Graphene waste rare and precious metal dissolving reaction kettle device and dissolving method

Abstract

The invention discloses a graphene waste rare and precious metal dissolving reaction kettle device and a dissolving method. The graphene waste rare and precious metal dissolving reaction kettle device comprises a dissolving cavity, a feeding unit, a heating device, an ultrasonic generation device, a pH online monitoring sensor, a temperature online monitoring sensor, a flue gas online monitoring sensor, a discharging unit and a control unit. The inner wall of the dissolving cavity is coated with a graphene-containing anti-corrosion coating, the feeding port is provided with a feeding weight sensor and an adjusting valve, the first liquid inlet is provided with a first liquid inlet flow adjusting valve and a liquid inlet weight sensor, and the second liquid inlet is provided with a second liquid inlet flow adjusting valve and a flow sensor. The heating device and the ultrasonic generating device are suspended in a cavity or fixed on the top cover of the dissolving cavity according to requirements; the bottom double receiving disc guide rails are switched, and an air outlet is provided with a check valve; the control unit is connected with all the sensors and the execution piece, and feeding, temperature control, ultrasonic treatment, liquid drainage, cleaning and end point judgment are automatically completed. According to the invention, efficient dissolution of waste precious and rare metals is realized, automatic operation is realized, and labor intensity and cost are reduced.

Description

Technical Field

[0001] This invention belongs to the field of waste precious and rare metal dissolution and recycling technology, and in particular relates to a graphene waste precious and rare metal dissolution reactor device and dissolution method. Background Technology

[0002] The recycling of rare and precious metals not only aligns with national policies and needs but also serves as a crucial supplement and necessary means to ensure the secure supply of these materials. It is highly beneficial for providing long-term, stable, sustainable, and effective solutions for sourcing rare and precious metals. Furthermore, graphene possesses excellent thermal and electrical conductivity, as well as outstanding corrosion resistance.

[0003] Currently, existing technologies for dissolving waste precious and rare metals generally suffer from problems such as pollution, high labor intensity, low efficiency, strong corrosiveness, high energy consumption, and serious secondary pollution. These issues make it difficult to meet the requirements of green and sustainable development, convenient provision of personalized and transparent services, and scalability as production capacity increases. To address these problems, this device integrates an acid, alkali, and salt corrosion-resistant automatic control and ultrasonic generation system, effectively improving reaction uniformity and mass transfer rate, enhancing the catalytic effect of graphene and ultrasonic vibration in the metal dissolution process, and achieving intelligent, efficient, low-consumption, and environmentally friendly recycling of waste precious and rare metals. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a graphene waste rare and precious metal dissolution reactor device and dissolution method, aiming to achieve efficient and green dissolution of waste rare and precious metals, which is safe and environmentally friendly, scalable, and maximizes intelligent and automated operation, significantly reducing labor and costs.

[0005] To achieve the above objectives, the specific solution of the present invention is as follows:

[0006] A graphene waste rare and precious metal dissolution reactor device includes a dissolution chamber, a feeding unit, a heating device, an ultrasonic generator, an online pH monitoring sensor, an online temperature monitoring sensor, an online flue gas monitoring sensor, a discharge unit, and a control unit;

[0007] The feeding unit includes a feed inlet, a first liquid inlet, and a second liquid inlet. The feed inlet is equipped with a check valve, a feed regulating valve, and a feed weight sensor, and is located at the top of the dissolving chamber. The first liquid inlet is equipped with a first liquid flow regulating valve and a liquid weight sensor, and the second liquid inlet is equipped with a second liquid flow regulating valve and a flow sensor, and are respectively located at the top of the dissolving chamber.

[0008] The heating device is located inside the dissolving chamber, and the ultrasonic generator is installed on the top cover of the dissolving chamber.

[0009] The detection ends of both the pH online monitoring sensor and the temperature online monitoring sensor are immersed in the liquid within the dissolution chamber;

[0010] The discharge unit includes a liquid outlet with a regulating valve, a discharge outlet, a first receiving tray, a second receiving tray, and an air outlet with a check valve. The discharge outlet and the liquid outlet are both located at the bottom of the dissolving chamber. The first receiving tray and the second receiving tray are coaxially arranged below the discharge outlet. The first receiving tray and the second receiving tray are respectively equipped with receiving weight sensors. The first receiving tray and the second receiving tray can be alternately removed and replaced through guide rails or tray supports to continuously receive solid slag.

