A method for recycling all resources of waste electronic cigarettes

Abstract

The application discloses a kind of waste electronic cigarette full resource recycling methods, the method is after the plastic shell of waste electronic cigarette is removed by cold grinding stripping treatment, carries out self-reduction pyrolysis, and pyrolysis product is separated out including low Co compound and Li2CO3 in powder and including copper foil, aluminum foil, wire and sensor element in component by physical screening.The method utilizes the low-temperature resistance difference of waste electronic cigarette organic shell component, and using cold stripping method can selectively recover plastic, and remaining mouthpiece, bottom cap and lithium cobalt oxide battery are co-pyrolyzed, and phenolic substances generated by PC material thermal cracking are used to realize the self-reduction of LiCoO2 to low Co compound and Li2CO3, and Co / Li can be separated by water immersion.Compared with traditional process, the method has the advantages of simple operation, large processing capacity, high safety, etc., and is used for waste electronic cigarette full resource recycling.

Description

Technical Field

[0001] This invention relates to a waste e-cigarette, and more particularly to a method for the resource-based recycling of all components of a waste e-cigarette, belonging to the field of electronic waste resource recycling technology. Background Technology

[0002] Used e-cigarettes contain a large amount of lithium batteries and organic plastic casings used in 3C products. If not properly disposed of, they will not only pose potential hazards to groundwater, soil, and humans, but also waste key / energy metal resources (such as cobalt, lithium, and nickel). Currently, global e-cigarette recycling is in its early stages, lacking a large-scale closed-loop recycling process, and mainly focuses on collecting used e-cigarettes (and cartridges) from consumers. For example, Japan's JTI has launched a return program for used e-cigarettes through recycling bins in its stores, and the UK's Imperial Brands has launched a recycling program for used e-cigarette devices and cartridges.

[0003] The difficulties in recycling e-cigarettes mainly include three parts: the packaging of organic components (plastics) usually requires a lot of costly manual disassembly to obtain the battery components; the added value of organic component recycling is low and the disposal is difficult; the obtained waste battery components still need to be processed by complex lithium battery recycling processes, such as further crushing and disassembling of lithium batteries, stripping of positive and negative electrode powder, hydrometallurgy of valuable metals, and extraction and separation of target metals. Summary of the Invention

[0004] To address the technical challenges in the recycling of waste e-cigarettes in existing technologies, the present invention aims to provide a method for the complete resource recovery of waste e-cigarettes. This method combines selective freeze-stripping, whole-body self-reducing catalytic pyrolysis, and physical separation processes to achieve the complete resource recovery of components such as ABS, nylon 6, wires, components, aluminum foil, cobalt powder, and lithium carbonate from waste e-cigarettes. It is simple to operate, highly safe, and has a large processing capacity, which is conducive to industrial production.

[0005] To achieve the above-mentioned technical objectives, the present invention provides a method for the complete recycling of waste e-cigarettes. The method involves removing the plastic shell of the waste e-cigarettes through freeze-grinding, followed by self-reducing pyrolysis. The pyrolysis products are then physically sieved to separate powders including low-valent Co compounds and Li2CO3, as well as components including copper foil, aluminum foil, wires, and sensor elements.

[0006] The present invention provides a method for the complete recycling of waste e-cigarettes. First, a cryogenic abrasion process is employed, utilizing the brittle nature of the plastic shell (styrene-butadiene-acrylonitrile copolymer) and the e-liquid cotton (nylon 6) at low temperatures to selectively break them down for separation and recycling. The remaining mouthpiece and bottom cap (polycarbonate), lithium cobalt oxide battery, sensors, etc., are almost undamaged and undergo self-reducing pyrolysis. During pyrolysis, the mouthpiece and bottom cap play a crucial role, generating a large amount of reducing substances (such as phenolic compounds). These substances reduce LiCoO2 in the lithium cobalt oxide battery of the e-cigarette to low-valence Co compounds and Li2CO3. This method utilizes the e-cigarette's own organic components to reduce LiCoO2 and regulate the Li / Co phase, while simultaneously processing the lower-value mouthpiece and bottom cap, achieving a "two birds with one stone" effect. Finally, physical sieving separates the electrode powder from the metal materials, thus allowing the separation and recycling of higher-value plastics and valuable metals from the waste e-cigarettes.

