041] In the technical solution of the embodiment of the present application, efficient treatment of cyanide tail liquid in a wide concentration range is achieved through pulse current and diaphragm electrolysis.

[0042] like Figure 1 As shown, further, in some embodiments, the diaphragm electrolysis device includes a pulse power supply, a diaphragm electrolysis cell and an aeration device.

[0043] In the technical solution of the embodiment of the present application, a dual pulse power supply is used as a power supply device, and the pulse current has specific waveform parameters, such as Figure 2 As shown, the output current can change periodically in a "power on-off-power on-off" pattern according to a preset rule. on Represents the power-on time, μs; T off represents the power-off time, μs; T represents one cycle time, μs. A diaphragm electrolytic cell consists of an anode chamber, a cathode chamber, a cathode plate, an anode plate, and a diaphragm material.

[0044] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0045] Example 1 This embodiment provides a method for recovering valuable metals and cyanide from cyanide tail liquid based on pulse current diaphragm electrolysis, comprising the following steps: S1. Assemble a diaphragm electrolysis device with an ion exchange membrane separating the anode chamber and the cathode chamber; S2. Add 500 mL of alkaline electrolyte solution (20% NaOH solution) to the anode chamber to enhance conductivity, and add 500 mL of the cyanide tail liquid to be treated to the cathode chamber. The ICP analysis of the cyanide tail liquid is as follows: Figure 3 As shown, the valuable substance is mainly zinc; a titanium-iridium-tantalum electrode is selected as the anode, and a carbon felt electrode is selected as the cathode, and the distance between the two plates and the bipolar membrane is adjusted to 2.5 cm; S3. Electrolysis was performed using a single pulse current with a voltage of 5.0 V and a current of 1 A, respectively, a pulse frequency of 250 Hz, a duty cycle of 50%, a current duration of 2000 μs, and a rest time of 2000 μs. Continuous aeration was introduced into the cathode chamber at a rate of 3 mL / min. No external reagents or pH adjustment were required, and the reaction was carried out at room temperature for 4 h. S4. After the reaction is completed, the cathode electrolyte is measured and the cyanide recovery rate and the valuable metal recovery rate are calculated, which can reach 96.6% and 90.3% respectively, achieving efficient recovery of cyanide and valuable metals. Figures 4 and 5 As shown in the figure, according to the SEM-EDS results, the cathode plate products are mainly composed of four elements: Zn, Cu, C, and N. Among them, the Zn content is the highest. This shows that the valuable substances in the solution have been effectively recovered.

[0046] The cathode current efficiency CE and specific energy consumption E were calculated according to formulas (1) and (2). Compared with direct current with the same current and voltage, the recovery rates of cyanide and valuable metals increased by 7.8% and 12%, respectively, the current efficiency increased by 38.1%, and the energy consumption decreased by 20 kw·h·m -3 In the process of achieving efficient recycling of useful materials, a significant reduction in electricity costs is simultaneously achieved, which symbolizes the needs of green development.

[0047] Where n is the number of electron transfers; F is the Faraday constant; c0 is the initial metal ion concentration, mol / L; c t is the metal ion concentration after the reaction, mol / L; I is the current intensity, A; t is the electrolysis time, h; M is the molar mass of the metal, g / mol; U is the cell voltage, V; V is the volume of the liquid to be treated, L.

[0048] Examples 2-3 and Comparative Examples 1-2 Examples 2-3 and Comparative Examples 1-2 respectively provide a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis. Compared with Example 1, the only difference is that the current and voltage are different, as shown in Table 1. The other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0049] Examples 4-5 and Comparative Examples 3-4 Examples 4-5 and Comparative Examples 3-4 respectively provide a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis. Compared with Example 1, the only difference is that the pulse frequency is different, as shown in Table 1. The other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0050] Examples 6-7 and Comparative Examples 5-6 Examples 6-7 and Comparative Examples 5-6 respectively provide a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis. Compared with Example 1, the only difference is that the duty cycle is different, as shown in Table 1. The other experimental parameters and conditions are basically the same as those in Example 1 and are not repeated here.

[0051] Examples 8-9 and Comparative Examples 7-8 Examples 8-9 and Comparative Examples 7-8 respectively provide a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis. Compared with Example 1, the only difference is that the pulse width is different, as shown in Table 1. The other experimental parameters and conditions are basically the same as those in Example 1 and will not be repeated here.

[0052] Examples 10-11 and Comparative Examples 9-10 Examples 10-11 and Comparative Examples 9-10 respectively provide a method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis. Compared with Example 1, the only difference is that the electrolysis time is different, as shown in Table 1. The other experimental parameters and conditions are basically the same as those in Example 1 and are not repeated here.

