Method for treating waste lithium battery
Technical Field
The invention belongs to the technical field of environmental protection, relates to a method for treating waste batteries, and particularly relates to a method for treating waste lithium batteries.
Background
The lithium ion battery has the obvious advantages of low cost, good safety performance, long service life, high specific energy, no memory effect, environmental friendliness and the like, and is widely applied to the fields of electronics, traffic, energy storage, aerospace and the like, so that a large amount of waste batteries can be generated after the service life of the lithium ion battery is over in the coming years. The scrapped or used power batteries which are utilized in a graded manner do not have use value, but the batteries also contain a large amount of electrolyte, nonferrous metals (aluminum foil, copper foil and the like) and valuable materials (anode and cathode materials), so that the environment is polluted and resources are wasted if no force is exerted or the treatment is not good.
The lithium ion battery is a complex chemical system, and the commercialization difficulty of intermediate products with high added values, such as a positive electrode material, a negative electrode material, an electrolyte and a diaphragm, directly recovered from waste lithium batteries is very high. Removing electrolyte and a binder polyvinylidene fluoride by adopting an incineration method, so that aluminum foils in the waste lithium batteries are melted, active materials are coated, even lithium aluminate is generated, and finally, the separation of active substances from the aluminum foils and the extraction of valuable metal elements are difficult to carry out; the waste lithium battery is treated by a physical method for recycling, namely, the waste lithium battery materials are separated by utilizing the physical characteristics of the materials, such as magnetism, density and the like, no chemical reagent is used, and the energy consumption is lower, but the positive and negative active materials of the waste lithium battery are often adhered to the diaphragm, so that the good splitting effect is difficult to realize; when valuable metals are extracted, a large amount of inorganic acid and reducing agent are consumed when the valuable metals are extracted by adopting a leaching mode of inorganic acid and reducing agent, and a large amount of alkali liquor is consumed for neutralizing solution in the later period, so that unnecessary waste is caused.
CN 109182732A discloses a waste ternary lithium battery grading recovery method, which comprises the steps of conducting alkaline leaching discharging, drying, cutting and crushing on a waste ternary lithium battery, exposing an open space inside a battery core and electrolyte outside, heating to evaporate organic impurities, vibrating and screening to obtain a screened mixture, mixing the screened mixture with inorganic acid and water, adding a reducing agent, adjusting a pH value, aging, filtering to obtain a first filtrate rich in lithium ions, nickel ions, cobalt ions and manganese ions, adding different materials and chemical reagents, or controlling the pH value, conducting grading extraction on the manganese ions, the cobalt ions, the nickel ions and the lithium ions, and respectively extracting and recovering valuable metal elements. However, the recovery method needs to consume inorganic acid and reducing agent, which is not beneficial to the later-stage wastewater treatment.
CN 108172923A discloses a waste lithium ion battery treatment system, which comprises a crushing device, a low-temperature gasification cracking furnace, a combustion device, a flue gas purification device, a fine crushing screening device, a metal recovery device, an acid leaching device and a positive electrode material precursor preparation device; the crushing device is used for crushing the battery cell of the waste lithium ion battery; the low-temperature gasification cracking furnace is used for carrying out low-temperature gasification cracking on the crushed battery materials and obtaining cracking gas and solid residues by carrying out low-temperature gasification cracking on the crushed battery materials; the air inlet of the combustion device is respectively connected with the pyrolysis gas outlet and the volatile organic compound outlet; the flue gas purification device comprises a purification furnace, a lime milk injection device and a dust remover; the metal recovery device is used for recovering iron, aluminum and copper in the metal sheet; the acid leaching device is used for performing acid leaching on the powder to obtain filtrate; the anode material precursor preparation device is used for preparing a precursor material by using the filtrate. However, the above treatment system has a drawback that it is difficult to separate the electrolyte from organic components such as the binder and the separator.
CN 111530884A discloses a method for recovering power lithium battery monomers, which comprises the following steps: (1) pretreating a lithium battery monomer, and then carrying out primary separation on heavy materials and light materials generated by pretreatment by utilizing airflow; (2) carrying out fine treatment on the heavy materials subjected to primary sorting, and separating to obtain Fe materials, thick plastics, Al shells, Al particles, Cu particles, anode and cathode powder and diaphragms; (3) and further treating the gas and the fine powder generated in the fine treatment process, wherein the dry black powder is collected, and the gas is discharged after post-treatment. However, the defects that the positive and negative active materials of the waste lithium ion battery are often adhered to the diaphragm and the good splitting effect is difficult to realize exist.
