JP2022085446A - Method for recovering valuable metal - Google Patents

Abstract

To provide an efficient pyrometallurgy process capable of recovering a valuable metal at a high recovery rate.SOLUTION: A method for recovering a valuable metal (Cu, Ni, Co) includes steps of: preparing a charging material at least including a valuable metal as a raw material; heating and melting the raw material to produce an alloy and slag; and separating the slag to recover the alloy containing the valuable metal. In the method, when heating and melting the raw material, a metallic aluminum is introduced as a reducer to the raw material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for recovering valuable metals.

In recent years, lithium-ion batteries have become widespread as lightweight, high-output batteries. A well-known lithium-ion battery has a structure in which a negative electrode material, a positive electrode material, a separator, and an electrolytic solution are enclosed in an outer can. Here, the outer can is made of a metal such as iron (Fe) or aluminum (Al). The negative electrode material is made of a negative electrode active material (graphite or the like) fixed to a negative electrode current collector (copper foil or the like). The positive electrode material is made of a positive electrode active material (lithium nickel oxide, lithium cobalt oxide, etc.) fixed to a positive electrode current collector (aluminum foil, etc.). The separator is made of a polypropylene porous resin film or the like. The electrolytic solution contains an electrolyte such as lithium hexafluorophosphate (LiPF ₆ ).

One of the main uses of lithium-ion batteries is hybrid and electric vehicles. Therefore, it is expected that a large amount of on-board lithium-ion batteries will be discarded in the future according to the life cycle of the automobile. There are also lithium-ion batteries that are discarded as defective products during manufacturing. It is required to reuse such used batteries and defective batteries generated during manufacturing (hereinafter, “waste lithium ion batteries”) as resources.

As a method of reuse, a pyrometallurgical process in which the entire amount of waste lithium ion batteries is melted in a high-temperature furnace (melting furnace) has been conventionally proposed. In the pyrometallurgical process, crushed waste lithium-ion batteries are melted and recovered, and valuable metals such as cobalt (Co), nickel (Ni) and copper (Cu), as well as iron (Fe) and aluminum (Fe) and aluminum (). This is a method for separating and recovering low-value-added metals such as Al) by utilizing the difference in oxygen affinity between them. In this method, low-value-added metals are oxidized as much as possible to form slag, while valuable metals are recovered as alloys by suppressing their oxidation as much as possible.

In the dry smelting process in which valuable metals are separated and recovered by utilizing the difference in oxygen affinity as described above, it is very important to control the degree of redox during the melting process. Insufficient control can lead to impurities in the alloy that should be recovered as a valuable metal. Alternatively, there is a problem that oxidized valuable metal is taken into the slag that should be recovered as an impurity, which lowers the recovery rate of the valuable metal. Therefore, in the pyrometallurgical process, an oxidizing agent such as air or oxygen or a reducing agent is introduced into the melting furnace to control the degree of redox.

For example, Patent Document 1 proposes a process of putting a waste lithium ion battery into a melting furnace and oxidizing it with oxygen as a method of recovering cobalt from a waste lithium ion battery by a dry method. Further, in Patent Document 2, when melting a waste lithium ion battery, SiO ₂ and CaO are added to lower the melting point of slag to promote the separation of metal and slag, and then to the metal after separating the slag. A process having a dephosphorization step of removing phosphorus by adding CaO while blowing oxygen has been proposed.

Japanese Patent No. 5818798 Japanese Patent No. 5853585

As described above, although it has been conventionally proposed to control the degree of redox by introducing air or oxygen during the melting process, there is room for improvement in the method. For example, Patent Document 1 states that cobalt can be recovered with a high recovery rate, but there is no description about removal of phosphorus. Therefore, it was unclear whether the process disclosed in this document could stably and efficiently recover valuable metals and remove phosphorus. In the process of Patent Document 2, since it is necessary to separately provide a dephosphorization step, there is a problem that the manufacturing cost is high.

The present invention has been completed in order to overcome such conventional problems, and an object of the present invention is to provide an efficient pyrometallurgical process capable of recovering valuable metals with a high recovery rate.

The present invention includes the following aspects (1) to (11). In the present specification, the expression "-" includes the numerical values at both ends thereof. That is, "X to Y" is synonymous with "X or more and Y or less".

