KR102502902B1 - Method for recovery of valuable metals in waste Lithium-Ion Battery(LIB) - Google Patents

Abstract

The present invention relates to a method for recovering valuable metals in a waste lithium ion battery, and more specifically, recovers valuable metals without a process of separating cathode and anode materials from a waste lithium ion battery, and optimizes recovery through modified carbon equivalent considering solubility. It relates to a valuable metal recovery method that provides conditions.
The method for recovering valuable metals in waste lithium ion batteries of the present invention enables high-efficiency dry recovery by controlling processing conditions of waste lithium ion batteries and mixing conditions of additives, omits pretreatment, and utilizes microwave heating to process the process. simplicity and efficiency can be maximized.

Description

A method for recovering valuable metals in waste lithium-ion batteries {Method for recovery of valuable metals in waste Lithium-Ion Battery (LIB)}

The present invention relates to a method for recovering valuable metals in a waste lithium ion battery, and more specifically, recovers valuable metals without a process of separating cathode and anode materials from a waste lithium ion battery, and optimizes recovery through modified carbon equivalent considering solubility. It relates to a valuable metal recovery method that provides conditions.

Lithium ion batteries are widely used as secondary batteries because of their excellent charge or discharge performance and high energy density, and are particularly widely used in small electronic products such as mobile phones and laptops. Recently, with the spread of electric vehicles and the like becoming visible, the development of large-capacity lithium batteries is actively progressing.

On the other hand, the positive electrode of a lithium ion battery is composed of a positive electrode material, a conductor, a binder, and a current collector. The positive electrode material has excellent reversibility, low self-discharge rate, high capacity, and high energy density, Lithium cobalt oxide (LiCoO ₂ ), which is easy to synthesize, is widely used. In addition, recently, in order to reduce the amount of expensive cobalt (Co), a ternary lithium composite metal oxide such as Li(NiCoMn)O _x containing Ni and Mn is also used as a cathode material. However, since all of the above positive electrode materials contain at least 5% by weight of lithium and a large amount of valuable metals such as nickel, cobalt, and manganese, there is interest in a method for recovering expensive valuable metals from the positive electrode material of a waste lithium ion battery. is being noticed.

In particular, lithium nickel cobalt aluminum oxide (LiNiCoAlO ₂ , NCA) is a typical cathode material used in lithium ion batteries, but the lithium nickel cobalt aluminum oxide has a layered structure and is popularly used, but the valuable metals that constitute it are expensive. Research on reusable methods is essential.

Conventionally, as one of the methods for recovering valuable metals from waste lithium ion batteries, strong acids such as nitric acid, sulfuric acid, and hydrochloric acid are used to dissolve the positive electrode material of the waste lithium ion battery, followed by a neutralization reaction to separate and recover lithium and other metal compounds. this was used However, since lithium and metal compounds are separated by acid elution in the recovery method, there is a limitation in that an additional process for separating lithium compounds and other metal compounds is required in order to use the same in the manufacture of a lithium ion battery again. In addition, although a method for recovering valuable metals is proposed as in Japanese Laid-Open Patent Publication No. 2019-071320, there is a problem in that a pre-process is required in that a reducing agent is introduced after separating the anode and the cathode.

Japanese Laid-open Patent No. 2019-071320

The present invention provides a method for recovering valuable metals in a waste lithium ion battery in order to solve the above problems.

In order to achieve the above object, the present invention,

Step 1 of preparing powder by shredding waste lithium-ion batteries;

a second step of preparing a mixture by adding additives to the powder;

Step 3 of heating the mixture in a crucible; and

A fourth step of taking a specimen after cooling the heated mixture in air,

Controlling the carbon content of the mixture by adjusting the addition amount of the additive,

The carbon content of the mixture provides a valuable metal recovery method in which the modified carbon equivalent represented by the following formula 1 is 0.8 to 1.5:

[Equation 1]

The additive is characterized in that the additive is an industrial by-product.

The industrial by-product is characterized in that it is a metal oxide.

The additive is characterized in that the waste lithium ion battery powder from which the cathode material is separated.

The heating is characterized in that using a microwave.

