KR101708149B1 - A Method For Recovering Lithium Compound From An Anode Material In Spent Lithium Batteries By Wet-Milling - Google Patents

Abstract

The present invention relates to a method for recovering a lithium compound from spent lithium battery cathode material. The method according to the present invention comprises the steps of: mixing a cathode material separated from a spent lithium battery, polybasic acid and water; and wet-milling the mixture to produce an aqueous leachate and water insolubles. The method for recovering a lithium compound from a spent lithium battery cathode material according to the present invention has advantages over conventional methods using inorganic acids, including hydrochloric acid, sulfuric acid and nitric acids, in that environmental pollution can be reduced and in that the process is simple so that lithium can be recovered at low costs. Furthermore, the method of the present invention has higher leaching efficiency than methods of leaching a cathode material using an organic acid such as oxalic acid, citric acid, maleic acid or tartaric acid, and thus it can achieve recovery of the lithium compound with high purity at a high recovery rate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for recovering a lithium compound from a spent lithium battery cathode material using a wet pulverization method,

The present invention relates to a method for recovering a lithium compound from a spent lithium battery cathode material. More particularly, the present invention relates to a method for recovering a lithium compound having a high recovery rate and high purity through a wet pulverization method.

Lithium batteries are widely used as secondary batteries because of their excellent charge / discharge performance and high energy density, and are widely used in small electronic products such as mobile phones and notebooks. Recently, development of large-capacity lithium batteries has been actively developed as the spread of electric vehicles becomes more visible.

Lithium battery Lithium contained in the positive electrode material is a very expensive metal, which is not produced domestically and is imported from abroad. Therefore, in view of the characteristics of a country without resources such as Korea and the prevention of environmental pollution by heavy metals, lithium is recovered from a cathode material scrap that is generated in a lithium battery manufacturing process or a lithium battery anode material which is disposed after use and reused need.

In a conventional method for extracting or recovering various metals such as lithium from a lithium battery cathode material, a cathode material separated from a spent lithium battery is extracted with a strong acid such as hydrochloric acid, sulfuric acid and nitric acid, and then neutralized with an alkali to produce cobalt, nickel, And a step of dissolving the cathode material with sulfuric acid or nitric acid in the presence of hydrogen peroxide and then separating and recovering the metal by the neutralization precipitation method has been generally used. However, since hydrochloric acid, sulfuric acid, and nitric acid, which are inorganic acids, are used in known processes for dissolving the above-mentioned cathode materials, since strong acids must be used in the extraction process, serious environmental pollution due to evaporation into the atmosphere, The problem is very serious.

In order to solve the above problem, a method of leaching an anode material using an organic acid such as oxalic acid, citric acid, maleic acid or tartaric acid has been disclosed. However, the leaching rate is slower than that of strong acid, There is a drawback that the recovery rate is lowered.

In order to improve the leaching efficiency using the organic acid, it is necessary to remove the binder and the conductive material contained in the cathode material in advance by using a heat treatment process or the like. This causes an uneconomical disadvantage in terms of time and cost do.

1. Patent Publication No. 10-1220672 (Mar. 01, 2013) 2. Patent Publication No. 10-1049937 (Jul. 11, 2011)

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a lithium- And a method of recovering the product at a high purity.

One aspect of the present invention for solving the above problems is a lithium secondary battery comprising a waste lithium battery anode including a cathode material separated from a waste lithium battery, a polybasic acid, and water, followed by wet pulverization to produce water leachate and water- And recovering the lithium compound from the material.

The present aspect may further include a purification step of separating the water leachate and the water-insoluble matter into filtration residues and filtrate, and removing impurities from the separated filtrate.

In the case of recovering the lithium compound from the cathode material of the spent lithium battery according to the method of the present invention, it is possible to reduce environmental pollution as compared with the conventional method using inorganic acid such as hydrochloric acid, sulfuric acid and nitric acid, There is an advantage that the compound can be recovered.

