CN113471515A - Method for recycling lithium battery electrolyte by combining supercritical extraction rectification and molecular distillation - Google Patents
Method for recycling lithium battery electrolyte by combining supercritical extraction rectification and molecular distillation Download PDFInfo
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Abstract
The invention provides a method for recovering lithium battery electrolyte by combining supercritical extraction rectification and molecular distillation, and relates to the technical field of lithium battery electrolyte recovery. The method of the invention comprises the following steps: introducing the lithium battery electrolyte into an extraction and rectification tower, introducing supercritical carbon dioxide or supercritical carbon dioxide mixed with an entrainer at the bottom of the extraction and rectification tower, carrying out continuous countercurrent extraction, discharging the gas phase after extraction and rectification from the top of the extraction and rectification tower, and discharging the liquid phase from the bottom of the extraction and rectification tower; collecting a liquid phase discharged from the extraction and rectification tower, cooling to separate out solids, and separating the solids to obtain lithium salt; collecting gas phase discharged from the extraction and rectification tower, and decompressing to enable carbon dioxide to escape to obtain an organic solvent; and (3) separating the low-boiling-point organic solvent in the organic solvent by vacuum distillation, and separating the chain carbonate and the cyclic carbonate by molecular distillation. The method can efficiently separate the lithium salt and the organic solvent, separate the chain carbonate and the cyclic carbonate, and has high yield and high purity of the separated product.
Description
Technical Field
The invention relates to the technical field of lithium battery electrolyte recovery, in particular to a method for recovering lithium battery electrolyte by combining supercritical extraction rectification and molecular distillation.
Background
With the popularization of new energy automobiles in China, the use demand of lithium batteries increases year by year, waste lithium batteries are recycled, the harm to the environment is reduced, and the problem which needs to be solved in the sustainable development process of the lithium batteries is solved. The electrolyte of the lithium battery is a carrier for ion transmission between the positive electrode and the negative electrode in the lithium battery, and is an important component of the lithium battery. The lithium battery electrolyte mainly comprises lithium salt and an organic solvent, wherein the lithium salt mainly comprises lithium tetrafluoroborate (LiBF)4) Lithium hexafluorophosphate (LiPF)6) Lithium perchlorate (LiClO)4) And the like, the organic solvent mainly comprises cyclic carbonate, chain carbonate and the like, and the electrolyte is usually separated and recycled by adopting an extraction or rectification method in the prior art, but the problems of low recovery efficiency, low purity of the recovered product and the like still exist.
Disclosure of Invention
In view of the above, there is a need to provide a method for recovering lithium battery electrolyte by combining supercritical extractive distillation and molecular distillation, which can efficiently separate lithium salt and organic solvent, separate chain carbonate and cyclic carbonate in organic solvent, and has high yield and purity of separated product, thereby contributing to reducing environmental pollution.
The method for recovering the lithium battery electrolyte by combining supercritical carbon dioxide and molecular distillation comprises the following steps:
and (3) extraction and rectification: introducing the lithium battery electrolyte into an extraction and rectification tower, introducing supercritical carbon dioxide or supercritical carbon dioxide mixed with an entrainer at the bottom of the extraction and rectification tower, carrying out continuous countercurrent extraction, discharging the gas phase after extraction and rectification from the top of the extraction and rectification tower, and discharging the liquid phase from the bottom of the extraction and rectification tower;
and (3) lithium salt recovery: collecting a liquid phase discharged from the extraction and rectification tower, cooling to separate out solids, and separating the solids to obtain lithium salt;
separating an extracting agent: collecting gas phase discharged from the extraction and rectification tower, and decompressing to enable carbon dioxide to escape to obtain an organic solvent;
and (3) organic solvent separation: and (2) separating out a low-boiling-point organic solvent in the organic solvent by vacuum distillation, wherein the low-boiling-point organic solvent is an organic solvent with a boiling point lower than that of the chain carbonate, separating out the chain carbonate in the organic solvent by molecular distillation, separating out the cyclic carbonate by molecular distillation, and respectively recovering the low-boiling-point organic solvent, the chain carbonate, the cyclic carbonate and the electrolyte waste residue.