The first step is characterized in that the powder is prepared by crushing before separating the positive and negative electrodes of the waste lithium ion battery.

In addition, an apparatus for recovering valuable metals from a waste lithium ion battery according to the method for recovering valuable metals of the present invention is provided.

The method for recovering valuable metals in waste lithium ion batteries of the present invention enables high-efficiency dry recovery by controlling processing conditions of waste lithium ion batteries and mixing conditions of additives, omits pretreatment, and utilizes microwave heating to process the process. simplicity and efficiency can be maximized.

1 is a state diagram of an experiment in which waste LIB powder in which positive and negative electrode materials are mixed and FeO-containing by-products are mixed according to the present invention.
Figure 2 is a graph showing the input-reaction carbon amount of the experiment in which the waste LIB powder in which the cathode and anode materials are mixed and FeO-containing by-products are mixed according to the present invention.
3 is a photograph showing the diameter of a bead in an experiment in which waste LIB powder in which a cathode material and an anode material are mixed and FeO-containing by-products are mixed according to the present invention.
4 is a graph showing the weight of beads in an experiment in which waste LIB powder in which positive and negative electrode materials are mixed and FeO-containing by-products are mixed according to the present invention.
5 is a state diagram of an experiment in which waste LIB powder in which a positive electrode material and a negative electrode material are mixed and waste LIB powder in which a positive electrode material is separated are mixed according to the present invention.
6 is a graph showing the input-reaction carbon content of an experiment in which waste LIB powder in which a cathode material and an anode material are mixed and waste LIB powder in which a cathode material is separated are mixed according to the present invention.
7 is a photograph showing the diameter of a bead in an experiment in which waste LIB powder in which a positive electrode material and a negative electrode material are mixed and waste LIB powder in which a positive electrode material is separated are mixed according to the present invention.
8 is a graph showing the weight of beads in an experiment in which waste LIB powder in which a positive electrode material and a negative electrode material are mixed and waste LIB powder in which a positive electrode material is separated are mixed according to the present invention.
9 is a graph showing the recovery rate of an experiment in which waste LIB powder in which a positive electrode material and a negative electrode material are mixed and waste LIB powder in which a positive electrode material is separated are mixed according to the present invention.
10 is a graph showing the mass of beads according to the modified carbon equivalent in the method for recovering valuable metals according to the present invention.
11 is a graph showing the recovery rate of valuable metals according to the corrected carbon equivalent of the method for recovering valuable metals according to the present invention.

Hereinafter, the present invention will be described in more detail.

According to one aspect of the present invention, a first step of preparing a powder by crushing the waste lithium ion battery; a second step of preparing a mixture by adding additives to the powder; Step 3 of heating the mixture in a crucible; and a fourth step of taking a sample after air-cooling the heated mixture, wherein the carbon content of the mixture is controlled by adjusting the addition amount of the additive, and the carbon content of the mixture is modified represented by Equation 1 below. Provides a valuable metal recovery method with a modified carbon equivalent of 0.8 to 1.5:

[Equation 1]

The additive may be an industrial by-product, preferably a metal oxide, and more preferably FeO including Fe. It may also be waste lithium ion battery powder from which the cathode material is separated. The present invention is characterized in that industrial by-products that can be used as additives can be used in a valuable metal recovery process, and at the same time, a reducing agent required for industrial by-product recovery can be supplied from a waste lithium-ion battery.

A waste lithium-ion battery in which cathode and anode materials are mixed is difficult to process in terms of valuable metals to be recovered, but considering that the metal must be recovered while reducing the oxidized metal, the coexisting anode material There is a possibility that it can be utilized as this reducing agent. In addition, since the reducing material and the reducing agent coexist in the form of powder, it is suitable for using the pyrometallurgical method, and microwave heating can also be applied. Microwave heating is a heating method using frictional heat by polarization rearrangement and dispersive energy effect under the conditions of electromagnetic waves of a specific wavelength. It can be applied to oxidation and reduction reactions. .

However, nickel and cobalt, which are valuable metals to be recovered, have relatively low solubility of carbon, so if carbon in the anode material is excessively present, the carbon that did not participate in the reduction reaction cannot be dissolved and exists in a powder state while continuously reducing slag/metal. There is a possibility of inhibiting the reaction and the formation of molten metal. That is, the initial carbon content should be appropriately diluted compared to the case of recovering iron using microwaves in the past.