In view of the above, it is desirable to provide a method which is environmentally friendly and can separate components in waste lithium batteries.
Disclosure of Invention
The invention aims to provide a method for treating waste lithium batteries, which can reasonably utilize organic components in the waste lithium batteries, can fully separate the organic components from inorganic components, has no secondary pollution risk in the treatment process, and is an environment-friendly treatment method.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for treating waste lithium batteries, which comprises the following steps:
(1) drying the crushed waste lithium battery to obtain a dry battery material and a first organic gas;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, so as to obtain a second organic gas and battery powder without organic matters;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum, copper and iron;
heating part of the first organic gas obtained in the step (1) and then reusing the heated first organic gas in the step (1) for drying, and purifying and then condensing the rest part of the first organic gas; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
The invention respectively treats the electrolyte, the diaphragm and the binder in the waste lithium battery. The electrolyte is separately treated, so that the difficulty of recycling subsequent organic gas is reduced, and the emission of the organic gas is reduced by matching with the recycling of the first organic gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
Preferably, the waste lithium battery includes any one or a combination of at least two of a module battery, a single battery, positive and negative electrode leftover materials and defective waste materials, and typical but non-limiting combinations include a combination of a module battery and a single battery, a combination of a single battery and positive and negative electrode leftover materials, a combination of positive and negative electrode leftover materials and defective waste materials, a combination of a module battery, a combination of a single battery and positive and negative electrode leftover materials, a combination of a single battery, positive and negative electrode leftover materials and defective waste materials, and a combination of a module battery, a single battery, positive and negative electrode leftover materials and defective waste materials.
Preferably, the crushing and drying in step (1) are carried out within an interval of not more than 60s, for example, 10s, 20s, 30s, 40s, 50s or 60s, but not limited to the recited values, and other values not recited in the range of values are also applicable.
According to the invention, the operation interval of crushing and drying is not more than 60s, so that the defect of thermal runaway caused by electrochemical reaction due to accumulation of battery pole pieces is effectively avoided; and the volatilization of the toxic and harmful electrolyte is reduced by ensuring that the operation time interval of crushing and drying does not exceed 60 s.
The crushing and drying operation of the invention can be carried out in a device with crushing and drying functions, which is conventional in the field, so as to control the crushing and drying operation interval not to exceed 60 s; the method can also be carried out in a conventional crushing device and a conventional drying device, as long as the operation interval of crushing and drying is not more than 60 s.
Preferably, the drying mode in the step (1) is hot air drying.
The invention adopts a hot air drying mode for drying, which is beneficial to improving the separation efficiency of the electrolyte, thereby saving the drying time, reducing the air volume of hot air used for drying and reducing the treatment difficulty of the subsequent first organic gas.
Preferably, the drying temperature in step (1) does not exceed 200 ℃, and may be, for example, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃ or 200 ℃, but is not limited to the recited values, and other values not recited within the range of values are equally applicable.
When the drying temperature in the step (1) exceeds 200 ℃, the pyrolysis of the electrode active material in the waste lithium battery exists, which is not beneficial to the separation and recovery of the metal material in the later period, so that the drying temperature needs to be controlled not to exceed 200 ℃.
Preferably, the drying of step (1) is carried out under oxygen-deficient or oxygen-free conditions; preferably, the pyrolysis in step (1) is carried out under the condition of oxygen concentration less than 2 vol%, for example, 0 vol%, 0.1 vol%, 0.5 vol%, 0.8 vol%, 1 vol%, 1.2 vol%, 1.5 vol%, 1.6 vol%, 1.8 vol% or 1.9 vol%, but not limited to the recited values, and other unrecited values in the numerical range are also applicable; preferably at an oxygen concentration of < 0.1 vol%.
When the drying is carried out under the condition that the oxygen concentration is more than 2 vol%, the electrolyte is flammable and explosive, so that the safety risk is caused; and the diaphragm is easier to reflow under the condition that the oxygen concentration is more than 2 vol%, so that black powder loss is caused, and the separation and recovery of metal materials in the later period are not facilitated.