(1) A method for recovering valuable metals (Cu, Ni, Co) in the following steps;
The process of preparing charged materials containing at least valuable metals as raw materials,
The process of heating and melting the raw material to make an alloy and slag,
It has a step of separating the slag and recovering an alloy containing a valuable metal.
A method of introducing metallic aluminum into a raw material as a reducing agent when the raw material is heated and melted.

(2) The method of (1) above, wherein the metallic aluminum is composed of a lump, and the average volume of the lump is 10.0 mm ³ or more.

(3) The method of (1) above, wherein the metallic aluminum is composed of grains and the average volume of the grains is 1.00 mm ³ or more and less than 10.00 mm ³ .

(4) The method of (1) above, wherein the metallic aluminum is composed of a powder, and the average volume of particles contained in the powder is less than 1.00 mm ³ .

(5) The method according to any one of (1) to (4) above, wherein the heating temperature at the time of heating and melting the raw material is 1300 ° C. or higher and 1500 ° C. or lower.

(6) The amount of the reducing agent introduced is 1.0 to 1.4 times the amount (equivalent) required to reduce all of the valuable metals contained in the raw material, as described in (1) above. Any method of (5).

(7) The method according to any one of (1) to (6) above, wherein the reducing agent does not contain a carbon component.

(8) The method according to any one of (1) to (7) above, wherein a flux is introduced into the raw material when the raw material is heated and melted.

(9) The method according to any one of (1) to (8) above, further comprising a step of oxidizing and roasting the raw material before heating and melting the raw material.

(10) The valuable metal according to the above (1) to (9), which comprises at least one metal or alloy selected from the group consisting of copper (Cu), nickel (Ni), cobalt (Co) and combinations thereof. Either way.

(11) The method according to any one of (1) to (10) above, wherein the charge includes a waste lithium ion battery.

INDUSTRIAL APPLICABILITY According to the present invention, an efficient pyrometallurgical process capable of recovering valuable metals with a high recovery rate is provided.

An example of a method for recovering valuable metals is shown.

A specific embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

The method for recovering the valuable metal (Cu, Ni, Co) of the present embodiment is as follows: a step of preparing a charge containing at least the valuable metal as a raw material (preparation step) and a step of heating and melting the prepared raw material. It has a step of forming an alloy and a slag (melting step) and a step of separating the slag from the obtained melt and recovering the alloy containing a valuable metal (slag separation step). Further, when the raw material is heated and melted, metallic aluminum is introduced into the raw material as a reducing agent.

The present embodiment is a method of recovering valuable metal from a charge containing at least valuable metal (Cu, Ni, Co). Here, the valuable metal is to be recovered and is at least one kind of metal or alloy selected from the group consisting of copper (Cu), nickel (Ni), cobalt (Co) and combinations thereof. The charge may contain phosphorus (P). Further, this embodiment is mainly a recovery method by a pyrometallurgical process. However, it may be composed of a dry smelting process and a wet smelting process. Details of each step will be described below.

<Preparation process>
In the preparation process, the charged material is prepared as a raw material. The charge is to be treated for recovering the valuable metal, and contains at least one kind of valuable metal selected from the group consisting of copper (Cu), nickel (Ni), cobalt (Co) and a combination thereof. .. The charge may contain these components (Cu, Ni, Co, etc.) in the form of a metal or an element, or may contain them in the form of a compound such as an oxide. Further, the charge may contain other inorganic components and organic components other than these components (Cu, Ni, Co).

The target of the charge is not particularly limited. Examples include waste lithium ion batteries, electronic components including dielectric or magnetic materials, and electronic devices. Further, the form is not limited as long as it is suitable for processing in the subsequent step. In the preparatory step, the charged material may be subjected to a treatment such as crushing treatment to form a suitable form. Further, in the preparatory step, the charged material may be subjected to heat treatment, separation treatment, or the like to remove unnecessary components such as water and organic substances.