[0011] The flue gas online monitoring sensor is installed on the inner wall of the top cover plate of the dissolution chamber;

[0012] The control unit is connected to the feed regulating valve, feed weight sensor, liquid inlet regulating valve, flow regulating valve, liquid inlet weight sensor, heating device, ultrasonic generator, pH online monitoring sensor, temperature online monitoring sensor, and flue gas online monitoring sensor.

[0013] Furthermore, the dissolution chamber is made of stainless steel or titanium, and the surface of the dissolution chamber in contact with the reaction medium is coated with a graphene-containing anti-corrosion coating.

[0014] Furthermore, the heating device is a digitally adjustable heating tube, the ultrasonic generator is a probe-type ultrasonic processor, and the heating device is suspended on the wall of the dissolving chamber or installed on the top cover of the dissolving chamber.

[0015] Furthermore, the flue gas online monitoring sensor is installed on the inner wall of the top cover plate of the dissolution chamber.

[0016] Furthermore, the rear end of the liquid outlet is connected to the solution storage tank, and the rear end of the gas outlet is connected to the waste gas collection and treatment system.

[0017] A method for dissolving waste rare and precious metals using the aforementioned device includes the following steps:

[0018] Step 1: The scrap rare and precious metals are fed into the dissolving chamber through the feed inlet, and then the dissolving liquid is added through the first liquid inlet;

[0019] Step 2: Start the heating device, online temperature monitoring sensor, and ultrasonic generator. The control unit automatically adjusts the heating power of the heating device by comparing the set temperature with the actual temperature monitored by the online temperature monitoring sensor, so that the reaction temperature of the solution is stabilized within the target range. The pH online monitoring sensor monitors the acidity and alkalinity of the solution reaction online, and the flue gas online monitoring sensor monitors the flue gas concentration online. When the pH value detected by the pH online monitoring sensor is 4.5~7.0, and the concentration of the released flue gas is lower than the detection limit, a signal is sent to the control unit, which then shuts off the heating device and ultrasonic generator and opens the regulating valve at the outlet, allowing the metal solution to be discharged into the solution storage tank through the outlet.

[0020] Step 3: Inject tap water through the second inlet for spray cleaning, and discharge the cleaning solution into the dissolving solution storage tank through the outlet. After cleaning, open the outlet and the solid residue falls into the first receiving tray. When the control unit detects the set weight through the receiving weight sensor on the first receiving tray, it sends a switching signal. The guide rail moves the second receiving tray below the outlet to continue receiving, while the first receiving tray is pulled out.

[0021] Further, the dissolving solution in step 1 is concentrated nitric acid with a concentration of 69.0 wt%, aqua regia, or concentrated nitric acid with a concentration of 34.5 wt%.

[0022] Furthermore, the set temperature in step 2 is 60℃~150℃, and the constant output power of the ultrasonic generator is 1.0~5.0kW.

[0023] Advantages of the present invention

[0024] 1. The dissolution chamber of the graphene waste rare and precious metal dissolution reactor of the present invention is made of 316L stainless steel or titanium plate, with an outer layer coated with graphene anti-corrosion coating to meet the requirement of long service life. The heating device and ultrasonic generator can be movable and suspended in the chamber wall or fixed to the top cover of the dissolution chamber as needed. They can automatically extend into and out of the container and move freely around the container, or be embedded in the container wall or container base, thereby heating and ultrasonic coupling of the same chamber without the need for additional through holes, reducing sealing difficulties and leakage points, and greatly accelerating the dissolution reaction process.

[0025] 2. This invention allows the outlet to be connected to a waste gas collection system. When a small amount of concentrated nitric acid is added, and the online flue gas monitoring system shows that the release of NO and NO2 tends to be zero, heating and ultrasonication can be stopped, achieving precise control of the acid quantity. By connecting the outlet to the waste gas collection system, there is no liquid or gas leakage during the reaction and cleaning process. On-site pH, temperature, and flue gas data are displayed in real time, creating a user-friendly, intelligent, and safe operating environment.

[0026] 3. This invention can complete the entire process of feeding, heating, ultrasonication, discharging, and cleaning through the control unit, eliminating the need for manual operation of the reactor, thus reducing the labor intensity of workers and the risk of acid mist overflow and dispersion.