Preferably, the drying in step (1) is performed to remove 90% or more of the electrolyte from the used lithium battery, for example, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, but not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the organic material in the first organic gas in step (1) includes any one or a combination of at least two of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate or propyl methyl carbonate, typical but non-limiting combinations include a combination of dimethyl carbonate and diethyl carbonate, a combination of diethyl carbonate and ethylene carbonate, a combination of ethylene carbonate and propylene carbonate, a combination of propylene carbonate and ethyl methyl carbonate, a combination of ethyl methyl carbonate and propyl methyl carbonate, a combination of dimethyl carbonate, diethyl carbonate and ethylene carbonate, a combination of ethylene carbonate, propylene carbonate and ethyl methyl carbonate, a combination of propylene carbonate, ethyl methyl carbonate and propyl methyl carbonate, or a combination of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate and propyl methyl carbonate.
The organic matter component in the first organic gas is related to the electrolyte component in the waste lithium battery, and the composition of the organic matter in the first organic gas is known.
Preferably, the organic matter in the condensate comprises any one or a combination of at least two of carbonates, olefins, alkanes or ketones; typical but non-limiting combinations include combinations of carbonates and olefins, olefins and paraffins, paraffins and ketones, carbonates, olefins and paraffins, olefins, paraffins and ketones, or carbonates, olefins, paraffins and ketones.
The pyrolysis temperature in step (2) of the present invention is 400-600 ℃, and may be, for example, 400 ℃, 420 ℃, 450 ℃, 480 ℃, 500 ℃, 540 ℃, 550 ℃, 560 ℃ or 600 ℃, but is not limited to the recited values, and other values not recited in the numerical range are also applicable; preferably 450-.
Preferably, the furnace kiln for pyrolysis in the step (2) is heated by external heating and/or internal heating, and is preferably heated by external heating.
Preferably, the sorting in step (3) comprises a combination of at least two of magnetic separation, air separation, electric separation, gravity separation, sieving or jigging separation; typical but non-limiting combinations include a combination of magnetic separation and air separation, a combination of air separation and electrical separation, a combination of electrical separation and gravity separation, a combination of gravity separation and screening, a combination of screening and jigging separation, a combination of magnetic separation, air separation and electrical separation, a combination of air separation, electrical separation and gravity separation, a combination of electrical separation, gravity separation and screening, a combination of gravity separation, screening and jigging separation, or a combination of magnetic separation, air separation, electrical separation, gravity separation, screening and jigging separation.
Preferably, the dried first organic gas recycled in step (1) accounts for more than 50 vol% of the total amount of the first organic gas, such as 50 vol%, 60 vol%, 70 vol%, 80 vol%, 90 vol% or 95 vol%, but not limited to the recited values, and other values not recited in the range of values are also applicable; preferably 80 vol% or more.
Preferably, the purification method comprises cyclone dust removal and/or activated carbon adsorption.