<Oxidation roasting process>
If necessary, a step (oxidative roasting step) of oxidatively roasting the raw material (preheating) to make an oxidative roasted product (preheated product) may be provided before the subsequent melting step. In the oxidative roasting process, the raw material is oxidatively roasted to reduce the carbon contained in the raw material (charged material). By providing this step, even when the raw material contains an excessive amount of carbon, the carbon can be oxidized and removed, thereby promoting the alloy integration of the valuable metal in the subsequent melting step. That is, in the melting step, the valuable metal is reduced to become local molten fine particles. Carbon can be a physical obstacle when molten particles (valuable metals) aggregate. Therefore, if the oxidative roasting step is not provided, carbon may hinder the aggregation and integration of the molten fine particles and the resulting separation of the fused gold (metal) and the slag, and the recovery rate of the valuable metal may decrease. On the other hand, by removing carbon in the oxidative roasting process in advance, the aggregation and integration of the molten fine particles (valuable metal) in the melting process progresses, and the recovery rate of the valuable metal can be further increased. It will be possible. Further, since phosphorus (P) is an impurity that is relatively easily reduced, if carbon is excessively present, phosphorus may be reduced and incorporated into the fusion metal together with the valuable metal. By removing excess carbon in advance, it is possible to prevent phosphorus from being mixed into the fused metal. The carbon content of the oxidized roasted product is preferably less than 1% by mass.

Moreover, by providing the oxidation roasting step, it is possible to suppress the variation in oxidation. In the oxidative roasting step, it is desirable to perform treatment (oxidative roasting) at an oxidation degree capable of oxidizing a metal (Al or the like) having a low added value contained in the raw material. On the other hand, the degree of oxidation can be easily controlled by adjusting the processing temperature, time and / or atmosphere of oxidative roasting. Therefore, the degree of oxidation can be adjusted more strictly by the oxidation roasting step, and the variation in oxidation can be suppressed.

The degree of oxidation is adjusted as follows. As mentioned above, aluminum (Al), lithium (Li), carbon (C), manganese (Mn), phosphorus (P), iron (Fe), cobalt (Co), nickel (Ni) and copper (Cu) are Generally, it is oxidized in the order of Al> Li> C> Mn> P> Fe> Co> Ni> Cu. In the oxidation roasting step, the oxidation proceeds until the entire amount of aluminum (Al) is oxidized. Oxidation may be promoted until a part of iron (Fe) is oxidized, but the degree of oxidation is maintained to such an extent that cobalt (Co) is not oxidized and distributed to slag.

Oxidative roasting is preferably carried out in the presence of an oxidant. This makes it possible to efficiently remove the oxidation of carbon (C), which is an impurity, and oxidize aluminum (Al). The oxidizing agent is not particularly limited. However, oxygen-containing gas (air, quasi-oxygen, oxygen-enriched gas, etc.) is preferable because it is easy to handle. The amount of the oxidizing agent introduced is preferably, for example, about 1.2 times the chemical equivalent required for oxidation of each substance to be oxidized.

The heating temperature for oxidative roasting is preferably 700 ° C. or higher and 1100 ° C. or lower. At 700 ° C. or higher, the carbon oxidation efficiency can be further increased and the oxidation time can be shortened. Further, at 1100 ° C. or lower, the heat energy cost can be suppressed and the efficiency of oxidative roasting can be improved. The oxidative roasting temperature may be 800 ° C. or higher. Further, the temperature may be 900 ° C. or lower.

Oxidative roasting can be performed using a known roasting furnace. Further, it is preferable to use a furnace (preliminary furnace) different from the melting furnace used in the subsequent melting step and perform the heating in the preliminary furnace. As the oxidation roasting furnace, any type of furnace can be used as long as it is a furnace capable of supplying an oxidizing agent (oxygen or the like) while roasting the charged material and performing an oxidation treatment inside the furnace. As an example, a conventionally known rotary kiln and tunnel kiln (hearth furnace) can be mentioned.

<Melting process>
In the melting step, the raw material (waste lithium ion battery) obtained through the preparation step or the oxidative roasting step is heated and melted to be separated into an alloy (metal) and slag. Specifically, the molten material is heated and melted to form a melt. This melt contains the fused gold and the slag in a molten state. Then, the obtained melt is made into a melt. This melt contains the fused gold and the slag in a solidified state. Fused gold mainly contains valuable metals. Therefore, each of the valuable metal and other components can be separated as a fused metal and slag. This is because metals with low added value (Al and the like) have high oxygen affinity, whereas valuable metals have low oxygen affinity. For example, aluminum (Al), lithium (Li), carbon (C), manganese (Mn), phosphorus (P), iron (Fe), cobalt (Co), nickel (Ni) and copper (Cu) are generally used. It is oxidized in the order of Al>Li>C>Mn>P>Fe>Co>Ni> Cu. That is, aluminum (Al) is most easily oxidized, and copper (Cu) is least easily oxidized. Therefore, low-value-added metals (Al and the like) are easily oxidized to become slag, while valuable metals (Cu, Ni, Co) are reduced to become molten metals (alloys). In this way, low-value-added metals and valuable metals can be separated into slag and fused metal.