[0027] In summary, this invention achieves efficient, intelligent, low-acid-consumption, and low-emission dissolution of waste rare and precious metals through a dissolution chamber with a "316L + graphene coating" and a movable / embedded integrated heating-ultrasound structure. The entire process is sealed and leak-free, solving the problems of severe equipment corrosion, high acid consumption, flue gas leakage, high manual labor intensity, and safety issues in existing technologies. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the graphene waste rare and precious metal dissolution reactor device of the present invention.

[0029] Figure 2 for Figure 1 A schematic diagram of the front structure.

[0030] Figure 3 for Figure 1 A schematic diagram of the side structure.

[0031] Figure 4 for Figure 1 A top-view structural diagram.

[0032] In the picture:

[0033] 1. Dissolving chamber; 2. Feed inlet; 3. First liquid inlet; 4. Second liquid inlet; 5. Discharge outlet; 6. Gas outlet and connecting pipe; 7. Liquid outlet; 8. First receiving tray; 9. Second receiving tray; 10. Heating device interface; 11. Ultrasonic generator interface; 12. pH online monitoring sensor interface; 13. Temperature online monitoring sensor interface; 14. Flue gas online monitoring sensor interface. Detailed Implementation

[0034] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It should be noted that the specific embodiments are not intended to limit the scope of the present invention.

[0035] like Figures 1 to 4 As shown in the figure, this specific embodiment provides a graphene waste rare and precious metal dissolution reactor device, including a dissolution chamber 1, a feeding unit, a heating device 10, an ultrasonic generator 11, a pH online monitoring sensor 12, a temperature online monitoring sensor, a flue gas online monitoring sensor 14, a discharge unit, and a control unit.

[0036] The dissolution chamber 1 is made of stainless steel or titanium and is coated with a graphene-containing anti-corrosion coating on the surface in contact with the reaction medium. It is used to provide a dissolution reaction space for the reaction of waste precious and rare metals with the dissolving liquid to form a metal dissolution liquid, ensuring the long service life of the equipment and the purity of the metal dissolution liquid formed.

[0037] The feeding unit includes a feed inlet 2, a first liquid inlet 3, and a second liquid inlet 4. The feed inlet 2 is equipped with a check valve, a feed regulating valve, and a feed weight sensor. The feed regulating valve is a CHQV947Y-16RL-DN300 model from Shanghai Chuanhu Valve Co., Ltd., and the corresponding weight sensor is a TR20V-1KN model from Shenzhen Jingdu Yuzaki Electronics Co., Ltd. The check valve is a H41F-16CS model from Yixing Zeus Pump Industry Co., Ltd. The feed inlet 2 is located on the upper part of the wall of the dissolution chamber 1 and is mainly used to monitor and control the amount of waste rare and precious metals fed in. The first liquid inlet 3 and the second liquid inlet 4 are both located on the upper part of the wall of the dissolution chamber 1 and are used to inject the reaction liquid and tap water, respectively. The first liquid inlet 3 is equipped with a first liquid flow regulating valve and a liquid weight sensor, and the second liquid inlet 4 is equipped with a second liquid flow regulating valve and a flow sensor.

[0038] The first inlet flow regulating valve 3 and the first inlet flow regulating valve 4 are both CHZRSP-16TA-DN32 models from Shanghai Chuanhu Valve Co., Ltd.

[0039] The liquid inlet weight sensor selected is the TR20V-1KN model from Shenzhen Kyoto Yuzaki Electronics Co., Ltd.

[0040] The flow sensor selected is model FE20-AS32FMC1FA5NP / 2 / L3 from Kowell (China) Automation Co., Ltd.

[0041] The heating device 10 can be suspended from the wall of the dissolution chamber 1 or fixed to the top cover of the dissolution chamber 1 as needed; the ultrasonic generator 11 is fixed to the top cover of the dissolution chamber 1, and the heating device 10 is a digitally adjustable heating device. The ultrasonic generator 11 is a probe-type ultrasonic processor, whose vibrating head is sealed through the cover wall of the dissolution chamber 1 and extends below the liquid surface. Both the heating device and the ultrasonic generator 11 are used to accelerate metal dissolution.

[0042] The heating device 10 is a PFA18 polytetrafluoroethylene electric heater from Shenzhen Duzhibao Technology Co., Ltd., which can be directly suspended on the side of the reactor.

