KR102822630B1 - Method for manufacturing organic acid based deep eutectic solvents and re-using after valuable metal recovery - Google Patents

Abstract

The present invention comprises a first step of preparing black powder, a second step of first separating lithium from the black powder prepared in the first step through a pretreatment process, a third step of leaching the black powder from which the lithium is first separated into DES to provide a first solvent, the third step comprising a third-1 step of preparing the DES in which a hydrogen bond acceptor and a hydrogen bond donor are synthesized at a certain molar ratio for leaching the black powder, and a third-2 step of introducing the black powder into the DES, a fourth step of providing a second solvent in which nickel is separated from the first solvent through a first filtration process, a fifth step of coagulating the second solvent into an organic acid through a first coagulation process, the fifth step comprising a fifth-1 step in which at least one of ultrapure water, distilled water, or an organic acid for coagulation is introduced for coagulation into an organic acid, and the second solvent coagulated into the organic acid is separated into cobalt and manganese through a second filtration process. The present invention provides a solvent regeneration method, comprising: a 6th step in which a third solvent is provided; a 7th step in which the third solvent is coagulated and precipitated into ethanol through a second coagulation process; an 8th step in which lithium is secondarily separated from the third solvent coagulated with ethanol through a third filtration process; a 9th step which is a post-addition process including a 9-1 step in which DES used in the third solvent from which lithium is secondarily separated is recovered; and a 9th step in which at least one of the hydrogen bond acceptor and the hydrogen bond donor is added to correct the molar ratio of the DES to regenerate the recovered DES; and a 10th step in which the corrected DES is supplied to the 3rd step for reuse.

Description

{Method for manufacturing organic acid based deep eutectic solvents and re-using after valuable metal recovery}

The present invention relates to a method for recovering resources from waste batteries, and to a method for recovering metal resources including lithium, nickel, cobalt, manganese, etc., which are valuable battery metals, and regenerating the solvent using DES (Deep Eutectic Solvent).

Recently, as awareness of greenhouse gas emissions has increased, the proportion of electric vehicles is increasing day by day. Electric vehicles are powered by electricity instead of conventional fossil fuels, and the electricity is stored and used using lithium-ion batteries (LIBs). As the sales of such electric vehicles increase exponentially, the production of LIBs is also rapidly increasing. However, since the lifespan of automotive LIBs is expected to be 7-10 years, the amount of waste batteries is expected to increase exponentially starting around 2028. Since waste batteries cannot be disposed of as general waste due to fire hazards and toxic metal content, separate storage, processing, and reuse methods are being discussed. It is reported that the cost of LIBs in electric vehicles is approximately 40%, and the largest cost of this is the cathode material, which is estimated to account for approximately 40% of the cost of LIBs. Various materials such as LiCoO ₂ (LCO), Li(Ni,Co,Al)O ₂ (NCA), LiMn ₂ O ₄ (LMO), and Li(Ni,Co,Mn)O ₂ (NCM) are applied as automotive LIB cathode materials, and it is considered a promising field where added value can be created through recycling when processing waste batteries. Since it does not use fossil fuels, it does not emit environmental pollutants, and due to the advantages of low maintenance costs, the amount of batteries used and discarded is increasing as the use of electric vehicles increases.

Since electric vehicle batteries contain many resources with economic value, such as cobalt, nickel, and lithium, recycling waste batteries is not only environmentally friendly, but also has the advantage of reducing battery manufacturing costs.

The domestic waste battery recycling industry is centered on wet refining, and there are ongoing issues regarding environmental friendliness and safety.

In addition, major advanced countries such as the EU's Core Materials Act and the New Battery Directive are promoting regulations on mandatory use of recycled raw materials in battery products, and a surge in demand for recycled raw materials from domestic battery export companies is expected. As of 2023, the amount of waste batteries generated for domestic EVs is estimated at 1,451 units, which is insignificant compared to meeting the mandatory use of recycled raw materials. Therefore, securing recycled raw materials for waste batteries is an urgent matter for the domestic battery industry, which is highly dependent on exports.

