Waste Circuit Board Resource Utilization System

Abstract

This utility model belongs to the technical field of electronic waste treatment, and specifically relates to a waste circuit board resource recovery system. The waste circuit board resource recovery system includes: a crushing unit for crushing waste circuit boards; a sorting unit using a first hydraulic shaking table to hydraulically separate the crushed circuit board fragments to obtain precious metals and sorting tailings; a tailings treatment unit for solid-liquid separation of the sorting tailings to obtain bottom sludge; and a bottom sludge treatment unit including a smoldering furnace and a second hydraulic shaking table. The smoldering furnace is used to smolder the collected bottom sludge to remove some organic matter and increase the content of precious metals in the bottom sludge; the second hydraulic shaking table is used to sort the smoldering bottom sludge to obtain precious metals and smoldering tailings. This utility model, through smoldering treatment of the bottom sludge, can significantly increase the content of precious metals in the bottom sludge, facilitating further separation of the precious metals from the bottom sludge.

Description

Technical Field

[0001] This utility model belongs to the technical field of electronic waste treatment, and specifically relates to a waste circuit board resource utilization system. Background Technology

[0002] As a type of electronic waste, discarded circuit boards have high recycling value. Circuit boards are rich in metallic elements such as gold, silver, and copper, which command high prices in the market.

[0003] In existing technologies, the disposal methods for waste circuit boards mainly include two major modes: pyrolysis and hydrolysis. Pyrolysis involves pyrolyzing or incinerating waste circuit boards at high temperatures to achieve waste reduction, harmlessness, and resource recovery. A typical application of pyrolysis is a pyrolysis device and method for the resource recovery of electronic waste disclosed in Chinese patent document CN118129155A. Hydrolysis is based on liquid assistance to recover metals. A hydrolysis process for waste circuit board crushing and water shaking separation disclosed in Chinese patent document CN114522795A is a hydrolysis process, including a pretreatment step, a crushing step, a water shaking separation step, and a semi-finished product collection step. The pretreatment step involves removing components from the waste circuit board, pressing multiple blind holes into the upper surface of the circuit board with a cutter, immersing the circuit board in a water tank containing suspended auxiliary crushing powder (the particle size of the auxiliary crushing powder is smaller than the diameter of the blind holes), removing the board, and then sending the waste circuit board to the crushing step for crushing. The crushed waste circuit board is then sent to a hydraulic shaking table to separate resin powder and metal powder.

[0004] In practice, when using a combination of "crushing equipment + hydraulic shaking table" for wastewater treatment, the wastewater needs to be recycled. Generally, flocculants and coagulants are added to the wastewater, and then solids are removed through vacuum filtration or a filter press, forming sediment. Typically, treating 1 ton of waste circuit boards produces approximately 10% sediment (40-45% moisture content). Industry consensus holds that sediment is only worthwhile for acquisition and purification when the gold content reaches 1g / ton and the silver content reaches 100g / ton. Only then can the sediment be sold as a valuable commodity. Otherwise, the sediment can only be treated as secondary hazardous waste generated during the hydraulic shaking table treatment process. Summary of the Invention

[0005] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a waste circuit board resource utilization system. Based on the process of "crushing device + hydraulic shaking table", the system further processes the bottom mud of the shaking table to realize the value of the bottom mud.

[0006] The solution of this utility model to the aforementioned technical problem is as follows:

[0007] Waste circuit board recycling system, including

[0008] The crushing unit is used to crush waste circuit boards.

[0009] The sorting unit uses a first hydraulic shaking table to hydraulically separate the broken circuit board fragments to obtain precious metals and sorting tailings.

[0010] The tailings processing unit performs solid-liquid separation on the sorted tailings to obtain bottom mud;

[0011] Also includes

[0012] The sediment treatment unit includes a smoldering furnace for smoldering the collected sediment to remove some of the organic matter and increase the content of precious metals in the sediment.

[0013] The inventive concept of this application lies in treating the sediment obtained from tailings processing using a smoldering technique, taking into account its high fiberglass content and high dry-basis calorific value. The high dry-basis calorific value facilitates heat self-sustaining during the smoldering process, effectively saving fuel consumption. Testing revealed that the dry-basis calorific value of the sediment is 3500~4000 kcal / kg (organic matter content 25~35%). Furthermore, the presence of fiberglass facilitates flue gas circulation during smoldering, and the moisture content in the material helps in effective temperature control during the smoldering process. After smoldering treatment, the precious metal content in the sediment is significantly improved, making it marketable as a valuable commodity or allowing for further sorting to obtain the precious metals.

[0014] As an improvement, the tailings treatment unit includes a first sedimentation tank and a first dewatering machine that are interconnected. The first sedimentation tank is connected to the sorting unit to receive the sorted tailings. After the sorted tailings enter the sedimentation tank, flocculants and coagulants are added to the sedimentation tank. Then, vacuum filtration or a filter press is used to filter out the solids in the water, forming bottom sludge.

