A short process device for extracting gold from waste printed circuit boards

Abstract

The application discloses a kind of short process gold extraction devices of waste printed circuit board.It includes separation module, collection module and electrodeposition part.Separation module contains leaching tank, and leaching liquid and cleaning liquid are alternately introduced, and leaching process is strengthened using micro-bubble generator and heater, so that gold foil is stripped from the surface of circuit board;Collection module contains filter and temporary storage tank, for intercepting and collecting gold foil and classifying temporary storage liquid;Electrodeposition part is connected to temporary storage tank, and copper in leaching solution is recovered through electrodeposition tank, and tail liquid flows back to leaching tank to realize closed circuit circulation.The application adopts integrated design, and combines selective leaching and physical interception by micro-bubble strengthening, without complex high-temperature or cyanide equipment, and one step realizes efficient stripping of gold and electrolytic recovery of copper;At the same time, leaching solution is closed circuit, and cleaning liquid is recovered in stages, which significantly shortens the process flow, reduces equipment investment and environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of secondary resource recycling technology, specifically to a short-process gold extraction device for waste printed circuit boards. Background Technology

[0002] Waste printed circuit boards (WPCBs) contain abundant metal resources, with gold grades typically reaching 300-500 g / t, making them highly valuable for recycling. However, WPCBs are classified as hazardous waste, and their environmentally friendly and efficient treatment remains a challenge for the industry.

[0003] Existing recycling technologies are mainly divided into pyrometallurgical and hydrometallurgical processes. Pyrometallurgy typically enriches precious metals through high-temperature combustion, but it produces highly toxic pollutants such as dioxins, requiring expensive exhaust gas treatment systems and energy-intensive equipment. Hydrometallurgy, while offering higher recovery rates, usually involves multiple complex processes such as crushing, sorting, acid leaching, cyanidation or aqua regia leaching, extraction, and reduction, resulting in long process flows, large equipment footprints, complex pipelines, and high wastewater treatment pressure.

[0004] Therefore, developing a waste printed circuit board gold extraction device that is short in process, simple in equipment, low in investment and environmentally friendly is an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a short-process gold extraction device for waste printed circuit boards, which solves the technical problems of long recycling processes, complex equipment, and serious environmental pollution in the existing technology.

[0006] To achieve the above-mentioned technical objectives, this application adopts the following technical solution:

[0007] This application provides a short-process gold extraction device for waste printed circuit boards, comprising: The separation module includes a leaching tank, a microbubble generator, and a heater. The aeration pipe of the microbubble generator is located at the bottom of the leaching tank, and the heater is located inside the leaching tank. Leaching solution and cleaning solution are alternately introduced into the leaching tank. The collection module includes a filter and a temporary storage tank. The input end of the filter is connected to the output end of the leaching tank via a pipeline, and the input end of the temporary storage tank is connected to the output end of the filter. The electrodeposition section includes an electrodeposition tank and a tailings tank. The input end of the electrodeposition tank is connected to the temporary storage tank via a pump, and the output end of the electrodeposition tank is connected to the tailings tank. The tailings tank is connected to the leaching tank via a return pipeline.

[0008] In some embodiments of this application, a partition is horizontally arranged inside the leaching tank, and a plurality of through holes are evenly opened on the partition. The aeration pipe of the microbubble generator is located below the partition.

[0009] In some embodiments of this application, the upper surface of the partition is provided with multiple support columns, each support column having the same height and arranged in an array.

[0010] In some embodiments of this application, the leaching tank is further provided with a stirring motor, and the stirring paddle of the stirring motor extends into the leaching tank.

[0011] In some embodiments of this application, the temporary storage tank is divided into an leaching solution storage chamber and a cleaning solution storage chamber by a partition; The output end of the filter can be selectively connected to the leachate storage chamber and the cleaning solution storage chamber respectively through a switching valve. The leachate storage chamber is connected to the electrodeposition tank through a pump, and the cleaning solution storage chamber is connected to the leachate tank through a circulation pump.