[0043] The ultrasonic generator 11 is the RT-T model from Shenzhen Fanying Ultrasonic Technology Co., Ltd. The operating rod passes through the wall of the dissolution chamber cover through a fluororubber O-ring seal, and the vibrating head is submerged 5~30 mm below the liquid surface.

[0044] The detection ends of both the pH and temperature online monitoring sensors are immersed in the liquid within the dissolution chamber. The temperature online monitoring sensor, model ERTGF from Jiangsu Wande Instrument Co., Ltd., is used to monitor the temperature of the dissolution solution. The pH online monitoring sensor 12, model SUP-PH5022-5MLCYJ from Hangzhou LianCe Automation Technology Co., Ltd., is used to monitor the acidity or alkalinity of the dissolution solution. The sensor rod is sealed and fixed to the upper side wall of the dissolution chamber 1 and submerged below the liquid surface. The signal line is led to the control unit through a polytetrafluoroethylene (PTFE) tube.

[0045] The discharge unit includes a liquid outlet 7, a discharge outlet 5, a first receiving tray, a second receiving tray, and an air outlet 6 with a check valve. The liquid outlet 7 is a CHZRSP-16TA-DN50 model from Shanghai Chuanhu Valve Co., Ltd., located on the circular discharge outlet at the bottom of the dissolving chamber 1, for adjusting and controlling the liquid outlet valve. The discharge outlet 5 is a CHQV947Y-16RL-DN300 model from Shanghai Chuanhu Valve Co., Ltd., located at the bottom of the dissolving chamber, for adjusting and controlling the discharge valve.

[0046] A detachable first and second receiving tray are coaxially arranged below the discharge port 5. The first and second receiving trays are respectively equipped with receiving weight sensors. The receiving weight sensors are TR20V-1KN models from Shenzhen Kyoto Yuzaki Electronics Co., Ltd. The first and second receiving trays can be alternately removed via guide rails or tray supports to continuously receive solid slag. The flue gas online monitoring sensor is installed on the inner wall of the top cover plate of the dissolution chamber. The flue gas online monitoring sensor is SUP-PH5022-5MLCYJ model from Beijing Xuedilong Technology Co., Ltd. The check valves for the inlet and outlet are H41F-16CS models from Yixing Zeus Pump Industry Co., Ltd., and are installed on the inlet pipe and outlet pipe respectively. The outlet 6 is connected to the waste gas treatment system and is located on the upper side of the dissolution chamber.

[0047] The feed inlet 2 and the outlet 6 for unidirectional discharge of NO and NO2 waste gases prevent backflow of waste gases and ensure that the waste gases enter the waste gas collection and treatment system and are discharged in compliance with standards.

[0048] The control unit is connected to the feed regulating valve, feed weight sensor, liquid inlet regulating valve, receiving weight sensor, flow regulating valve, liquid inlet weight sensor, heating device 10, ultrasonic generator 11, pH online monitoring sensor 12, temperature online monitoring sensor and flue gas online monitoring sensor 14 respectively.

[0049] The control unit is connected to the feed regulating valve to automatically feed materials according to the set weight, avoiding overfeeding that could lead to overflow or violent reaction.

[0050] The control unit is connected to the flow regulating valve and the inlet weight sensor of the first inlet 3 for quantitative injection of the dissolving solution; the closed-loop regulating valve opening is used to keep the pH online monitoring sensor 12 reading between the set upper and lower limits to prevent excessive acid.

[0051] The control unit is connected to the flow regulating valve and flow meter of the second liquid inlet 4 for automatic spray cleaning according to the set volume. The flow meter accumulates the water volume to ensure that the residual silver ions are completely recovered.

[0052] The control unit is connected to the heating device 10 for closed-loop regulation based on online temperature monitoring sensor feedback, maintaining the rapid dissolution reaction temperature range, accelerating the metal dissolution reaction, and shortening the reaction cycle.

[0053] The control unit is connected to the ultrasonic generator 11 to control the cavitation effect to crush the surface passivation layer, improve the dissolution rate of rare and precious metals, and reduce the reaction temperature requirement.

[0054] The control unit is connected to the pH online monitoring sensor 12 for real-time pH feedback. Based on this feedback, the control unit increases or decreases the acid flow rate at the first inlet 3 to ensure timely and accurate endpoint control and avoid excessive acid usage.

[0055] The control unit is connected to an online temperature monitoring sensor to monitor the liquid temperature in real time, maintain the optimal reaction temperature, accelerate the reaction between silver and nitric acid, and ensure the reaction proceeds efficiently.