According to the method, the supercritical extraction rectification is adopted to separate the organic solvent and the lithium salt in the lithium battery electrolyte, and the vacuum distillation and the molecular distillation are utilized to separate the low-boiling-point organic solvent (such as an entrainer and the like), the chain carbonate and the cyclic carbonate in the organic solvent, so that the continuous rectification separation of the lithium battery electrolyte can be realized, the treatment capacity is large, the yield of the separated and recovered product is high, the purity is high, and the environmental pollution is favorably reduced.
Moreover, the distillation temperature of molecular distillation is far lower than the boiling point, the oxidation and the darkening of carbonic ester can be avoided in a high vacuum environment, and various components can be continuously and stably separated.
It is to be understood that the above-mentioned low-boiling organic solvent means an organic solvent having a boiling point lower than that of the chain carbonate in the system under the same pressure, for example, an entrainer and the like.
In one embodiment, the entrainer is selected from the group consisting of: one or more of absolute methanol, absolute ethanol or ethyl butyl ketone. Under normal pressure, the boiling point of absolute methanol is 64.7 ℃, the boiling point of absolute ethanol is 78.4 ℃, and the boiling point of ethyl butyl ketone is 75.6 ℃.
The ethyl butyl ketone has low viscosity, low boiling point, easy separation and moderate polarity, and simultaneously, the invention avoids the generation of toxic gases (such as HF, PF5 and the like) caused by the decomposition of conductive salts (electrolytes) in the air or water vapor in the dry carbon dioxide atmosphere.
In one embodiment, in the extractive distillation step, glass beads with the diameter of 2.5-10 mm are used as a filler in an extractive distillation tower, the height of the tower is 3-15 m, the inner diameter of the tower is 200-500 mm, ultrasonic treatment is performed while the extractive distillation is performed, the frequency of ultrasonic treatment is 25-100 KHz, and the power is 50-200W.
The glass beads do not react with the electrolyte, dirt is easy to clean, the porosity of the filler is large, the specific surface area is large, ultrasonic waves can be effectively transmitted, and full mass change is facilitated.
Ultrasonic treatment is beneficial to the dispersion of materials in the soaking process, the interphase mass transfer rate is accelerated, and the extraction efficiency is improved.
In one embodiment, in the extractive distillation step, the pressure in the extractive distillation tower is 25-35 MPa, and the temperature is 40-50 ℃.
In one embodiment, the temperature in the lithium salt recovery step is 35-45 ℃.
In one embodiment, in the extraction agent separation step, the pressure is 6-8 MPa, and the temperature is 50-55 ℃.
In one embodiment, in the organic solvent separation step, the vacuum degree of vacuum distillation is less than 2000Pa, and the temperature is 35-40 ℃; the vacuum degree is less than or equal to 50Pa when the chain-shaped carbonic ester is separated, and the temperature is 45-50 ℃; the vacuum degree is less than or equal to 1Pa when the cyclic carbonate is separated, and the temperature is 90-95 ℃.
In one embodiment, the method for recovering the lithium battery electrolyte is carried out in a lithium battery electrolyte separation and recovery system, wherein the lithium battery electrolyte separation and recovery system comprises an extraction rectifying tower, a separation kettle, a thin film evaporator, a first molecular distillation apparatus and a second molecular distillation apparatus which are sequentially and fluidly connected;
the extraction and rectification tower comprises a tower body and a jacket, wherein a light component outlet is formed in the top of the tower body, a heavy component outlet is formed in the bottom of the tower body, and a cavity is formed between the light component outlet and the heavy component outlet; the lower end of the tower body is provided with a supercritical fluid spray head, a material spray head is arranged above the supercritical fluid spray head, the supercritical fluid spray head and the material spray head are arranged oppositely, the supercritical fluid spray head is communicated with a supercritical fluid pipeline, and the material spray head is communicated with a material pipeline; the cavity between the supercritical fluid spray head and the material spray head is filled with fillers, and gaps are formed among the fillers for the supercritical fluid and the materials to exchange substances; the jacket is arranged on the outer wall of the tower body in a surrounding manner and used for heating the tower body;
a heavy component outlet of the extraction rectifying tower is connected with a collection kettle;
the extractive distillation step is carried out in an extractive distillation tower, the lithium salt recovery step is carried out in a collection kettle, the extractant separation step is carried out in the separation kettle, the vacuum distillation in the organic solvent separation step is carried out in the thin film evaporator, the separation of chain carbonate is carried out in the first molecular distillation apparatus, and the separation of cyclic carbonate is carried out in the second molecular distillation apparatus.