Therefore, there is a need to develop innovative recycling technologies to secure recycled raw materials from domestic and foreign waste battery resources.

Chinese Patent Publication No. 117276731 relates to the field of waste lithium-ion battery recovery and processing, and relates to a method for recovery and regeneration of waste lithium-ion battery cathode materials using DES (Deep Eutectic Solvent). It discloses a technology for leaching lithium, nickel, cobalt, and manganese using DES, and only discloses a hydrogen bond acceptor (guanidine hydrochloride) and a hydrogen bond donor (fomic acid), and does not disclose DES synthesis using choline chloride.

Chinese Patent Publication No. 116751987 relates to a method for recovering a spent lithium ion battery cathode material, and discloses a hydrogen bond acceptor comprising at least one of choline chloride, betaine, formamide, and acetamide as a eutectic solvent, and a hydrogen bond donor comprising at least one of formic acid, acetic acid, propionic acid, butyric acid, valeric acid, oxalic acid, malonic acid, succinic acid, and glutaric acid. The invention discloses choline chloride:formic acid molar ratios of 1:1, 1:2, 1:4, and 1:5, and provides data for different leaching times, polishing times, and heating temperatures. However, the invention differs from the present invention in that it does not consider regeneration of the solvent.

Chinese Patent Publication No. 116676484 relates to a deep eutectic solvent for selectively leaching valuable metals from spent lithium batteries, wherein the solvent is synthesized in which betaine hydrochloride is a hydrogen bond acceptor and formic acid is used as a hydrogen bond donor, and the molar ratio is 1:7 to 12, preferably 1:9. However, it does not disclose DES synthesis using choline chloride.

Chinese Patent Publication No. 115216620 relates to a method for recovering nickel, cobalt and manganese precipitates step by step from spent ternary lithium batteries, wherein at least one of formic acid, acetic acid, oxalic acid, citric acid, tartaric acid, malic acid, lactic acid and ascorbic acid is used as a hydrogen bond donor, and at least one of choline chloride, succinylcholine chloride, acetylcholine chloride and bethanechol chloride is used as a hydrogen bond acceptor. However, it does not disclose specific efficiency, etc. for DES synthesized using choline chloride and formic acid.

Chinese Patent Application Publication No. 117418106 relates to a method for recovering lithium, nickel, cobalt and manganese from spent ternary lithium batteries by a step-by-step leaching method. The hydrogen bond donors include 2.5 to 5 mol/L of acid, acetic acid, oxalic acid, citric acid, tartaric acid, malic acid, lactic acid and ascorbic acid, and the hydrogen bond acceptors include 3 to 8 mol/L of choline chloride, succinylcholine chloride, acetylcholine chloride and carbamoyl choline chloride. However, the specific efficiency of DES synthesized using choline chloride and formic acid is not disclosed.

Chinese Patent Publication No. 114300777 relates to a method for recovering lithium battery cathode powder, which includes choline chloride as a hydrogen bond acceptor and uses 3-hydroxypyridine, 2-cyanophenol, 4-cyanophenol, and p-nitrophenol as hydrogen bond donors, but does not disclose the synthesis of choline chloride and formic acid.

Although DES using choline chloride and formic acid is disclosed in the above prior art, the solvent regeneration targeted in the present invention is not disclosed, and thus, a specific regeneration process is not disclosed.

Chinese Patent Publication No. 117276731 Chinese Patent Publication No. 116751987 Chinese Patent Publication No. 116676484 Chinese Patent Publication No. 115216620 Chinese Patent Publication No. 117418106 Chinese Patent Publication No. 114300777

The present invention is intended to solve the above problems, and provides a method for efficiently recovering a regenerative raw material from a spent battery using DES synthesized using choline chloride and formic acid, and then regenerating the solvent.

