JP3057321B1 - Method for recovering valuable metals from metal oxides containing alkali metals - Google Patents

Abstract

The present invention provides a method of recovering valuable metals from metal oxides containing alkali metals, which efficiently recovers valuable metals particularly from metal oxides containing alkali metals generated in the process of manufacturing a secondary battery. SOLUTION: A reducing agent and a slag-making agent are added to a metal oxide containing an alkali metal generated in a process of manufacturing a secondary battery to melt, and a valuable metal which is reduced and settles is recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering a valuable metal from a metal oxide containing an alkali metal which is generated in a process of manufacturing a secondary battery, for example.

[0002]

2. Description of the Related Art In recent years, demand for secondary batteries has increased along with demand for portable telephones and computers, and it is expected that the market for lithium secondary batteries in particular will continue to expand in the future. This lithium secondary battery uses a metal oxide containing valuable metals such as Co, Ni and Mn for its positive electrode, and collects and recycles these valuable metals from used lithium secondary batteries. This is extremely important from the viewpoint of effective utilization of resources.

[0003]

However, this lithium secondary battery also has Co, Ni,
A large amount of by-products (defective products, etc.) composed of metal oxides containing valuable metals such as Mn are generated. In the future, development of secondary batteries using not only lithium secondary batteries but also alkali metals such as Na and K is expected. The present invention has been made in view of such circumstances, in particular, to efficiently recover valuable metals from metal oxides containing alkali metals generated in the process of manufacturing a secondary battery, and to recover valuable metals from metal oxides containing alkali metals efficiently. The purpose is to provide a collection method.

[0004]

According to the first aspect of the present invention, there is provided a method for recovering valuable metals from a metal oxide containing an alkali metal, the method comprising the steps of: Reducing agents and slag-making agents are added to the oxide to melt it, and valuable metals that are reduced and settled are recovered.

[0005] In general, as a method of recovering valuable metals contained in metal oxides, there is a method of adding a reducing agent to metal oxides, melting them, and recovering reduced and precipitated valuable metals. In order to efficiently recover the target metal (valuable metal) by this method, the basicity of the slag is kept high (CaO
/ SiO ₂ ≧ 1.5), and the slag must have high fluidity so that valuable metals reduced in the slag can be easily settled. However,
In order to keep the basicity high, the amount of CaO having a high melting point necessarily increases, and the melting point of the slag increases (about 1940).
Degree), as a result, the fluidity of the slag decreases.

Therefore, in the method for recovering valuable metals from a metal oxide containing an alkali metal according to the first invention,
The melting point of slag can be lowered by adding a reducing agent and a slag-making agent to a metal oxide containing an alkali metal having a low melting point and melting. Therefore, even if CaO having a high melting point is added, the slag can maintain high fluidity. That is, slag having high fluidity can be generated while maintaining high basicity by adding CaO, and valuable metals can be efficiently collected.

[0007] Here, a metal oxide containing the alkali _{metal, Li n Co m O x,} Na n Co m O x, K n Co
_{m O x, Li n Ni m} O x, Na n Ni m O x, K n N
_{i m O x, Li n Mn} m O x, Na n Mn m O x, K n
It is desirable to contain any one or more of Mn _m O _x . Metal oxides containing these alkali metals include:
It contains valuable metals such as Co and Ni, which can be recovered. In addition, n, m, and x show all positive integers considered as a composition. Further, the reducing agent is F
It is desirable to contain any one or more of eSi, Si, CaSi, and SiC. Since Si is used as a reducing agent, it is oxidized to SiO ₂ , and it is not necessary to separately add SiO ₂ related to basicity. Also, S
Since the reduction reaction using i is an exothermic reaction, it becomes a heat source and can reduce required energy. The slag-making agent desirably contains one or more of CaO, Ca (OH) ₂ , and CaCO ₃ . This makes it possible to maintain a high basicity and promote reduction. The slag-making agent blocks oxygen and prevents oxidation of valuable metals.