[0012] In some embodiments of this application, the cleaning solution storage chamber stores an ethanol solution with a concentration of 50%-75%, the leachate includes 0.5-2 mol / L sulfuric acid and 100-500 mg / L sodium chloride, and the microbubble generated by the microbubble generator has a diameter in the range of 10-100 micrometers.

[0013] In some embodiments of this application, the number of electrodeposition tanks is at least two, and the electrodeposition tanks are connected in parallel or in series. Each electrodeposition tank is provided with a cathode plate and an anode plate, and the cathode plate and the anode plate are electrically connected to a DC power supply.

[0014] In some embodiments of this application, the cathode plate is made of stainless steel or titanium, and the anode plate is made of iridium-plated tantalum titanium mesh, lead dioxide titanium mesh, or graphite plate.

[0015] In some embodiments of this application, the tail liquid tank is provided with a dosing port and a stirring device.

[0016] In some embodiments of this application, the number of leaching tanks is two, and the two leaching tanks are arranged in parallel and both are connected to the same filter.

[0017] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include: This invention integrates selective gold stripping, physical interception and collection, and electrolytic copper recovery into a single, segmented, modular design. Utilizing microbubbles to enhance leaching eliminates the need for highly toxic cyanide or corrosive aqua regia, achieving efficient gold foil stripping. Alternating introduction of leaching and cleaning solutions, coupled with a unique collection module, enables one-step gold extraction and liquid diversion. Closed-loop circulation of the leaching solution and electrolytic copper recovery significantly reduce wastewater discharge and resource waste. The overall device has a compact structure, significantly shortening the gold extraction process and reducing equipment investment costs and environmental impact. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the embodiments will be briefly described below: Figure 1 This is a schematic diagram of a short-process gold extraction device for waste printed circuit boards according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a leaching tank in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a filter according to an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a temporary storage slot in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of an electrodeposition tank according to an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a tailings tank in an embodiment of this application.

[0019] Figure label: Leaching tank 1; Filter 2; Temporary storage tank 3; Electrodeposition tank 4; Tailings tank 5; 11. Microbubble generator; 12. Heater; 13. Baffle plate; 14. Support column; 15. Stirring motor; 16. Stirring paddle; 17. Aeration pipe; Leachate storage chamber 31; cleaning solution storage chamber 32. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] Those skilled in the art will understand that, in this specification, the term "comprising" is an open-ended expression, meaning that the stated feature is present but other features are excluded. Directional terms such as "upper," "lower," "left," and "right" refer to exemplary directions based on the accompanying drawings. Features specified as "first" or "second" implicitly include one or more of that feature. Singular expressions can also be used in plural forms. "Multiple" means two or more. The terms "installed," "connected," and "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection via an intermediate medium, and it can be a connection within two components. Furthermore, "linked" can include wireless connections.

[0022] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a short-process gold extraction device for waste printed circuit boards, which solves the technical problems of long recycling processes, complex equipment, and serious environmental pollution in the existing technology.

[0023] To achieve the above-mentioned technical objectives, this application adopts the following technical solution: like Figures 1-6 As shown, this embodiment provides a short-process gold extraction device for waste printed circuit boards, which mainly consists of a separation module, a collection module and an electrodeposition section.

[0024] The separation module is the core of the device, including a leaching tank 1. A microbubble generator 11 and a heater 12 are installed inside the leaching tank 1. The aeration pipe 17 of the microbubble generator 11 is located at the bottom of the leaching tank 1, and the heater 12 is located inside the leaching tank. Leaching solution and cleaning solution are alternately introduced into the leaching tank 1. Specifically, refluxed leaching solution is introduced into the leaching tank 1 through an inlet pipe, and cleaning solution is sprayed into the leaching tank 1 through a spray gun.

[0025] The collection module, used for solid-liquid separation and liquid transfer, includes a filter 2 and a temporary storage tank 3. The input end of the filter 2 is connected to the bottom output end of the leaching tank 1 via corrosion-resistant piping and a pump. The filter 2 is preferably a bag filter. When the slurry passes through the filter 2 during the leaching process, the solid gold foil is trapped in the filter bag, while the liquid passes through the filter into the temporary storage tank 3 at the rear end.

