KR102650212B1 - Method for selective recovery of nickel and cobalt from nickel-cobalt-manganese mixture - Google Patents

Abstract

A method for selective recovery of nickel and cobalt from a nickel-cobalt-manganese mixture is disclosed. The method for selective recovery of nickel and cobalt from the nickel-cobalt-manganese mixture includes a first step of carbonating the nickel-cobalt-manganese mixture; A second step of washing the carbonated mixture with water and then separating the solid phase and the liquid phase into solid and liquid; A first step of selective hydrogen reduction of nickel and cobalt by heating the solid phase; And a second step of adding flux to the selectively hydrogen-reduced solid to melt it and then removing the slag to obtain a nickel and cobalt alloy.

Description

Method for selective recovery of nickel and cobalt from nickel-cobalt-manganese mixture}

The present invention relates to a method for selective recovery of nickel and cobalt from a nickel-cobalt-manganese mixture, and more particularly, to a method for selective recovery of nickel and cobalt from a nickel-cobalt-manganese mixture using a selective hydrogen reduction of metal oxide and molten slag removal process. and a method for selective recovery of cobalt.

Metal resources currently in use are divided into mine resources and renewable resources, and the mine resources are decreasing day by day and may be depleted further. Therefore, renewable resources using the above metal resources will become the main method of raw material production today. Cathode materials, a core material that accounts for about 40% of lithium-ion battery components, contain heavy metals such as rare metals nickel, cobalt, and manganese, and the demand for and value of cathode raw materials is expected to increase depending on the usage of lithium-ion batteries.

Lithium is used in a variety of industries, including batteries, glass, alloys, ceramics, lubricants, and pharmaceuticals. Lithium-ion batteries, which were previously mainly used only in portable electronic devices, are beginning to be used as the main power source for electric vehicles, and the lithium-ion battery market is emerging as the most important market in terms of lithium consumption. Most manganese has been consumed by steel manufacturers and battery manufacturers, but as demand for secondary batteries increases, demand from battery companies is increasing. Cobalt is used for a wide variety of purposes in many industries depending on its properties, but generally half of cobalt demand is concentrated in lithium-ion batteries. As demand for electric vehicles increases, demand for cobalt, a core material for lithium-ion batteries, is expected to steadily increase. Demand for nickel is expected to increase significantly following the development of cathode materials that increase the nickel content in lithium ions for electric vehicles. In addition, current cathode active materials are developing in the direction of increasing the nickel content to increase energy density, and as the demand for nickel expands explosively, the supply shortage of nickel is leading to an increase in the price of NCM (Ni _x Co _y Mn _z ) cathode active materials. Because this is a factor, the development of recycling technology for the above components is urgently needed to stabilize the supply and demand of nickel.

First, a conventional technology for recovering valuable metals from used lithium-ion batteries for electric vehicles is the hydrometallurgical process. This is a method of leaching electrode material using acid and then separating cobalt and lithium using solvent extraction. It is possible to produce lithium carbonate and cobalt sulfate, but the solvent extraction process is complicated, and the disadvantages are the burden of wastewater treatment and increased environmental costs due to acid leaching. This exists. Second, a conventional technology for recovering cobalt from spent lithium-ion batteries and LCO powder includes a liquid phase reduction process. This is a process of recovering cobalt from waste LCO by dissolving harmful organic substances such as acids and chemicals and then manufacturing the product through a liquid phase reduction process. Compared to other processes, the reaction rate and yield are higher, and powder particle size and shape are easy to control. The disadvantage is that strong acid solutions and chemicals that are harmful to the environment must be used, a large amount of intermediate products are generated, the production process is complicated, and as the amount of waste solution generated increases, the production cost decreases. Lastly, a conventional technique for recovering lithium carbonate from natural seawater and salt lakes is the evaporation method. This is a process of obtaining lithium carbonate by evaporating water from salt water containing lithium and adding sodium carbonate. The salt water is concentrated until the lithium content exceeds 0.5%, and lithium carbonate, which does not dissolve well in water, is taken out. Use . Through the above process, lithium can be obtained by reacting lithium chloride with sodium carbonate in seawater through a reaction shown in Chemical Formula 1 below.