As a preferable technical scheme of the method, the method comprises the following steps:
(1) drying the crushed waste lithium battery, wherein the operation interval between crushing and drying is not more than 60s, so as to obtain a dried battery material and a first organic gas; the drying mode is hot air drying, the drying temperature is not more than 200 ℃, the oxygen concentration is less than 2 vol% during drying, and the drying end point is that the removal rate of the electrolyte in the waste lithium battery is more than or equal to 90%;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, wherein the pyrolysis temperature is 400-600 ℃, and a second organic gas and battery powder containing no organic matter are obtained;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum, copper and iron;
heating more than 50 vol% of the first organic gas obtained in the step (1) and then reusing the first organic gas in the step (1) for drying, and purifying and condensing the rest of the first organic gas, wherein the purification method comprises cyclone dust removal and/or activated carbon adsorption; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
Compared with the prior art, the invention has the following beneficial effects:
(1) the method can reasonably utilize organic components in the waste lithium batteries, can fully separate the organic components from inorganic components, has no secondary pollution risk in the treatment process, and is an environment-friendly treatment method;
(2) the invention respectively treats the electrolyte, the diaphragm and the binder in the waste lithium battery; the electrolyte is separately treated, so that the difficulty of recycling subsequent organic gas is reduced, and the emission of the organic gas is reduced by matching with the recycling of the first organic gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foils and copper foils is ensured, the separation difficulty is reduced, the recovery rate of black powder, aluminum, copper and iron is facilitated, the recovery rate of the black powder is more than or equal to 98 percent and the purity is more than or equal to 99 percent, the recovery rate of the aluminum foil is more than or equal to 97 percent and the purity is more than or equal to 97 percent, the recovery rate of the copper foil is more than or equal to 99 percent and the purity is more than or equal to 99 percent, and the recovery rate; and the method is matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
Drawings
Fig. 1 is a process flow diagram of the method for treating waste lithium batteries according to the present invention.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
The embodiment provides a method for treating waste lithium batteries, a process flow chart of the method is shown in fig. 1, the waste lithium batteries treated by the method are module batteries of which electrolyte contains dimethyl carbonate and ethylene carbonate, and diaphragms and binders contain polyethylene, polypropylene, polyvinylidene fluoride and other organic matters, and the method comprises the following steps:
(1) drying the crushed waste lithium battery at an operation interval of 20s to obtain a dried battery material and a first organic gas; the drying mode is hot air drying, the drying is carried out under the condition that the oxygen concentration is 0.08 vol%, the drying temperature is 160 ℃, and the drying end point is that the removal rate of the electrolyte in the waste lithium battery is 95%;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, wherein the pyrolysis temperature is 500 ℃, and a second organic gas and battery powder containing no organic matter are obtained;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum foil, copper foil and iron shell;
heating 90 vol% of the first organic gas obtained in the step (1) to 160 ℃, recycling the first organic gas for drying in the step (1), and purifying and condensing the rest of the first organic gas, wherein the purification method is cyclone dust removal; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
In the embodiment, the electrolyte, the diaphragm and the binder in the waste lithium battery are respectively treated; the electrolyte is separately treated, so that the difficulty of recycling the subsequent organic gas is reduced, the emission of the organic gas is reduced by matching with the recycling of the first organic gas, and the energy consumption is reduced by utilizing the waste heat of the gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
In this example, the recovery rate of black powder was 98.1% and the purity was 99.4%, the recovery rate of aluminum foil was 97.7% and the purity was 97.1%, the recovery rate of copper foil was 99.4% and the purity was 99.1%, and the recovery rate of iron shell was 99.4% and the purity was 99.2%.
Example 2
The embodiment provides a method for treating waste lithium batteries, a process flow chart of the method is shown in fig. 1, the waste lithium batteries treated by the method are single batteries of which electrolyte contains diethyl carbonate and ethylene carbonate, and diaphragms and binders contain polyethylene, polypropylene, polyvinylidene fluoride and other organic matters, and the method comprises the following steps:
(1) drying the crushed waste lithium battery at an operation interval of 40s to obtain a dried battery material and a first organic gas; the drying mode is hot air drying, the drying is carried out under the condition that the oxygen concentration is 0.01 vol%, the drying temperature is 150 ℃, and the drying end point is that the removal rate of the electrolyte in the waste lithium battery is 90%;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, wherein the pyrolysis temperature is 450 ℃, and a second organic gas and battery powder containing no organic matter are obtained;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum foil, copper foil and iron shell;
heating 80 vol% of the first organic gas obtained in the step (1) to 150 ℃, recycling the first organic gas for drying in the step (1), and purifying and condensing the rest of the first organic gas, wherein the purification method is activated carbon adsorption; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
In the embodiment, the electrolyte, the diaphragm and the binder in the waste lithium battery are respectively treated; the electrolyte is separately treated, so that the difficulty of recycling the subsequent organic gas is reduced, the emission of the organic gas is reduced by matching with the recycling of the first organic gas, and the energy consumption is reduced by utilizing the waste heat of the gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
In this example, the recovery rate of black powder was 98.8% and the purity was 99.6%, the recovery rate of aluminum foil was 97.8% and the purity was 98.7%, the recovery rate of copper foil was 99.3% and the purity was 99.9%, and the recovery rate of iron shell was 99.3% and the purity was 99.7%.