In the method of the present embodiment, when the raw material is heated and melted, metallic aluminum is introduced into the raw material as a reducing agent. Conventionally, reducing agents (carbonaceous reducing agents) containing carbon atoms such as coal and coke have been widely used. However, the carbonaceous reducing agent has a problem that the wettability with the molten slag is very poor and the reduction reaction is difficult to proceed. Specifically, in the melting process, the carbonaceous reducing agent was repelled from the slag and often ignited on the slag. On the other hand, when metallic aluminum is used as a reducing agent and the aluminum is poured onto the molten slag, the charged aluminum melts rapidly and easily reacts with the slag. In addition, the problem of ignition can be suppressed. Therefore, it is possible to efficiently proceed with the reduction reaction and it is also excellent in terms of safety. The metallic aluminum introduced as a reducing agent is distributed to the slag in the melting step. Therefore, it does not mix with the alloy and does not impair the recovery rate of valuable metals.

The shape of the metallic aluminum used as the reducing agent is not limited. For example, it may be lumpy, granular, or powdery. Moreover, the purity of metallic aluminum is not limited. However, the purity is preferably 90% or more. With such purity, the reduction efficiency does not significantly decrease.

According to one aspect of the present embodiment, it is preferable that the metallic aluminum is composed of a lump and the average volume of the lump is 10.0 mm ³ or more. A large amount of lump-shaped metallic aluminum can be easily put into the furnace, and dust can be prevented from being generated. However, excessively large lumps take time to melt. The average volume is preferably 1000.0 mm ³ or less, more preferably 100.0 mm ³ or less.

According to another aspect of the present embodiment, it is preferable that the metallic aluminum is composed of grains and the average volume of the grains is 0.50 mm ³ or more and less than 10.00 mm ³ . Granular metallic aluminum is easy to transport and handle. From the viewpoint of facilitating handling, the average volume of the grains is more preferably 1.00 mm ³ or more, and further preferably 3.00 mm ³ or more. However, excessively large grains take a long time to melt. The average volume is more preferably 7.00 mm ³ or less.

According to still another aspect of this embodiment, it is preferable that the metallic aluminum is composed of a powder and the average volume of the particles contained in the powder is less than 0.50 mm ³ . The powdered metallic aluminum easily reacts with slag, and the reduction reaction can be efficiently promoted. From the viewpoint of efficiently advancing the reduction reaction, the average volume of the particles is more preferably 0.30 mm ³ or less.

It is preferable that the amount of the reducing agent introduced is 1.0 to 1.4 times the amount (equivalent) required for reducing all of the valuable metals contained in the raw material. If the amount of the reducing agent added is excessively small, the reduction of the valuable metal becomes insufficient. Therefore, the valuable metal may be mixed into the slag, and the recovery rate of the valuable metal may decrease. On the other hand, if the amount of the reducing agent added is excessively large, impurities that are easily reduced may be mixed in the alloy (metal). In particular, when phosphorus (P), which is easily reduced, is mixed in the alloy, there is a problem that the phosphorus quality of the alloy is improved.

It is preferable that the reducing agent does not contain a carbon component. The carbonaceous reducing agent has a problem that the reduction reaction does not proceed easily and ignites on the slag. By using a reducing agent that does not contain a carbon component, it becomes possible to efficiently and safely recover valuable metals.

The heating temperature when the raw material is heated and melted is not particularly limited. However, it is preferably 1300 ° C. or higher and 1500 ° C. or lower. By setting the heating temperature to 1300 ° C. or higher, valuable metals (Cu, Co, Ni) are sufficiently melted to form a fused fusion gold in a state where the fluidity is enhanced. Therefore, the fused metal and the slag can be efficiently separated in the slag separation step described later. The heating temperature is more preferably 1350 ° C. or higher. On the other hand, if the heating temperature exceeds 1500 ° C., heat energy is wasted, and refractories such as crucibles and furnace walls are consumed more severely, which may reduce productivity. The heating temperature is more preferably 1450 ° C. or lower.