[0056] The control unit is connected to the flue gas online monitoring sensor 14 and the pH online monitoring sensor 12 to monitor the acidity / alkalinity of the solution and the concentration of flue gas online, respectively. When the pH value detected by the pH online monitoring sensor is 4.5~7.0 and the concentration of released flue gas is lower than the detection limit, a signal is sent to the control unit, which then shuts down the heating device and the ultrasonic generator. The reaction endpoint is determined, and a signal is sent to the control unit, which then controls the automatic shutdown of the heating device 10 and the ultrasonic generator 11.

[0057] Working principle:

[0058] Upon activating the aforementioned device, the control unit first weighs a set amount of waste rare and precious metals using a feed weight sensor, then opens the feed regulating valve to add the raw material into the dissolution chamber 1. Subsequently, the flow regulating valve of the first inlet 3 is opened according to the set flow rate to inject the dissolving liquid. The feed weight sensor measures the liquid in real time, and the pH online monitoring sensor 12 sends the acidity signal back to the control unit. The closed-loop fine-tuning valve opening is then used to maintain the pH value within the set range of 4.5 to 7.0, preventing excessive acidity. Simultaneously, the heating device 10 is heated in a controlled manner, and the online temperature monitoring sensor provides feedback on the liquid temperature. The control unit stabilizes the temperature within the dissolution chamber 1 within the rapid dissolution reaction temperature range, accelerating the rare and precious metal dissolution reaction. The ultrasonic generator 11 operates at the set output power, with the vibrating head generating vibration and cavitation 10-30 mm below the liquid surface, shattering the passivation layer on the metal surface and accelerating the dissolution rate, thereby improving the dissolution efficiency of the rare and precious metals and lowering the required temperature. The flue gas generated by the reaction can only enter the waste gas collection system in one direction through the outlet 6 with a check valve on the upper side wall of the dissolution chamber 1, avoiding backflow of waste gas. The flue gas online monitoring sensor 14 sends the flue gas concentration and the pH value monitoring sensor 12 send the monitoring results to the control unit in real time. When the pH value of the dissolved solution is detected by the pH online monitoring sensor to be 4.5~7.0, and the flue gas concentration is lower than the detection limit (5.0~50.0 ppm), the reaction is determined to be over, and the control unit immediately shuts off the heating device 10 and the ultrasonic generator 11. After the reaction is completed, the liquid outlet 7 is opened to discharge the dissolved solution into the storage tank; then the second liquid inlet 4 is opened for spray cleaning, and the flow meter of the second liquid inlet 4 accumulates the water volume to ensure that residual silver ions are completely removed. After the cleaning fluid is drained, the bottom outlet 5 opens, and the solid residue falls into the first receiving tray. The weight sensor on the first receiving tray weighs the material in real time. Once the tray is full, the guide rail quickly switches to the second receiving tray for continuous feeding. Throughout the process, all weight, flow rate, pH, temperature, and flue gas signals are sent back to the control unit, forming a closed loop to ensure the equipment is corrosion-resistant, the metals are pure, the exhaust gas meets standards, and the operation is fully automated. The entire reaction process requires no manual operation, intelligently and precisely controlling the amount of acid and alkali used, with no pollution or toxic gas or liquid leakage. This greatly reduces the labor intensity of workers, improves the comfort and safety of the environment and operators, and is beneficial to the physical and mental health of operators, while ensuring the complete leaching of precious and rare metals.

[0059] Examples 1 to 3 all employ the above-described apparatus to dissolve waste rare and precious metals, as detailed below:

[0060] Example 1:

[0061] Materials: 5.0 kg of scrap silver, 8.46 kg of concentrated nitric acid (69.0 wt%), and municipal tap water.

[0062] Step 1: 5 kg of waste rare and precious metal silver is put into the dissolving chamber through the feed inlet, and then 69.0 wt% concentrated nitric acid is added as the dissolving solution through the first liquid inlet;

[0063] Step 2: Start the heating device, online temperature monitoring sensor, and ultrasonic generator. The control unit adjusts the power of the heating device according to the set temperature of 60℃. The constant output power of the ultrasonic generator 11 is 3.0kW. The concentration of NO and NO2 in the flue gas is monitored by the flue gas online monitoring sensor. During the acid addition process, the control unit reads the values ​​monitored by the pH online monitoring sensor and the flue gas online monitoring sensor in real time. When the pH online monitoring sensor detects that the pH value of the solution is 4.5 and the concentration of NO and NO2 in the flue gas is lower than the detection limit of 50.0ppm, a signal is sent to the control unit. The control unit automatically closes the flow regulating valve of the heating device 10, the ultrasonic generator 11, and the first liquid inlet, and opens the regulating valve of the liquid outlet. The solution is discharged into the storage tank.