In the method for recovering valuable metals from a metal oxide containing an alkali metal according to the second invention, an iron material, a metal oxide containing an alkali metal, a reducing agent, and a slag-making agent are charged into a furnace. The valuable metal that is melted, reduced and settled is recovered as an iron alloy. In the method for recovering valuable metals from a metal oxide containing an alkali metal according to the second invention,
Since the metal oxide containing an alkali metal having a low melting point is charged into the furnace and melted, the melting point of the slag can be lowered. Therefore, even if CaO having a high melting point is added, slag can maintain high fluidity, and slag having high basicity and high fluidity can be produced. Further, by introducing an iron material, the reducibility can be improved. When FeSi is used instead of pure metal Si as the reducing agent, the process of removing Fe can be omitted because Fe does not become an extra component.

[0009] Here, a metal oxide containing the alkali _{metal, Li n Co m O x,} Na n Co m O x, K n Co
_{m O x, Li n Ni m} O x, Na n Ni m O x, K n N
_{i m O x, Li n Mn} m O x, Na n Mn m O x, K n
It is desirable to contain any one or more of Mn _m O _x . Metal oxides containing these alkali metals include:
It contains valuable metals such as Co and Ni, which can be recovered. Note that n, m, and x are the same as in the first invention. Further, the reducing agent is FeSi, Si,
It is desirable to contain one or more of CaSi and SiC. Since Si is used as a reducing agent, it is oxidized into SiO ₂ , and there is no need to separately add SiO ₂ . Further, since the reduction reaction using Si is an exothermic reaction, the reduction reaction becomes a heat source and required energy can be reduced. And, the slag-making agent is CaO, Ca (O
H) _2, it is desirable to include any one or more of CaCO _3. This makes it possible to maintain a high basicity and promote reduction. The slag-making agent blocks oxygen and prevents oxidation of valuable metals.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a process explanatory diagram of a method for recovering valuable metals from a metal oxide containing an alkali metal according to one embodiment of the present invention.

A method for recovering a valuable metal from a metal oxide containing an alkali metal according to an embodiment of the present invention is a method of recovering a valuable metal from a metal oxide containing an alkali metal, which is an example of a metal oxide containing an alkali metal generated in a process of manufacturing a lithium secondary battery. ₂ (Li ₂ O ・ Co ₂
O ₃ ) to recover Co (an example of a valuable metal) as FeCo. This will be described below. First, as shown in FIG. 1, a raw material (LiCoO ₂ ) recovered as a by-product in the process of manufacturing a lithium secondary battery is briquetted (Step 1). This briquette is obtained by adding, as an aggregate, FeSi, which is an example of a reducing agent of 10% by weight, to LiCoO ₂ , as an aggregate, and further adding a binder. This can prevent scattering when charged into the furnace, increase the adhesion between LiCoO ₂ and FeSi, and promote reduction.

Next, for example, about 4.5 t of an iron material (scrap) is charged into an arc furnace and melted (step 2). About 12 t of LiCoO ₂ briquetted in the previous step, about 1.7 t of FeSi (an example of a reducing agent), and CaO which is an example of a slag-making agent, were placed in an arc furnace in which the iron material was melted.
4. Charge about 1t. At this time, since the molten iron material exists in the furnace, it is possible to suppress the outflow of the input material to the dust collector. Then, these are melted (step 3). Thereafter, FeSi as a reducing agent can be charged while further confirming the progress of the reduction. And
The temperature is held at about 1500 to 1650 ° C. for about 30 minutes (step 4). The reducing agent used here (FeS
The total amount of i) is preferably an amount capable of sufficiently reducing the valuable metal (Co), for example, 1 to 1.5 times equivalent to 1 equivalent of the valuable metal. The amount of the slag-making agent (CaO) is S
It is preferable that the amount is such that the basicity can be maintained at 1.5 or more corresponding to the amount of SiO ₂ generated by the reduction of i.