Flux may be introduced (added) to the melting raw material during the melting step. By adding the flux, the melting treatment temperature can be lowered, and the removal of phosphorus (P) can be further promoted. The flux preferably contains an element that incorporates an impurity element to form a basic oxide having a low melting point. Since phosphorus becomes an acidic oxide when oxidized, the more basic the slag formed in the melting step, the easier it is for the slag to take in phosphorus and remove it. Among them, those containing a calcium compound which is inexpensive and stable at room temperature are more preferable. Examples of the calcium compound include calcium oxide (CaO) and calcium carbonate (CaCO ₃ ). Further, silicon dioxide (SiO ₂ ) may be used as the flux.

<Slag separation process>
In the slag separation step, the slag is separated from the melt obtained in the melting step, and the fused gold containing the valuable metal is recovered. Slag and fused gold have different specific densities. Since the slag having a smaller specific gravity than that of the fused metal is collected on the upper part of the fused metal, it can be easily separated and recovered by the specific gravity separation.

After the slag separation step, a sulfurization step of sulfurizing the obtained alloy and a pulverization step of pulverizing the obtained sulfide or alloy may be provided. Further, a wet smelting process may be applied to the valuable metal alloy obtained through such a dry smelting process. Impurity components can be removed, valuable metals (Cu, Ni, Co) can be separated and purified by a hydrometallurgy process, and each can be recovered. Examples of the treatment in the hydrometallurgy process include known methods such as neutralization treatment and solvent extraction treatment.

According to the method of the present embodiment as described above, the uptake of phosphorus into the alloy can be suppressed, and the valuable metal can be recovered more efficiently. For example, the phosphorus content (phosphorus grade in metal) of the alloy is set to 0.50% by mass or less, 0.10% by mass or less, 0.05% by mass or less, 0.03% by mass or less, or 0.01% by mass or less. be able to. Further, the recovery rate of cobalt (Co), which is a valuable metal, can be 90.0% by mass or more, 95.0% by mass or more, 96.0% by mass or more, or 97.0% by mass or more. Here, the cobalt (Co) recovery rate is calculated according to the following equation (1) using the finally obtained fused gold and the content of cobalt (Co) contained in the slag.

The charge of the present embodiment is not limited as long as it contains a valuable metal. However, the charge preferably contains a waste lithium ion battery. The waste lithium ion battery contains lithium (Li) and valuable metals (Cu, Ni, Co), and also contains low value-added metals (Al, Fe) and carbon components. Therefore, by using a waste lithium-ion battery as a charge, valuable metals can be efficiently separated and recovered. The waste lithium-ion battery is not only a used lithium-ion battery, but also a lithium-ion battery such as defective products generated in the manufacturing process of the positive electrode material constituting the battery, residues inside the manufacturing process, and generated waste. It is a concept that includes waste materials in the process. Therefore, the waste lithium-ion battery can also be called a lithium-ion battery waste material.

A method of recovering valuable metal from a waste lithium ion battery will be described with reference to FIG. FIG. 1 is a process diagram showing an example of a recovery method. As shown in FIG. 1, this method involves removing the electrolytic solution and the outer can of the waste lithium ion battery to obtain the waste battery contents (waste battery pretreatment step S1), and crushing the waste battery contents. The step of making a crushed product (first crushing step S2), the step of oxidatively roasting the crushed product into an oxidative roasted product (oxidative roasting step S3), and the step of melting the oxidative roasted product into a molten product. It has (melting step S4) and a step (slag separation step) of separating slag from the melt and recovering the fused gold. Further, although not shown, a sulfurization step for sulfurizing the obtained alloy and a second grinding step for pulverizing the obtained sulfide or alloy may be provided after the slag separation step. The details of each process will be described below.

<Waste battery pretreatment process>
The waste battery pretreatment step (S1) is performed for the purpose of preventing the waste lithium ion battery from exploding, detoxifying it, and removing the outer can. Since the lithium ion battery is a closed system, it has an electrolytic solution and the like inside. Therefore, if the crushing process is performed as it is, there is a risk of explosion, which is dangerous. It is preferable to perform discharge treatment or electrolyte removal treatment by some method. The specific method of waste battery pretreatment is not particularly limited. For example, a method of physically opening a waste battery with a needle-shaped cutting edge to remove an electrolytic solution can be mentioned. Another method is to heat the waste battery and burn the electrolytic solution to make it harmless.