In the extraction and rectification tower, supercritical fluid (namely supercritical carbon dioxide) can be introduced into the tower body through the supercritical fluid nozzle, materials (lithium battery electrolyte) to be separated and recovered are introduced into the tower body through the material nozzle, the supercritical fluid rises, the materials descend, the components are uniformly dispersed by the filler, the supercritical fluid and the materials are fully contacted and changed, the materials comprise organic solvent, salt and other components, the solubility in the supercritical fluid is different, the organic solvent is dissolved in the supercritical fluid and rises along with the supercritical fluid to be taken out of the tower body, the salt and other heavy components are concentrated, and the heavy components are discharged and collected from a heavy component outlet below the tower body. Through the structure, the extraction and the rectification are integrated, the continuous countercurrent rectification is realized, the organic solvent and the salts in the material can be efficiently separated, the treatment continuity is high, the treatment capacity is large, the purity of the separated product is high, and the pollutants are few.
In the lithium battery electrolyte separation and recovery system, the supercritical fluid extraction rectifying tower is used for separating the organic solvent and the salts of the electrolyte, and the separation kettle is used for separating the organic solvent and the supercritical fluid; the supercritical fluid is sometimes mixed with entrainer to increase the solubility of the separated components in the gas phase, the electrolyte contains a plurality of organic solvents, so that the types of the organic solvents in the separation kettle are more, the system utilizes the thin film evaporator to separate the low-boiling-point organic solvents (such as the entrainer and the like) in the organic solvent mixed solution, and then utilizes the molecular distillation instrument to separate the organic solvents in the electrolyte respectively. The system can not only realize the separation of the organic solvent and the salts in the electrolyte, but also separate the organic solvent according to the boiling point difference, further improve the separation effect and be beneficial to the recycling of different types of organic solvents.
In one embodiment, the tower body is provided with an ultrasonic generator for generating ultrasonic waves to vibrate the filler.
In one embodiment, the tower body is formed by splicing a plurality of unit towers up and down, and the unit towers are mutually in fluid communication; the connecting part of two adjacent sections of unit towers is provided with a tower plate which separates the cavities of the two sections of unit towers; the height of the unit tower body is 1-5 m; the material spray head is arranged at the upper end of the unit tower.
Preferably, except the uppermost unit tower, the upper end of each other unit tower is provided with a material spray nozzle, a plurality of material spray nozzles can simultaneously introduce materials, and one of the material spray nozzles can also be selected to spray the materials. Different numbers of unit towers can be selected for extraction and rectification according to the treatment requirements.
The extraction and rectification efficiency can be further improved through a plurality of sections of unit towers, the quality change effect is improved, and the purity of a separated product is improved.
Preferably, the number of unit towers is 3.
In one embodiment, the material pipeline and part of the pipeline of the supercritical fluid pipeline are laid in the jacket in a surrounding manner, and the material in the material pipeline and the supercritical fluid in the supercritical fluid pipeline are preheated by a heat source in the jacket.
The material and the supercritical fluid need to be preheated before being introduced into the tower body, the material pipeline and the supercritical fluid pipeline are laid in the jacket, and the heat medium in the jacket can be utilized for preheating, so that the utilization rate of heat is improved.
