WO2023070801A1

WO2023070801A1 - Recovery method for valuable components of waste lithium-ion batteries

Info

Publication number: WO2023070801A1
Application number: PCT/CN2021/133275
Authority: WO
Inventors: 吴光辉; 王振云; 甄必波
Original assignee: 湖南江冶机电科技股份有限公司
Priority date: 2021-10-31
Filing date: 2021-11-25
Publication date: 2023-05-04
Also published as: CN113999976A

Abstract

Disclosed is a recovery method for valuable components of waste lithium-ion batteries. Lithium battery materials such as a lithium battery cell, a soft-pack battery, a mobile phone battery, and a 18650 small cylinder are directly pyrolyzed, and then crushed, stripped, and sorted. In the present invention, crushing is not performed first, rather, only a housing is removed by means of a simple cutting process, and then a square housing battery cell, a soft pack battery, a small cylinder, and a mobile phone battery having housings and pile heads removed are directly pyrolyzed; compared with pyrolyzation after crushing, the materials do not expand, the pyrolysis treatment amount is greatly reduced, pyrolysis furnace equipment is small in size, investment is low, and installation power and operating cost are greatly reduced.

Description

A kind of recovery method of valuable component of waste lithium ion battery

technical field

The invention belongs to the regeneration utilization of waste lithium ion batteries, in particular to a method for recovering valuable components of waste lithium ion batteries.

Background technique

The recycling of waste lithium-ion batteries is faced with safety and environmental hazards caused by electrolyte volatilization during the crushing and sorting process, as well as difficulties in peeling off the electrode powder and high copper and aluminum foil impurities in the electrode powder.

Chinese invention CN109193058A discloses a method and equipment for treating waste lithium batteries. In the method, the electric core is preheated (150-250° C.) and then heated to 250-500° C. for pyrolysis, and the pyrolysis time is 0.5-0.8 hours. Although the invention involves preheating and pyrolysis, this method is only applicable to the extracted batteries, and does not include soft pack batteries, mobile phone batteries and small cylindrical batteries (which can be directly pyrolyzed). The second is that its pyrolysis temperature is 250- 500°C cannot fully pyrolyze and carbonize the electrode powder binder PVDF. Third, the battery is a compacted package material before it is broken. The pyrolysis time of 0.5-0.8 hours is far from meeting the requirements of sufficient pyrolysis and carbonization. The air tightness of the tunnel kiln is poor, and the air is easy to intrude under the negative pressure conditions, and the internal oxygen content cannot be controlled, and the oxygen concentration of no more than 2% cannot be accurately controlled. At the same time, the temperature control of this type of tunnel kiln is not accurate, and the internal The temperature uniformity and constant temperature state, the pyrolysis effect is poor, resulting in poor stripping effect and low recovery rate of electrode powder.

At present, the existing waste lithium-ion battery recycling generally includes the following two processes: 1. Crushing, low-temperature volatilization, air separation, magnetic separation, multi-stage fine crushing or friction breaking up and stripping the pole powder, screening, and specific gravity sorting to obtain the pole powder and Copper and aluminum foil; 2. Primary crushing, pyrolysis, air separation, magnetic separation, and dry or wet stripping to obtain black powder and copper and aluminum foil. The above process 1 is finely crushed or dispersed by friction to make the pole powder and copper and aluminum foil become fine particles with a small difference in the actual spherical surface area of 0.1mm-3mm. It is difficult to completely separate the pole powder and copper and aluminum foil by using the specific gravity separation method to dope each other, resulting in extreme The powder recovery rate is low (≤96%), and the impurity content of copper and aluminum foil is high (≥4%), which not only has poor economic benefits, but also increases the impurity removal cost of subsequent hydrometallurgy. At the same time, low-temperature volatilization can only volatilize about 70% of the electrolyte, and the residual electrolyte will bring safety and environmental risks to the subsequent treatment process. The volume of the lithium battery in the above process 2 will expand by about 7 times (cylindrical), 14 times (square shell) and 21 times (soft package) after being broken, resulting in a substantial increase in the volume and total installed power of the pyrolysis furnace, which will greatly increase the investment cost, Operating cost and maintenance difficulty. Moreover, it is crushed first and then pyrolyzed. During the crushing, due to the safety of the electrolyte, it needs to be filled with inert gas (mainly nitrogen) for protection, which not only increases the cost of the crushing section, but also increases the amount of pyrolysis gas (nitrogen gas in the crushing section) The difficulty and cost of the denitrification treatment of the environmental protection system in the latter stage are greatly reduced.