In order to achieve these purposes, a first step of preparing black powder, a second step of first separating lithium from the black powder prepared in the first step through a pretreatment process, a third step of leaching the black powder from which the lithium was first separated into DES to provide a first solvent, the third step including a third-1 step of preparing the DES in which a hydrogen bond acceptor and a hydrogen bond donor are synthesized at a certain molar ratio for leaching the black powder, and a third-2 step of introducing the black powder into the DES, a fourth step of providing a second solvent in which nickel is separated from the first solvent through a first filtration process, a fifth step of coagulating the second solvent into an organic acid through a first coagulation process, the fifth step including a fifth-1 step in which at least one of ultrapure water, distilled water, or an organic acid for coagulation is introduced for coagulation into an organic acid, and the second solvent coagulated into the organic acid is separated into cobalt and manganese through a second filtration process. The present invention provides a solvent regeneration method, comprising: a 6th step in which a third solvent is provided; a 7th step in which lithium is coagulated and precipitated with ethanol through a second coagulation process in the third solvent; an 8th step in which lithium is secondarily separated from the third solvent coagulated with ethanol through a third filtration process; a 9th step which is a post-addition process including a 9-1 step in which DES used in the third solvent from which lithium is secondarily separated is recovered; and a 9th step in which at least one of the hydrogen bond acceptor and the hydrogen bond donor is added to correct the molar ratio of the DES to regenerate the recovered DES; and a 10th step in which the corrected DES is supplied to the 3rd step for reuse.

Additionally, the hydrogen bond donor may include at least one of formic acid, thiourea, glycerol, urea, lactic acid, oxalic acid, malonic acid, ascorbic acid, ethylene glycol, and citric acid.

Additionally, the hydrogen bond acceptor may include one or more of choline chloride, glycine, zinc chloride (ZnCl ₂ ), betaine, iron III chloride (FeCl ₃ ), and proline.

In addition, the DES synthesized in the above step 3-1 can be synthesized at 0°C to 120°C with a molar ratio of hydrogen bond acceptor and hydrogen bond donor of 1:1 to 1:5.

In addition, the above pretreatment process can selectively utilize one or more of washing, distillation, ion exchange membrane, ion exchange resin, electrodeposition, and coprecipitation.

In addition, the first filtration process, the second filtration process, and the third filtration process may selectively use one or more of the following methods: filter filtration, washing, distillation, ion exchange membrane, ion exchange resin, electrodeposition, and coprecipitation.

In addition, the above pretreatment process, the first filtration process, the second filtration process, and the third filtration process may utilize at least one of a chemical-resistant liquid filter having pores of 0.1 ㎛ to 1.0 ㎛ or centrifugation.

In addition, in order to improve the leaching efficiency of the black powder into DES, one or more of the following conditions may be adjusted.

1) Control of DES supply amount, leaching time, stirring speed and leaching temperature

2) DES raw material mixing ratio adjustment

3) One or more means or methods of wet milling, ultrasonic, stirring, vibration, circulation, fluidization, bubbling, vortex, drum, paddle and mixer.

In addition, the 9-2 step of correcting the molar ratio of the DES may add at least one of a hydrogen bond acceptor and a hydrogen bond donor to the DES.

The present invention can also be provided in a form in which various means for solving the above problems are combined.

As described above, the present invention uses DES using organic acid and choline chloride instead of a large amount of leaching solvent (inorganic acid), so that the inorganic acid and extraction solvent for each metal can be omitted and recycled, thereby reducing the generation of wastewater, waste, and hazardous gases generated in the conventional wet refining process.

In addition, by resolving the problems of excessive energy use and greenhouse gas emissions in conventional dry refining, carbon emissions can be significantly reduced in the waste battery recycling process.

In addition, concerns about a decline in the domestic secondary battery business can be resolved by smoothly supplying high-quality recycled raw materials to secondary battery material manufacturers.

Additionally, waste can be reduced because _sodium sulfate ( _Na2SO4 ) is not generated.

Additionally, process simplification is possible and profitability can be increased.

Additionally, the working environment can be improved by using non-toxic/non-flammable, environmentally friendly solvents.