In one embodiment, the supercritical fluid spray head is communicated with a confluence pipeline, the confluence pipeline is respectively connected with a supercritical fluid pipeline and an entrainer pipeline, and the supercritical fluid pipeline and the entrainer pipeline are arranged in parallel. By adopting the structure, the entrainer can be mixed in the supercritical fluid, and the entrainer can improve the solubility of the component to be separated in the gas component and improve the extraction efficiency.
In one embodiment, the separation kettle comprises a kettle body and a water jacket heating layer arranged on the outer wall of the kettle body, wherein the water jacket heating layer is used for heating the organic solvent mixed liquid in the kettle body, and a water injection port and a water discharge port are arranged on the water jacket heating layer.
In one embodiment, the collection vessel is in communication with the material conduit. Concentrated electrolyte in the collection kettle can enter the supercritical fluid extraction rectifying tower through the material pipeline to continue extraction and rectification, and the separation effect is further improved.
Compared with the prior art, the invention has the following beneficial effects:
according to the method for recycling the lithium battery electrolyte, the organic solvent and the lithium salt in the lithium battery electrolyte are separated by supercritical extraction rectification, and the low-boiling-point organic solvent, the chain carbonate and the cyclic carbonate in the organic solvent are separated by vacuum distillation and molecular distillation, so that the lithium battery electrolyte can be separated by continuous rectification, the processing capacity is large, the yield of the separated and recycled product is high, the purity is high, and the pollution to the environment is reduced.
Drawings
FIG. 1 is a schematic structural diagram of a supercritical fluid extractive distillation column in an embodiment.
FIG. 2 is a schematic diagram of the structure of a unit column in the example.
FIG. 3 is a schematic diagram of a lithium battery electrolyte separation and recovery system in an embodiment.
The device comprises a supercritical fluid extraction and rectification tower, a supercritical fluid extraction and rectification tower 11, a tower body 111, a light component outlet 112, a heavy component outlet 113, a unit tower 114, tower plates 115, sealing rings 12, a cavity 13, a supercritical fluid nozzle 131, a supercritical fluid pipeline 132, an entrainer pipeline 14, a material nozzle 141, a material pipeline 15, a filler 16, a jacket 17 and an ultrasonic generator; 2. the device comprises a collecting kettle, 3, a separating kettle, 31, a kettle body, 32, a water jacket heating layer, 4, a thin film evaporator, 5, a first molecular distillation instrument, 6 and a second molecular distillation instrument.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "coupled" to another element, it can be directly coupled to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Example 1
A supercritical fluid extraction rectifying tower 1 comprises a tower body 11 and a jacket 16, as shown in figure 1-2, the tower body 11 is formed by splicing three sections of unit towers 113 up and down, the bottom of the unit tower 113 is provided with internal threads, the top of the unit tower 113 is provided with external threads matched with the internal threads, and two adjacent sections of unit towers 113 are in threaded connection. To improve the sealing of the joint, a sealing ring 115 is provided at the joint. The outer wall of the tower body 11 is provided with a jacket 16, and the jacket 16 can heat the tower body 11. The height of the tower body 11 in this embodiment is 3m, the height of each unit tower 113 is 1m, and the inner diameter is 200 mm.
The tower body 11 is cylindrical, a light component outlet 111 is arranged at the top of the tower body, a heavy component outlet 112 is arranged at the bottom of the tower body, a cavity 12 is arranged between the light component outlet 111 and the heavy component outlet 112, and the cavity 12 provides a space for contacting materials and an extracting agent. The lower end of the lowermost unit tower 113 is provided with an upward supercritical fluid nozzle 13, the supercritical fluid nozzle 13 is communicated with a confluence pipeline, the confluence pipeline is respectively connected with a supercritical fluid pipeline 131 and an entrainer pipeline 132, the supercritical fluid pipeline 131 and the entrainer pipeline 132 are arranged in parallel, the supercritical fluid pipeline 131 is used for conveying supercritical fluid (such as supercritical carbon dioxide), the entrainer pipeline 132 is used for conveying entrainer (such as methanol, ethanol or ethyl butyl ketone), and the supercritical fluid and the entrainer can be mixed in the confluence pipeline and are introduced into the cavity 12. By controlling the valve, a supercritical fluid or a supercritical fluid mixed with an entrainer can be introduced into the cavity 12.
