KR20240124660A - Method of recovering valuable metals from waste cathode materials or complex metal compounds - Google Patents

Abstract

The present invention relates to a method for recovering valuable metals from waste cathode materials or composite metal compounds.

Description

{METHOD OF RECOVERING VALUABLE METALS FROM WASTE CATHODE MATERIALS OR COMPLEX METAL COMPOUNDS}

The present invention relates to a method for recovering valuable metals from waste cathode materials or composite metal compounds.

A lithium ion battery (LIB) is a secondary battery composed of a cathode, anode, a separator, and an electrolyte, and is charged and discharged through the insertion and delamination reactions of lithium ions. Lithium ion batteries have high energy density and can exhibit high capacity, so they are used as a power source for electronic devices as well as automobiles.

With the increase in electric vehicles, the demand for lithium-ion batteries is also rapidly increasing. The cathode material composed of a composite oxide is important enough to account for more than 60% of the total battery manufacturing cost. Accordingly, the demand for lithium, nickel, manganese, and cobalt, which are the main metals that make up the cathode, is increasing explosively. However, since the reserves of the above main metals are limited, the reuse or recycling of used lithium-ion batteries is becoming an increasingly important issue from an economic perspective. Among them, recycling technology is gradually becoming important because it can extract expensive main metal components after dismantling discarded batteries and use them as raw materials for manufacturing new lithium-ion batteries.

The recycling methods of spent batteries can be divided into three types: direct recycling, pyro-metallurgy, and hydro-metallurgy. Among them, the hydro-metallurgy method is a widely used technology because it can selectively separate only active metals and requires low energy costs. The current hydro-metallurgy process focuses on recycling cathode materials containing major metal components after dismantling spent batteries.

Cathode materials are composite oxides synthesized through a solid-state reaction of lithium and a metal precursor, and their type and performance vary depending on the combination of metal components. The most representative cathode material currently used is a material denoted as LiNi _{1 -xy} Mn _x Co _y O ₂ (lithium nickel manganese cobalt oxide; NMC), in which nickel, manganese, and cobalt are all dissolved in the cobalt position in the LiCoO 2 structure. When the ratio of Ni:Mn:Co is 1:1:1, it is denoted as 'NMC-111', and when the ratio of Ni:Mn:Co is 8:1:1, it is denoted as 'NMC-811'. In addition, composite oxide cathode materials with nickel cobalt aluminum (NCA) and lithium iron phosphate (LFP) compositions are being used.

The wet metallurgical method generally uses an acidic aqueous solution to extract the desired metal from the cathode material. In particular, all the powder in the cathode is dissolved with a strong acid such as sulfuric acid or hydrochloric acid, and components unrelated to the electrode material such as iron or aluminum are purified through precipitation from the molten solution, and then the active metals are sequentially recovered while increasing the pH. Although it is slightly different for each process, manganese, cobalt, and nickel are generally separated in that order through a selective precipitation method. Lithium is converted to lithium carbonate, and then recovered as lithium hydroxide through an evaporation and concentration process.

Among the extraction reagents reported so far, a relatively widely used combination is sulfuric acid and hydrogen peroxide (H ₂ SO ₄ /H ₂ O ₂ ). Many studies have been conducted to achieve the optimal extraction efficiency of the reagent, and the main variables include acid concentration, extraction time, extraction temperature, solid-liquid ratio, and reducing agent addition. Many previous studies have confirmed that the extraction efficiency increases when hydrogen peroxide is used as an additive. Here, hydrogen peroxide is known to act as a reducing agent that converts insoluble Co(Ⅲ) material into soluble Co(Ⅱ).

Although the wet metallurgical process has the advantage of being able to extract active valuable metals through a relatively easy acid treatment process, it has problems such as using a large amount of strong acid such as sulfuric acid and generating a lot of wastewater that is harmful to the environment because various solvents are used for additional separation. Therefore, if a new method is developed that can extract useful metals while suppressing the excessive use of strong acid and the type or amount of solvent, it is expected that discarded lithium-ion batteries can be recycled in a more environmentally friendly and economical way.

Republic of Korea Patent Publication No. 10-2020-0096965.

The present invention provides a method for recovering valuable metals from waste cathode materials or composite metal compounds.