Figure 1 illustrates a process flow for extracting valuable metals from black powder processed from waste batteries using DES according to one embodiment of the present invention, regenerating the used DES, and reusing it to extract valuable metals again.
Figure 2 shows the results of the total metal element analysis using inductively coupled plasma spectroscopy to demonstrate the purity of DES regenerated through this process.
Figure 3 is an example of HBA and HBD that can be used in the manufacture of DES.
Figure 4 is a multi-circulation filtration system (multi-pass) that can utilize chemical-resistant filters with a filtration performance of 0.1 to 1 micron, which can be used in the regeneration process, in series and in parallel.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those with ordinary knowledge in the technical field to which the present invention pertains can easily practice the present invention. However, when describing the operating principle of a preferred embodiment of the present invention in detail, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

Also, the same drawing symbols are used for parts that have similar functions and actions throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only cases where it is directly connected, but also cases where it is indirectly connected with other elements in between. Also, including a certain component does not mean excluding other components unless specifically stated otherwise, but rather means that other components can be included.

Additionally, the description specifying or adding elements may be applied to all inventions unless there is a special limitation, and is not limited to a description of a specific invention.

Additionally, throughout the description and claims of the invention herein, any reference to the singular includes the plural unless otherwise stated.

Additionally, throughout the description and claims of the present invention, the term "or" includes "and" unless stated otherwise. Therefore, "comprising A or B" means all three cases of including A, including B, or including A and B.

The present invention is described in detail with examples according to the drawings.

FIG. 1 is a flow diagram illustrating a process for extracting valuable metals using DES from black powder processed from waste batteries, regenerating the used DES, and reusing it to extract valuable metals again according to an embodiment of the present invention. FIG. 2 is a result of analyzing all metal elements using inductively coupled plasma spectroscopy to demonstrate the purity of DES regenerated through the process. FIG. 3 is an example of HBA and HBD that can be utilized in the production of DES. FIG. 4 is a multi-circulation filtration system (multi-pass) that can utilize chemical-resistant filters having a filtration performance of 0.1 to 1 micron in series and parallel that can be utilized in the regeneration process.

A first step for preparing black powder, a second step for first separating lithium from the black powder prepared in the first step through a pretreatment process, a third step for providing a first solvent by leaching the black powder from which the lithium is first separated into DES, the third step including a third-1 step for preparing the DES in which a hydrogen bond acceptor and a hydrogen bond donor are synthesized at a certain molar ratio for leaching the black powder, and a third-2 step for introducing the black powder into the DES, a fourth step for providing a second solvent in which nickel is separated from the first solvent through a first filtration process, a fifth step for coagulating the second solvent into an organic acid through a first coagulation process, the fifth step including a fifth-1 step in which at least one of ultrapure water, distilled water, or an organic acid for coagulation is introduced for coagulation into an organic acid, and a third solvent in which cobalt and manganese are separated from the second solvent coagulated into the organic acid through a second filtration process is provided. The present invention provides a solvent regeneration method, comprising: a 6th step; a 7th step of coagulating and precipitating lithium with ethanol through a second coagulation process in the third solvent; an 8th step of secondarily separating lithium from the third solvent coagulated with ethanol through a third filtration process; a 9th step which is a post-addition process including a 9-1 step of recovering DES used in the third solvent from which the lithium was secondarily separated; and a 9th step of correcting the molar ratio of DES by adding at least one of the hydrogen bond acceptor and the hydrogen bond donor to regenerate the recovered DES; and a 10th step of supplying the corrected DES to the 3rd step for reuse.

In addition, a step 7-1 for introducing ethanol used in the above step 7 may be additionally included.

Additionally, the hydrogen bond donor may include at least one of formic acid, thiourea, glycerol, urea, lactic acid, oxalic acid, malonic acid, ascorbic acid, ethylene glycol, and citric acid.

Additionally, the hydrogen bond acceptor may include one or more of choline chloride, glycine, zinc chloride (ZnCl ₂ ), betaine, iron III chloride (FeCl ₃ ), and proline.