Contents of the invention

In view of the above technical problems, the present invention provides a method for recovering valuable components of waste lithium-ion batteries. Direct pyrolysis of small cylindrical lithium battery materials such as lithium battery cells, pouch batteries, mobile phone batteries, 18650, and then crushing, peeling, and sorting.

Technical scheme of the present invention is as follows:

A method for recovering valuable components of spent lithium-ion batteries, comprising the steps of:

(1) Use cutting equipment to cut off the upper cover, remove the shell, and separate the battery core of the waste lithium-ion battery in an inert gas environment; cut or directly pyrolyze the soft pack battery, small cylindrical battery, and mobile phone battery;

(2) After the battery cover is crushed, use magnetic separation, eddy current or air separation to separate different materials on the cover, such as copper poles, stainless steel poles, iron shells, plastic shells, aluminum shells or Stainless steel casing, etc., and the casing can be crushed and cleaned to obtain pure casing materials;

(3) Pyrolysis of batteries, pouch batteries, small cylindrical batteries and mobile phone batteries, so that the electrolyte, binder (PVDF glue or other binders), and organic components of the separator are fully pyrolyzed, and the waste gas is pyrolyzed After being treated by the environmental protection system in the back stage, the discharge reaches the standard;

(4) The pyrolyzed material is crushed to obtain a 0.5-110mm crushed material;

(5) The crushed material is stripped by pneumatic dry method to obtain a mixture of positive and negative electrode powder and 3-5mm copper and aluminum particles with a particle size of 0.045-0.075mm; or by hydrodynamic wet stripping, sieving and concentration to obtain a particle size A mixture of 0.150-0.180mm positive and negative powder wet material and 0.5-110mm copper-aluminum sheet;

(6) The copper and aluminum particles after dry stripping are directly separated by color separation to obtain pure copper and aluminum particle products; the copper and aluminum flake mixture after wet stripping is dried and then obtained by color separation to obtain clean copper and aluminum foil products .

Further, in step (1), the cutting equipment is equipped with smoke detection, temperature sensing and video monitoring devices. When cutting, the cut waste lithium-ion batteries and cutting tools are in a relatively closed space. Under certain conditions, there are two protection modes of inert gas automatic injection and manual injection to ensure the safety of cutting work.

Further, in step (2), the upper cover is composed of an upper cover plate, a pole and a safety valve. Vortex separation or air separation equipment is used for classification and recycling; the shell is made of the same material, and after crushing and cleaning, clean recycled products can be obtained.

Further, in step (3), the pyrolysis is carried out in a pyrolysis furnace, the pyrolysis furnace is a rotary calciner, which adopts electromagnetic heating or electric heat radiation, and fuel combustion heating, and the heating method is 360 ^° C heating method to ensure that The material is evenly heated; because the volume of the material does not increase, the volume required by the converter is greatly reduced compared with the traditional process, and the filling rate can be increased to 30-100%; the pyrolysis furnace is inert gas, the pressure is 0.05 ~ 1kpa, slightly Positive pressure pyrolysis can prevent oxidation of metal materials; the temperature of the pyrolysis furnace is controlled at 530-600°C, and the pyrolysis time is 1.5-3 hours, which can fully meet the above pyrolysis requirements and achieve a good pyrolysis effect; The rear section of the pyrolysis furnace is a cooling device to ensure that the discharge temperature of the material after pyrolysis is below 150°C; the pyrolysis waste gas is produced by pyrolysis of electrolyte and PVDF glue, and its components are mostly combustible organic gases.

Further, in step (4), the crushing does not require inert gas protection; the pyrolyzed electric core, pouch battery, mobile phone battery and small cylindrical battery no longer contain electrolyte, binder (PVDF glue or other Binder) and other organic substances, the crushing, sorting and other processes are safe enough, and there is no risk of explosion, so inert gas protection is no longer needed.

Further, in step (5), the crushed material does not contain hard objects such as hard shells and poles, and is directly subjected to pneumatic dry stripping and sorting, which can safely, environmentally friendly, and efficiently strip the pole powder, and obtain a mixture of copper and aluminum particles ;Crush materials or carry out hydrodynamic wet stripping (including 1-5% acid stripping), high recovery rate of electrode powder, bright appearance of copper and aluminum foil, good color sorting effect, stripping liquid can be recycled.

Further, in step (6), the copper and aluminum particles directly obtained by dry stripping are sieved and then enter the color separation process to obtain copper and aluminum particle products; the copper and aluminum foil sheets obtained by wet stripping are dried and then enter the color separation process, Get copper and aluminum sheet products.