Example 3
The present embodiment provides a method for treating waste lithium batteries, which has a process flow diagram as shown in fig. 1, wherein the waste lithium batteries treated by the method are waste products and waste products of electrolyte containing dimethyl carbonate, diethyl carbonate and ethylene carbonate, and a diaphragm and a binder containing hydrocarbon organic matters, and the method comprises the following steps:
(1) drying the crushed waste lithium battery at an operation interval of 30s to obtain a dried battery material and a first organic gas; the drying mode is hot air drying, the drying is carried out under the condition that the oxygen concentration is 0.05 vol%, the drying temperature is 180 ℃, and the drying end point is that the removal rate of the electrolyte in the waste lithium battery is 94%;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, wherein the pyrolysis temperature is 550 ℃, and a second organic gas and battery powder containing no organic matter are obtained;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum foil, copper foil and iron shell;
heating 70 vol% of the first organic gas obtained in the step (1) to 180 ℃, recycling the first organic gas for drying in the step (1), and purifying and condensing the rest of the first organic gas, wherein the purification method is activated carbon adsorption; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
In this example, the recovery rate of black powder was 99.2% and the purity was 99.1%, the recovery rate of aluminum foil was 97.9% and the purity was 97.1%, the recovery rate of copper foil was 99.1% and the purity was 99.4%, and the recovery rate of iron shell was 99.1% and the purity was 99.5%.
In the embodiment, the electrolyte, the diaphragm and the binder in the waste lithium battery are respectively treated; the electrolyte is separately treated, so that the difficulty of recycling the subsequent organic gas is reduced, the emission of the organic gas is reduced by matching with the recycling of the first organic gas, and the energy consumption is reduced by utilizing the waste heat of the gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
Example 4
The embodiment provides a method for treating waste lithium batteries, a process flow chart of the method is shown in fig. 1, the waste lithium batteries treated by the embodiment are waste products of electrolytes containing propylene carbonate, diaphragms and binders containing hydrocarbon organic matters, and the method comprises the following steps:
(1) drying the crushed waste lithium battery, wherein the operation interval between crushing and drying is not more than 60s, so as to obtain a dried battery material and a first organic gas; the drying mode is hot air drying, the drying is carried out under the condition that the oxygen concentration is 0.04 vol%, the drying temperature is 180 ℃, and the drying end point is that the removal rate of the electrolyte in the waste lithium battery is 99%;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, wherein the pyrolysis temperature is 400 ℃, and a second organic gas and battery powder containing no organic matter are obtained;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum foil, copper foil and iron shell;
heating 50 vol% of the first organic gas obtained in the step (1) to 180 ℃, recycling the first organic gas for drying in the step (1), and purifying and condensing the rest of the first organic gas, wherein the purification method is activated carbon adsorption; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
In this example, the recovery rate of black powder was 99.2% and the purity was 99.5%, the recovery rate of aluminum foil was 97.8% and the purity was 98.6%, the recovery rate of copper foil was 99.7% and the purity was 99.4%, and the recovery rate of iron shell was 99.2% and the purity was 99.5%.
In the embodiment, the electrolyte, the diaphragm and the binder in the waste lithium battery are respectively treated; the electrolyte is separately treated, so that the difficulty of recycling the subsequent organic gas is reduced, the emission of the organic gas is reduced by matching with the recycling of the first organic gas, and the energy consumption is reduced by utilizing the waste heat of the gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
Example 5
The embodiment provides a method for treating waste lithium batteries, a process flow chart of the method is shown in fig. 1, the waste lithium batteries treated by the method are a combination of a single battery, a positive electrode leftover material and a negative electrode leftover material, wherein an electrolyte contains methyl ethyl carbonate, a diaphragm and a binder contain hydrocarbon organic matters, and the method comprises the following steps:
(1) drying the crushed waste lithium battery, wherein the operation interval between crushing and drying is not more than 60s, so as to obtain a dried battery material and a first organic gas; the drying mode is hot air drying, the drying is carried out under the condition that the oxygen concentration is 0.08 vol%, the drying temperature is 200 ℃, and the drying end point is that the removal rate of the electrolyte in the waste lithium battery is 96%;
(2) pyrolyzing the dried battery material obtained in the step (1) to remove the diaphragm and the binder, wherein the pyrolysis temperature is 600 ℃, and a second organic gas and battery powder containing no organic matter are obtained;
(3) sorting the battery powder obtained in the step (2) to obtain black powder, aluminum foil, copper foil and iron shell;
heating 60 vol% of the first organic gas obtained in the step (1) to 200 ℃, recycling the first organic gas for drying in the step (1), and purifying and condensing the rest of the first organic gas, wherein the purification method is cyclone dust removal; condensing the second organic gas obtained in the step (2);
and (3) recycling the organic liquid obtained by condensation for pyrolysis in the step (2), and discharging the non-condensable gas obtained by condensation after tail gas treatment.