In addition, the leaching efficiency is excellent as compared with a method of leaching the positive electrode material using an organic acid such as oxalic acid, citric acid, maleic acid or tartaric acid, and consequently, recovery of a lithium compound having a high recovery rate and high purity can be achieved.

1 is a flowchart schematically illustrating a method of recovering a lithium compound from a cathode material of a waste lithium battery according to an aspect of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings may be exaggerated for clarity of description, and the elements denoted by the same reference numerals in the drawings are the same elements.

The present invention relates to a method for recovering a lithium compound having a high recovery rate and high purity from a waste lithium battery cathode material through a wet pulverization method. FIG. 1 schematically shows a flow chart of a method of recovering a lithium compound from a cathode material of a spent lithium battery according to an aspect of the present invention.

Referring to FIG. 1, one aspect of the present invention relates to a method for producing a waste lithium battery, which comprises mixing a positive electrode material separated from a waste lithium battery, a polybasic acid, and water, followed by wet pulverization to produce water leachate and water- And recovering the lithium compound from the cathode material.

The positive electrode material is pulverized to a very fine particle size while being subjected to a wet grinding process, and at the same time, the lithium component is leached by the polybasic acid.

Examples of the positive electrode material include, but are not limited to, lithium cobalt oxide (LiCoO ₂ ), lithium cobalt nickel manganese oxide (LiCoxNiyMnzO ₂ , x + y + z = 1), lithium cobalt nickel oxide (LiCoxNiO ₂ , x + y (LiN x Al y O ₂ , x + y = 1) system, lithium manganese oxide (LiMnO ₂ ) system, lithium manganese phosphate oxide (LiMnPO ₄ ) system, lithium iron phosphate oxide (LiFePO ₄ ) Lithium nickel cobalt aluminum oxide (LiNixCoyAlzO ₂ , x + y + z = 1) system may be used alone or in combination.

The cathode material separated from the spent lithium battery may contain, in addition to the oxide component, a binder, a conductive material, and other additives added when forming the anode plate. This is because only the substrate (for example, aluminum substrate) can be removed from the anode of the spent lithium battery and then used.

As the polybasic acid, a dibasic acid, a tribasic acid, a dibasic acid, a dibasic acid, and a dibasic acid in which two or more carboxy (-COOH) groups are present in the molecule may be used alone or in combination. Although only a pyrophosphoric acid has been described here, it is not limited thereto, and a base acid having a carboxyl group further may be used.

The polybasic acid has high acidity so that it can dissolve the anode material and form a salt with the metal ion. A lithium salt formed by combining a polybasic acid with lithium which is a monovalent metal dissolves in water while a salt formed by combining a polybasic acid with a divalent metal such as nickel, cobalt and manganese can be made insoluble in water It should be acid. Therefore, a monobasic acid is not suitable, and a polybasic acid having a carbon chain longer than a dibasic acid can not be used.

Dibasic acid refers to a compound having two carboxyl groups in the molecule. Tribasic acid refers to a compound having three carboxyl groups in its molecule. As the polybasic acid, an anhydride or a hydrate may be used. For example, in the case of oxalic acid, oxalic acid anhydride or oxalic acid dihydrate can be used.

Examples of dibasic acids include oxalic acid, malonic acid, malic acid, fumaric acid, maleic acid, succinic acid, glutaric acid Adipic acid, tartaric acid, pimelic acid, suberic acid, sebacic acid, and phthalic acid), adipic acid, aspartic acid, Can be used alone or in combination.

Examples of the tribasic acid include citric acid, isocitric acid, aconitic acid, propane-1,2,3-tricarboxylic acid, , Benzene-1,3,5-tricarboxylic acid and 5-sulfo-1,2,4-benzenetricarboxylic acid (5-sulfo-1,2, 4-benzenetricarboxylic acid) may be used alone or in combination.