[0007] As a preferred embodiment, the cryo-peeling conditions are: a temperature of -45℃ to -55℃ and a time of 30 to 60 minutes. By setting the preferred cryo-peeling conditions, selective peeling of the electronic cigarette casing can be achieved. The specific structure of the electronic cigarette is shown in the attached figure. Figure 1 The external structure of an electronic cigarette includes a mouthpiece, a bottom cap, and a cigarette holder; the internal components mainly consist of the cigarette chamber (or cartridge), a lithium battery (primarily a 13450 LiCoO2 battery used in 3C products, with a voltage of 3.70V), sensors, wires, and a heating wire. The mouthpiece and bottom cap are primarily made of polycarbonate (PC), with an operating temperature range of -60℃ to 130℃; the plastic shell is primarily made of styrene-butadiene-acrylonitrile copolymer (ABS), a common engineering plastic, with an operating temperature range of -40℃ to 100℃; and the e-liquid cotton in the cigarette chamber is primarily made of nylon 6 (polyamide 6), with an operating temperature range of -20℃ to 80℃. A temperature range of -45℃ to -55℃ exceeds the minimum operating temperature of the ABS plastic shell and nylon 6, causing them to become brittle, but does not reach the operating limit of the PC material. Selective crushing of the plastic shell and cigarette chamber can be achieved through appropriate extrusion, hammering, or other methods.

[0008] As a preferred embodiment, the cryogenic abrasion is achieved through a cryogenic stripping device; the cryogenic stripping device includes a crushing chamber; the crushing chamber has a smaller diameter at the top and bottom ends and a larger diameter in the middle; two parallel cylindrical crushing rollers are provided in the center of the largest cross-section inside the crushing chamber, the crushing rollers are fixed to the inner wall of the crushing chamber by a telescopic device, and the surface of the crushing rollers is uniformly provided with multiple protrusions; the top of the crushing chamber is a feed inlet, and a liquid nitrogen inlet is provided below the feed inlet; the bottom of the crushing chamber is a discharge outlet, and a vibrating screen is provided below the discharge outlet.

[0009] As a preferred embodiment, the raised structure on the surface of the crushing roller is a prismatic structure, which is arranged parallel to the axis of the crushing roller. The prismatic protrusions on the surface of the crushing roller produce a splitting effect when they come into contact with the electronic cigarette casing.

[0010] As a preferred embodiment, the raised structures on the surfaces of the two parallel cylindrical crushing rollers are staggered.

[0011] As a preferred embodiment, the liquid nitrogen inlet is connected to a temperature detection and control system. This system allows for real-time monitoring of the temperature within the crushing chamber, enabling adjustments to the liquid nitrogen input and ensuring the temperature inside the crushing tank remains within the required range.

[0012] As a preferred embodiment, the feed end of the vibrating screen is connected to one side of the discharge port of the crushing chamber and is inclined to the other side of the discharge port of the crushing chamber. The discharge end of the vibrating screen is connected to the coarse material conveyor belt, and a fine material conveyor belt is provided directly below the vibrating screen.