In addition, the DES synthesized in the above step 3-1 can be synthesized at 0°C to 120°C with a molar ratio of hydrogen bond acceptor and hydrogen bond donor of 1:1 to 1:5.

In addition, the above pretreatment process can selectively utilize one or more of the following methods: filter filtration, washing, distillation, ion exchange membrane, ion exchange resin, electrodeposition, and coprecipitation.

In addition, the first filtration process, the second filtration process, and the third filtration process may selectively use one or more of the following methods: filter filtration, washing, distillation, ion exchange membrane, ion exchange resin, electrodeposition, and coprecipitation.

In addition, the above pretreatment process, the first filtration process, the second filtration process, and the third filtration process may utilize at least one of a chemical-resistant liquid filter having pores of 0.1 ㎛ to 1.0 ㎛ or centrifugation.

Additionally, the above chemical resistant liquid filter may be a PTFE (polytetrafluoroethylene) liquid filter.

In addition, in order to improve the leaching efficiency of the black powder into DES, one or more of the following conditions may be adjusted.

1) Control of DES supply amount, leaching time, stirring speed and leaching temperature

2) DES raw material mixing ratio adjustment

3) One or more means or methods of wet milling, ultrasonic, stirring, vibration, circulation, fluidization, bubbling, vortex, drum, paddle and mixer.

Step 9-2 of correcting the molar ratio of the above DES may include adding at least one of a hydrogen bond acceptor and a hydrogen bond donor to the DES.

Additionally, the DES recovered for correction in step 9-2 may be DES removed after ethanol has been coagulated and precipitated.

Additionally, the above-mentioned circular resources may be rare metals or valuable metals generated in the waste battery recycling process.

The above recycling method may be a method of recovering circular resources by using an eco-friendly DES synthesized using an organic acid and choline chloride instead of the conventional wet refining method using sulfuric acid as a leaching solution.

In addition, the above-mentioned common solvent can be a non-toxic, non-flammable solution synthesized by simply mixing organic acid or ethylene glycol with choline chloride, and is an efficient solvent that can be reused after leaching of the renewable raw material.

Additionally, the above DES (Deep Eutectic Solvent; DES) may be a deep eutectic solvent.

Additionally, the above choline chloride may be a Hydrogen Bond Acceptor (HBA).

Additionally, the organic acid may be a Hydrogen Bond Donor (HBD).

In addition, the above DES can be implemented as a Natural DES, and for this purpose, sugars, organic acids, alcohols, amines, amino acids, etc. can be used.

In addition, the organic acid may also be other types of organic acids not described in the present invention.

Additionally, the above 0℃ may include room temperature.

In addition, if the organic acid in the above synthesis is formic acid, it can be synthesized at room temperature, and other than formic acid, if it can be synthesized at room temperature or is efficient, it can be used.

Additionally, the ratio may be preferably 1:1 to 1:5, and 1:2 may be more preferable.

Additionally, the above ratio may be a molar ratio.

In addition, the synthesis is preferably performed at 0°C to 120°C, but more preferably can be performed at 0°C to 100°C.

Additionally, in the second to fourth steps, the color of DES can gradually change from black to emerald or from emerald to pink.

Additionally, in the fifth step, the color of the DES may change from pink to cloudy pink.

Additionally, the amount of hydrogen bond donor added in the fifth step may be 0.5 to 2 times that of the black powder.

Additionally, a filter having pores of 0.05 μm to 0.5 μm can be used to remove sediment in the fifth step.

In addition, a step 5-2 may be additionally included in which reduced pressure distillation is performed at 40°C to 80°C to remove the ultrapure water and distilled water introduced in the step 5-1.

Additionally, the above step 5-1 can be performed for 0.1 to 2 hours.

Additionally, when ethanol is added in the above step 7, DES or hydrogen bond donor may evaporate.

Additionally, in the seventh step, the color of DES can be changed to white.

Additionally, in the above step 8, a filter having pores of 0.05 μm to 0.5 μm can be used to remove sediment.