Examples of the tetrabasic acid include ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3-tetracarboxylic acid, -1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3 Cyclopentane-1,2,3,4-tetracarboxylic acid, and benzene-1,2,4,5-tetracarboxylic acid. Benzene-1,2,3,4,5-pentacarboxylic acid is used as the contaminated base, and benzene-1,2,3,4,5-pentacarboxylic acid is used as the contaminated base. As the physicochemical acid, benzene-1,2,3,4,5,6-hexacarboxylic acid (mellitic acid) can be used.

As the water, it is preferable to use distilled water or purified water. When water containing impurities such as tap water is used, an unexpected side reaction may occur between the impurity and the starting material.

The wet pulverization can be performed after mixing the positive electrode material obtained from the spent lithium battery with the polybasic acid component and water. Through the wet pulverization process, the cathode material is pulverized into a very fine particle size, and at the same time, the lithium component can be leached by the polybasic acid.

The apparatus used in the wet grinding process may be a conventional wet mill capable of temperature control. Specifically, but not limited to, a beads mill, a ball mill, an attrition mill, an apex mill, a super mill or a basket mill ) Can be selected and used.

In the wet grinding process, the content ratio of the cathode material and the polybasic acid can be determined in consideration of the equivalence ratio of the reaction occurring during the leaching process. The reaction that takes place during the leaching process is that the anode material is dissolved in the polybasic acid and the metal component and the polybasic acid component in the cathode material are ion-bonded to form a salt. The content of the polybasic acid is preferably 100 to 300 equivalents, preferably 120 to 200 equivalents relative to 100 equivalents of the cathode material. If the amount of the polybasic acid component is less than 100 equivalents relative to 100 equivalents of the cathode material, the recovery efficiency of the lithium compound is lowered, and if it exceeds 300 equivalents, it is uneconomical. The reaction of the anionic material with the polybasic acid occurring during the leaching process is not mentioned as it is a known fact.

The amount of water to be added in the wet pulverizing step is preferably 500 to 10,000 parts by weight per 100 parts by weight of the cathode material. If the amount of water is less than 500 parts by weight based on 100 parts by weight of the positive electrode material, the amount of lithium dissolved and leached is insufficient. If the amount of water exceeds 10,000 parts by weight, the amount of lithium leached does not increase even if the amount of water is increased. Because it is uneconomical.

The wet grinding time varies depending on the type of equipment and the process conditions, but it is preferably carried out for 30 minutes to 6 hours. If the wet milling time is less than 30 minutes, the amount of lithium dissolved and leached is insufficient, and when it exceeds 6 hours, the amount of lithium to be leached is not increased, which is uneconomical.

In this aspect, wet milling can be performed by further mixing a reducing agent. When the reducing agent is added, the rate of lithium component leaching of the positive electrode material by the polybasic acid can be improved.

As the reducing agent, carbon, ascorbic acid, sodium borohydride, and hydrogen peroxide (H2O2) may be used alone or in combination.

The amount of the reducing agent is preferably 0.5 to 10 parts by weight relative to 100 parts by weight of the positive electrode material. When the amount of the reducing agent is less than 0.5 part by weight based on 100 parts by weight of the positive electrode material, the effect of improving the lithium component leaching rate is insignificant. When the amount of the reducing agent is more than 10 parts by weight,

In this aspect, wet milling can be performed after further mixing of an anionic surfactant. Addition of an anionic surfactant can improve the crushability of the cathode material.

Examples of anionic surfactants include, but are not limited to, carboxylic acid salts, sulfonic acid salts, sulfuric acid ester salts, phosphoric acid ester salts, phosphonic acid salts, alkylbenzenesulfonic acid salts, -olefin sulfonic acid salts, alkyl sulfuric acid ester salts, Ester salts and alkane sulfonic acid salts may be used alone or in combination.