[0026] The electrodeposition section, used to recover base metals and regenerate the leachate, includes an electrodeposition tank 4 and a tailings tank 5. The output of the temporary storage tank 3 is connected to the electrodeposition tank 4 via a chemical pump, which delivers the copper-rich leachate to the electrodeposition tank 4. The overflow port or output pipeline of the electrodeposition tank 4 is connected to the tailings tank 5, which is then connected to the leaching tank 1 via a return pipeline, forming a closed-loop circulation.

[0027] Working Principle: During operation, waste printed circuit boards (WPCBs) are placed in leaching tank 1, and a leaching solution based on a sulfuric acid / sodium chloride system is introduced. Heater 12 and microbubble generator 11 are turned on. The microbubbles burst in the liquid, generating cavitation and producing highly oxidizing hydroxyl radicals that selectively dissolve the copper / nickel substrate beneath the gold layer, causing the gold foil to lose adhesion and detach. Simultaneously, the agitation of the microbubbles carries the detached gold foil into the suspension. After the reaction, the suspension is pumped into filter 2, and the gold foil is collected. Subsequently, a cleaning solution (such as an ethanol solution) is introduced to clean the tank and the surface of the WPCBs of any remaining gold foil, which is then collected again through filter 2. The copper-rich leaching solution enters electrodeposition tank 4 for electrolytic recovery of copper, while the copper-poor tailings enter tailings tank 5 for reprocessing and reuse.

[0028] This embodiment utilizes the synergistic effect of physical (microbubbles, heating) and chemical (selective leaching) processes to achieve efficient gold extraction under mild conditions. The device organically connects the leaching, filtration, and electrowinning units in series, greatly shortening the traditional hydrometallurgical process, avoiding the waste gas pollution of pyrometallurgical processes, and is simple and easy to operate.

[0029] This embodiment improves the internal structure of leaching tank 1. For example... Figure 2 As shown, a partition plate 13 is horizontally arranged inside the leaching tank 1. Multiple support columns 14 are vertically welded to the upper surface of the partition plate 13. These support columns 14 are of uniform height and arranged in an array to form a crisscrossing channel structure. Simultaneously, multiple through holes, preferably with a diameter of 5 mm, are uniformly formed on the partition plate 13.

[0030] In practice, the circuit boards to be processed are not laid flat on the partitions 13 or support columns 14, but are inserted in a roughly vertical position into the channel structure formed by adjacent support columns 14, and are supported and limited by the support columns 14 along the row or column direction. Multiple circuit boards can be inserted into the same channel in the same direction, forming a horizontal stacked state. The design of the support column array allows the circuit boards to remain stable and not tip over without being tightly packed together. At the same time, this structure can actively ensure that there are uniform and sufficient gaps between adjacent circuit boards, providing a stable flow channel for the leachate.

[0031] Through the above structure, this embodiment achieves orderly and three-dimensional placement of circuit boards within the leaching tank 1, avoiding the problems of poor board adhesion and mass transfer caused by traditional stacking methods. The array of support columns 14 not only provides clamping and stabilization but also forcibly maintains the gap between boards, allowing the leachate to fully surround and penetrate the surface of each circuit board, significantly improving mass transfer efficiency and leaching reaction uniformity. The through holes on the partition 13 allow the leachate and microbubbles to pass through from bottom to top, while also allowing the peeled-off fine gold foil to pass through the partition from top to bottom with the liquid and enter the drain port at the bottom of the tank. The 5mm diameter through holes ensure smooth fluid flow while intercepting large circuit board fragments from entering the pumping system, thus playing a preliminary screening role.

[0032] This embodiment further defines the position of the microbubble generator 11. The aeration pipe 17 of the microbubble generator 11 is located at the bottom or lower part of the leaching tank 1, and is strictly located below the partition plate 13.

[0033] Microbubbles are generated below the partition 13, rise due to buoyancy, are refined and rectified through the through holes on the partition 13, and then impact the circuit board surface on the support column 14 evenly.

[0034] This bottom-blowing design utilizes baffles as bubble distributors, resulting in a more uniform distribution of bubbles across the entire groove cross-section. As the bubbles rise and pass through the gaps in the circuit board, the resulting scrubbing action effectively removes the weakened gold foil, improving peeling efficiency.