The beneficial effects of the present invention are:

(1) Pyrolysis of prismatic battery cells with shells and pile heads removed, and direct pyrolysis of pouch batteries, small cylinders, and mobile phone batteries. Compared with pyrolysis after the battery is broken, the material does not expand, and the pyrolysis treatment capacity is greatly increased. The furnace is small in size, low in investment, and the installed power and operating costs are greatly reduced.

(2) Remove the casing first to prevent plastic coating and other substances from entering the pyrolysis furnace, thereby eliminating the generation of dioxins, thereby reducing the temperature of exhaust gas combustion from 1200°C to below 800°C, greatly reducing environmental protection facilities such as exhaust gas combustion The investment cost; only the small cylindrical battery needs plastic for the shell, and it still needs 1200 °C to treat the exhaust gas.

(3) The pyrolysis furnace adopts electromagnetic heating rotary furnace for pyrolysis. Compared with the traditional resistance heating furnace, the installed power of this kind of furnace is smaller, the temperature rises faster, the thermal efficiency utilization rate is high, the service life is long, and the operation and maintenance cost is low. And the filling rate can be increased to 30-50% compared with 15-18% of the traditional furnace, and the production efficiency is greatly improved.

(4) Post-crushing, because the electrolyte has been completely volatilized, there is no need to refill nitrogen gas, which reduces the cost of crushing. At the same time, there is no pile head and shell, so the crushing is simple, the service life of the cutter head is extended, and the equipment maintenance is simplified.

(5) The crushing link does not require inert gas protection such as nitrogen, which greatly reduces the flue gas treatment capacity of the environmental protection system in the latter stage, and reduces the treatment pressure and cost.

(6) After pyrolysis, the stripping efficiency of the pole powder is high, the effect is good, and the recovery rate is high.

Description of drawings

Fig. 1 is a schematic block diagram of the process of the present invention.

As shown in the figure, the waste lithium-ion battery is firstly cut the upper cover (remove the shell) in an inert gas atmosphere to obtain the upper cover shell and the battery cell respectively; the upper cover is crushed, and then magnetic separation and eddy electric separation are carried out to obtain Part of the casing, poles and other products; the bottom casing can be broken and cleaned to obtain the remaining casing products; the cell enters the pyrolysis process and is pyrolyzed at high temperature in an inert gas atmosphere to completely pyrolyze the electrolyte and PVDF glue It is pyrolysis waste gas; the pyrolysis waste gas is combusted, and the exhaust gas is purified and discharged up to the standard; the pyrolyzed battery cells are stripped after being crushed; there are two stripping processes, namely dry stripping and wet stripping. Dry stripping uses airflow crushing and separation to obtain a mixture of dry electrode powder products and copper-aluminum particles with a particle size of 0.045-0.075mm; wet stripping uses weak acid soaking, and then sieves to obtain a mixture of copper and aluminum flakes on the sieve And the 80-100 mesh wet pole powder product of the under-sieve; the dry stripped copper and aluminum particles are screened and then color-selected to obtain copper and aluminum particle products; the copper-aluminum flake mixture obtained by wet stripping is obtained by drying and color separation Copper and aluminum grain products.

Detailed ways

The present invention will be described in further detail below in conjunction with specific examples, but the present invention is not limited thereto.

Example 1

For stainless steel prismatic batteries, the following treatment processes can be used:

Step 1: Use cutting equipment to safely remove the upper cover, remove the outer shell, and separate the battery cell from the waste lithium-ion battery in an inert gas environment; among them, the upper cover and outer shell, which account for about 16% of the total weight of the battery, enter step 2; the remaining The battery enters step 3 when the weight is reduced and the volume is reduced;

Step 2: After simple crushing and cleaning of the upper cover, the stainless steel shell material with a purity of more than 98% and the pile head material with a purity of more than 98% are selected by eddy current separation and sold separately. The rubber, plastic tape and other materials attached to the shell are made Solid waste treatment.