However, the problems that the present invention seeks to solve are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

The first aspect of the present invention provides a method for recovering valuable metals, comprising catalytically reacting waste cathode material or a composite metal compound; nitric acid; carbon dioxide; and hydrogen to obtain metal and ammonia compounds.

The second aspect of the present invention provides a ruthenium oxide catalyst, which is represented by the following chemical formula Ⅰ and has a monoclinic crystal structure, and is used in the method for recovering a valuable metal according to the first aspect:

[Chemical Formula I]

H _x RuO ₂ ;

In the above chemical formula I, 0< x ≤4.

The method for recovering valuable metals according to the embodiments of the present invention can implement an environmentally friendly process by reducing the amount of wastewater generated compared to conventional recovery methods because it does not use an excessive amount of strong acid.

The method for recovering valuable metals according to the embodiments of the present invention can supplement the shortage of valuable metals supplied from natural ores.

The method for recovering valuable metals according to the embodiments of the present invention can recover high-quality valuable metals from waste cathode materials or composite metal compounds through a single process, compared to conventional wet metallurgical processes.

The method for recovering valuable metals according to the embodiments of the present invention may produce expensive ammonia compounds as a side effect.

The yield ratio of the valuable metal that can be obtained using the method for recovering the valuable metal according to the embodiments of the present invention may be about 60% or more, about 70% or more, about 80% or more, about 85% or more, about 90% or more, about 95% or more, about 98% or more, or about 99% or more.

The catalyst used in the method for recovering valuable metals according to the embodiments of the present invention is economical because it does not melt or lose its structure during the reaction, so the reaction can be performed for a long time, and can be separated and recovered after the reaction and reused.

The method for recovering valuable metals according to the embodiments of the present invention can reduce carbon dioxide by using captured carbon dioxide as a reactant.

FIG. 1 is a schematic diagram of a reaction for obtaining lithium carbonate, cobalt carbonate, and ammonia compounds by catalytically reacting nitric acid, carbon dioxide, and hydrogen including LiCoO ₂ in one embodiment of the present invention.
FIG. 2 is a powder X-ray diffraction graph of lithium carbonate (Li ₂ CO ₃ ) manufactured according to Example 1 of the present invention.
Figure 3 is a powder X-ray diffraction analysis graph of cobalt carbonate (CoCO ₃ ) manufactured according to Example 1 of the present invention.
FIG. 4 is a powder X-ray diffraction analysis graph of ammonium bicarbonate (NH ₄ HCO ₃ ) manufactured according to Example 1 of the present invention.
Figure 5 is a powder X-ray diffraction analysis graph of a precipitate separated according to Example 2 of the present invention.
Figure 6 is a powder X-ray diffraction analysis graph of NH ₄ FePO ₄ ·H ₂ O manufactured according to Example 5 of the present invention.

Hereinafter, with reference to the attached drawings, the implementation examples and embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be implemented in various different forms and is not limited to the implementation examples and embodiments described herein. In addition, in order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are assigned similar drawing reference numerals throughout the specification.

Throughout this specification, when a part is said to be "connected" to another part, this includes not only the case where it is "directly connected" but also the case where it is "electrically connected" with another element in between.

Throughout this specification, when it is said that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where there is another element between the two elements.

Throughout this specification, whenever a part is said to "include" a component, this does not exclude other components, but rather includes other components, unless otherwise specifically stated.

The terms “about,” “substantially,” and the like, as used in this specification, are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly utilizing the disclosure in which exact or absolute values are mentioned to aid the understanding of the present application.

The terms “step of” or “step of” as used throughout this specification do not mean “step for”.

Throughout this specification, the term "combination(s) thereof" included in the expressions in the Makushi format means one or more mixtures or combinations selected from the group consisting of the components described in the Makushi format, and means including one or more selected from the group consisting of said components.

Throughout this specification, references to “A and/or B” mean “A or B, or A and B.”

Below, the implementation examples of the present invention are described in detail, but the present invention may not be limited thereto.

The first aspect of the present invention provides a method for recovering valuable metals, comprising catalytically reacting waste cathode material or a composite metal compound; nitric acid; carbon dioxide; and hydrogen to obtain metal and ammonia compounds.