Except the uppermost unit tower 113, the upper ends of the other unit towers 113 are provided with downward material nozzles 14, and the material nozzles 14 are communicated with a material pipeline 141 and can introduce materials to be separated (such as lithium battery electrolyte) into the cavity 12. The bottom of each unit tower 113 is provided with a tower plate 114, the tower plate 114 can separate the adjacent unit towers 113, the tower plate 114 can also receive the packing 15, and the tower plate 114 is provided with a plurality of through holes, so that the liquid phase (material) can stay on the tower plate 114 and flow down, and the gas phase (supercritical fluid) can pass through the through holes and rise. The cavity 12 in each section of the unit tower 113 is filled with the filler 15, the filler 15 in the embodiment is glass beads with the diameter of 2.5-10 mm, the glass beads do not react with the electrolyte, dirt is easy to clean, the porosity of the filler 15 is large, the specific surface area is large, and sufficient mass change is facilitated. The mode of the single unit tower 113 or the mode of the multiple unit towers 113 connected in series can be adjusted by adjusting the pipes and valves connected to each unit tower 113.
In order to further improve the extractive distillation effect, an ultrasonic generator 17 is disposed at the bottom of the lowermost unit column 113 for generating ultrasonic waves to vibrate the packing 15. Preferably, the sonication frequency is 50-100 KHz. Ultrasonic treatment is beneficial to the dispersion of materials in the soaking process, the interphase mass transfer rate is accelerated, and the extraction efficiency is improved.
Generally, the material and the supercritical fluid need to be preheated, and in order to improve the heat utilization rate, part of pipelines of the material pipeline 141 and the supercritical fluid pipeline 131 are laid in the jacket 16 in a surrounding manner, and the heat medium in the jacket 16 is used for preheating.
Example 2
An electrolyte separation and recovery system, as shown in fig. 3, includes a supercritical fluid extraction rectification tower 1, a collection kettle 2, a separation kettle 3, a thin film evaporator 4, a first molecular distillation apparatus 5 and a second molecular distillation apparatus 6 which are fluidly connected in sequence, where the supercritical fluid extraction rectification tower 1 is the supercritical fluid extraction rectification tower 1 in example 1.
The heavy component outlet 112 of the supercritical fluid extraction rectification tower 1 is connected with the collection kettle 2, and the collection kettle 2 is used for collecting the concentrated electrolyte after extraction rectification. In order to further improve the separation and purification effect, the collection kettle 2 is connected with a material pump on the material pipeline 141, the concentrated electrolyte in the collection kettle 2 can be pumped into the material pipeline 141, and is introduced into the tower body 11 through the material spray head 14 to continue the extraction and rectification. The separation kettle 3 is used for collecting organic solvent, the separation kettle 3 comprises a kettle body 31 and a water jacket heating layer 32 arranged on the outer wall of the kettle body 31, the water jacket heating layer 32 is used for heating the organic solvent in the kettle body 31, and the water jacket heating layer 32 is provided with a water injection port and a water discharge port which are respectively used for injecting hot water and discharging the hot water. The thin film evaporator 4 is used to distill off the low boiling point organic solvent. The first molecular still 5 is for separating the chain carbonate, and the second molecular still 6 is for separating the cyclic carbonate.
Example 3
A method for recycling lithium battery electrolyte by combining supercritical extraction rectification and molecular distillation is carried out by adopting the electrolyte separation and recovery system in embodiment 2.