Step 3: The battery cells accounting for 84% of the total weight of the battery enter the pyrolysis furnace. The temperature of the pyrolysis furnace is controlled at about 550°C, and the pyrolysis time is 1 hour. Binder), the organic components of the diaphragm are fully pyrolyzed in a nitrogen atmosphere, and the pyrolysis waste gas is treated by the environmental protection system in the latter stage and then discharged up to the standard. The pyrolysis waste gas does not contain dioxins, and the combustion temperature of the waste gas is controlled at about 800°C Can;

Step 4: The components of the pyrolyzed battery core are complete copper foil, aluminum foil, and positive and negative electrode powder materials attached to or falling off, which are directly sent to a high-speed shear crusher with a sieve hole of 30mm to obtain particle size Copper and aluminum foil fragments and positive and negative electrode powder mixtures less than 30mm;

Step 5: The crushed material is peeled off by pneumatic dry method to obtain a mixture of positive and negative electrode powder and 3-5mm copper and aluminum particles with a particle size of 0.045-0.075mm; the impurity content of the positive and negative electrode powder is less than 3%, which can be directly packaged for sale or Enter the hydrometallurgical process to obtain further products; the mixture of copper and aluminum particles enters step 6;

Step 6: Copper and aluminum particles are mixed and sorted by a color sorter that is ubiquitous in the market to obtain 98% pure copper particles and 95% pure aluminum particles, which can be packaged and sold separately.

Example 2

The following treatment process can be used for 18650 small cylindrical batteries:

Step 1: Put the 18650 small cylindrical battery directly into the pyrolysis furnace. The temperature of the pyrolysis furnace is controlled at about 550°C, and the pyrolysis time is 1.5 hours. The rubber wrapping paper, electrolyte, binder (PVDF glue or other binder), the organic components of the diaphragm are fully pyrolyzed in a nitrogen atmosphere, and the pyrolysis waste gas is discharged up to the standard after being treated by the environmental protection system in the latter stage. Because of the decomposition of rubber wrapping paper-dioxin, the pyrolysis waste gas needs to be burned to 1200 ℃, and the rapid cooling down to below 400 ℃ can guarantee the discharge standard;

Step 2: The 18650 small cylindrical battery after pyrolysis, due to the complete decomposition of various organic components, has a weight loss rate of about 20%, and the remaining part is directly sent to a high-speed shear crusher with a sieve hole of 10mm to obtain particles with a particle size of less than 10mm Iron shell fragments, copper and aluminum foil fragments and positive and negative electrode powder mixture;

Step 3: Sieve the mixture in step 2 to sieve the shed positive and negative electrode powder (about 40% of the total amount of the electrode powder) with a particle size of 0.180mm (-80 mesh). If the impurity content is less than 3%, it can be packaged and sold directly or entered into hydrometallurgy to obtain further products. The oversize enters step 4;

Step 4: Carry out magnetic separation on the sieve in step 3, and sort out the iron casing fragments, copper and aluminum foil fragments and the positive and negative electrode powder attached to them; simple cleaning of the casing can obtain a purity of more than 98% The iron shell products can be packaged and sold directly; the copper-aluminum foil mixture and the positive and negative electrode powder attached to it enter step 5;

Step 5: The copper-aluminum foil mixture and the positive and negative electrode powder attached to it are subjected to hydrodynamic wet stripping (1-5% acid solution stripping), and then sieved through a wet high-frequency vibrating sieve to obtain: oversized copper The aluminum foil fragments enter step 6, and the undersize electrode powder slurry enters step 7.

Step 6: The copper and aluminum foil fragments on the sieve are bright in color, and are directly color-sorted after drying to obtain copper foil with a purity of more than 99% and aluminum foil with a purity of more than 98%, which are sold separately;

Step 7: The impurity rate of the undersieve ultrapowder slurry is less than 2%, and the ultrapowder wet material is obtained by concentrating through a filter press or a thickener, which can be directly sold or entered into a hydrometallurgical process to obtain further products.

Example 3

For the single pouch battery, the following treatment process can be adopted:

Step 1: Send the single pouch battery directly into the pyrolysis furnace. The temperature of the pyrolysis furnace is controlled at about 550°C, and the pyrolysis time is 1 hour. agent), the organic components of the diaphragm are fully pyrolyzed in a nitrogen atmosphere, and the pyrolysis waste gas is discharged after being treated by the environmental protection system in the latter stage. Because the single soft pack battery does not contain rubber substances, it will not produce dioxins. The exhaust gas only needs to be burned to above 800°C;

Step 2: After pyrolysis, the monomer pouch battery, due to the complete decomposition of various organic components, has a weight loss rate of about 25%, and the remaining part is directly sent to a high-speed shear crusher with a sieve hole of 30mm to obtain a particle size of less than 30mm Aluminum foil shell fragments, copper and aluminum foil fragments and positive and negative electrode powder mixture;

Step 3: Peel off the crushed materials by pneumatic dry method to obtain a mixture of positive and negative electrode powders with a particle size of 0.045-0.075mm and copper-aluminum particles of 3-5mm; the impurity content of the positive and negative electrode powders is less than 3%, which can be packaged and sold directly Or enter the hydrometallurgical process to obtain further products; the mixture of copper and aluminum particles enters step 4;

Step 4: Copper and aluminum particles are mixed and sorted by a color sorter that is ubiquitous in the market to obtain 98% pure copper particles and 95% pure aluminum particles, which can be packaged and sold separately.