In one embodiment of the present invention, if the waste cathode material is a material that can be applied to a cathode material that is used in the present technical field or is expanded according to the development of the present technical field, the scope to which the present invention can be applied can be expanded. For example, the waste cathode material can include at least one selected from Li, Ni, Co, Mn, Al, and Fe, and can be NCM (nickel-cobalt-manganese), NCA (nickel-cobalt-aluminum), or LFP (lithium-iron phosphate).

In one embodiment of the present invention, the complex metal compound may include at least one selected from Li, Ni, Co, Mn, Al, and Fe, and may be, for non-limiting examples, an oxide, a phosphate, or a sulfide.

In one embodiment of the present invention, the metal may be obtained as a single element or an ionic compound. The compound may be obtained as a salt, and its type is not particularly limited. As a non-limiting example, the compound may be a carbonate, a phosphate, or a sulfate.

In one embodiment of the present invention, the metal included in the composite metal compound and the metal obtained may include a material that can be applied to a cathode material used in the present technical field or expanded with the development of the present technical field. For example, the metal included in the composite metal compound and the metal obtained may include one or more metals selected from Li, Ni, Mn, Co, Fe, and Al.

In one embodiment of the present invention, the concentration of the nitric acid can be from about 0.1 M to about 5 M. In one embodiment of the present invention, the concentration of the nitric acid can be from about 0.1 M to about 5 M, from about 0.1 M to about 4 M, from about 0.1 M to about 3 M, from about 0.1 M to about 2 M, from about 0.1 M to about 1 M, from about 1 M to about 5 M, from about 1 M to about 4 M, from about 1 M to about 3 M, from about 1 M to about 2 M, from about 2 M to about 5 M, from about 2 M to about 4 M, from about 2 M to about 3 M, from about 3 M to about 5 M, from about 3 M to about 4 M, or from about 4 M to about 5 M. In one embodiment of the present invention, when the concentration of the nitric acid is less than about 0.1 M, the formation rate of the carbonate metal compound is slow, and when it exceeds about 5 M, the reaction may not proceed due to high acidity, but is not limited thereto.

In one embodiment of the present invention, the catalyst may be selected from a metal, alloy or oxide including at least one selected from titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au).

In one embodiment of the present invention, the catalyst may include ruthenium oxide represented by the following chemical formula Ⅰ:

[Chemical Formula I]

H _x RuO ₂ ;

In the above chemical formula I, 0< x ≤4.

In one embodiment of the present invention, when the diameter of the particles of the catalyst is about 10 nm or less, the reaction activity may be enhanced, but may not be limited thereto. In one embodiment of the present invention, the diameter of the particles of the catalyst may be about 10 nm or less, about 8 nm or less, about 6 nm or less, or about 4 nm or less.

In one embodiment of the present invention, the catalyst does not melt or its structure collapse during the reaction, so the reaction can be performed for a long period of time.

In one embodiment of the present invention, the catalyst can be separated and recovered after the reaction is completed and reused.

In one embodiment of the present invention, it is preferable in terms of activity and/or stability to use a catalyst including ruthenium oxide represented by the chemical formula I for the reaction, but another metal or metal salt may be additionally used as an auxiliary catalyst.

In one embodiment of the present invention, the catalyst may be used in an amount of about 0.1 part by weight to about 50 parts by weight based on 100 parts by weight of the waste cathode material or the composite metal compound. In one embodiment of the present invention, the catalyst is present in an amount of from about 0.1 part by weight to about 50 parts by weight, from about 0.1 part by weight to about 40 parts by weight, from about 0.1 part by weight to about 30 parts by weight, from about 0.1 part by weight to about 20 parts by weight, from about 0.1 part by weight to about 10 parts by weight, from about 1 part by weight to about 50 parts by weight, from about 1 part by weight to about 40 parts by weight, from about 1 part by weight to about 30 parts by weight, from about 1 part by weight to about 20 parts by weight, from about 1 part by weight to about 10 parts by weight, from about 10 part by weight to about 50 parts by weight, from about 10 part by weight to about 40 parts by weight, from about 10 part by weight to about 30 parts by weight, from about 10 part by weight to about 20 parts by weight, from about 20 part by weight to about 50 parts by weight, from about 20 parts by weight The catalyst may be used in an amount of about 20 parts by weight to about 30 parts by weight, about 30 parts by weight to about 50 parts by weight, about 30 parts by weight to about 40 parts by weight, or about 40 parts by weight to about 50 parts by weight. In one embodiment of the present invention, when the weight ratio of the catalyst to the waste cathode material or the composite metal compound is about 0.1 or less, it may take 24 hours or more until the reaction is completed, but may not be limited thereto.