In order to dilute the carbon content in waste lithium-ion batteries, metal oxides consisting only of reducing products can be added, and dust, scale, sludge, etc. generated during the metal production process can be used in an environmentally friendly way. It has a complex meaning of utilizing industrial by-products in the valuable metal recovery process and at the same time using the reducing agent required for industrial by-product recovery from waste lithium-ion batteries.

Excessive dilution of the carbon content is advantageous in forming molten metal, but the reduction rate is lowered and there is a concern that the final valuable metal content may be low. . In other words, it is necessary to find the optimal conditions for dilution of carbon content and additives (by-products) that can maximize the recovery efficiency of valuable metals.

The most important thing in selecting optimal conditions is to accurately predict the amount of carbon that can be dissolved in the recovered metal. In the case of metals with high carbon solubility, the excess carbon dissolves in the metal even if a sufficient amount of reducing agent is used, and it is advantageous for molten metal formation, or at least, there is no problem. is to avoid That is, by calculating the amount of carbon that can be dissolved in a metal having a predictable composition from the waste lithium ion battery and additives, it is possible to control the existence of only the carbon required for reduction and the carbon that can be dissolved. The amount of carbon is defined as Modified Carbon Equivalent in this specification, and the present invention proposes a modified carbon equivalent as shown in Equation 1 as an optimal condition for each additive condition.

More preferably, the modified carbon equivalent according to the present invention may be 1.0 to 1.4. When the proportion of carbon is small, sufficient reduction cannot occur because the reducing agent is insufficient for the valuable metal to be reduced. Accordingly, there is a problem in that the recovery efficiency is lowered because valuable metals such as nickel or cobalt cannot be metalized. On the other hand, when the ratio of carbon is high, valuable metals such as nickel or cobalt are sufficiently metallized, but the reducing agent becomes excessive and interferes with metal aggregation for the purpose of recovery, thereby reducing the recovery efficiency of valuable metals.

The method for recovering valuable metals of the present invention may use powder crushed prior to separation of positive and negative electrodes of a waste lithium ion battery. Conventional methods for recovering valuable metals used crushed powder after separating the positive electrode and the negative electrode. In order to increase the recovery efficiency by separating the valuable metal, which is a reducing agent, and graphite (C), which is a reducing agent, a reducing agent is introduced after separating the anode and cathode, whereas the present invention does not separate the anode and cathode, and according to the proposed modified carbon equivalent, carbon It is characterized by controlling a small amount to increase recovery efficiency. Additives or cathode materials are separated to control the carbon content according to the addition of waste lithium ion battery powder (Low C LIB powder) having a low C content, and metal oxides and industrial by-products can be used as additives.

In the case of using waste LIB powder from which mill scale and cathode material are separated, an effective mixing range for valuable metal recovery can be set. Based on 50~57% for mill scale and 60~70% for Low C LIB powder, as the addition amount increases, the input amount becomes smaller than the C content required for the reduction reaction, increasing the recovery efficiency of valuable metals.

The heating of the present invention preferably uses microwaves, but is not limited thereto.

In addition, an apparatus for recovering valuable metals from a waste lithium ion battery according to the method for recovering valuable metals of the present invention is provided.

<Experiments and Results>

As an additive for diluting the carbon content in waste lithium-ion battery powder (LIB 1), FeO-containing by-products (mill scale, MS) and waste lithium-ion battery powder (LIB 2) with low carbon content through a crushing process were used.

In order to derive the optimal mixing conditions of additives mixed with waste lithium-ion battery powder, the following confirmation experiment was conducted. In the experiment, powder (1) obtained by crushing the cathode and anode materials of the waste lithium ion battery was used. Among them, as additives to dilute the carbon content (37.6% by mass), by-products containing Fe oxide (2) and waste lithium were used. The powder (3) in which the carbon content was reduced by separating the anode material from the ion battery was used. Each component of the raw material used in the experiment is shown in Table 1 below.