Claims

A method for recovering valuable components of waste lithium-ion batteries, characterized in that it comprises the steps of:

(1) Use cutting equipment to cut off the upper cover, remove the shell, and separate the battery core of the waste lithium-ion battery in an inert gas environment; cut or directly pyrolyze the soft pack battery, small cylindrical battery, and mobile phone battery;

(2) After the battery cover is crushed, use magnetic separation, eddy current or air separation to separate different materials on the cover, such as copper poles, stainless steel poles, iron shells, plastic shells, aluminum shells or Stainless steel casing, etc., and the casing can be crushed and cleaned to obtain pure casing materials;

(3) Pyrolysis of batteries, pouch batteries, small cylindrical batteries and mobile phone batteries, so that the organic components such as electrolyte, binder, and diaphragm are fully pyrolyzed, and the pyrolysis waste gas reaches the standard after being treated by the environmental protection system in the latter stage emission;

(4) The pyrolyzed material is crushed to obtain a 0.5-110mm crushed material;

(5) The crushed material is stripped by pneumatic dry method to obtain a mixture of positive and negative electrode powder and 3-5mm copper and aluminum particles with a particle size of 0.045-0.075mm; or by hydrodynamic wet stripping, sieving and concentration to obtain a particle size A mixture of 0.150-0.180mm positive and negative powder wet material and 0.5-110mm copper-aluminum sheet;

(6) The copper and aluminum particles after dry stripping are directly separated by color separation to obtain pure copper and aluminum particle products; the copper and aluminum flake mixture after wet stripping is dried and then obtained by color separation to obtain clean copper and aluminum foil products .
The method for recovering valuable components of waste lithium-ion batteries according to claim 1, wherein in step (3), pyrolysis is carried out in a pyrolysis furnace, and the pyrolysis furnace is a rotary calciner, using electromagnetic Heating or electric radiation, fuel combustion heating, the heating method is 360° heating, to ensure that the materials in the furnace are heated evenly; the pyrolysis furnace is inert gas, and the pressure is 0.05 ~ 1kpa; the temperature of the pyrolysis furnace is controlled at 530 -600°C, the pyrolysis time is 1.5-3 hours; the rear section of the pyrolysis furnace is a cooling device to ensure that the discharge temperature of the material after pyrolysis is below 150°C.
The method for recovering valuable components of waste lithium-ion batteries according to claim 1 or 2, wherein in step (1), the cutting equipment is equipped with smoke detection, temperature sensing and video monitoring devices, and when cutting, The cut waste lithium-ion batteries and cutting tools are in a relatively closed space. Under the conditions set by the smoke and temperature sensing devices, there are two protection modes of inert gas automatic injection and manual injection to ensure the safety of cutting work.
The method for recovering valuable components of waste lithium-ion batteries according to claim 1 or 2, wherein in step (2), the upper cover is composed of an upper cover plate, a pole and a safety valve, and the upper cover is first The cover is crushed, and then according to the different materials of the upper cover plate, pole and safety valve, magnetic separation, eddy current separation or wind separation equipment is used for classification and recycling; the shell is of the same material, after crushing and cleaning, clean Recycle the product.
The method for recovering valuable components of spent lithium-ion batteries according to claim 1 or 2, characterized in that, in step (4), the crushing does not require inert gas protection.
The method for recovering valuable components of waste lithium-ion batteries according to claim 1 or 2 is characterized in that, in step (5), the crushed material does not contain hard matter, and directly performs pneumatic dry stripping and sorting, The pole powder can be stripped to obtain a mixture of copper and aluminum particles; or wet stripping, that is, stripping with 1-5% acid solution, to obtain pole powder and copper-aluminum foil.
The method for recovering valuable components of waste lithium-ion batteries according to claim 1 or 2, characterized in that in step (6), the copper and aluminum particles directly obtained by dry stripping are sieved and then enter the color separation process to obtain copper , Aluminum granule products; copper and aluminum foil sheets obtained by wet stripping, after drying, enter the color sorting process to obtain copper and aluminum sheet products.