In one embodiment of the present invention, the catalytic reaction may be performed at a temperature range of about 20° C. to about 150° C. In one embodiment of the present invention, the catalytic reaction may be performed at a temperature range of about 20° C. to about 150° C., about 20° C. to about 140° C., about 20° C. to about 130° C., about 30° C. to about 150° C., about 30° C. to about 140° C., about 30° C. to about 130° C., about 40° C. to about 150° C., about 40° C. to about 140° C., about 40° C. to about 130° C., about 50° C. to about 150° C., about 50° C. to about 140° C., or about 50° C. to about 130° C. In one embodiment of the present invention, it may be most preferable that the catalytic reaction is performed at a temperature range of about 60°C to about 120°C.

In one embodiment of the present invention, the catalytic reaction may be performed in a hydrothermal reactor.

In one embodiment of the present invention, the pressure of the carbon dioxide may be from about 0.1 MPa to about 5 MPa. In one embodiment of the present invention, the pressure of the carbon dioxide may be from about 0.1 MPa to about 5 MPa, from about 0.1 MPa to about 4 MPa, from about 0.1 MPa to about 3 MPa, from about 0.1 MPa to about 2 MPa, from about 0.1 MPa to about 1 MPa, from about 0.3 MPa to about 5 MPa, from about 0.3 MPa to about 4 MPa, from about 0.3 MPa to about 3 MPa, from about 0.3 MPa to about 2 MPa, or from about 0.3 MPa to about 1 MPa. In one embodiment of the present invention, the pressure of the carbon dioxide may be most preferably about 0.5 MPa.

In one embodiment of the present invention, the pressure of the hydrogen may be from about 0.1 MPa to about 10 MPa. In one embodiment of the present invention, the pressure of the hydrogen is from about 0.1 MPa to about 10 MPa, from about 0.1 MPa to about 9 MPa, from about 0.1 MPa to about 8 MPa, from about 0.1 MPa to about 7 MPa, from about 0.1 MPa to about 6 MPa, from about 0.1 MPa to about 5 MPa, from about 0.1 MPa to about 4 MPa, from about 0.1 MPa to about 3 MPa, from about 1 MPa to about 10 MPa, from about 1 MPa to about 9 MPa, from about 1 MPa to about 8 MPa, from about 1 MPa to about 7 MPa, from about 1 MPa to about 6 MPa, from about 1 MPa to about 5 MPa, from about 1 MPa to about 4 MPa, from about 1 MPa to about 3 MPa, from about 1.5 MPa to about 10 MPa, from about 1.5 MPa to about 9 MPa, about 1.5 MPa to about 8 MPa, about 1.5 MPa to about 7 MPa, about 1.5 MPa to about 6 MPa, about 1.5 MPa to about 5 MPa, about 1.5 MPa to about 4 MPa, or about 1.5 MPa to about 3 MPa. In one embodiment of the present disclosure, the pressure of the hydrogen may be most preferably about 2 MPa.

In one embodiment of the present invention, the catalytic reaction may be performed under solution conditions containing a solvent, but may not be limited thereto.

In one embodiment of the present invention, the solvent may be selected from distilled water, methanol, and ethanol.

In one embodiment of the present invention, the metal may be obtained as a precipitate of the solution through filtration, but is not limited thereto. In one embodiment of the present invention, the ammonia may be obtained in the form of an ammonia compound by adding an acid to the solution, but is not limited thereto.

The second aspect of the present invention provides a ruthenium oxide catalyst, which is represented by the following chemical formula Ⅰ and has a monoclinic crystal structure, and is used in the method for recovering a valuable metal according to the first aspect:

[Chemical Formula I]

H _x RuO ₂ ;

In the above chemical formula I, 0< x ≤4.

Detailed descriptions of parts that overlap with the first aspect of the present application have been omitted, but the contents described for the first aspect of the present application may be applied equally even if the description is omitted for the second aspect of the present application.