[0053] Comparative Example 11 Comparative Example 11 provides a method for recovering valuable metals and cyanide from cyanide tail liquor using pulsed current diaphragm electrolysis. Compared to Example 1, this method differs only in that aeration is not performed during the reaction. Other experimental parameters and conditions are essentially the same as those in Example 1 and are not further described here. Calculations and analysis indicate that the cyanide recovery rate is 84.7% and the valuable metal recovery rate is 45.4%, indicating that effective recovery of the valuable metals is not achieved.

[0054] Comparative Example 12 Comparative Example 12 provides a method for recovering valuable metals and cyanide from cyanide tail liquor using pulsed current diaphragm electrolysis. This method differs from Example 1 only in the use of a Ti cathode electrode. Calculation and analysis show that the cyanide recovery rate is 78.6% and the valuable metal recovery rate is 56.9%, indicating that effective recovery of the valuable metals is not achieved.

[0055] Table 1 Diaphragm electrolysis parameters and test results of the embodiments and comparative examples Comparing Examples 1-3 and Comparative Examples 1-2, it can be seen that when the current and voltage are too small, the recovery rate of valuable metals will be low and the reaction effect will be unsatisfactory. When the current and voltage are too large, the effect can be achieved, but at this time the power consumption is too large, the cost is too high, and the economic benefit cost is not appropriate. Comparing Examples 4-5 and Comparative Examples 3-4, it can be seen that when the pulse frequency is too low, it is not conducive to the elimination of concentration polarization, which leads to a decrease in the reaction effect. When the pulse frequency is too high, the rate of reaction will be reduced, which is not conducive to the reaction. Comparing Examples 6-7 and Comparative Examples 5-6, it can be seen that when the duty cycle is too small, the effective time of the current is too short, which leads to an unsatisfactory reaction effect. When the duty cycle is too large, it cannot achieve the effect of reducing overall energy consumption and reducing electricity costs. Comparing Examples 8-9 and Comparative Examples 7-8, it can be seen that when the pulse width is too small, the reaction will not be thorough and the valuable metal recovery effect will be poor. When the pulse width is too large, it is not conducive to the elimination of concentration polarization. Comparing Examples 10-11 and Comparative Examples 9-10, it can be seen that when the electrolysis time is too short, the reaction will not be thorough and the valuable metal recovery effect is poor. When the electrolysis time is too long, it will lead to increased energy consumption. As shown in Comparative Example 11, no aeration treatment is performed during the reaction process, the cyanide recovery rate is 84.7%, and the valuable metal recovery rate is 45.4%, and effective recovery of valuable metals is not achieved. As shown in Comparative Example 12, using a Ti electrode as the cathode, the cyanide recovery rate is 78.6%, and the valuable metal recovery rate is 56.9%, and effective recovery of valuable metals is not achieved.

[0056] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for recovering valuable metals and cyanide from cyanide tail liquid based on pulse current diaphragm electrolysis, characterized in that: The following steps are involved: S1. Assemble a diaphragm electrolysis device with an ion exchange membrane separating the anode chamber and the cathode chamber; S2. adding an alkaline electrolyte solution to the anode chamber and adding the cyanide tail liquid to be treated to the cathode chamber; S3. Electrolysis reaction is carried out using a single pulse current, and continuous aeration is provided to the cathode chamber; S4. After the reaction is completed, the cathode electrolyte is measured to calculate the cyanide recovery rate and the valuable metal recovery rate.

2. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 1, characterized in that: The cathode of the diaphragm electrolysis device is one of a graphite felt electrode, a carbon felt electrode, a stainless steel electrode, a foam nickel electrode, and a foam copper electrode.

3. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 2, characterized in that: The anode of the diaphragm electrolysis device is one of a titanium-iridium-tantalum electrode, a platinum-titanium electrode, a ruthenium-iridium-titanium electrode, and a tin-antimony-titanium electrode.

4. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 1, characterized in that: The parameters of the electrolysis reaction include: voltage 1-7V, current 0.4-2A, pulse frequency 50Hz-1kHz, duty cycle range 30-70%, and pulse width range 500-5000μs.

5. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 4, characterized in that: The electrolysis reaction time is 1 to 8 hours.

6. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 5, characterized in that: The aeration flow rate is 1-4 mL / min.

7. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 1, characterized in that: The ion exchange membrane is one of a cation exchange membrane, an anion exchange membrane, and a bipolar membrane.

8. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 1, characterized in that: The concentration of valuable metals in the cyanide tail liquid is 1000-5000 ppm, and the concentration of cyanide is 1000-10000 ppm.

9. The method for recovering valuable metals and cyanide in cyanide tail liquid based on pulse current diaphragm electrolysis according to claim 1, characterized in that: The diaphragm electrolysis device comprises a pulse power supply, a diaphragm electrolysis cell and an aeration device.

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