[0013] As a preferred embodiment, the retractable device includes a spring or hydraulic cylinder and a fixed bracket. One end of the fixed bracket is fixedly connected to the spring or hydraulic cylinder, and the other end is connected to both ends of the shaft of the crushing roller. A drive is provided at the connection between the fixed bracket and the shaft of the crushing roller to control the rolling of the crushing roller. The drive is commonly a small motor. The drive causes the two crushing rollers to rotate in opposite directions. During operation, the crushing rollers reciprocate and compress under the control of the retractable device (e.g., spring or hydraulic cylinder), and the minimum distance between the two crushing rollers is the diameter of the lithium battery inside the e-cigarette, and the maximum distance is 1-3 mm greater than the diameter of the lithium battery used in the e-cigarette. The surface of the crushing rollers has a raised structure, which can achieve a certain splitting effect on the outer shell of the crushed material. The distance between the crushing rollers during the compression process is set to be slightly greater than the diameter of a 13450 or 13400 cylindrical lithium battery to ensure that the outer shell is crushed without damaging the battery cell. The overall damage to components such as the lithium battery, mouthpiece, and bottom cap is small, and they are preserved relatively intact, achieving safe and efficient dismantling of waste e-cigarettes. Currently, the battery models in electronic cigarettes are 13450 or 13400, with a diameter of 13mm and a length of 40 or 45mm. The minimum and maximum distances between the crushing rollers can be adjusted according to actual needs.

[0014] As a preferred embodiment, the self-reducing pyrolysis conditions are: temperature 700–850℃, time 4–6 hours. The bottom cap of an e-cigarette is typically connected to the battery by wires and a pressure (air pressure) sensor. After freezing and crushing, manual sorting is still required. To reduce labor costs, it is considered to perform synergistic pyrolysis of both components. Traditional reductive pyrolysis (or roasting) is carbothermic reduction, using carbon monoxide or carbon powder to reduce and roast or pyrolyze lithium batteries. The main reducing agent is carbon monoxide. This invention cleverly utilizes phenolic substances generated by the thermal decomposition of the PC material components of waste e-cigarettes as a reducing agent (organic phenolic substances are commonly used in selective metal reduction leaching processes) to reduce LiCoO2 in the lithium battery of the e-cigarette to low-valence Co compounds and Li2CO3. This achieves two goals at once: simultaneously reducing LiCoO2 and regulating the Li / Co phase using the organic components of the e-cigarette, while also treating the low-value-added mouthpiece and bottom cap. Under the preferred temperature conditions, LiCoO2 can be reduced and Li / Co phase regulation can be achieved. The temperature range for the overall self-reducing pyrolysis of waste e-cigarettes is 700-850℃. If the temperature is too low, the pyrolysis is not sufficient and less reducing phenolic substances are released, resulting in poor reduction effect. If the temperature is too high, it will easily lead to high energy consumption and waste.

[0015] As a preferred embodiment, the physical sieving uses a sieve size of 0.10–0.15 mm. Controlling the sieve size facilitates the precise separation of powders, including low-valence Co compounds and Li₂CO₃.

[0016] As a preferred embodiment, the powder is used for lithium recovery through water leaching, and the leaching residue is cobalt-enriched residue.

[0017] This invention uses liquid nitrogen for cooling. On the one hand, liquid nitrogen can provide a low-temperature environment, which is beneficial to the embrittlement of plastics. On the other hand, after liquid nitrogen sublimates into nitrogen gas, it can provide an inert atmosphere for the peeling of the outer shell, thus preventing the battery from igniting or exploding during the peeling process.

[0018] Compared with the prior art, the beneficial technical effects of this invention are as follows:

[0019] 1. It avoids the traditional manual disassembly method of electronic cigarettes. Based on the difference in the low temperature resistance limit of electronic cigarette components, it selectively freezes and peels off the ABS plastic shell to expose the battery. The liquid nitrogen used for freezing and breaking can protect the battery.

[0020] 2. This invention involves the overall pyrolysis and self-reduction of electronic cigarette components (PC material components such as mouthpieces and bottom caps, and batteries) after the plastic has been stripped and recycled. Specifically, it utilizes the reducing properties of phenolic substances produced by the pyrolysis of PC to convert the LiCoO2 cathode in 13450 into low-valence Co compounds and Li2CO3. Co / Li can then be selectively separated by water leaching. This avoids the need for additional reducing agents such as carbon powder or carbon monoxide in traditional reduction roasting, and achieves self-reduction of the lithium battery cathode material using the pyrolysis products of the mouthpiece and cap's own organic matter.