In one embodiment of the present invention, for the chemical formula I, x (atomic ratio of hydrogen) is greater than 0 and less than or equal to 4, about 0.1 to about 3.5, about 0.1 to about 3, about 0.1 to about 2.5, about 0.1 to about 2, about 0.1 to about 1.5, about 0.1 to about 1.2, about 0.2 to about 3.5, about 0.2 to about 3, about 0.2 to about 2.5, about 0.2 to about 2, about 0.2 to about 1.5, about 0.2 to about 1.2, about 0.3 to about 3.5, about 0.3 to about 3, about 0.3 to about 2.5, about 0.3 to about 2, about 0.3 to about 1.5, about 0.3 to about 1.2, about 0.4 to about 3.5, about 0.4 to about 3, about 0.4 to about 2.5, about 0.4 to about 2, about 0.4 to about 1.5, or about 0.4 to about 1.2, but is not limited thereto.

In one embodiment of the present invention, with respect to the chemical formula I, the closer x (atomic ratio of hydrogen) is to about 1, the easier it is to produce the monoclinic ruthenium oxide. Specifically, when the ratio of hydrogen is about 0.6 to about 1.4, the monoclinic ruthenium oxide may be easier to produce. Here, when x is 0 in the chemical formula I, a structural transition into a tetragonal rutile structure ruthenium oxide may occur, and therefore it is preferable to maintain the hydrogen content.

In one embodiment of the present invention, the atomic ratio of hydrogen included in the chemical formula I can be calculated by thermo-gravimetric analysis (TGA). Specifically, in the analysis using the thermo-gravimetric analysis, a solid sample can be placed in a platinum container and the weight change can be measured while increasing the temperature. All hydrogen included in the monoclinic ruthenium oxide (H _x RuO ₂ ) is removed and converted to tetragonal ruthenium oxide (RuO ₂ ). The amount of hydrogen can be quantitatively analyzed from the weight change according to the temperature.

In one embodiment of the present invention, the ruthenium oxide has an incident angle (2θ) of 18.38°<2θ <18.42°, 25.45°<2θ <25.51°, 26.26°<2θ <26.32°, 33.45°<2θ <33.51°, 35.28°<2θ <35.34°, 36.24°<2θ <36.30°, 37.32°<2θ <37.38°, 39.55°<2θ <39.61°, 40.61°<2θ <40.67°, 41.46°<2θ <41.52°, 49.17°<2θ Diffraction peaks can be observed at each position: <49.23°, 52.31°< 2θ <52.37°, 54.03°< 2θ <54.09°, 54.70°< 2θ <54.76°, 55.95°< 2θ <56.01°, 59.97°< 2θ <60.03°, 60.40°< 2θ <60.46°, 61.92°< 2θ <61.98°, 63.94°< 2θ <64.00°, 65.79°< 2θ <65.85°, and 69.13°< 2θ <69.19°. In one embodiment of the present invention, the ruthenium oxide may have diffraction peaks observed at positions where the incident angles (2θ) are 18.40°, 25.48°, 26.29°, 33.48°, 35.31°, 36.27°, 37.35°, 39.58°, 40.64°, 41.49°, 49.20°, 52.34°, 54.06°, 54.73°, 55.98°, 58.00°, 60.43°, 61.95° 63.97°, 65.82°, and 69.16°, as determined by X-ray powder diffraction measurement (Cu Kα line).

In one embodiment of the present invention, the ruthenium oxide may have a structure of a monoclinic space group P2 ₁ /c, C2/m, P2/c, C2/c, P2/m, or P2 ₁ /m, but is not limited thereto.

In one embodiment of the present invention, the unit cell of the monoclinic crystal structure of the monoclinic ruthenium oxide can be represented as shown in the drawing below, and the lattice constants a to c and the angles between the edges can be defined as follows:

In one embodiment of the present invention, in the monoclinic structure, 5 Å≤ a ≤6 Å, 5 Å≤ b ≤6 Å, and 5 Å≤ c ≤6 Å, and the beta (β) angle may be about 110° to about 120°. For example, each of a to c is independently about 5 Å to about 6 Å, about 5.1 Å to about 6 Å, about 5.2 Å to about 6 Å, about 5.3 Å to about 6 Å, about 5 Å to about 5.8 Å, about 5.1 Å to about 5.8 Å, about 5.2 Å to about 5.8 Å, about 5.3 Å to about 5.8 Å, about 5 Å to about 5.6 Å, about 5.1 Å to about 5.6 Å, about 5.2 Å to about 5.6 Å, about 5.3 Å to about 5.6 Å, about 5 Å to about 5.4 Å, about 5.1 Å to about 5.4 Å, about 5.2 Å to about 5.4 Å, about 5.3 Å to can be about 5.4 Å or about 5.35 Å to about 5.4 Å, wherein b can be about 5 Å to about 6 Å, about 5 Å to about 5.8 Å, about 5 Å to about 5.6 Å, about 5 Å to about 5.4 Å, about 5 Å to about 5.2 Å or about 5 Å to about 5.1 Å, and wherein the beta (β) angle is about 110° to about 120°, about 112° to about 120°, about 114° to about 120°, about 110° to about 118°, about 112° to about 118°, about 114° to about 118°, about 110° to about 116°, about 112° to about 116° or about 114° to about It could be 116°.

In one embodiment of the present invention, in the monoclinic structure, a = 5.3533 Å, b = 5.0770 Å, c = 5.3532 Å, and the beta (β) angle may be 115.9074°, but may not be limited thereto.

Hereinafter, the present invention will be described in more detail using examples. However, the following examples are provided only to help understand the present invention, and the contents of the present invention are not limited to the following examples.

[Example]

Example 1

0.2 g of LiCoO ₂ (2.04 mmol), 10 mg of H _x RuO ₂ (0.075 mmol) as a catalyst (x is 0< x ≤4), and 2 mL of 1 M HNO ₃ were placed in a hydrothermal reactor, and the inside of the hydrothermal reactor was filled with 0.5 MPa of carbon dioxide and 2.0 MPa of hydrogen pressure, and the reaction was performed at 100°C for 20 hours. After the reaction was completed, the hydrothermal reactor was cooled to room temperature, and the generated precipitate and residual solution were separated.

Li ₂ CO ₃ was dissolved in water and separated from CoCO ₃ . The mass of Li ₂ CO ₃ obtained after drying was 0.731 g (0.99 mmol) and the yield of Li ₂ CO ₃ calculated based on LiCoO ₂ was 95.1%. The mass of CoCO ₃ obtained was 0.234 g (1.97 mmol) and the yield of CoCO ₃ calculated based on LiCoO ₂ was 91.6%. The precipitate was confirmed to be lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) through powder X-ray diffraction analysis (see Figs. 2 and 3).

After the reaction, the residual solution was analyzed by ultraviolet-visible spectroscopy, and nitrogen oxide ions (NO ₃ ^- and NO ₂ ^- ) were not confirmed, confirming that all nitrate ions were reduced to ammonia or nitrogen. Acetone was added to the residual solution, followed by separation and drying to obtain a white powder, which was confirmed to be ammonium bicarbonate (NH ₄ HCO ₃ ) through X-ray powder diffraction analysis (see Fig. 4). The mass of the obtained NH ₄ HCO ₃ is 0.095 g (0.72 mmol), and the yield of NH ₄ HCO ₃ calculated based on nitric acid is 81.7%.

<Change reactant>

Example 2

Except that LiNi _0.33 Mn _0.33 Co _0.33 O ₂ (0.197 g, 2.04 mmol) was used as a reactant, the same method as in Example 1 was carried out. After the reaction was completed, the Li ₂ CO ₃ included in the precipitate was dissolved in water and separated from other carbonate compounds, and the crystal structure was confirmed by X-ray diffraction analysis, and the separated precipitates were identified as NiCO ₃ , MnCO ₃ , and CoCO ₃ (see Fig. 5). The yield ratio of Li ₂ CO ₃ produced based on LiNi _0.33 Mn _0.33 Co _0.33 O ₂ was 90.1%, and the yield ratios of NiCO ₃ , MnCO ₃ , and CoCO ₃ were 84.8%. After the reaction, acetone was added to the residual solution, which was then separated and dried to obtain a white powder, which was confirmed to be NH ₄ HCO ₃ through X-ray powder diffraction analysis.