And cleaning the waste lithium ion battery, and carrying out complete discharge treatment. The battery and the prepared charging bucket are put into a glove box protected by high-purity nitrogen, the battery is opened, and the electrolyte is carefully taken out and put into the charging bucket. The electrolyte of the waste lithium battery mainly comprises lithium salt and an organic solvent, and also contains a certain amount of impurities. The lithium salt includes lithium tetrafluoroborate, lithium hexafluorophosphate, lithium perchlorate, etc., and the organic solvent includes cyclic carbonate and chain carbonate. The cyclic carbonate mainly comprises ethylene carbonate and propylene carbonate, and the chain carbonate comprises dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and ethyl propyl carbonate.
The specific processing flow is as follows:
1) starting three unit towers 113, sequentially named as a first unit tower, a second unit tower and a third unit tower from bottom to top, introducing supercritical carbon dioxide to the bottom of the first unit tower, and introducing materials (namely lithium battery electrolyte) to the upper ends of the first unit tower and the second unit tower. The height of the tower is 3 meters, and the inner diameter of the tower is 200 mm. The extraction pressure in the supercritical fluid extraction rectifying tower 1 is controlled to be 35MPa, the extraction temperature is controlled to be 45 ℃, and the circulation time is controlled to be 1 h. Meanwhile, the ultrasonic frequency is 25KHz and the power is 50W. The total flow of the materials in the tower is 1kg/h, and the circulation flow of the supercritical carbon dioxide is 2 kg/h.
2) Through the extractive distillation of the supercritical fluid extractive distillation tower 1, the concentrated electrolyte flows into the collection kettle 2 through the heavy component outlet 112, the temperature in the collection kettle 2 is controlled to be 40 ℃, and lithium salt is separated out.
3) The organic solvent in the electrolyte is dissolved in the extracting agent, enters the separation kettle 3 along with the extracting agent, and is detected by ICP OES (inductively coupled plasma emission spectrometer), and the organic solvent extract is recovered and does not contain lithium element. The pressure in the separation vessel 3 was controlled to 6MPa at 50 ℃ and carbon dioxide was released to a 4 ℃ storage tank and liquefied. The carbon dioxide can be recycled.
4) And (3) introducing the organic solvent in the separation kettle 3 into the thin film evaporator 4, controlling the vacuum degree in the thin film evaporator 4 to be 1000Pa and the temperature to be 35 ℃, and distilling out 2 wt% of low-boiling-point organic matters.
5) Introducing the residual components in the step 4) into a first molecular distillation apparatus 5, controlling the vacuum degree to be 50Pa and the temperature to be 50 ℃, and distilling out the chain carbonate mixture (the yield is more than 95%). In the first molecular still 5, the mixture of chain carbonates is a light component, and the cyclic carbonates containing impurities are a heavy component. Under normal pressure, the boiling point of dimethyl carbonate is 90.1 ℃, the boiling point of diethyl carbonate is 110 ℃, the boiling point of ethyl methyl carbonate is 109.2 ℃ and the boiling point of ethyl propyl carbonate is 90.0 ℃.
6) The cyclic carbonate containing impurities is introduced into a second molecular distillation apparatus 6, the vacuum degree is controlled to be 1Pa, the temperature is controlled to be 95 ℃, and the cyclic carbonate mixture is distilled out (the yield is more than 95 percent). In the second molecular distillation apparatus 6, the cyclic carbonate mixture is a light component, and the electrolyte waste residue is a heavy component. At normal pressure, the boiling point of ethylene carbonate is 243.0 ℃ and the boiling point of propylene carbonate is 240.0 ℃.
It can be seen that the distillation temperature of the molecular distillation is much lower than the boiling point of the carbonate at normal pressure, so that the oxidation of the carbonate can be effectively avoided, and the color of the carbonate can be prevented from being darkened.