Li ₂ O Al ₂ O ₃ SiO ₂ NiO Co ₃ O ₄ MnO Cu ₂ O FeO _x P ₂ O ₅ C total valuable metals
Ni+Co+Mn+Cu Waste LIB powder mixed with cathode and anode materials
(One) 4.1 2.6 - 16.3 8.2 7.7 1.1 0.0330 0.16 36.7 33.4 FeO-containing by-products
(2) - - 0.78 0.15 - 0.73 - 98.3 - - 0.68 Waste LIB powder separated from cathode material
(3) 6.7 0.0370 - 34.9 11.4 9.6 0.001 0.008 - 2.39 55.9

, 양극재·음극재가 혼합된 폐LIB 분말 및 양극재를 분리한 폐LIB 분말 혼합시(1+3):

(Ni:50~63wt%, Co:19~27wt%, Mn:18~24wt%)에 따라 계산하였다. It is possible to calculate the components of metals recovered when valuable metals are reduced from the components of each raw material, and the solubility of carbon according to the components was predicted using a thermodynamic calculation program. When mixing waste LIB powder with cathode and anode materials and FeO-containing by-products (1+2):

, When mixing waste LIB powder mixed with cathode and anode materials and waste LIB powder from which cathode materials are separated (1+3):

Calculated according to (Ni: 50 ~ 63wt%, Co: 19 ~ 27wt%, Mn: 18 ~ 24wt%).

The result of calculating the maximum amount of carbon that can be dissolved in the reduced metal and the amount of carbon for reducing the valuable metal present in the form of an oxide are set as the target carbon amount, and the ratio of the carbon content in the raw material is set as described above. It was defined as Modified Carbon equivalent. As described above, if the amount of carbon compared to the modified carbon equivalent is excessive, there is a concern that the reduction reaction may not proceed smoothly due to undissolved carbon, and if it is insufficient, the reduction reaction may not be sufficient. The reduction experiment was conducted while changing in the range of ~1.8.

After thoroughly mixing each raw material and slag component to a predetermined modified carbon equivalent, they were placed in a quartz crucible, insulated well using a refractory lead and refractory cotton, and then placed in a microwave oven and heated. The temperature change was measured in real time using an infrared thermometer, and in all cases, the temperature was raised to 1600 ° C or higher within 5 minutes and maintained at the high temperature for 20 minutes. After cooling in air, a metal ring was collected from the specimen and analyzed for composition. The recovery rate of valuable metals is shown in Equation 2 below.

[Equation 2]

When looking at the amount of reduced metal and the reduction rate, the total recovery rate of valuable metals when using by-products containing Fe was slightly lower than when only waste lithium-ion batteries were used, but more than 75% of the total valuable metals were recovered under appropriate mixing conditions. Could. Assuming that the recovery rate of valuable metals in waste lithium-ion batteries is 75%, the appropriate mixing conditions of additives for diluting carbon can be determined in the range of 1.0 to 1.4 modified carbon equivalents.

The experimental conditions and results are explained in more detail.

Table 2 below shows the mixing ratio of the composition in which the waste LIB powder (1) in which the positive electrode material and the negative electrode material are mixed and the FeO-containing by-product (2) as an additive are mixed. 1 is a state diagram of an experiment in which waste LIB powder (1) in which positive and negative electrode materials are mixed and FeO-containing by-products (2) are mixed according to the present invention.

mixing ratio mixture Ni
(wt%) Co
(wt%) Mn
(wt%) Fe
(wt%) Total
(wt%) (One) (%) (2) (%) 4 60 40 19.6 9.82 9.66 60.9 100 5 50 50 15.0 7.51 7.56 69.9 100 5.2 48 52 14.2 7.10 7.18 71.5 100 5.4 46 54 13.4 6.69 6.82 73.1 100 5.6 44 56 12.6 6.30 6.46 74.6 100 5.7 43 57 12.3 6.11 6.29 75.4 100 5.8 42 58 11.9 5.92 6.12 76.1 100 6 40 60 11.2 5.55 5.78 77.5 100 7 30 70 7.83 3.87 4.25 84.1 100

Table 3 below is a condition calculation table of an experiment in which the waste LIB powder (1) in which the positive electrode material and the negative electrode material are mixed and the FeO-containing by-product (2) as an additive are mixed. Figure 2 is a graph showing the input-reaction carbon amount of the experiment in which the waste LIB powder (1) in which the cathode and anode materials are mixed and the FeO-containing by-product (2) are mixed according to the present invention.