[0015] As a further improvement, the tailings processing unit is equipped with a recycling pipeline connected to the sorting unit for recycling the liquid separated material obtained from solid-liquid separation, which can be recycled to the first hydraulic shaking table or the crushing unit.

[0016] As an improvement, the tailings processing unit includes a drum screen. After the tailings are screened by the drum screen, the undersize material enters the first sedimentation tank, and the oversize material is returned to the crushing unit.

[0017] As an improvement, the sediment treatment unit includes a second hydraulic shaking table for sorting the smoldering sediment to obtain precious metals and smoldering tailings.

[0018] As a further improvement, the sediment treatment unit includes a second sedimentation tank connected to a second hydraulic shaking table. The second sedimentation tank is used to receive smoldering tailings, which are then dewatered by a second dewatering machine to obtain waste material.

[0019] As a further improvement, a smoldering gas treatment unit is also included. The smoldering gas treatment unit includes a combustion chamber, a waste heat boiler, and a tail gas treatment device. The combustion chamber is connected to the smoldering furnace and is used to treat the waste gas generated by smoldering in a harmless manner. The high-temperature flue gas generated by combustion is used to heat the waste heat boiler, and the tail gas is discharged after passing through the tail gas treatment device.

[0020] As a further improvement, a heat exchanger is installed between the waste heat boiler and the exhaust gas treatment device to reduce the exhaust gas temperature and increase the temperature of the combustion air in the combustion chamber.

[0021] As an alternative, a smoldering gas treatment unit is also included. The smoldering gas treatment unit includes a combustion chamber, a drying furnace, and a tail gas treatment device. The combustion chamber is connected to the smoldering furnace and is used to treat the exhaust gas generated by smoldering in a harmless manner. The high-temperature flue gas generated by combustion is used to dry and dehydrate the waste material. The tail gas is discharged after passing through the tail gas treatment device.

[0022] As a further improvement, a heat exchanger is installed between the drying furnace and the exhaust gas treatment device to reduce the exhaust gas temperature and increase the temperature of the combustion air in the combustion chamber.

[0023] The beneficial effects of this utility model are:

[0024] By subjecting the sediment to smoldering treatment, the content of precious metals in the sediment was significantly increased. Practical applications have shown that the sediment volume reduction rate after smoldering treatment reaches 70%–75%, and the precious metal content in the sediment increases by 3–4 times. Furthermore, the combustible gases produced during smoldering can be burned for heat utilization. Attached Figure Description

[0025] Figure 1 This is a structural layout diagram of Embodiment 1 of the present utility model;

[0026] Figure 2 This is a structural layout diagram of Embodiment 2 of the present invention. Detailed Implementation Example 1

[0027] like Figure 1 As shown, the waste circuit board resource utilization system described in this application includes a crushing unit, a sorting unit, a tailings processing unit, a bottom sludge processing unit, and a smoldering gas processing unit.

[0028] The crushing unit is used to crush waste circuit boards. It employs a two-stage crushing method, first using a semi-wet hammer crusher for initial crushing, and then using a wet high-speed disc crusher for secondary crushing. Humidification during crushing is to prevent the material from overheating and igniting during the crushing process.

[0029] The sorting unit is the first hydraulic shaking table, which uses the density difference between water and materials to perform hydraulic separation of the broken circuit board fragments to obtain precious metals and sorting tailings.

[0030] The tailings processing unit is used to perform solid-liquid separation on the sorted tailings to obtain bottom sludge. The tailings processing unit includes a first sedimentation tank and a first dewatering machine connected to each other. The first sedimentation tank is connected to the sorting unit to receive the sorted tailings. A drum screen is installed above the first sedimentation tank. After the sorted tailings are screened by the drum screen, the undersize material enters the first sedimentation tank, while the oversize material is returned to a wet high-speed disc crusher for further crushing. A dosing system can be installed on one side of the first sedimentation tank for adding flocculants, coagulants, etc. The first dewatering machine uses a vacuum filter or filter press to perform solid-liquid separation on the sorted tailings in the first sedimentation tank. The filtered solid product forms the bottom sludge. The tailings processing unit is equipped with a reuse pipeline connected to the sorting unit for reusing the liquid separated material obtained from the solid-liquid separation. The liquid separated material can be reused to the first hydraulic shaking table and the crushing unit.

[0031] The sediment treatment unit includes a smoldering furnace, a second hydraulic shaking table, and a second sedimentation tank. The smoldering furnace is used to smolder the collected sediment to remove some organic matter and increase the content of precious metals in the sediment. The sediment obtained after filtration has a moisture content of 40-45% and can be directly subjected to smoldering treatment. The smoldering temperature is controlled at 800-850℃. After ignition, the organic components in the sediment burn, releasing heat. This heat dries the material and promotes ignition, allowing smoldering to continue. The second hydraulic shaking table is used to separate the smoldering sediment to obtain precious metals and smoldering tailings. The second sedimentation tank, connected to the second hydraulic shaking table, receives the smoldering tailings. The tailings are dewatered by a second dewatering machine to obtain waste. Obviously, the liquid separated by the second dewatering machine can also be reused.