In this example, no entrainer was introduced and the overall recovery of organic solvent was about 75%.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A method for recovering lithium battery electrolyte by combining supercritical extraction rectification and molecular distillation is characterized by comprising the following steps:
and (3) extraction and rectification: introducing the lithium battery electrolyte into an extraction and rectification tower, introducing supercritical carbon dioxide or supercritical carbon dioxide mixed with an entrainer at the bottom of the extraction and rectification tower, carrying out continuous countercurrent extraction, discharging the gas phase after extraction and rectification from the top of the extraction and rectification tower, and discharging the liquid phase from the bottom of the extraction and rectification tower;
and (3) lithium salt recovery: collecting a liquid phase discharged from the extraction and rectification tower, cooling to separate out solids, and separating the solids to obtain lithium salt;
separating an extracting agent: collecting gas phase discharged from the extraction and rectification tower, and decompressing to enable carbon dioxide to escape to obtain an organic solvent;
and (3) organic solvent separation: and (2) separating out a low-boiling-point organic solvent in the organic solvent by vacuum distillation, wherein the low-boiling-point organic solvent is an organic solvent with a boiling point lower than that of the chain carbonate, separating out the chain carbonate in the organic solvent by molecular distillation, separating out the cyclic carbonate by molecular distillation, and respectively recovering the low-boiling-point organic solvent, the chain carbonate, the cyclic carbonate and the electrolyte waste residue.
2. The method as claimed in claim 1, wherein in the step of extractive distillation, glass beads with the diameter of 2.5-10 mm are used as packing in an extractive distillation tower, the height of the tower is 3-15 m, the inner diameter of the tower is 200-500 mm, ultrasonic treatment is carried out while the extractive distillation is carried out, the frequency of ultrasonic treatment is 25-100 KHz, and the power is 50-200W.
3. The method as claimed in claim 1, wherein in the step of extractive distillation, the pressure in the extractive distillation column is 25-35 MPa, and the temperature is 40-50 ℃.
4. The method according to claim 1, wherein the temperature in the lithium salt recovery step is 35 to 45 ℃.
5. The method according to claim 1, wherein in the extractant separating step, the pressure is 6-8 MPa, and the temperature is 50-55 ℃.
6. The method according to claim 1, wherein in the organic solvent separation step, the vacuum degree of vacuum distillation is < 2000Pa, and the temperature is 3540 ℃; the vacuum degree is less than or equal to 50Pa when the chain-shaped carbonic ester is separated, and the temperature is 45-50 ℃; the vacuum degree is less than or equal to 1Pa when the cyclic carbonate is separated, and the temperature is 90-95 ℃.
7. The method according to any one of claims 1 to 6, wherein the recovery of the lithium battery electrolyte is carried out in a lithium battery electrolyte separation and recovery system, and the lithium battery electrolyte separation and recovery system comprises an extractive distillation tower, a separation kettle, a thin film evaporator, a first molecular distillation apparatus and a second molecular distillation apparatus which are sequentially and fluidly connected;
the extraction and rectification tower comprises a tower body and a jacket, wherein a light component outlet is formed in the top of the tower body, a heavy component outlet is formed in the bottom of the tower body, and a cavity is formed between the light component outlet and the heavy component outlet; the lower end of the tower body is provided with a supercritical fluid spray head, a material spray head is arranged above the supercritical fluid spray head, the supercritical fluid spray head and the material spray head are arranged oppositely, the supercritical fluid spray head is communicated with a supercritical fluid pipeline, and the material spray head is communicated with a material pipeline; the cavity between the supercritical fluid spray head and the material spray head is filled with fillers, and gaps are formed among the fillers for the supercritical fluid and the materials to exchange substances; the jacket is arranged on the outer wall of the tower body in a surrounding manner and used for heating the tower body;
a heavy component outlet of the extraction rectifying tower is connected with a collection kettle;
the extractive distillation step is carried out in an extractive distillation tower, the lithium salt recovery step is carried out in a collection kettle, the extractant separation step is carried out in the separation kettle, the vacuum distillation in the organic solvent separation step is carried out in the thin film evaporator, the separation of chain carbonate is carried out in the first molecular distillation apparatus, and the separation of cyclic carbonate is carried out in the second molecular distillation apparatus.
8. The method of claim 7, wherein the tower body is provided with an ultrasonic generator for generating ultrasonic waves to vibrate the packing.