Input reaction (1)+(2)
(g) C
(g) Modified Ceq C(g) of reduction reaction in bead
[C](g) [C]
(wt%) Total
(g) 4 6.27 1.38 1.66 0.689 0.142 4.49 0.831 5 5.76 1.06 1.26 0.686 0.149 4.74 0.835 5.2 5.67 0.998 1.19 0.686 0.151 4.78 0.836 5.4 5.58 0.941 1.12 0.685 0.152 4.82 0.837 5.6 5.49 0.886 1.06 0.685 0.153 4.86 0.838 5.7 5.45 0.859 1.03 0.684 0.154 4.88 0.838 5.8 5.40 0.833 0.99 0.684 0.154 4.90 0.839 6 5.32 0.781 0.93 0.684 0.156 4.94 0.839 7 4.95 0.545 0.64 0.682 0.167 5.30 0.849

Table 4 below shows the initial input amount in the composition in which the waste LIB powder (1) in which the cathode and anode materials are mixed and the FeO-containing by-product (2) is mixed. 3 is a photograph showing the diameter of a bead in an experiment in which waste LIB powder (1) in which a cathode material and an anode material are mixed according to the present invention and a FeO-containing by-product (2) are mixed. 4 is a graph showing the weight of beads in an experiment in which waste LIB powder (1) in which a cathode material and a cathode material are mixed according to the present invention and a by-product containing FeO (2) are mixed. 4, it is 1.155g for 40%, 3.037g for 50%, 2.7987g for 60%, and 1.4857g for 70%.

amount of additives
(%) (1) (g) (2) (g) CaO
(g) SiO2
(g) Ceq 40 3.76 2.51 3.3 2.7 2 50 2.88 2.88 3.3 2.7 1.5 60 2.13 3.19 3.3 2.7 1.1 70 1.48 3.46 3.3 2.7 0.8

Table 5 below shows the mixing ratio of the composition in which the waste LIB powder (1) in which the positive electrode material and the negative electrode material are mixed and the waste LIB powder (3) in which the positive electrode material is separated are mixed. 5 is a state diagram of an experiment in which waste LIB powder (1) in which positive electrode and negative electrode materials are mixed and waste LIB powder (3) in which the positive electrode material is separated are mixed according to the present invention.

mixing ratio mixture Ni
(wt%) Co
(wt%) Mn
(wt%) Total
(wt%) (One) (%) (3) (%) One 90 10 50.4 27.7 21.9 100 2 80 20 52.6 26.2 21.2 100 3 70 30 54.5 24.9 20.6 100 4 60 40 56.3 23.7 20.1 100 5 50 50 57.9 22.6 19.6 100 6 40 60 59.3 21.6 19.1 100 6.2 38 62 59.6 21.4 19.0 100 6.4 36 64 59.9 21.2 18.9 100 6.6 34 66 60.1 21.0 18.9 100 6.8 32 68 60.4 20.9 18.8 100 7 30 70 60.6 20.7 18.7 100 8 20 80 61.9 19.8 18.3 100 9 10 90 63.0 19.1 18.0 100

Table 6 below is a condition calculation table for an experiment in which the waste LIB powder (1) in which the cathode and anode materials are mixed and the waste LIB powder (3) in which the cathode material is separated are mixed. 6 is a graph showing the input-reaction carbon content of an experiment in which waste LIB powder (1) in which cathode and anode materials are mixed and waste LIB powder (3) in which cathode materials are separated according to the present invention are mixed.