The content of the anionic surfactant is preferably 0.1 to 5 parts by weight relative to 100 parts by weight of the positive electrode material. When the content of the anionic surfactant is less than 0.1 parts by weight based on 100 parts by weight of the positive electrode material, the effect is insignificant. When the amount of the anionic surfactant is more than 5 parts by weight, the effect of improving the crushability of the positive electrode material is less than the amount added with the anionic surfactant,

When the wet grinding process is completed, water leachate and water insoluble matter are produced. In this aspect, the water leachate and the water insoluble material are separated by filtration to separate the filtrate and the filtrate, and impurities are separated from the separated filtrate And a purification process step of removing the purification process. The lithium compound having a high purity can be obtained through a purification process.

The filtration process can be performed using a conventional filtration device, and the filtration rate can be improved by using the reduced pressure filtration.

The water-insoluble filtrate residue components obtained through the filtration process are compounds containing metal components such as cobalt, nickel or manganese, which can be used for recovering valuable metals according to generally known purification and processing methods. However, since the present invention does not include the recovery of metals other than lithium, the process for recovering valuable metals is not mentioned.

Since the filtrate obtained in the filtration step contains not only the compound having lithium component but also other impurities dissolving in water, the purification process can be performed after the filtration step. The purification process may be performed by a precipitation method using difference in solubility, a solvent extraction method using an organic solvent and an extractant, a method using an ion exchange resin, and a concentration method, either alone or in combination.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the embodiments.

<Examples>

First, lithium nickel cobalt manganese composite oxide system (NCM (523)) was cut from the waste cathode material of the lithium battery, and then the aluminum material was removed without removing the binder and the conductive material to prepare 500 g of the cathode material.

The prepared anode material was subjected to component analysis using ICP (Perkin Elmer Optima 7000DV), and the results are shown in Table 1. Based on the results of ICP analysis, each component was expressed in terms of weight ratio. The components and the contents of the binder and the conductive material in the anode material were not analyzed.

ingredient Li Ni Co Mn Na Mg Ca Al Cu Fe content
(wt%) 4.88 29.45 11.81 16.52 0.05 0.01 0.01 1.62 0.54 0.16

The reason why the Li content in Table 1 is lower than the composition ratio of the NCM (523) active material itself is because lithium intercalated in the cathode exists.

As the polybasic acid, reagent grade oxalic acid · dihydrate, maleic acid, tartaric acid and 4-hydroxyphthalic acid were prepared. As a reducing agent, reagent grade ascorbic acid was prepared. As the surfactant, reagent grade sodium lauryl sulfate was prepared.

Subsequently, the positive electrode material, the polybasic acid, the water (distilled water), the reducing agent, and the surfactant were put into a wet pulverizer, followed by wet pulverization. The composition ratios are shown in Table 2. The amount of water was adjusted to 200 ml. Fritsch's planetery ball mill was used as the wet grinding machine. The vessel size was 500 ml (zirconia material), the ball was zirconia (φ 0.5 mm, 20 g + φ 0.1 mm, 4 g) Was set at 500 r / min and the crushing time was fixed at 1 hour. Wet mill cooling was carried out using the operating ON / OFF time program.

Anode material Polybasic acid reducing agent Surfactants Example 1 4g Oxalic acid · dihydrate, 7.59 g 0 0 Example 2 4g Oxalic acid · dihydrate, 7.59 g Ascorbic acid, 0.2 g 0 Example 3 4g Oxalic acid · dihydrate, 7.59 g Ascorbic acid, 0.2 g Sodium lauryl sulfate
0.1 g Example 4 4g Maleic acid, 6.99 g 0 0 Example 5 4g Tartaric acid, 9.04 g 0 0 Example 6 4g 4-hydroxyphthalic acid, 10.97 g 0 0 Comparative Example 1 4g Oxalic acid · dihydrate, 7.59 g 0 0 Comparative Example 2 4g Maleic acid, 6.99 g 0 0 Comparative Example 3 4g 4-hydroxyphthalic acid, 10.97 g 0 0

Next, after completion of water leaching through a wet grinding process, filtration under reduced pressure was performed using an aspirator and a glass filter (fine filter).