9. The method of claim 7, wherein the tower body is formed by splicing a plurality of unit towers up and down, wherein the unit towers are in fluid communication with each other; the connecting part of two adjacent sections of unit towers is provided with a tower plate which separates the cavities of the two sections of unit towers; the height of the unit tower body is 1-5 m; the material spray head is arranged at the upper end of the unit tower.
10. The method according to any one of claims 8 or 9, wherein the material pipeline and a part of the pipeline of the supercritical fluid pipeline are laid around the jacket, and the material in the material pipeline and the supercritical fluid in the supercritical fluid pipeline are preheated by a heat source in the jacket.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114243145A (en) * | 2021-12-09 | 2022-03-25 | 深圳市爱派思新能源科技有限公司 | Method for recovering electrolyte of waste lithium ion battery |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2561484Y (en) * | 2002-02-07 | 2003-07-23 | 武汉凯迪精细化工有限公司 | Fractionating rectifying tower for supercritical carbon dioxide fluid continuous countercurrent extraction |
| JP5360328B1 (en) * | 2013-06-04 | 2013-12-04 | Ｊｏｉｎｔエンジニアリング株式会社 | Method and apparatus for simultaneously recovering lithium salt for electrolyte and organic solvent from waste electrolyte |
| US20170073827A1 (en) * | 2015-09-15 | 2017-03-16 | Kabushiki Kaisha Toshiba | Producing system of reduction product |
| CN108288738A (en) * | 2018-01-30 | 2018-07-17 | 常州大学 | A method of lithium-ion battery electrolytes are recycled using supercritical carbon dioxide fluid |
| CN108565519A (en) * | 2018-04-10 | 2018-09-21 | 佛山市欧特克朗科技有限公司 | A kind of waste lithium cell electrolyte recycling processing method |
| CN110203949A (en) * | 2019-07-19 | 2019-09-06 | 郑州中科新兴产业技术研究院 | A kind of full recovery method of waste and old lithium ionic cell electrolyte |
| CN111573953A (en) * | 2020-06-22 | 2020-08-25 | 湖南航盛新能源材料有限公司 | Method and device for treating waste lithium ion battery electrolyte |
| CN212631834U (en) * | 2020-06-02 | 2021-03-02 | 中国科学技术大学先进技术研究院 | Supercritical extraction-molecular distillation combined device |
-
2021
- 2021-06-30 CN CN202110736506.9A patent/CN113471515A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2561484Y (en) * | 2002-02-07 | 2003-07-23 | 武汉凯迪精细化工有限公司 | Fractionating rectifying tower for supercritical carbon dioxide fluid continuous countercurrent extraction |
| JP5360328B1 (en) * | 2013-06-04 | 2013-12-04 | Ｊｏｉｎｔエンジニアリング株式会社 | Method and apparatus for simultaneously recovering lithium salt for electrolyte and organic solvent from waste electrolyte |
| US20170073827A1 (en) * | 2015-09-15 | 2017-03-16 | Kabushiki Kaisha Toshiba | Producing system of reduction product |
| CN108288738A (en) * | 2018-01-30 | 2018-07-17 | 常州大学 | A method of lithium-ion battery electrolytes are recycled using supercritical carbon dioxide fluid |
| CN108565519A (en) * | 2018-04-10 | 2018-09-21 | 佛山市欧特克朗科技有限公司 | A kind of waste lithium cell electrolyte recycling processing method |
| CN110203949A (en) * | 2019-07-19 | 2019-09-06 | 郑州中科新兴产业技术研究院 | A kind of full recovery method of waste and old lithium ionic cell electrolyte |
| CN212631834U (en) * | 2020-06-02 | 2021-03-02 | 中国科学技术大学先进技术研究院 | Supercritical extraction-molecular distillation combined device |
| CN111573953A (en) * | 2020-06-22 | 2020-08-25 | 湖南航盛新能源材料有限公司 | Method and device for treating waste lithium ion battery electrolyte |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114243145A (en) * | 2021-12-09 | 2022-03-25 | 深圳市爱派思新能源科技有限公司 | Method for recovering electrolyte of waste lithium ion battery |
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