In this example, the recovery rate of black powder was 98.6% and the purity was 99.4%, the recovery rate of aluminum foil was 97.5% and the purity was 98.6%, the recovery rate of copper foil was 99.4 and the purity was 99.1%, and the recovery rate of iron shell was 99.3% and the purity was 99.7%.
In the embodiment, the electrolyte, the diaphragm and the binder in the waste lithium battery are respectively treated; the electrolyte is separately treated, so that the difficulty of recycling the subsequent organic gas is reduced, the emission of the organic gas is reduced by matching with the recycling of the first organic gas, and the energy consumption is reduced by utilizing the waste heat of the gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
Example 6
This example provides a method for treating waste lithium batteries, which is the same as example 1 except that the crushing and drying operation interval in step (1) is 90 s.
Because the operation interval of crushing and drying exceeds 60s, the battery plate in the processing process of the method generates heat due to electrochemical reaction, the local temperature is 300 ℃, and local thermal runaway is caused, so that potential safety hazards are caused.
Example 7
This example provides a method for treating waste lithium batteries, which is the same as example 1 except that the drying temperature in step (1) is 220 ℃.
Since the drying temperature exceeds 200 ℃, the method causes the membrane to be molten and sticky and cannot discharge smoothly, so that the final black powder recovery rate is only 72.5%.
Example 8
This example provides a method for treating used lithium batteries, which is the same as example 1 except that the oxygen concentration during drying in step (1) is between 0.2 and 2 vol%.
As the oxygen concentration is increased during pyrolysis, and the carbonate organic gas volatilized from the electrolyte belongs to flammable and explosive gas, the method has potential safety hazard.
Example 9
This example provides a method for treating used lithium batteries, which is the same as example 1 except that the oxygen concentration during drying in step (1) is 5 vol%.
As the oxygen concentration is increased during pyrolysis, and the carbonate organic gas volatilized from the electrolyte belongs to flammable and explosive gas, the method has potential safety hazard.
Example 10
This example provides a method for treating waste lithium batteries, which is the same as example 1 except that only 40 vol% of the first organic gas is recycled for drying in step (1), and the rest is purified and condensed.
Because the recycling amount of the first organic gas is reduced, the energy recovery efficiency is low, the energy consumption is increased by 30 percent, the pressure of subsequent purification and condensation is increased, the generation amount of non-condensable gas is increased, and the method is not beneficial to energy conservation and environmental protection.
In conclusion, the method can overcome the defect of melting of the aluminum foil and the copper foil caused by the traditional incineration, and can realize the separation of active substances from the aluminum foil and the copper foil and the extraction of valuable metal elements; the defect that the positive and negative electrode active materials are difficult to separate from the diaphragm by adopting the traditional physical separation method is overcome; meanwhile, the defect of large consumption of chemical agents caused by adopting inorganic acid and reducing agent is overcome.
The method disclosed by the invention can reasonably utilize the organic components in the waste lithium batteries, can fully separate the organic components from the inorganic components, has no secondary pollution risk in the treatment process, and is an environment-friendly treatment method; the invention respectively treats the electrolyte, the diaphragm and the binder in the waste lithium battery; the electrolyte is separately treated, so that the difficulty of recycling subsequent organic gas is reduced, and the emission of the organic gas is reduced by matching with the recycling of the first organic gas; the binder and the diaphragm are treated independently, so that the separation effect of electrode active components such as the binder and the like and aluminum foil and copper foil is ensured, the separation difficulty is reduced, the recovery of black powder, aluminum, copper and iron is facilitated, and the binder and the diaphragm are matched with condensation, so that the emission of organic gas in the method is reduced, and the method is green and environment-friendly.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.