[0064] Step 3: Inject tap water through the second inlet for spray cleaning, and discharge the cleaning solution into the storage tank through the outlet. After cleaning, open the outlet and the solid residue falls into the first receiving tray. When the control unit detects the set weight through the receiving weight sensor on the first receiving tray, it sends a switching signal. The guide rail moves the second receiving tray below the outlet to continue receiving, while the first receiving tray is pulled out.

[0065] Silver leaching rate ≥99.99%; no NO or NO2 leakage throughout the entire process.

[0066] Example 2:

[0067] Materials: 1.0kg of scrap gold, 6.25kg of aqua regia, and municipal tap water.

[0068] Step 1: 1.0 kg of waste rare and precious metal gold is put into the dissolving chamber through the feed inlet, and then aqua regia is added as the dissolving solution through the first liquid inlet;

[0069] Step 2: Start the heating device, online temperature monitoring sensor, and ultrasonic generator. The control unit adjusts the power of the heating device according to the set temperature of 120℃. The constant output power of the ultrasonic generator 11 is 3.0kW. The concentration of Cl2 and NO2 in the flue gas is monitored by the flue gas online monitoring sensor. During the acid addition process, the control unit reads the values ​​monitored by the pH online monitoring sensor and the flue gas online monitoring sensor in real time. When the pH online monitoring sensor detects that the pH value of the solution is 5.0, and the concentration of Cl2 and NO2 monitored by the flue gas online monitoring sensor is lower than the detection limit of 30.0ppm, a signal is sent to the control unit. The control unit automatically closes the flow regulating valve of the heating device 10, the ultrasonic generator 11, and the first liquid inlet, and opens the regulating valve of the liquid outlet. The solution is discharged into the storage tank.

[0070] Step 3: Inject tap water through the second inlet for spray cleaning, and discharge the cleaning solution into the storage tank through the outlet. After cleaning, open the outlet and the solid residue falls into the first receiving tray. When the control unit detects the set weight through the receiving weight sensor on the first receiving tray, it sends a switching signal. The guide rail moves the second receiving tray below the outlet to continue receiving, while the first receiving tray is pulled out.

[0071] Gold leaching rate ≥99.99%; no Cl2 or NO2 leakage throughout the entire process.

[0072] Example 3:

[0073] Materials: 10.0 kg of scrap crude silver (silver content 95%), 17.00 kg of concentrated nitric acid (34.5 wt%), and municipal tap water.

[0074] Step 1: 10.0 kg of waste rare and precious metal silver is put into the dissolving chamber through the feed inlet, and then 34.5 wt% concentrated nitric acid is added as the dissolving solution through the first liquid inlet;

[0075] Step 2: Start the heating device, online temperature monitoring sensor, and ultrasonic generator. The control unit adjusts the power of the heating device according to the set temperature of 90℃. The constant output power of the ultrasonic generator 11 is 1.0kW. The concentration of NO and NO2 in the flue gas is monitored by the flue gas online monitoring sensor. During the acid addition process in Step 2, the control unit reads the values ​​monitored by the pH online monitoring sensor and the flue gas online monitoring sensor in real time. When the pH online monitoring sensor detects that the pH value of the solution is 6.0 and the concentration of NO and NO2 monitored by the flue gas online monitoring sensor is lower than the detection limit of 5.0ppm, a signal is sent to the control unit. The control unit automatically closes the flow regulating valve of the heating device 10, the ultrasonic generator 11, and the first liquid inlet, and opens the regulating valve of the liquid outlet. The solution is discharged into the storage tank.

[0076] Step 3: Inject tap water through the second inlet for spray cleaning, and discharge the cleaning solution into the storage tank through the outlet. After cleaning, open the outlet and the solid residue falls into the first receiving tray. When the control unit detects the set weight through the receiving weight sensor on the first receiving tray, it sends a switching signal. The guide rail moves the second receiving tray below the outlet to continue receiving, while the first receiving tray is pulled out.