In addition, a step 7-2 may be additionally included in which reduced pressure distillation is performed at 40°C to 80°C to remove ethanol introduced in step 7-1.

Additionally, the above step 7-2 can be performed for 0.1 to 2 hours.

Additionally, at least one of the hydrogen bond acceptor or hydrogen bond donor added in the above step 9 may be added so that the amount of DES is the amount of DES that has passed through the above steps 2 to 8.

Anyone with ordinary knowledge in the field to which the present invention belongs will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (9)

Step 1: Preparing black powder;
A second step of initially separating lithium from the black powder prepared in the first step through a pretreatment process;
A third step in which the first solvent is provided by leaching the black powder from which the lithium is first separated into DES;
The third step includes a third step of preparing the DES by synthesizing a hydrogen bond acceptor and a hydrogen bond donor at a certain molar ratio for black powder leaching, and a third step of introducing the black powder into the DES.
A fourth step of providing a second solvent from which nickel is separated through a first filtration process in the first solvent;
A fifth step of coagulating with an organic acid through a first coagulation process in the above second solvent;
The above-mentioned fifth step includes the fifth-first step in which at least one of ultrapure water, distilled water or organic acid for coagulation is added for coagulation with an organic acid.
Step 6: providing a third solvent from which cobalt and manganese are separated through a second filtration process using the second solvent coagulated with the organic acid;
Step 7 of coagulating and precipitating the third solvent into ethanol through a second coagulation process;
Step 8 of secondary separation of lithium through a third filtration process from the third solvent coagulated with the above ethanol;
Step 9, which is a post-addition process including step 9-1 of recovering DES used in the third solvent from which the lithium is secondarily separated, and step 9-2 of correcting the molar ratio of DES by adding at least one of the hydrogen bond acceptor and the hydrogen bond donor to regenerate the recovered DES; and
A solvent regeneration method comprising a 10th step of supplying the above-mentioned corrected DES to the above-mentioned 3rd step for reuse.
In the first paragraph,
A solvent regeneration method wherein the hydrogen bond donor comprises at least one of formic acid, thiourea, glycerol, urea, lactic acid, oxalic acid, malonic acid, ascorbic acid, ethylene glycol, and citric acid.
In the first paragraph,
A solvent regeneration method wherein the hydrogen bond acceptor comprises at least one of choline chloride, glycine, zinc chloride (ZnCl ₂ ), betaine, iron III chloride (FeCl ₃ ), and proline.
In the first paragraph,
The DES synthesized in the above step 3-1 is a solvent regeneration method in which a hydrogen bond acceptor and a hydrogen bond donor are synthesized at a molar ratio of 1:1 to 1:5 at 0°C to 120°C.
In the first paragraph,
The above pretreatment process is a solvent regeneration method that selectively uses one or more of washing, distillation, ion exchange membrane, ion exchange resin, electrodeposition, and coprecipitation.
In the first paragraph,
The above first filtration process, second filtration process and third filtration process are solvent regeneration methods that selectively use one or more of filter filtration, washing, distillation, ion exchange membrane, ion exchange resin, electrodeposition and coprecipitation.
In the first paragraph,
The above pretreatment process, the first filtration process, the second filtration process and the third filtration process are a solvent regeneration method using at least one of a chemical-resistant liquid filter having pores of 0.1 ㎛ to 1.0 ㎛ or centrifugation.
In the first paragraph,
A solvent regeneration method for improving the leaching efficiency of the above black powder with DES by controlling at least one of the following conditions.
1) Control of DES supply amount, leaching time, stirring speed and leaching temperature
2) DES raw material mixing ratio adjustment
3) One or more means or methods of wet milling, ultrasonic, stirring, vibration, circulation, fluidization, bubbling, vortex, drum, paddle and mixer.
In the first paragraph,
Step 9-2 of correcting the molar ratio of the above DES is a solvent regeneration method of adding at least one of a hydrogen bond acceptor and a hydrogen bond donor to the DES.