(One)

However, the above process has the advantage that there is no problem of resource depletion as seawater is an almost infinite resource. However, it takes a lot of time to recover as it is a process of evaporating water and adding sodium carbonate, and the concentration of lithium obtained in seawater is low. The disadvantage is that a large amount of processing equipment is required.

Therefore, there is a need for a novel recovery method for compounds in lithium ion batteries that can overcome all of the above shortcomings.

One object of the present invention is to provide a method for selective recovery of nickel and cobalt from a nickel-cobalt-manganese mixture using selective hydrogen reduction of metal oxides and molten slag removal processes.

As one aspect, the present invention includes a first step of heat treating a mixture of oxides of one or more of nickel, cobalt, and manganese in a hydrogen atmosphere; And it provides a method for producing and selectively recovering a nickel-cobalt alloy, comprising a second step of melting the product obtained after the first step in an inert atmosphere in a crucible and then removing slag.

The present invention discloses a method for selectively recovering nickel and cobalt from a nickel-cobalt-manganese mixture, preferably powder from spent nickel-cobalt-manganese (NCM) batteries.

The oxide is carbonated from a waste NCM battery in a CO, CO ₂ or mixed gas atmosphere of CO and CO ₂ ; and a water leaching process including the step of water leaching the product obtained after the carbonation process. The carbonation process is a step for selectively recovering the lithium component from the lithium-nickel-cobalt-manganese mixture, and the lithium can be phase changed into Li ₂ CO ₃ . At this time, the lithium can be carbonated by injecting a gas containing carbon dioxide (CO ₂ ) into the lithium-nickel-cobalt-manganese mixture. The carbonation process may be performed by a thermal reaction between CO ₂ and the lithium component in the nickel-cobalt-manganese mixture. Through the carbonation process, the lithium may react with CO ₂ to form Li ₂ CO ₃ there is. At this time, the carbon dioxide (CO ₂ )-containing gas may be a mixed gas of CO and CO ₂ or may be a CO ₂ gas alone. Additionally, the carbonation process includes raising the temperature to 700 to 900° C. in an inert atmosphere; and maintaining the mixture for a certain period of time in an atmosphere of CO, CO ₂ , or a mixed gas atmosphere of CO and CO ₂ . Before performing the thermal reaction of the carbonation process, an inert gas is injected into the nickel-cobalt-manganese mixture at a rate of 100 cc/min to 300 cc/min and the temperature is raised. The temperature may be raised for the thermal reaction of the carbonation process, and the temperature may be raised under an inert atmosphere. At this time, the inert gas is characterized in that it contains one or more of nitrogen (N ₂ ) and argon (Ar). After the temperature rise, when the thermal reaction target temperature is reached, the calcination reaction can be performed by injecting CO ₂ -containing gas (reducing gas) as a reaction gas. In this case, the thermal reaction time is 1 to 3 hours. It can be done during The water leaching process is a step of separating the lithium component from the lithium-nickel-cobalt-manganese mixture, and can be performed by water leaching Li ₂ CO ₃ formed through the carbonation process. Since Li ₂ CO ₃ has high water solubility, it can be separated from the nickel-cobalt-manganese component in the mixture by washing the carbonated mixture with water. At this time, the Li ₂ CO ₃ may be leached with water and have a liquid phase, and the nickel-cobalt-manganese component may be filtered in the form of a solid oxide. The water leaching process is characterized in that the carbonated nickel-cobalt-manganese mixture and water are washed at a weight ratio of 1:10 to 1:50. Additionally, the water washing in the water leaching process may preferably be performed for 1 hour to 5 hours. After the solid-liquid separation of the water leaching process, the process of drying the formed solid phase is further included. Reduced pressure filtration can be used to separate the liquid phase comprising Li ₂ CO ₃ dissolved in water and the solid phase in the form of oxides of nickel, cobalt and manganese. In order to recover the solid phase after the solid-liquid separation, it is preferably dried at 200°C for 24 hours.