[0021] 3. This invention achieves synergistic recycling of PC components in electronic cigarettes, which have low added value and are difficult to recycle, by co-pyrolyzing them with lithium batteries.

[0022] 4. Compared with general processes (manual disassembly of plastic casing—discharge of battery salt solution—detachment of positive and negative electrode powder—acidic leaching of target metal—extraction separation, etc.), the present invention (selective freeze-peeling—overall pyrolysis self-reduction—physical sorting—water immersion) has obvious advantages of simple operation, high safety and large processing capacity.

[0023] 5. This invention uses a cryogenic stripping device to selectively strip and recycle plastics from waste e-cigarettes. The overall damage to components such as battery cells, lithium batteries, mouthpieces, and bottom caps is minimal, and they are preserved relatively intact, achieving safe and efficient dismantling of waste e-cigarettes. Attached Figure Description

[0024] Figure 1 This is a disassembly diagram of the structure of a waste electronic cigarette according to the present invention.

[0025] Figure 2 This is a process flow diagram of the present invention.

[0026] Figure 3 This is a schematic diagram of the cryogenic stripping device.

[0027] Figure 4 This is a top view of the crushing rollers in the cryogenic stripping device.

[0028] Figure 5 This is a cross-sectional view of the crushing roller of the cryogenic stripping device.

[0029] Among them, 1 is the feed inlet, 2 is the temperature detection and control system, 3 is the crushing roller, 4 is the vibrating screen, 5 is the fine material conveyor belt, 6 is the coarse material conveyor belt, 7 is the crushing chamber, 8 is the liquid nitrogen inlet, 9 is the fixed support, 10 is the spring or hydraulic cylinder, and 11 is the protruding structure. Detailed Implementation

[0030] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0031] The cryogenic peeling device provided by this invention is specifically as follows: Figures 1-3As shown, its main structure includes a crushing chamber 7. The crushing chamber 7 has a small diameter at both the top and bottom ends and a large diameter in the middle. That is, the diameter of the feed inlet at the top and the discharge outlet at the bottom is small, while the diameter of the grinding zone in the middle is large. The advantages of this crushing chamber structure design are: the upper part is narrow, so that the material will not hit the temperature sensor during feeding, thus ensuring accurate temperature control in the chamber; the middle part is coarse, so as to make full use of the space of the crushing rollers to selectively peel off the waste e-cigarettes, avoiding "bloating" and improving the processing capacity; the lower part is narrow, so that the crushed material can be concentrated on the vibrating screen, which is conducive to subsequent separation. The largest cross-section of the crushing chamber is provided with two parallel cylindrical crushing rollers 3. The crushing rollers are fixed to the inner wall of the crushing chamber by a telescopic device, which includes a spring 10 (or a hydraulic cylinder can be used instead) and a fixed bracket 9. One end of the fixed bracket is fixedly connected to the spring, and the other end is connected to both ends of the shaft of the crushing roller. A small motor is provided at the connection between the fixed bracket and the shaft of the crushing roller to drive the two crushing rollers to rotate in opposite directions. The surface of the crushing roller is uniformly provided with multiple raised structures 11. These raised structures are prismatic and are parallel to the roller's axis. The staggered arrangement of the raised structures on the surfaces of two parallel cylindrical crushing rollers facilitates better action on the waste e-cigarettes and prevents battery damage. During operation, the crushing rollers reciprocate under spring control, with the minimum distance between the two rollers being the diameter of the lithium battery inside the e-cigarette, and the maximum distance slightly larger. The prismatic raised structures on the surface of the crushing rollers can effectively split the outer shell of the fragments. The distance between the rollers during the crushing process is set slightly larger than the diameter of a 13450 or 13400 mm cylindrical lithium battery to ensure that the outer shell is crushed without damaging the battery cell. The overall damage to components such as the lithium battery, mouthpiece, and bottom cap is minimal, preserving them relatively intact, thus achieving safe and efficient dismantling of waste e-cigarettes. The top of the crushing chamber is the feed inlet 1, and below the feed inlet is a liquid nitrogen inlet 8. Material entering through the feed inlet is rapidly frozen by liquid nitrogen. The liquid nitrogen inlet is connected to a temperature detection and control system 2, which monitors the temperature inside the crushing chamber in real time to regulate the liquid nitrogen input, ensuring the temperature inside the crushing chamber remains within the required range. The ABS shell and nylon cartridge become brittle under the rapid freezing of liquid nitrogen, and can be selectively peeled off by the squeezing action of the crushing rollers and the splitting action of the raised protrusions on the roller surface. The bottom of the crushing chamber is the discharge outlet 12, and below the discharge outlet is a vibrating screen 4. The feed end of the vibrating screen is connected to one side of the discharge outlet of the crushing chamber and is inclined to the other side of the discharge outlet. The discharge end of the vibrating screen is connected to a coarse material conveyor belt 6, and a fine material conveyor belt 5 is located directly below the vibrating screen.After selective freezing and stripping, the waste e-cigarettes fall onto a vibrating screen for sieving. The selectively stripped ABS shells, cartridge sponges, etc. fall into the lower screen and are transported away by the under-screen conveyor belt, while the mouthpiece, bottom cap, and lithium battery roll off the screen onto the upper screen conveyor belt and are transported away.