Addition ratio
(%) Input reaction (1)+(3)
(g) C
(g) Modified Ceq C(g) of reduction reaction in bead
[C](g) [C]
(wt%) Total
(g) 50 7.06 1.38 1.75 0.654 0.096 3.1 0.791 60 6.72 1.08 1.37 0.695 0.095 3 0.789 66 6.53 0.918 1.17 0.695 0.093 2.96 0.788 68 6.47 0.865 1.10 0.695 0.093 2.96 0.788 70 6.41 0.813 1.03 0.695 0.093 2.95 0.788 80 6.13 0.567 0.72 0.695 0.092 2.93 0.787 90 5.88 0.342 0.43 0.695 0.092 2.9 0.787

Table 7 below shows the initial input amount in a composition in which waste LIB powder (1) in which the cathode and anode materials are mixed and waste LIB powder (3) in which the cathode material is separated are mixed. 7 is a photograph showing the diameter of a bead in an experiment in which waste LIB powder (1) in which positive and negative electrode materials are mixed and waste LIB powder (3) in which the positive electrode material is separated according to the present invention are mixed. 8 is a graph showing the weight of beads in an experiment in which waste LIB powder (1) in which positive and negative electrode materials are mixed and waste LIB powder (3) in which the positive electrode material is separated according to the present invention are mixed. 8, it is 2.4807g for 50%, 2.8979g for 60%, 2.8556g for 66%, 2.8694g for 68%, 2.8406g for 70%, and 2.342g for 80%.

Addition ratio
(%) mixture CaO
(g) SiO2
(g) Ceq (1) (g) (3) (g) 50 7.06 1.38 3.3 2.7 2 60 6.72 1.08 3.3 2.7 1.6 66 6.53 0.918 3.3 2.7 1.3 68 6.47 0.865 3.3 2.7 1.2 70 6.41 0.813 3.3 2.7 1.2 80 6.13 0.567 3.3 2.7 0.8

9 is a graph showing the recovery rate of an experiment in which waste LIB powder (1) in which positive electrode and negative electrode materials are mixed and waste LIB powder (3) from which the positive electrode material is separated are mixed according to the present invention. (a) is the recovery rate of Ni, (b) Co, and (c) Mn. Table 8 shows the recovery rates of valuable metals according to the addition amount of the waste LIB powder (3) from which the cathode material was separated.

Amount added (%) 50 60 66 68 70 80 Ni 56.5 58.4 62.2 55.2 60.8 71.8 Co 20.9 20.9 24.2 21.8 24.2 20.6 Mn 5.63 9.18 4.99 6.61 4.38 0

Overall, FIG. 10 is a graph showing the bead mass according to the modified carbon equivalent of the method for recovering valuable metals according to the present invention, and FIG. 11 is a graph showing the recovery rate of valuable metals according to the modified carbon equivalent of the method for recovering valuable metals according to the present invention.

The method for recovering valuable metals of the present invention is capable of recovering valuable metals from a waste lithium ion battery without a process of separating cathode and anode materials. Other valuable metal-containing by-products can be used to dilute the excessive carbon content, and appropriate recovery conditions can be derived through the modified carbon equivalent considering solubility, so that it can be recovered by the existing simple smelting reduction process and can be applied to microwaves. excellent in

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the scope of the invention which follows may be better understood. Those skilled in the art to which the present invention pertains will understand that the present invention can be embodied in other specific forms without changing its technical spirit or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting. The scope of the present invention is indicated by the appended claims rather than the detailed description above, and all changes or modifications derived from the claims and equivalent concepts should be construed as being included in the scope of the present invention.

Claims (7)

A first step of preparing powder by crushing the waste lithium-ion battery in which the cathode and anode materials are mixed;
A second step of preparing a mixture by adding Fe-containing by-products (additives) or waste lithium battery powder from which negative electrode material components are removed to the powder as an additive;
Step 3 of heating the mixture in a crucible; and
A fourth step of taking a specimen after cooling the heated mixture in air,
The solubility of carbon that can be dissolved in the recovered metal is a valuable metal recovery method in which the modified carbon equivalent represented by the following formula 1 is 1.0 to 1.4:
[Equation 1]

delete delete delete According to claim 1,
The method for recovering valuable metals, characterized in that the heating uses microwaves. According to claim 1,
The first step is a method for recovering valuable metals, characterized in that the powder is prepared by crushing the waste lithium ion battery prior to separation of the positive and negative electrodes. An apparatus for recovering valuable metals from waste lithium-ion batteries according to the method for recovering valuable metals according to any one of claims 1, 5 and 6.

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