[0035] This embodiment adds a mechanical stirring function. A stirring motor 15 is also installed on the upper part of the leaching tank 1. The stirring paddle 16 shaft of the stirring motor 15 passes through the top cover and extends into the interior of the leaching tank 1. The stirring paddle 16 is located above or in the gap of the material.

[0036] After aeration is stopped during leaching, or during the cleaning phase, the stirring motor 15 is turned on. The stirring paddle 16 macroscopically mixes the liquid. Although microbubbles can provide microscopic disturbances, mechanical stirring can achieve macroscopic homogenization more quickly during the cleaning or reagent mixing phase, especially accelerating the contact between the cleaning solution and residual dead corners in the tank, thus improving cleaning efficiency.

[0037] This embodiment optimizes the collection module. The temporary storage tank 3 is physically divided into two independent chambers: a leachate storage chamber 31 and a cleaning solution storage chamber 32. A three-way switching valve is installed on the output pipe of the filter 2, which can be selectively connected to the leachate storage chamber 31 and the cleaning solution storage chamber 32, respectively. The leachate storage chamber 31 is connected to the electrodeposition tank 4 via a pump, while the cleaning solution storage chamber 32 is reconnected to the leachate tank 1 via a circulation pump.

[0038] During the leaching stage, the valve is switched to the leaching solution storage chamber 31, where the filtered copper-rich leaching solution enters and then proceeds to electrodeposition. During the cleaning stage, the valve is switched to the cleaning solution storage chamber 32, where the filtered ethanol-containing cleaning solution enters and is circulated back to the leaching tank 1 by a pump for repeated rinsing. The cleaning solution circulation pump is configured to pump the filtered ethanol solution back to the leaching tank 1 to rinse the circuit board.

[0039] This dual-chamber design cleverly solves the problem of separating liquids with different properties, allowing one set of filtration equipment to serve two different process steps. This not only saves on equipment investment but also enables independent closed-loop circulation of the cleaning solution, reducing solvent consumption.

[0040] This embodiment specifically defines the process parameters. The cleaning solution storage chamber 32 stores an ethanol solution with a concentration of 50%-75%. The leachate formulation consists of 0.5-2 mol / L sulfuric acid and 100-500 mg / L sodium chloride. The microbubble generator 11 generates microbubbles with a diameter in the range of 10-100 micrometers.

[0041] The surface tension of 50%-75% ethanol solution is much lower than that of water, which can easily wet the micropores of the circuit board and remove the gold foil that adheres due to the surface tension of water. Microbubbles in this diameter range have better mass transfer specific surface area and cavitation energy.

[0042] The optimized reagent formulation system is key to the efficient operation of this device. The elimination of aqua regia and cyanide significantly improves the operating environment. Ethanol washing significantly increases the final gold recovery rate and solves the problem of fine gold foil adhering to the wall and causing loss.

[0043] This embodiment expands upon the electrodeposition section. There are at least two electrodeposition tanks 4, connected in parallel or series. Each electrodeposition tank 4 contains alternating cathode and anode plates and is connected to a DC power supply.

[0044] The copper-rich leaching solution flows through a multi-stage electrodeposition tank 4, where copper ions are reduced to metallic copper at the cathode under the influence of electric current. The multi-tank design increases the electrolysis area and residence time, adapting to the throughput of pilot-scale or large-scale production, ensuring that copper in the leaching solution is fully recovered, and that the copper-poor solution has better re-leaching capacity after being returned to the leaching tank.

[0045] This embodiment specifies the electrode materials. The cathode plate is made of stainless steel or titanium, and the anode plate is made of iridium-tantalum titanium mesh, lead dioxide titanium mesh, or graphite plate.

[0046] Stainless steel or titanium cathodes have smooth surfaces, facilitating the stripping of deposited copper. Coated titanium or graphite anodes are resistant to acid and chlorine corrosion, and have suitable oxygen / chlorine evolution overpotentials. The selected electrode materials exhibit strong corrosion resistance and long service life, reducing the cost of frequent electrode replacements and ensuring the stability of the electrolysis process.