[0032] The waste electronic cigarettes in this embodiment of the invention originated from a new energy company in Hunan Province, such as... Figure 1 The disassembled structure, as shown, is analyzed to include the following main components and structures: ABS (plastic shell), PC (mouthpiece, bottom cap), nylon 6 (cartridge sponge), pressure sensor, and 13450 model lithium cobalt oxide battery.

[0033] Example 1

[0034] First, the cryogenic stripping device of this invention is used to cryogenically strip waste e-cigarettes at -55°C for 40 minutes. The outer shell is then squeezed and hammered to strip away the plastic components, while the remaining lithium battery and PC components are almost completely removed. These components are then placed together in an 800°C pyrolysis furnace for self-reduction pyrolysis for 5 hours. The collected pyrolysis residue is then physically sorted through a 0.10mm sieve. The products on the sieve are mainly aluminum foil, wires, and sensors, while the products below the sieve are mainly reduced electrode powder. The obtained electrode powder can be separated into Li and Co by water leaching at room temperature. The recovery rate of Co in the leaching residue can reach over 95%, and the recovery rate of Li in the leachate can reach over 90%.

[0035] Comparative Example 1

[0036] Similar to Example 1, the difference is that the calcination temperature is set to 500°C, resulting in extremely low pyrolysis efficiency and a final Li recovery rate of less than 20% in the leachate.

[0037] Comparative Example 2

[0038] Similar to Example 1, the difference is that this comparative scheme does not use cryogenic crushing to disassemble the e-cigarette. Instead, it uses traditional manual disassembly to remove the 13400 lithium battery, followed by discharge and conventional reduction pyrolysis at 800°C for 5 hours. The positive electrode powder is recovered by sieving, and Li is recovered by water leaching at room temperature. The final Li recovery rate is 54%. The results indicate that the overall pyrolysis of the disassembled battery can utilize the electrolyte to reduce the positive electrode to low-valence Co compounds and Li₂CO₃. However, the small amount of electrolyte results in less reduced material after pyrolysis, leading to low reduction efficiency and a lower Li recovery rate than in the embodiments of this invention. Furthermore, the process in this comparative example is longer and requires discharge treatment.

[0039] Comparative Example 3:

[0040] Similar to Example 1, the difference is that this comparative scheme does not use a cryogenic stripping device to disassemble the e-cigarettes. Instead, a commercially available electric crusher is used to directly crush the waste e-cigarettes, then the 13400 lithium batteries, and then the electrode powder obtained from the crushing is recovered by physical sorting through sieving. The recovery rates of Co and Li are both less than 30%. This may be because the plastic component content is high, which can generate electrostatic effects on the electrode powder after crushing. Also, the surface wrinkles of the organic packaging increase the specific surface area after traditional crushing, resulting in poor detachment. Further pyrometallurgical or wet treatment is still needed to increase the recovery rate.