The first step is to selectively recover nickel and cobalt, excluding manganese, as a metal phase by selectively hydrogenating the recovered solid phase, wherein the manganese maintains the form of an oxide, but the nickel and cobalt change to a metal phase. You can. At this time, for the selective hydrogen reduction, the solid phase may be subjected to a heating reaction with hydrogen (H ₂ ) gas at 500°C to 700°C, and preferably, the heating reaction may be performed for 30 to 120 minutes. . When the heating temperature is 500°C to 700°C, a hydrogen reduction reaction occurs in the nickel and cobalt, but a hydrogen reduction reaction does not occur in the manganese, so that the oxide state can be maintained. In this way, hydrogen reduction occurs only in some components, making component separation possible. In the selective hydrogen reduction of the first step, the hydrogen (H ₂ ) is characterized in that it is injected at a rate of 100 cc/min to 300 cc/min.

The second step is to obtain nickel and cobalt in an alloy state by adding flux to the partially hydrogen-reduced solid phase, preferably to the powder phase of manganese oxide, nickel and cobalt, and adding flux to the solid phase. In the third step, the non-hydrogenated manganese oxide reacts with the flux and forms slag, so it can be removed to obtain the remaining nickel and cobalt alloy. At this time, the flux is characterized in that it contains calcium oxide (CaO) and silicon dioxide (SiO ₂ ). In addition, the addition ratio of calcium oxide (CaO) and silicon dioxide (SiO ₂ ) in the flux is 1:1. The CaO is added at a molar ratio of 0.5 to 2 times that of the MnO, and the SiO ₂ is added at a molar ratio of 1 to 2 times that of the MnO.

In addition, the second stage melting may be performed at 700°C to 900°C, preferably at 1500°C to 1700°C, and more preferably at 1600°C. In one embodiment, the second step of melting is performed under an inert atmosphere. This is to prevent nickel and cobalt contained in the solid phase from being reoxidized, and the inert atmosphere can be maintained by nitrogen or argon gas. Through the melting, the manganese oxide in the solid phase is formed into slag by the flux and can be easily separated and removed. The manganese oxide is removed through slag, and components excluding slag can be obtained as nickel and cobalt alloy. Additionally, the crucible in the second step is characterized in that it is a crucible in which an alumina crucible is charged into a carbon crucible.

According to the present invention, the components in the nickel-cobalt-manganese mixture of a used lithium ion battery can be fractionated and obtained through a simple and cost-effective method called thermal reaction using a selective hydrogen reduction and molten slag removal process of metal oxide. , it can be obtained by separating the components in the nickel-cobalt-manganese mixture of a lithium-ion battery after use through an environmentally friendly method that does not use harmful strong acids or chemicals.

1 is a flow diagram of the method for selective recovery of nickel and cobalt of the present invention.
Figure 2 is an XRD graph of the selective hydrogen reduction solid phase according to the temperature of the selective hydrogen reduction.
Figure 3 is a binary phase diagram graph of nickel and cobalt alloy.
Figure 4 is a ternary phase diagram graph of manganese oxide, calcium oxide, and silicon dioxide at 1600°C.
Figure 5 is a ternary phase diagram graph at 1600°C of a calcium oxide (CaO):silicon dioxide (SiO2):manganese oxide (MnO) mixture with a mixing ratio of 40:40:20.
Figure 5 is a photograph of Example 4 in which the second stage melting and slag formation process was performed in an alumina crucible without flux.
Figure 6 is a photograph of Example 7 in which the second stage melting and slag formation process was performed in a carbon crucible with flux.
Figure 7 is a photograph of Example 5 in which the second stage melting and slag formation process was performed in an alumina crucible with flux.
Figure 8 is a photograph of Example 6 in which the second stage melting and slag formation process was performed in an alumina crucible with flux.
Figure 9 is an XRD graph of slag prepared through Example 6.

Hereinafter, embodiments of the present invention will be described in detail. Since the present invention can be subject to various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Terms such as first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Throughout the specification, when a part “includes” or “contains” a certain element, this means that it may further include other elements, unless specifically defined otherwise. Additionally, as used herein, singular expressions include plural expressions, unless the context clearly dictates otherwise.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains, and are clearly stated in this application. Unless defined, it is not to be interpreted in an idealistic or overly formal sense.

Hereinafter, the method for selective recovery of nickel and cobalt from the nickel-cobalt-manganese mixture disclosed by the present invention will be described in more detail with reference to the drawings of the present invention.