Example 3

The reaction was performed in the same manner as in Example 1, except that LiNi _0.8 Mn _0.1 Co _0.1 O ₂ (0.198 g, 2.04 mmol) was used as a reactant. After the reaction was completed, the Li ₂ CO ₃ included in the precipitate was dissolved in water and separated from other carbonate compounds. The crystal structure was confirmed by X-ray diffraction analysis, and the separated precipitates were identified as NiCO ₃ , MnCO ₃ , and CoCO ₃ . The yield ratio of Li ₂ CO ₃ produced based on LiNi _0.8 Mn _0.1 Co _0.1 O ₂ was 93.1%, and the yield ratios of NiCO ₃ , MnCO ₃ , and CoCO ₃ were 80.1%. After the reaction, acetone was added to the residual solution, which was then separated and dried to obtain a white powder, which was confirmed to be NH ₄ HCO ₃ through X-ray powder diffraction analysis.

Example 4

Except that LiNi _0.6 Mn _0.2 Co _0.2 O ₂ (0.198 g, 2.04 mmol) was used as a reactant, the same method as in Example 1 was carried out. After the reaction was completed, the Li ₂ CO ₃ included in the precipitate was dissolved in water and separated from other carbonate compounds. The crystal structure was confirmed by X-ray diffraction analysis, and the separated precipitates were identified as NiCO ₃ , MnCO ₃ , and CoCO ₃ . The yield ratio of Li ₂ CO ₃ produced based on LiNi _0.6 Mn _0.2 Co _0.2 O ₂ was 92.1%, and the yield ratios of NiCO ₃ , MnCO ₃ , and CoCO ₃ were 82.8%. After the reaction, acetone was added to the residual solution, which was then separated and dried to obtain a white powder, which was confirmed to be NH ₄ HCO ₃ through X-ray powder diffraction analysis.

Example 5

The reaction was performed in the same manner as in Example 1, except that LiFePO ₄ (0.322 g, 2.04 mmol) was used as a reactant. After the reaction was completed, the crystal structure was confirmed by X-ray diffraction analysis, and it was confirmed that the precipitate had a crystal phase of Li ₂ CO ₃ and NH ₄ FePO ₄ ·H ₂ O (see Fig. 6). The yield of Li ₂ CO ₃ produced based on LiFePO ₄ was 95.1%.

Example 6

Except that the reaction was performed using a spent battery as a reactant, the reaction was performed in the same manner as in Example 1. The spent battery was heat-treated at 800°C for 10 hours before the reaction, and then elemental analysis confirmed that it had a composition of Li _0.98 Ni _0.60 Mn _0.19 Co _0.17 O ₂ containing a trace amount of aluminum. After the reaction was completed, the Li ₂ CO ₃ contained in the precipitate was dissolved in water and separated from other carbonate compounds, and the separated precipitate was confirmed to be NiCO ₃ , MnCO ₃ , and CoCO ₃ through an X-ray diffraction method (see Fig. 7). Based on the elemental analysis of the spent battery, the yield ratio of the obtained Li ₂ CO ₃ was 86.7%, and the yield ratios of NiCO ₃ , MnCO ₃ , and CoCO ₃ were 78.8%. After the reaction, acetone was added to the residual solution, which was then separated and dried to obtain a white powder, which was confirmed to be NH ₄ HCO ₃ through X-ray powder diffraction analysis.

<Change the type of catalyst>

Example 7

The reaction was performed in the same manner as in Example 1, except that ruthenium powder (7.6 mg, 0.075 mmol) was used as a catalyst. After completion of the reaction, the yield ratio of the obtained carbonate compounds (Li ₂ CO ₃ and CoCO ₃ ) was less than 5%, so it is estimated that the carbonate compounds were produced in very small amounts.

Example 8

Except that platinum powder (14.6 mg, 0.075 mmol) was used as a catalyst, the reaction was performed in the same manner as in Example 1. After the reaction was completed, Li ₂ CO ₃ included in the precipitate was dissolved in water and separated from other carbonate compounds, and the separated precipitate was identified as CoCO ₃ through an X-ray diffraction method. The yield of Li ₂ CO ₃ was 25.8%, and the yield of CoCO ₃ was 32.5%. After the reaction, acetone was added to the residual solution, followed by separation and drying to obtain a white powder, which was identified as NH ₄ HCO ₃ through X-ray powder diffraction analysis.

Example 9

The reaction was performed in the same manner as in Example 1, except that palladium powder (8.0 mg, 0.075 mmol) was used as a catalyst. After completion of the reaction, the yield ratio of the obtained carbonate compounds (Li ₂ CO ₃ and CoCO ₃ ) was less than 5%, so it is estimated that the carbonate compounds were produced in very small amounts.