Next, a small amount (about 50 ml) of water filtered through the glass filter was poured in several times to sufficiently wash the filtration residue. The filtration residue obtained through the filtration process was subjected to a series of procedures for recovering valuable metals with compounds containing components such as cobalt, nickel and manganese. (However, since the present invention does not include the recovery of metals other than lithium, the process for recovering valuable metals is not mentioned.)

Next, the filtrate obtained through the filtration process was purified according to the following procedure. 1) A stirrer and a pH meter were installed in a container containing the filtrate obtained in the filtration step, and sodium carbonate powder was gradually added thereto while slowly stirring at room temperature to adjust the pH of the filtrate to 9. 2) Thereafter, stirring was further continued for 30 minutes, and then ethanol was added to make the total solution 1000 ml. 3) and then stirred for 1 hour to allow the formation of a precipitate. 4) It was filtered with a glass filter to obtain a precipitate, and the precipitate filtered through the glass filter was sufficiently washed with ethanol.

Next, the precipitate was dried in a vacuum oven at 120 DEG C for 24 hours to obtain lithium carbonate as a final lithium compound. It is a well-known fact that the lithium compound obtained through the purification process is lithium carbonate.

<Comparative Example>

A lithium compound was obtained through the same procedure as in Example 1 except that a positive electrode material, a polybasic acid and water were added to a 500 ml round flask equipped with a stirrer instead of the wet pulverization and stirred for 3 hours.

<Component analysis for lithium compound>

Lithium content and impurity content of the finally obtained lithium compound were analyzed by ICP analysis equipment. Based on the results of ICP analysis, the components are shown in Table 3 in terms of weight ratio.

Final yield amount Lithium carbonate Recovery rate water Example 1 0.99g 0.97 g 93.3% 98.0% Example 2 1.01 g 0.99g 95.3% 98.0% Example 3 1.03 g 1.00 g 96.2% 97.1% Example 4 0.99g 0.98 g 94.3% 99.0% Example 5 0.99g 0.97 g 93.3% 98.0% Example 6 0.97 g 0.95 g 91.4% 97.9% Comparative Example 1 0.95 g 0.85g 81.8% 89.5% Comparative Example 2 0.97 g 0.86g 82.8% 88.7% Comparative Example 3 0.92 g 0.81 g 77.9% 88.0%

In Table 3, the final amount is the weight of the lithium compound dried in a drying oven at 120 캜 for 24 hours, and the amount of lithium carbonate is the weight calculated on the basis of the ICP analysis results of the final lithium compound, Represents the ratio of the amount of lithium carbonate obtained relative to the content, and the purity represents the ratio of lithium carbonate in the final obtained lithium compound.

From the above results, it can be seen that the recovery rate and the purity of the lithium compound of the Examples are significantly higher than those of Comparative Examples. However, there was a slight difference in recovery rate and purity of the lithium compound depending on the kind and amount of the polybasic acid and addition of additives.

As a result, when recovering lithium from the cathode material of the spent lithium battery according to the method of the present invention, compared with the conventional method using inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, environmental pollution can be minimized because no strong acid is used , It can be confirmed that high purity lithium can be obtained at a high recovery rate as compared with the conventional lithium compound recovery process using an organic acid.

The terms used in the present invention are intended to illustrate specific embodiments and are not intended to limit the invention. The singular presentation should be understood to include plural meanings, unless the context clearly indicates otherwise. The word "comprises" or "having" means that there is a feature, a number, a step, an operation, an element, or a combination thereof described in the specification. The present invention is not limited to the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. something to do.