1 is a flow diagram of the method for selective recovery of nickel and cobalt of the present invention.

(1) Carbonation reaction

[Nickel-cobalt-manganese mixture → Li ₂ CO ₃ , NiO, CoO, MnO]

Referring to FIG. 1, after using a spent lithium ion battery, nickel-cobalt-manganese (NCM) powder can be prepared and then carbonated. Lithium may be included in the nickel-cobalt-manganese (NCM) powder, and lithium in the powder may be formed into Li ₂ CO ₃ through the carbonation. Additionally, the nickel, cobalt, and manganese components in the powder may be in the form of oxides such as NiO, CoO, and MnO. For the carbonation, gas containing CO ₂ may be injected into the powder to cause a thermal reaction between the gas and the powder. At this time, the thermal reaction may be performed by raising the temperature to 700°C to 900°C under an inert atmosphere, injecting a reducing gas containing CO ₂ , and calcining for 1 to 3 hours.

(2) Water leaching and solid-liquid separation

[Mixture → liquid phase (Li ₂ CO ₃ ), solid phase (NiO, CoO, MnO)]

After the carbonation reaction, using the water-soluble characteristics of the formed Li ₂ CO ₃ , lithium in the powder can be separated by performing water leaching and reduced-pressure filtration. Since Li ₂ CO ₃ formed after the carbonation reaction of the lithium in the powder has water-soluble characteristics, when the powder is leached with water, only the water-soluble Li ₂ CO ₃ can be dissolved in water and included in the liquid phase, and the remaining nickel-cobalt -Powders containing manganese oxide do not dissolve in water and may remain in a solid state. Component separation may be performed by separating the liquid phase and the solid phase into solid and liquid. At this time, reduced pressure filtration can be used to separate the solid and liquid.

(3) Selective hydrogen reduction

[Solid phase (NiO, CoO, MnO) → metal phase (Ni, Co), oxide (MnO)]

Selective hydrogen reduction can be performed by heating the solid phase obtained through the solid-liquid separation to 500°C to 700°C under a hydrogen atmosphere. Through the selective hydrogen reduction, nickel oxide and cobalt oxide present in the solid phase can be reduced and converted into nickel and cobalt metal phases. At this time, since the heating temperature is low enough for the manganese oxide to be reduced, the manganese oxide can maintain its oxide form without being reduced. For the selective hydrogen reduction, hydrogen gas may be injected at 100 cc/min to 300 cc/min, and the heating reaction may be performed for 30 to 120 minutes.

(4) Melting and slag formation

[Metal phase (Ni, Co), oxide (MnO) -> molten metal (Ni, Co), slag (MnO)]

Calcium oxide (CaO) and silicon dioxide (SiO ₂ ) are injected and melted as a flux into a mixture containing three types of nickel metal, cobalt metal, and manganese oxide formed through the selective hydrogen reduction to form slag. You can. At this time, the melting temperature may be 1500°C to 1700°C. The slag is a non-metallic material with a low melting point formed through melting, has oxide as its main component, and can float on the surface of the molten metal due to a density difference. Through the melting, the manganese oxide that has not formed a metal phase by forming slag can be separated from the nickel and cobalt metals. After the manganese oxide is separated into slag form, the nickel and cobalt alloy remaining in the molten metal phase can be obtained.

Hereinafter, various embodiments and evaluation examples of the present invention will be described. However, the following examples are only some examples of the present invention, and the present invention should not be construed as being limited to the following examples.

Example 1

In Example 1, selective hydrogen reduction was performed at 500°C ,

In the alumina crucible charged into the carbon crucible , 4.53 g of CaO, 11.33 g flux of SiO2, and 40 g of hydrogen reduction powder were charged at a molar ratio of CaO:SiO2:MnO = 20:50:30 to proceed with melting and slag formation.

A more specific manufacturing method is as follows.

[Water leaching]

Nickel-cobalt-manganese (NCM) powder was prepared after using a spent lithium-ion battery, CO2-containing gas was injected into the powder, and the temperature was raised to 800°C under an inert atmosphere. After raising the temperature, reducing gas containing CO2 was injected and calcined for 2 hours. After the carbonation reaction, the powder that had undergone the carbonation reaction was water leached, and the solid phase and liquid phase formed by the water leaching were separated through reduced pressure filtration.