[0047] In this embodiment, a dosing port and a stirring device are provided on the tail liquid tank 5.

[0048] The copper ion concentration in the tailings solution after electrodeposition decreases, and sulfuric acid and sodium chloride are consumed. A measured amount of concentrated sulfuric acid and sodium chloride are added to the tailings solution tank 5 through the dosing port, and the stirring device is activated to mix thoroughly, restoring the concentration to the initial leachate level. Through tailings regeneration, the entire system generates virtually no wastewater discharge, saving water resources and reagent costs while also preventing environmental pollution.

[0049] This embodiment employs a parallel leaching design. There are two leaching tanks 1, which are connected in parallel, and their output pipelines merge and connect to the same filter 2.

[0050] The two leaching tanks 1 can operate alternately (one leaching while the other loads and unloads) or simultaneously. This improves the time utilization and processing capacity of the equipment, and the shared back-end filtration and electrodeposition systems optimize the return on investment.

[0051] The aperture of the through-hole on the partition 13 is configured to allow the leaching solution and the stripped gold foil to pass through. This ensures smooth circulation of the leaching solution and successful settling and discharge of the detached gold foil.

[0052] The aeration pipe 17 of the microbubble generator 11 is configured to generate microbubbles with a flow rate of 40-250 L / h. The specific pore size combined with the microbubble parameters can prevent large debris from clogging the substrate, strengthen the copper-nickel oxide layer by utilizing the hydroxyl radicals generated by the microbubble rupture, and promptly remove the gold foil from the substrate surface by utilizing the bubble disturbance.

[0053] The heater 12 is configured to maintain the liquid temperature in the leaching tank at 60-80°C. The synergistic effect of aeration and heating ensures a uniform distribution of the temperature and concentration fields within the leaching system, improves the reaction kinetic rate, and ensures thorough gold foil stripping.

[0054] The filter bag in the bag filter 2 has a pore size smaller than the minimum size of the gold foil, and the filter bag material is resistant to acid corrosion. The specific filter bag selection ensures effective interception of fine gold foil, while the corrosion-resistant material guarantees long-term stability in acidic leaching environments.

[0055] The DC power supply is configured to provide a current density of 5-20 mA / cm². The optimized combination of electrode materials and current density parameters ensures the purity and current efficiency of the electrolytic copper, while extending the electrode's lifespan and reducing operating and maintenance costs.

[0056] The pipelines are equipped with corrosion-resistant pumps and flow control valves to control the flow rate of the leachate between units. The corrosion-resistant fluid transport control system ensures long-term stable operation of the entire unit and precise flow control in acidic, chloride-containing salt environments.

[0057] The microbubble generator 11 generates microbubbles that are configured to create a cavitation effect on the surface of a waste printed circuit board, producing hydroxyl radicals. This clarifies the core mechanism of the device: utilizing the strong oxidizing radicals generated by microbubble cavitation to replace traditional strong oxidants, achieving cyanide-free and aqua regia-free green gold extraction.

[0058] The gold separation section is configured to complete the leaching process within 24 hours, and aeration and heating are stopped after leaching is completed. This limits the device's time and control logic, ensuring the process cycle remains within a controllable range and optimizing the balance between energy consumption and output.

[0059] In this embodiment, an ultrasonic transducer is installed on the outer wall or inside the leaching tank 1.

[0060] During the microbubble leaching process, ultrasonic waves are simultaneously activated. The ultrasonic waves propagate in the liquid, generating rarefaction waves that lower the cavitation threshold for microbubble collapse, making the microbubbles more prone to cavitation collapse and releasing stronger shock waves and microjets. The ultrasonic waves and microbubbles form an acoustic-cavitation coupling field, which significantly enhances the ability to peel gold foil from deep within areas such as blind vias and interlayer gaps in circuit boards, further shortening the leaching time and improving the gold extraction rate for complex circuit board structures.