Claims (13)

A polybasic acid for leaching a lithium component present in the positive electrode material, a reducing agent for improving the leaching rate of the lithium component, an anionic surfactant for improving the crushability of the positive electrode material, and water A wet milling and leaching step of pulverizing the positive electrode material by wet milling after the milling apparatus is pulverized and simultaneously leaching the lithium component with a polybasic acid to produce a water leachate and a water-insoluble product;
A filtration step of separating the water leachate and the water-insoluble matter into a filtrate residue and a filtrate;
And a purifying step of adding impregnation to the filtrate with stirring and with addition of sodium carbonate and ethanol to remove impurities from the filtrate,
The amount of the polybasic acid is 100 to 300 equivalents based on 100 equivalents of the positive electrode material,
The amount of the water is 500 to 10,000 parts by weight based on 100 parts by weight of the cathode material,
The amount of the reducing agent is 0.5 to 10 parts by weight based on 100 parts by weight of the positive electrode material,
Wherein the anionic surfactant is used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the positive electrode material.
delete The lithium _secondary battery according to claim 1, wherein the positive electrode material is selected from the group consisting of lithium cobalt oxide (LiCoO ₂ ), lithium cobalt nickel manganese oxide (LiCoxNiMnZO ₂ , x + y + z = 1), lithium cobalt nickel oxide (LiCoxNiO ₂ , (LiN x Al y O ₂ , x + y = 1) system, lithium manganese oxide (LiMnO ₂ ) system, lithium manganese phosphate oxide (LiMnPO ₄ ) system, lithium iron phosphate oxide (LiFePO ₄ ) A method for recovering a lithium compound from a spent lithium battery cathode material using lithium nickel cobalt aluminum oxide (LiNixCoyAlzO ₂ , x + y + z = 1) system singly or in combination.
The method according to claim 1, wherein the polybasic acid is a dibasic acid, a tribasic acid, a tetrabasic acid, a dibasic acid, and a hypobaric acid, either singly or in combination.
The dibasic acid according to claim 4, wherein the dibasic acid is selected from the group consisting of oxalic acid, malonic acid, malic acid, fumaric acid, maleic acid, succinic acid, Glutaric acid, adipic acid, aspartic acid, tartaric acid, pimelic acid, suberic acid, sebacic acid, ) And phthalic acid are used alone or in combination. The method for recovering a lithium compound from a cathode material of a spent lithium battery.
5. The method of claim 4, wherein the tribasic acid is selected from the group consisting of citric acid, isocitric acid, aconitic acid, propane-1,2,3-tricarboxylic acid, 2,3-tricarboxylic acid, benzene-1,3,5-tricarboxylic acid and 5-sulfo-1,2,4-benzenetricarboxylic acid (5 -sulfo-1,2,4-benzenetricarboxylic acid), either alone or in combination, is used to recover the lithium compound from the spent lithium battery cathode material.
5. The method according to claim 4, wherein the tetrabasic acid is ethane-1,1,2,2-tetracarboxylic acid, propane-1,1,2,3 Propane-1,1,2,3-tetracarboxylic acid, butane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,3,4-tetracarboxylic acid, Cyclopentane-1,2,3,4-tetracarboxylic acid and benzene-1,2,4,5-tetracarboxylic acid (benzene-1,2, 4,5-tetracarboxylic acid) are used alone or in combination, and as the contaminating acids, benzene-1,2,3,4,5-pentacarboxylic acid (benzene-1,2,3,4,5- pentacarboxylic acid) as a solvent and a benzene-1,2,3,4,5,6-hexacarboxylic acid as a pyrogenic acid, a method of recovering a lithium compound from a cathode material of a spent lithium battery .
The method according to claim 1, wherein the wet grinding is performed using a beads mill, a ball mill, an attrition mill, an apex mill, a super mill, and a basket mill mill), either alone or in combination, to recover the lithium compound from the spent lithium battery cathode material.
delete 2. The method of claim 1, wherein the reducing agent is selected from the group consisting of a carbonaceous material, ascorbic acid, sodium borohydride, and hydrogen peroxide (H ₂ O ₂ ) A method for recovering a lithium compound from a cathode material.
delete The anionic surfactant according to claim 1, wherein the anionic surfactant is selected from the group consisting of carboxylic acid salts, sulfonic acid salts, sulfuric acid ester salts, phosphoric acid ester salts, phosphonates, alkylbenzenesulfonic acid salts, A method for recovering a lithium compound from a waste lithium battery cathode material, wherein the ester salt and the alkane sulfonate are used singly or in combination. delete

Images