[Selective hydrogen reduction]

The solid phase obtained through water leaching and solid-liquid separation was subjected to selective hydrogen reduction at 500°C for 60 minutes under a hydrogen atmosphere. The selective hydrogen reduction was performed by injecting hydrogen gas at 300 cc/min. Through the selective hydrogen reduction, nickel oxide and cobalt oxide present in the solid phase were reduced and converted into nickel and cobalt metal phases. At this time, because the heating temperature is too low to reduce the manganese oxide, the manganese oxide is not reduced and maintains its oxide form. Therefore, through the selective hydrogen reduction, the reduced metal phase of nickel and cobalt oxide and the manganese oxide phase coexist.

[Melting and slag formation]

40 g of hydrogen reduction powder, which is a mixture containing the reduced metal phase of nickel and cobalt oxide and the manganese oxide phase formed through the selective hydrogen reduction, was injected into an alumina crucible loaded in a carbon crucible. Into the alumina crucible, 4.53 g of CaO and 11.33 _g of SiO2 were injected as fluxes at a molar ratio of CaO:SiO2:MnO = 20:50:30 and melted to form slag. . At this time, the melting temperature was set at the most appropriate temperature of 1600°C for 180 minutes, referring to the binary and ternary phase diagrams disclosed in Figures 3 and 4 of the present invention. The melting and slag formation were performed by injecting argon gas at 300 cc/min to prevent change back to the oxide phase by forming an inert atmosphere. Slag was formed through the flux injection, and the manganese oxide that did not become a metal phase was separated from nickel metal and cobalt metal. After the manganese oxide was separated into slag form, nickel and cobalt remaining as molten metal were obtained in the form of an alloy.

Example 2

In Example 2, selective hydrogen reduction was carried out at 700°C ,

In the alumina crucible charged into the carbon crucible , 4.53 g of CaO, 11.33 g flux of SiO2, and 40 g of hydrogen reduction powder were charged at a molar ratio of CaO:SiO2:MnO = 20:50:30 to proceed with melting and slag formation.

The manufacturing method was carried out in the same manner as in Example 1, except that the manufacturing method was slightly different as described above.

Example 3

In Example 3, selective hydrogen reduction was performed at 900°C ,

In the alumina crucible charged into the carbon crucible , 4.53 g of CaO, 11.33 g flux of SiO2, and 40 g of hydrogen reduction powder were charged at a molar ratio of CaO:SiO2:MnO = 20:50:30 to proceed with melting and slag formation.

The manufacturing method was carried out in the same manner as in Example 1, except that the manufacturing method was slightly different as described above.

Example 4

In Example 4, selective hydrogen reduction was performed at 900°C ,

In an alumina crucible charged into a carbon crucible , 100 g of hydrogen reduction powder was charged without adding additives, and melting and slag formation were carried out.

The manufacturing method was carried out in the same manner as in Example 1, except that the manufacturing method was slightly different as described above.

Example 5

In Example 5, selective hydrogen reduction was performed at 900°C ,

In the alumina crucible charged into the carbon crucible , 13.6 g of CaO and 13.6 g of SiO2 flux, and 40 g of hydrogen reduction powder were charged at a molar ratio of CaO:SiO2:MnO = 40:40:20 to proceed with melting and slag formation.

The manufacturing method was carried out in the same manner as in Example 1, except that the manufacturing method was slightly different as described above.

Example 6

In Example 6, selective hydrogen reduction was carried out at 900°C ,

In the alumina crucible charged into the carbon crucible , 4.53 g of CaO, 11.33 g flux of SiO2, and 40 g of hydrogen reduction powder were charged at a molar ratio of CaO:SiO2:MnO = 20:50:30 to proceed with melting and slag formation.

The manufacturing method was carried out in the same manner as in Example 1, except that the manufacturing method was slightly different as described above.

Example 7

In Example 7, selective hydrogen reduction was performed at 900°C ,

In a carbon crucible , 13.6 g of CaO and 13.6 g of SiO 2 flux, and 40 g of hydrogen reduction powder were charged at a molar ratio of CaO:SiO2:MnO = 40:40:20 to proceed with melting and slag formation.