Example 10

The reaction was performed in the same manner as in Example 1, except that nickel powder (7.1 mg, 0.075 mmol) was used as a catalyst. After completion of the reaction, the yield ratio of the obtained carbonate compounds (Li ₂ CO ₃ and CoCO ₃ ) was less than 5%, so it is estimated that the carbonate compounds were produced in very small amounts.

The above description of the present invention is for illustrative purposes only, and those skilled in the art will understand that the present invention can be easily modified into other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single component may be implemented in a distributed manner, and likewise, components described as distributed may be implemented in a combined manner.

The scope of the present application is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present application.

Claims (15)

Comprising a process for catalytically reacting a waste cathode material or a composite metal compound; nitric acid; carbon dioxide; and hydrogen to obtain a metal and ammonia compound.
Method for recovering valuable metals.
In paragraph 1,
A method for recovering a valuable metal, wherein the catalyst is selected from a metal, alloy or oxide comprising at least one selected from titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), platinum (Pt), and gold (Au).
In the second paragraph,
A method for recovering valuable metals, wherein the catalyst comprises ruthenium oxide represented by the following chemical formula Ⅰ:
[Chemical Formula I]
H _x RuO ₂ ;
In the above chemical formula I, 0< x ≤4.
In paragraph 1,
A method for recovering valuable metals, wherein the catalyst is used in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the waste cathode material or the composite metal compound.
In paragraph 1,
A method for recovering valuable metals, wherein the above catalytic reaction is performed at a temperature range of 20°C to 150°C.
In paragraph 1,
A method for recovering valuable metals, wherein the above catalytic reaction is performed in a hydrothermal reactor.
In paragraph 1,
A method for recovering valuable metals, wherein the pressure of the carbon dioxide is 0.1 MPa to 5 MPa.
In paragraph 1,
A method for recovering valuable metals, wherein the pressure of the hydrogen is 0.1 MPa to 10 MPa.
In paragraph 1,
A method for recovering valuable metals, wherein the above catalytic reaction is performed under solution conditions containing a solvent.
In Article 9,
A method for recovering valuable metals, wherein the solvent is selected from distilled water, methanol, and ethanol.
It is represented by the following chemical formula I,
As a ruthenium oxide catalyst having a monoclinic structure,
Ruthenium oxide catalyst used in the method for recovering valuable metal according to Article 1:
[Chemical Formula I]
H _x RuO ₂ ;
In the above chemical formula I, 0< x ≤4.
In Article 11,
The above ruthenium oxide catalyst was measured by X-ray powder diffraction (Cu Kα line) and had the following incident angles (2θ): 18.38°<2θ <18.42°, 25.45°<2θ <25.51°, 26.26°<2θ <26.32°, 33.45°<2θ <33.51°, 35.28°<2θ <35.34°, 36.24°<2θ <36.30°, 37.32°<2θ <37.38°, 39.55°<2θ <39.61°, 40.61°<2θ <40.67°, 41.46°<2θ <41.52°, 49.17°<2θ <49.23°, A ruthenium oxide catalyst, wherein diffraction peaks are observed at respective positions of 52.31°<2θ <52.37°, 54.03°<2θ <54.09°, 54.70°<2θ <54.76°, 55.95°<2θ <56.01°, 59.97°<2θ <60.03°, 60.40°<2θ <60.46°, 61.92°<2θ <61.98°, 63.94°<2θ <64.00°, 65.79°<2θ <65.85°, and 69.13°<2θ <69.19°.
In Article 11,
The above ruthenium oxide catalyst is a ruthenium oxide catalyst having a structure of a monoclinic space group P2 ₁ /c, C2/m, P2/c, C2/c, P2/m, or P2 ₁ /m.
In Article 11,
In the above monoclinic structure,
5 Å≤ a ≤6 Å, 5 Å≤ b ≤6 Å, and 5 Å≤ c ≤6 Å,
A ruthenium oxide catalyst having a beta (β) angle of 110° to 120°.
In Article 11,
In the above monoclinic structure,
A ruthenium oxide catalyst having a=5.3533 Å, b=5.0770 Å, c=5.3532 Å, and the beta (β) angle is 115.9074°.