[0061] A redox potential (ORP) meter is installed in leaching tank 1 to monitor the redox potential of the reaction system in real time. Simultaneously, the tank is equipped with a microbubble aeration device, the gas flow rate of which can be adjusted by the control system. The ORP meter detects the redox potential of the solution in leaching tank 1 in real time. When the detected value is lower than a set threshold, the control system automatically adjusts the air flow rate of the microbubble aeration device to improve the dissolved oxygen and oxidant transfer efficiency until the ORP recovers to the required process range.

[0062] A pH meter is installed in the tailings tank 5 to continuously monitor the acidity and alkalinity of the tailings. The tank is also equipped with an automatic sulfuric acid dosing pump to replenish sulfuric acid based on the pH signal. The pH meter continuously monitors the pH value of the solution in the tailings tank 5. When the pH exceeds the set range, the control system activates the sulfuric acid dosing pump to quantitatively replenish sulfuric acid into the tailings tank 5, maintaining the required acidic environment and ensuring the continuous progress of the leaching reaction.

[0063] The addition of oxidant / sodium chloride can be set to be done automatically according to the process requirements, either proportionally or periodically. Since it is theoretically completely consumed in the system, it can also be achieved by linking with aeration or by quantitative addition.

[0064] The aeration intensity is directly controlled based on the ORP signal in the leaching tank, which has a rapid response and avoids the lag and experience error of traditional manual control. pH monitoring and sulfuric acid replenishment in the tail liquid tank can accurately reflect the overall acidity change of the leachate and facilitate the mixing and transportation of reagents. The two control loops work together to ensure the continuous stability of the chemical state of the leaching system, which significantly improves leaching efficiency, process reproducibility and production automation level.

[0065] In this embodiment, a coarse filter screen is added between the leaching tank 1 and the filter 2, preferably with a pore size of 1-2 mm.

[0066] The leachate first passes through a coarse filter to intercept any potentially detached resistors, capacitors, or larger substrate fragments before entering the bag filter. This protects the delicate bag filter from punctures by sharp objects, extends its lifespan, and ensures the safety of gold foil collection.

[0067] The working process is as follows: Waste printed circuit boards are placed into the parallel leaching tank 1 and stacked in an orderly manner using partitions 13 and support columns 14. A sulfuric acid-sodium chloride leaching solution prepared by the tailings tank 5 is added, and the temperature is controlled at 60-80℃. Microbubbles are generated using the bottom microbubble generator 11. The microbubbles cavitate on the surface of the circuit board, generating hydroxyl radicals that rapidly oxidize and dissolve the copper-nickel substrate under the gold plating layer. The gold foil is detached due to the agitation of the bubbles. After coarse filtration, the leaching solution enters the bag filter 2, where the gold foil is retained. Then, the process switches to the ethanol cleaning solution storage chamber 32, where a 50%-75% ethanol solution is pumped in to clean the circuit board and the tank. The low surface tension causes residual gold foil to detach and be collected by the filter 2. The leaching solution enters the electrodeposition tank 4, where copper is recovered through electrodeposition at a current density of 5-20 mA / cm². The copper-poor tailings solution is returned to the tailings tank 5, regenerated after monitoring and replenishment, and then pumped back to the leaching tank 1 for circulation.

[0068] Case 1: Gold was recovered from three types of waste printed circuit boards (waste mobile phone circuit boards, CPUs, and probe mounting substrates) under the following experimental conditions. Leaching was performed at a 2:1 liquid-to-solid ratio, requiring 50 kg of material and a 100 L leachate solution (1 mol / L sulfuric acid, 200 mg / L sodium chloride). During leaching, the 100 L leachate solution was evenly divided into two leaching tanks, each containing 25 kg of material (waste mobile phone circuit boards, CPUs, or probe mounting substrates). The leaching solution temperature was controlled at 60°C, and aeration was initiated at a rate of 125 L / h. After leaching, the leachate was filtered, and the leaching tanks were cleaned. The material in the filter bags was collected, refined, weighed, and the gold recovery rate was calculated. As shown in Table 1, this device achieved a gold recovery rate of over 98% for different types of waste printed circuit boards, demonstrating excellent adaptability.