Further, the outer can is often composed of aluminum (Al) and iron (Fe), which are metals, and it is relatively easy to recover the outer can made of such metal as it is. By removing the electrolytic solution and the outer can in the waste battery pretreatment step (S1) in this way, it is possible to enhance safety and increase the recovery rate of valuable metals (Cu, Ni, Co). When recovering aluminum (Al) and iron (Fe) contained in the outer can in the waste battery pretreatment step (S1), the removed outer can is crushed and then the crushed material is sieved using a sieve. It may be sieved. Since aluminum (Al) is easily powdered by light pulverization, it can be efficiently recovered. Further, iron (Fe) contained in the outer can may be recovered by magnetic force sorting.

<First crushing process>
In the first pulverization step (S2), the waste lithium ion battery or its contents (battery contents) are pulverized to obtain a pulverized product. This process aims to increase the reaction efficiency in the pyrometallurgical process. By increasing the reaction efficiency, the recovery rate of valuable metals (Cu, Ni, Co) can be increased. The specific pulverization method is not particularly limited. It can be crushed using a conventionally known crusher such as a cutter mixer. The waste battery pretreatment step and the first crushing step together correspond to the preparatory step described above.

<Oxidation roasting process>
In the oxidative roasting step (S3), the pulverized product obtained in the first crushing step (S2) is oxidatively roasted to obtain an oxidative roasted product. The details of this process are as described above.

<Melting process>
In the melting step (S4), the oxidative roasted product obtained in the oxidative roasting step (S3) is melted to obtain a molten product. The details of this process are as described above.

<Slag separation process>
In the slag separation step, the slag is separated from the melt obtained in the melting step (S4), and the fused gold is recovered. The details of this process are as described above.

A sulfurization step or a pulverization step may be provided after the slag separation step. Further, a wet smelting process may be performed on the obtained valuable metal alloy. The details of the sulfurization process, the pulverization process and the hydrometallurgy process are as described above.

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

(1) Recovery of valuable metals [Example 1]
Valuable metals were recovered using a waste lithium-ion battery as a charge. Recovery was carried out according to the following steps.

<Waste battery pretreatment process (preparation process)>
As waste lithium-ion batteries, used batteries and defective products collected in the battery manufacturing process were prepared. Then, the waste lithium ion batteries are collectively immersed in salt water to be discharged, then the water is removed, and the batteries are roasted in the air at 260 ° C. to decompose and remove the electrolytic solution and the outer can to remove the battery contents. Obtained. The main elemental compositions of the battery contents are as shown in Table 1 below.

<Crushing process>
The obtained battery contents were crushed by a crusher (trade name: Good Cutter, manufactured by Ujiie Seisakusho Co., Ltd.) to obtain a crushed product.

<Oxidation roasting process>
The obtained pulverized product was put into a rotary kiln and roasted in the air at 800 ° C. for 180 minutes to obtain a molten material.

<Melting process>
Calcium oxide (CaO) and silicon dioxide (SiO ₂ ) were added as fluxes to the oxidatively roasted crushed product (melting raw material), and a reducing agent was further added to adjust the degree of redox, and these were mixed. .. The obtained mixture was charged into an alumina crucible, and this was heated and melted by resistance heating to obtain a melt. Then, a melt containing fused gold and slag was obtained. At this time, as the reducing agent, lump metallic aluminum having an average volume of 12 mm ³ or more was used. The amount of the reducing agent added was 1.1 times the amount (equivalent) required to reduce all of the valuable metals contained in the raw material. Further, the mixture was heated under the conditions of 1400 ° C. × 30 minutes.

<Slag separation process>
The slag was separated from the obtained melt by utilizing the difference in specific densities, and the fused gold was recovered.