[0041] In summary, the cryogenic crushing method used in this invention can selectively remove most of the plastic packaging from large quantities of waste e-cigarettes, and can also provide a sufficient reducing atmosphere for subsequent overall pyrolysis to achieve selective separation of Co and Li. It has the advantages of short process, large processing capacity, continuous operation and low pollution.

Claims

1. A method for the complete resource recovery of waste electronic cigarettes, characterized in that: After the waste e-cigarettes are cryogenically ground to remove the plastic shell and e-liquid cotton, they are subjected to self-reducing pyrolysis. The pyrolysis products are physically sieved to separate powders including low-valent Co compounds and Li2CO3, as well as components including copper foil, aluminum foil, wires and sensor elements. The structure of the waste electronic cigarette includes an external mouthpiece, a bottom cap, and a cigarette holder, while the internal components mainly consist of a cigarette chamber, a lithium battery, a sensor, wires, and a heating wire. The mouthpiece and bottom cap are primarily made of polycarbonate.

2. The method for the complete resource recovery of waste electronic cigarettes according to claim 1, characterized in that: The conditions for cryogenic abrasion are: temperature -45°C to -55°C, time 30 to 60 minutes.

3. A method for the complete resource recovery of waste electronic cigarettes according to claim 1 or 2, characterized in that: The cryogenic abrasion is achieved using a cryogenic peeling device; The cryogenic stripping device includes a crushing chamber; The crushing chamber has a smaller diameter at the top and bottom ends and a larger diameter in the middle. The crushing chamber has two parallel cylindrical crushing rollers at the center of its largest cross-section. The crushing rollers are fixed to the inner wall of the crushing chamber by a telescopic device. The surface of the crushing rollers is uniformly provided with multiple protrusions. The top of the crushing chamber is the feed inlet, and a liquid nitrogen inlet is provided below the feed inlet; The bottom of the crushing chamber is the discharge port, and a vibrating screen is provided below the discharge port.

4. The method for the complete resource recovery of waste electronic cigarettes according to claim 3, characterized in that: The liquid nitrogen inlet is connected to a temperature detection and control system.

5. The method for the complete resource recovery of waste electronic cigarettes according to claim 3, characterized in that: The feed end of the vibrating screen is connected to one side of the discharge port of the crushing chamber and is inclined to the other side of the discharge port of the crushing chamber. The discharge end of the vibrating screen is connected to the coarse material conveyor belt, and a fine material conveyor belt is provided directly below the vibrating screen.

6. The method for the complete resource recovery of waste electronic cigarettes according to claim 5, characterized in that: The raised structure on the surface of the crushing roller is a prismatic structure, and the prismatic structure is arranged parallel to the axis of the crushing roller.

7. The method for the complete resource recovery of waste electronic cigarettes according to claim 3, characterized in that: During operation, the crushing rollers are retracted and reciprocated under the control of a telescopic device, and the minimum distance between the two crushing rollers is the diameter of the lithium battery inside the electronic cigarette, while the maximum distance is 1-3 mm greater than the diameter of the lithium battery used in the electronic cigarette.

8. The method for the complete resource recovery of waste electronic cigarettes according to claim 1, characterized in that: The conditions for the self-reducing pyrolysis are: temperature 700~850°C, time 4~6h.

9. The method for the complete resource recovery of waste electronic cigarettes according to claim 1, characterized in that: The physical sieving process uses a screen size of 0.10~0.15mm.

10. A method for the complete resource recovery of waste electronic cigarettes according to claim 1, characterized in that: The powder is used to recover lithium by water leaching, and the leaching residue is cobalt-enriched residue.

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