[0077] Silver leaching rate ≥99.99%; no NO or NO2 leakage throughout the entire process.

[0078] The method of this invention is not limited to the above-mentioned numerical ranges, rare and precious metal types, and acid / base types. To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described in detail with reference to embodiments. The specific embodiments described are merely illustrative of the invention and are not intended to limit it; they are also applicable to the dissolution of other metals. This invention may have many other embodiments. Without departing from the spirit and essence of this invention, those skilled in the art can make various corresponding changes based on this invention, but these corresponding changes should all fall within the protection scope of the appended claims.

Claims

1. A graphene waste precious metal dissolving reactor device, characterized in that, The device comprises a dissolving cavity, a feeding unit, a heating device, an ultrasonic generating device, a pH online monitoring sensor, a temperature online monitoring sensor, a flue gas online monitoring sensor, a discharging unit and a control unit. The feeding unit comprises a feeding port, a first liquid inlet and a second liquid inlet. The heating device is arranged in the dissolving cavity, and the ultrasonic generating device is mounted on the top cover of the dissolving cavity. The detection ends of the pH online monitoring sensor and the temperature online monitoring sensor are immersed in the liquid in the dissolving cavity. The discharging unit comprises a liquid outlet with a regulating valve, a discharging port, a first receiving disc, a second receiving disc and a gas outlet with a check valve. The flue gas online monitoring sensor is mounted on the inner wall of the top cover of the dissolving cavity. The control unit is connected with the feeding regulating valve, the feeding weight sensor, the liquid inlet regulating valve, the flow regulating valve, the liquid inlet weight sensor, the heating device, the ultrasonic generating device, the pH online monitoring sensor, the temperature online monitoring sensor and the flue gas online monitoring sensor.

2. The apparatus of claim 1, wherein, The dissolving cavity is made of stainless steel or titanium, and a graphene-containing anticorrosive coating is coated on the surface of the dissolving cavity in contact with the reaction medium.

3. The apparatus of claim 1, wherein, The heating device is a digital regulating type heating pipe, and the ultrasonic generating device is a probe type ultrasonic processor.

4. The apparatus of claim 1, wherein, The flue gas online monitoring sensor is mounted on the inner wall of the top cover of the dissolving cavity.

5. The apparatus of claim 1, wherein, The rear end of the liquid outlet is connected with a dissolving liquid storage tank, and the rear end of the gas outlet is connected with a waste gas collection and treatment system.

6. A method for dissolving waste precious metals using the device according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: Step 1: feeding the waste and old precious metals into the dissolving cavity through the feeding port, and then adding a dissolving liquid through the first liquid inlet; Step 2: starting the heating device, the temperature online monitoring sensor and the ultrasonic generating device, and automatically adjusting the heating power of the heating device by the control unit based on the comparison between the set temperature and the measured temperature monitored by the temperature online monitoring sensor, so that the reaction temperature of the dissolving liquid is stabilized in the target range, the pH online monitoring sensor monitors the pH of the solution reaction online, the flue gas online monitoring sensor monitors the flue gas concentration online, when the pH value of the dissolving liquid monitored by the pH online monitoring sensor is 4.5-7.0 and the released flue gas concentration is lower than the lower limit of detection, a signal is sent to the control unit, the heating device and the ultrasonic generating device are turned off by the control unit, and the regulating valve of the liquid outlet is opened, so that the metal dissolving liquid is discharged into the dissolving liquid storage tank through the liquid outlet; Step 3, tap water is injected through the second liquid inlet to spray and clean, the cleaning liquid is discharged to the dissolving liquid storage tank through the liquid outlet; after the cleaning is completed, the discharge outlet is opened, the solid slag falls into the first receiving tray, and when the set weight is monitored by the receiving weight sensor arranged on the first receiving tray, the control unit sends a switching signal, the guide rail moves the second receiving tray to the position below the discharge outlet to continue receiving, and at the same time, the first receiving tray is extracted.

7. The method of claim 6, wherein, The dissolving liquid in step 1 is concentrated nitric acid with a concentration of 69.0 wt%, aqua regia or concentrated nitric acid with a concentration of 34.5 wt%.

8. The method of claim 6, wherein, In step 2, the set temperature is 60℃-150℃, the constant output power of the ultrasonic generating device is 1.0-5.0kW, and the detection lower limit is 5.0-50.0ppm.

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