[Example 2]
As the reducing agent, lump metallic aluminum having an average volume of 35 mm ³ or more was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 3]
As the reducing agent, granular metallic aluminum having an average volume of 1.3 mm ³ was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 4]
As the reducing agent, granular metallic aluminum having an average volume of 4.6 mm ³ was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 5]
As the reducing agent, powdered metallic aluminum having an average volume of 0.27 mm ³ (average particle size 0.8 mm) was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 6]
As the reducing agent, powdered metallic aluminum having an average volume of 0.01 mm ³ (average particle size 0.3 mm) was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 7]
As the reducing agent, lump metallic aluminum having an average volume of 18 mm ³ was used. Further, heating in the melting step was performed under the conditions of 1320 ° C. × 40 minutes. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 8]
As the reducing agent, lump metallic aluminum having an average volume of 18 mm ³ was used. Further, heating in the melting step was performed under the conditions of 1480 ° C. × 20 minutes. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 9 (Comparative example)]
As the reducing agent, granular coal having an average volume of 4.6 mm ³ was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

[Example 10 (Comparative example)]
As the reducing agent, powdered coal having an average volume of 0.27 mm ³ (average particle size 0.8 mm) was used. Other than that, valuable metals were recovered in the same manner as in Example 1.

(2) Evaluation The fused metal (metal) and slag recovered in Examples 1 to 10 were subjected to elemental analysis using an ICP analyzer (Agilent Technologies Co., Ltd., Alloy 5100SUDV). At this time, cobalt (Co), which is the most easily oxidized and difficult to recover as a metal, and phosphorus (P), which is an impurity which is difficult to remove from the metal, were used as analytical elements.

Then, the content (mass%) of phosphorus (P) in the fused metal (metal) was defined as the phosphorus grade. The recovery rate of cobalt (Co) was determined as follows. That is, the cobalt (Co) recovery rate was calculated according to the following equation (1) using the content of cobalt (Co) in the fused gold and slag obtained by elemental analysis.

(3) Results Table 2 shows the phosphorus grade and cobalt recovery rate obtained for Examples 1 to 10. Good results were obtained in Examples 1 to 8 as Examples. Specifically, in the obtained alloy, the recovery rate of cobalt, which is a valuable metal contained in the battery, was 95% or more, and the phosphorus grade in the obtained alloy was less than 0.01% by mass. As described above, by using aluminum as a reducing agent, the reduction reaction of the valuable metal in the slag by the molten aluminum could be rapidly promoted. As a result, valuable metals could be obtained with a high recovery rate, and phosphorus could be effectively removed.

On the other hand, in Examples 9 and 10, which are comparative examples, the cobalt recovery rate was low, and worse results were obtained as compared with the examples. This is because the wettability between the coal and the slag is poor, so that the coal floats on the slag and the reduction reaction does not proceed promptly.

Claims (11)

A method for recovering valuable metals (Cu, Ni, Co) in the following steps;
The process of preparing charged materials containing at least valuable metals as raw materials,
The process of heating and melting the raw material to make an alloy and slag,
It has a step of separating the slag and recovering an alloy containing a valuable metal.
A method of introducing metallic aluminum into a raw material as a reducing agent when the raw material is heated and melted. The method according to claim 1, wherein the metallic aluminum is composed of a lump, and the average volume of the lump is 10.0 mm ³ or more. The method according to claim 1, wherein the metallic aluminum is composed of grains, and the average volume of the grains is 0.50 mm ³ or more and less than 10.00 mm ³ . The method according to claim 1, wherein the metallic aluminum is composed of a powder, and the average volume of particles contained in the powder is less than 0.50 mm ³ . The method according to any one of claims 1 to 4, wherein the heating temperature at the time of heating and melting the raw material is 1300 ° C. or higher and 1500 ° C. or lower. Any of claims 1 to 5, wherein the amount of the reducing agent introduced is 1.0 to 1.4 times the amount (equivalent) required for reducing all of the valuable metals contained in the raw material. The method described in item 1. The method according to any one of claims 1 to 6, wherein the reducing agent does not contain a carbon component. The method according to any one of claims 1 to 7, wherein a flux is introduced into the raw material when the raw material is heated and melted. The method according to any one of claims 1 to 8, further comprising a step of oxidizing and roasting the raw material before heating and melting the raw material. The value according to any one of claims 1 to 9, wherein the valuable metal consists of at least one metal or alloy selected from the group consisting of copper (Cu), nickel (Ni), cobalt (Co) and combinations thereof. the method of. The method according to any one of claims 1 to 10, wherein the charge includes a waste lithium ion battery.

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