[0069] Table 1 Gold recovery rate of different materials

[0070] Comparative Case 1: To investigate the effect of microbubble aeration on gold recovery, four leaching systems were set up: no aeration, aeration rates of 40 L / h, microbubble aeration of 125 L / h, and forced draft aeration of 125 L / h. All other conditions were the same for all gold extraction experiments. The experimental conditions are as follows: Leaching was carried out at a 2:1 liquid-to-solid ratio, requiring 50 kg of material and 100 L of leaching solution (1 mol / L sulfuric acid, 200 mg / L sodium chloride). During leaching, the 100 L of leaching solution was evenly added to two leaching tanks. 25 kg of waste probe mounting substrate was added to each tank. The leaching solution temperature was controlled at 60℃. Different aeration methods were used for each system. After leaching, the leaching solution was filtered and the leaching tanks were cleaned. The material in the filter bags was collected, refined, weighed, and the gold recovery rate was calculated. As shown in Table 2, gold is difficult to recover without aeration; conventional bubble aeration has a certain ability to recover gold, but the efficiency is low; microbubble aeration has a gold recovery rate of over 98% within the set aeration volume range.

[0071] Table 2 Gold recovery rate at different inflation volumes

[0072] Comparative Case 2: To investigate the effect of temperature on gold recovery, three leaching systems were set up at 25℃, 60℃, and 80℃, with other conditions remaining the same for three groups of gold extraction experiments. The experimental conditions are as follows: Leaching was carried out with a 2:1 liquid-to-solid ratio, requiring 50 kg of material and 100 L of leaching solution (1 mol / L sulfuric acid, 200 mg / L sodium chloride). During leaching, the 100 L of leaching solution was evenly added to two leaching tanks, and 25 kg of waste probe mounting substrate was added to each tank. The leaching solution temperature was controlled at 25℃, 60℃, and 80℃, respectively. Aeration was carried out in the leaching tanks at a rate of 125 L / h. After leaching, the leaching solution was filtered and the leaching tanks were cleaned. The material in the filter bag was collected, refined, weighed, and the gold recovery rate was calculated. As shown in Table 3, the gold recovery rate was lower at 25℃, while the gold recovery rate was above 98% within the set temperature range.

[0073] Table 3 Gold recovery rates at different temperatures

[0074] Comparative Case 3: To investigate the effect of sodium chloride concentration on gold recovery, three leaching systems with sodium chloride concentrations of 0 mg / L, 200 mg / L, and 500 mg / L were set up. Three gold extraction experiments were conducted under the same conditions. The experimental conditions are as follows: Leaching was carried out at a 2:1 liquid-to-solid ratio, requiring 50 kg of material and preparing 100 L of leaching solution (1 mol / L sulfuric acid, 0 mg / L, 200 mg / L, and 500 mg / L sodium chloride). During leaching, the 100 L of leaching solution was evenly added to two leaching tanks. 25 kg of waste probe mounting substrate was added to each leaching tank. The leaching solution temperature was controlled at 60℃, and aeration was carried out at a rate of 125 L / h. After leaching, the leaching solution was filtered, and the leaching tanks were cleaned. The material in the filter bag was collected, refined, weighed, and the gold recovery rate was calculated. As shown in Table 4, the gold recovery rate was low without the addition of sodium chloride, while within the sodium chloride addition range, the gold recovery rate was above 98%.

[0075] Table 4 Gold recovery rates at different sodium chloride concentrations

[0076] Case 2: Five closed-loop circulation experiments were conducted on the leaching solution under the following conditions. Leaching was carried out at a 2:1 liquid-to-solid ratio, requiring 50 kg of material and preparing 100 L of leaching solution (1 mol / L sulfuric acid, 200 mg / L sodium chloride). During leaching, the 100 L of leaching solution was evenly added to two leaching tanks, with 25 kg of waste probe mounting substrate added to each tank. The leaching solution temperature was controlled at 60°C, and aeration was carried out in the leaching tanks at a rate of 125 L / h. After leaching, the leaching solution was filtered and the leaching tanks were cleaned. The material in the filter bags was collected, refined, weighed, and the gold recovery rate was calculated. After the first cycle, sulfuric acid and sodium chloride were added to the tail liquid tank to form a new leaching solution, which was then pumped back to the leaching tank for the next cycle. As shown in Table 5, the gold recovery rate was above 98% in all five cycles, indicating good cycle stability of the device.