[0032] The smoldering furnace is equipped with a smoldering gas treatment unit, which includes a condenser, a combustion chamber, a waste heat boiler, and a tail gas treatment device. The smoldering exhaust gas first enters the condenser for condensation, removing water vapor and reducing the volume of exhaust gas. Then, the combustion chamber treats the exhaust gas to render it harmless, maintaining a temperature of 1100°C for at least 2 seconds. The high-temperature flue gas generated from combustion is used to heat the waste heat boiler, and then exchanges heat with the air entering the combustion chamber through a heat exchanger. This process lowers the tail gas temperature while increasing the temperature of the combustion air in the combustion chamber, thus saving energy consumption. Finally, the tail gas is discharged after passing through the tail gas treatment device.

[0033] The contents of gold, silver, palladium, copper, and tin in the sediment and smoldering treated sediment (a mixture of precious metals and smoldering tailings) during a single treatment are listed in the table below:

[0034] Gold (g / t) Silver (g / t) Palladium (g / t) copper(%) tin(%) Bottom mud 0.92 57.24 0.11 0.44 0.16 Substrate after smoldering 3.17 152.57 0.44 1.41 0.45 Increase by percentage (%) 244.6 166.5 300 220.5 181.3 Example 2

[0035] like Figure 2 As shown, the difference between Example 2 and Example 1 is that the combustion gas treatment unit includes a condenser, a combustion chamber, a drying furnace, and a tail gas treatment device. The high-temperature flue gas generated by combustion is used to dry and dehydrate the waste material, and the tail gas is discharged after passing through the tail gas treatment device.

[0036] As an obvious variation, the high-temperature flue gas produced by combustion can be used to heat waste heat boilers and drying furnaces. In cold weather, it can also be used to heat sedimentation tanks to improve their flocculation effect.

Claims

1. Waste circuit board resource utilization system, including The crushing unit is used to crush waste circuit boards. The sorting unit uses a first hydraulic shaking table to hydraulically separate the broken circuit board fragments to obtain precious metals and sorting tailings. The tailings processing unit performs solid-liquid separation on the sorted tailings to obtain bottom mud; Its features are: Also includes The sediment treatment unit includes a smoldering furnace for smoldering the collected sediment to remove some of the organic matter and increase the content of precious metals in the sediment.

2. The waste circuit board resource utilization system as described in claim 1, characterized in that: The tailings processing unit includes a first sedimentation tank and a first dewatering machine that are interconnected. The first sedimentation tank is connected to the sorting unit to receive sorted tailings.

3. The waste circuit board resource utilization system as described in claim 1 or 2, characterized in that: The tailings processing unit is equipped with a reuse pipeline connected to the sorting unit for reusing the liquid separated material obtained from solid-liquid separation.

4. The waste circuit board resource utilization system as described in claim 2, characterized in that: The tailings processing unit includes a drum screen. After the tailings are separated by the drum screen, the undersize material enters the first sedimentation tank, and the oversize material is returned to the crushing unit.

5. The waste circuit board resource utilization system as described in claim 1, characterized in that: The sediment treatment unit includes a second hydraulic shaking table for sorting the smoldering sediment to obtain precious metals and smoldering tailings.

6. The waste circuit board resource utilization system as described in claim 5, characterized in that: The sediment treatment unit includes a second sedimentation tank connected to a second hydraulic shaking table. The second sedimentation tank is used to receive smoldering tailings, which are then dewatered by a second dewatering machine to obtain waste material.

7. The waste circuit board resource utilization system as described in claim 1, characterized in that: It also includes a smoldering gas treatment unit, which includes a combustion chamber, a waste heat boiler, and a tail gas treatment device. The combustion chamber is connected to the smoldering furnace and is used to treat the waste gas generated by smoldering in a harmless manner. The high-temperature flue gas generated by combustion is used to heat the waste heat boiler, and the tail gas is discharged after passing through the tail gas treatment device.

8. The waste circuit board resource utilization system as described in claim 7, characterized in that: A heat exchanger is installed between the waste heat boiler and the tail gas treatment device to reduce the tail gas temperature and increase the temperature of the combustion air in the combustion chamber.

9. The waste circuit board resource utilization system as described in claim 6, characterized in that: It also includes a smoldering gas treatment unit, which includes a combustion chamber, a drying furnace, and a tail gas treatment device. The combustion chamber is connected to the smoldering furnace and is used to treat the exhaust gas generated by smoldering in a harmless manner. The high-temperature flue gas generated by combustion is used to dry and dehydrate the waste material. The tail gas is discharged after passing through the tail gas treatment device.

10. The waste circuit board resource utilization system as described in claim 9, characterized in that: A heat exchanger is installed between the drying furnace and the exhaust gas treatment device to reduce the exhaust gas temperature and increase the temperature of the combustion air in the combustion chamber.

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