The manufacturing method was carried out in the same manner as in Example 1, except that the manufacturing method was slightly different as described above.

<Evaluation example>

Figure 2 is an XRD graph of the selective hydrogen reduction solid phase of Examples 1 to 3, depending on the temperature of selective hydrogen reduction.

To set the temperature of the selective hydrogen reduction of the present invention, the selective hydrogen reduction of the examples of the present invention was performed on 10 g of water-leached solid phase at 500°C, 700°C, and 900°C. Referring to FIG. 2, in Example 1, which was selectively hydrogen-reduced at 500°C, cobalt was not hydrogen-reduced and still existed in the form of cobalt oxide. However, from Example 2, which was selectively hydrogen-reduced at 700°C, individual metal phases of nickel and cobalt began to appear, and it can be seen that selective hydrogen reduction of nickel and cobalt occurred from Example 2, making component separation possible.

Additionally, Table 1 below shows the XRF value of the solid phase of Example 3 selectively hydrogenated at 900°C. Referring to Table 1 below, it can be seen that nickel and cobalt single phases exist in 58.49% and 22.97%, respectively, in the solid phase mixture.

Figure 3 is a binary phase diagram graph of nickel and cobalt alloy.

A phase diagram graph is a graph showing the equilibrium phase according to external factors such as temperature, pressure, and composition that affect the structure of the phase. Through the phase diagram graph, it is possible to know what phase the material exists in and what kind of mixture of phases it exists in at any temperature, pressure, and composition. Using the phase diagram graph, the melting temperature for component separation in the melting and slag forming steps of the present invention can be set.

A two-component system state diagram graph refers to a state diagram of a system consisting of two components. If you put a point on the phase diagram graph that corresponds to the desired composition and temperature, you can find out what phase exists through the area the point belongs to. Referring to the binary phase diagram of nickel and cobalt in FIG. 3, it can be seen that the nickel and cobalt are in a liquid phase in the total composition range above 1500°C.

Figure 4 is a ternary phase diagram graph of manganese oxide, calcium oxide, and silicon dioxide at 1600°C.

FIG. 4 is a phase diagram of calcium oxide (CaO)-silicon dioxide (SiO2)-manganese oxide (MnO), which is generally used to determine slag fluidity in melting and slag formation. Referring to FIG. 4, when a three-component system is contained in the slag-liquid region on the diagram graph, the calcium oxide (CaO)-silicon dioxide (SiO2)-manganese oxide (MnO) mixture forms an ideal molten slag. .

Figure 5 is a ternary phase diagram graph at 1600°C of a calcium oxide (CaO):silicon dioxide (SiO2):manganese oxide (MnO) mixture with a mixing ratio of 40:40:20. Figure 5 is an example of a ternary phase diagram. Referring to Figure 5, when the mixing ratio of calcium oxide (CaO): silicon dioxide (SiO2): manganese oxide (MnO) mixture is 40:40:20, slag -It can be confirmed that a three-component system is in the liquid area.

Figure 5 is a photograph of Example 4 in which the second stage melting and slag formation process was performed in an alumina crucible without flux.

To perform the melting of FIG. 5, an alumina crucible was charged into a carbon crucible, and 100 g of the selectively hydrogen-reduced solid powder was charged without additives such as flux. Thereafter, the solid powder was melted at 1600°C under argon gas, an inert atmosphere. At this time, the solid phase was melted and the slag layer was separated due to the difference in specific gravity, but it was confirmed that manganese was present in the metal component (alloy) shown in the photograph of FIG. 5. Therefore, in order to completely separate the manganese, it was found that, in addition to using an alumina crucible, it was necessary to add additional additives such as flux. Table 2 below shows the results of XRF component analysis of the alloy and slag. Referring to Table 2 below, it can be seen that 10.42% of manganese is present in the alloy, so the components between nickel-cobalt and manganese are not completely separated.

On the other hand, Figure 6 is a photograph of Example 7 in which the second stage melting and slag formation process was performed in a carbon crucible with flux.