[0077] Table 5 Gold recovery rates in different leachate circulating solutions

[0078] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include: This device successfully solves the problems of long and polluting traditional processes by integrating microbubble enhancement, a low-toxicity reagent system, low-surface-tension ethanol cleaning, and closed-loop electrowinning technology. Experiments show that the device can achieve a gold recovery rate of over 98% for materials such as waste mobile phone boards and CPUs, and maintains high efficiency even after more than 5 cycles of leachate circulation, demonstrating significant economic and environmental benefits.

[0079] Those skilled in the art will understand that the steps, measures, and schemes in the various operations, methods, processes, and procedures discussed in this application can be alternated, modified, rearranged, decomposed, combined, or deleted.

[0080] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of the claims of this application.

Claims

1. A short-process gold extraction device for waste printed circuit boards, characterized in that, include: The separation module includes a leaching tank, a microbubble generator, and a heater. The aeration pipe of the microbubble generator is located at the bottom of the leaching tank, and the heater is located inside the leaching tank. Leaching solution and cleaning solution are alternately introduced into the leaching tank. The collection module includes a filter and a temporary storage tank. The input end of the filter is connected to the output end of the leaching tank via a pipeline, and the input end of the temporary storage tank is connected to the output end of the filter. The electrodeposition section includes an electrodeposition tank and a tailings tank. The input end of the electrodeposition tank is connected to the temporary storage tank via a pump, and the output end of the electrodeposition tank is connected to the tailings tank. The tailings tank is connected to the leaching tank via a return pipeline.

2. The short-process gold extraction device for waste printed circuit boards according to claim 1, characterized in that, The leaching tank is equipped with a horizontal partition, and the partition has multiple through holes evenly distributed on it. The aeration pipe of the microbubble generator is located below the partition.

3. The short-process gold extraction device for waste printed circuit boards according to claim 2, characterized in that, The upper surface of the partition is vertically provided with multiple support columns, all of which are of the same height and arranged in an array.

4. The short-process gold extraction device for waste printed circuit boards according to claim 1, characterized in that, The leaching tank is also equipped with a stirring motor, and the stirring paddle of the stirring motor extends into the leaching tank.

5. The short-process gold extraction device for waste printed circuit boards according to claim 1, characterized in that, The temporary storage tank is divided into an leaching solution storage chamber and a cleaning solution storage chamber by a partition. The output end of the filter can be selectively connected to the leachate storage chamber and the cleaning solution storage chamber respectively through a switching valve. The leachate storage chamber is connected to the electrodeposition tank through a pump, and the cleaning solution storage chamber is connected to the leachate tank through a circulation pump.

6. The short-process gold extraction device for waste printed circuit boards according to claim 5, characterized in that, The cleaning solution storage chamber contains an ethanol solution with a concentration of 50%-75%, the leachate includes 0.5-2 mol / L sulfuric acid and 100-500 mg / L sodium chloride, and the microbubble generated by the microbubble generator has a diameter in the range of 10-100 micrometers.

7. The short-process gold extraction device for waste printed circuit boards according to claim 1, characterized in that, The number of electrodeposition tanks is at least two, and the electrodeposition tanks are connected in parallel or in series. Each electrodeposition tank is provided with a cathode plate and an anode plate, and the cathode plate and the anode plate are electrically connected to a DC power supply.

8. The short-process gold extraction device for waste printed circuit boards according to claim 7, characterized in that, The cathode plate is made of stainless steel or titanium, and the anode plate is made of iridium-plated tantalum titanium mesh, lead dioxide titanium mesh, or graphite plate.

9. The short-process gold extraction device for waste printed circuit boards according to claim 1, characterized in that, The tail liquid tank is equipped with a dosing port and a stirring device.

10. The short-process gold extraction device for waste printed circuit boards according to claim 1, characterized in that, The number of leaching tanks is two, and the two leaching tanks are arranged in parallel and both are connected to the same filter.

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