To perform the melting of FIG. 6, 18 g of calcium oxide (CaO) as a flux, 18 g of silicon dioxide (SiO2) as a flux, and 50 g of the selectively hydrogen-reduced solid phase powder were charged into a carbon crucible. Thereafter, the flux and the solid phase powder were melted at 1600° C. under argon gas, an inert atmosphere. At this time, it can be seen in FIG. 6 that the solid phase was melted, but the slag and the metal (alloy) component were not separated. Therefore, in order to separate the metal components, it may be considered necessary to use an alumina crucible. Table 3 below shows the results of XRF component analysis of the alloy. Referring to Table 3 below, nickel, cobalt, and manganese are all present in the alloy, indicating that separation of alloy components did not occur through melting.

Figure 7 is a photograph of Example 5 in which the second stage melting and slag formation process was performed in an alumina crucible with flux.

In order to perform the melting of FIG. 7, an alumina crucible was charged into a carbon crucible, and 13.6 g of calcium oxide (CaO) as a flux, 13.6 g of silicon dioxide (SiO2) as a flux, and 40 g of the selectively hydrogen-reduced solid phase powder were added. Charged. Thereafter, the solid powder was melted at 1600°C under argon gas, an inert atmosphere. At this time, it can be confirmed that the solid phase was melted and the slag layer was separated due to the difference in specific gravity. Table 4 below shows the results of XRF component analysis of the slag. Referring to Table 4 below, it can be seen that 4.86% of manganese oxide exists in the slag and 15.23% of manganese in the metal exists, so the manganese component is not completely removed in the form of manganese oxide through the slag.

Figure 8 is a photograph of Example 6 in which the second stage melting and slag formation process was performed in an alumina crucible with flux.

In order to perform the melting of FIG. 8, an alumina crucible was charged into a carbon crucible, and 4.53 g of calcium oxide (CaO) as a flux, 11.33 g of silicon dioxide (SiO2) as a flux, and 40 g of the selectively hydrogen-reduced solid phase powder were added. Charged. Thereafter, the solid powder was melted at 1600°C under argon gas, an inert atmosphere. At this time, it can be confirmed that the solid phase was melted and the slag layer was separated due to the difference in specific gravity.

Figure 9 is an XRD graph of the slag prepared through Example 6, and Table 5 below shows the XRF component analysis results of the slag and metal. Referring to Figure 9 and Table 5, in the distribution of manganese, 17.99% of manganese oxide is present in the slag and there is no manganese or manganese oxide in the metal, and in the distribution of nickel and cobalt, nickel or cobalt in the slag is oxide. It exists in very small quantities in the form of 74.54% nickel and 23.98% cobalt in the metal, so it can be confirmed that nickel-cobalt present in the metal is 98.52%. This shows that manganese oxide is completely removed through the slag produced through the method of Example 6, and that the metal produced through the method of Example 6 consists of only nickel-cobalt alloy about 98.52%.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the following patent claims. You will understand that it is possible.

Claims (12)

A first step of heat treating the waste NCM battery in a CO, CO ₂ or mixed gas atmosphere of CO and CO ₂ ;
A second step of water leaching the product obtained after the heat treatment;
A third step of heat treating the solid material obtained after the second step in a hydrogen atmosphere; and
A fourth step of removing the slag after melting the product obtained after the third step in an inert atmosphere in a crucible charged with an alumina crucible in a carbon crucible,
The heat treatment temperature in the third step is 700 to 900°C,
The melting temperature of the crucible in the fourth step is 1500°C to 1700°C,
When melted, CaO and SiO ₂ are additionally included, and the slag includes MnO,
The CaO is added at a molar ratio of 0.5 to 2 times that of the MnO, and the SiO ₂ is added at a molar ratio of 1 to 2 times that of the MnO.
Method for recovering nickel-cobalt alloy from waste NCM.
delete According to paragraph 1,
The first step is,
Raising the temperature to 700 to 900° C. in an inert atmosphere; and
Including the step of maintaining for a certain period of time in a gas atmosphere of CO, CO ₂ or a mixed gas of CO and CO ₂ .
Method for recovering nickel-cobalt alloy from waste NCM. delete delete delete delete delete delete delete delete delete