At this time, the slag (Li ₂ O—SiO ₂ —
It is considered that the melting point of (CaO-based) decreases to a range of about 1100 to 1500 ° C. even when the volatilization of lithium (about 50%) is considered. This is because the slag contains Li ₂ O. In addition, the basicity of the slag can be maintained at about 1.7 to 2.3 exceeding 1.5. That is,
The state of the slag has a high fluidity and a high basicity. Therefore, CoO (Co ₂ O)
₃ ) The reduction is promoted, and the reduced Co easily precipitates in the slag. In order to maintain high reducibility,
It is desirable to keep the molten steel (in the molten iron material) in a state where about 2% of Si exists. This is because the reduction is considered to be performed also in the molten steel (or the interface between the molten steel and the slag). Further, Fe is also considered to contribute to the reduction, and the presence of molten steel improves the reducibility.

After about 30 minutes, a slag analysis is performed. At this time, if the amount of CoO is large, FeSi can be further added and retained, and further reduction can be performed. Then, after confirming that the CoO has been sufficiently reduced, the slag is discharged (step 5). And blowing oxygen,
The Si remaining in the molten steel from which the slag has been discharged is oxidized and removed (step 6), and then Co (a valuable metal) is recovered as FeCo. In the above embodiment,
First, the iron material was charged and the valuable metal was recovered as an iron alloy (FeCo). However, the valuable metal (Co) can be recovered by performing the same operation as in the above-described embodiment without charging the iron material. is there. At this time, it is desirable to use a reducing agent that does not contain other metals, for example, Si or the like, and recover it as pure Co.

[0015]

Next, examples of the present invention will be described. As raw materials, iron materials (scraps) and metal oxides (Li) containing alkali metals generated as by-products in the production process of lithium secondary batteries
CoO ₂ ), a reducing agent (FeSi), and a slag-making agent (Ca
O) and the Fe of Co in the same manner as in the above embodiment.
A recovery experiment as Co was performed. The amounts of Fe and Co to be charged into the furnace were grasped in advance by analysis and the like. Table 1 shows the results.

[0016]

[Table 1]

As shown in Table 1, approximately 97.4% of Co, which is a valuable metal contained in LiCoO ₂ generated as a by-product in the process of manufacturing the lithium secondary battery, can be recovered.

As described above, the present invention has been described with reference to an embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and is described in the claims. The present invention also includes other embodiments and modifications that can be considered within the scope of the matters. For example, although a battery using Li is used as the secondary battery, a secondary battery using Na, K, or the like may be used. Also, as the reducing agent,
Although FeSi was used, one or more of Si, CaSi, SiC, C, and the like can be used. Although CaO was used as a slag-making agent, Ca (OH) ₂ , CaCO ₃
One or more of these can be used, and other calcium compounds can be used as long as they generate CaO at the melting temperature. The metal oxides containing alkali _{metals, Li n Co m O x,} Na n Co m O x,
_{K n Co m O x, Li} n Fe m O x, Na n Fe m O
_{x, K n Fe m O x} , Li n Ni m O x, Na n Ni m
_{O x, K n Ni m O} x, Li n Mn m O x, Na n Mn
_m O _x, can be used those containing either one or more of K _n Mn _m O _x.

[0019]

According to the first aspect and the third aspect dependent thereon,
In the method for recovering valuable metals from a metal oxide containing an alkali metal according to 4, the metal oxide containing a low melting point and a reducing agent and a slag-making agent are added to the metal oxide and melted. Fluid slag can be generated, and valuable metals can be efficiently recovered from metal oxides containing alkali metals generated in large quantities in the process of manufacturing the secondary battery. And the reducing agent is FeS
i, Si, CaSi, and SiC, which contain any one or more of them, are oxidized to form SiO ₂ ,
The step of separately adding SiO ₂ can be omitted.
Also, since the reduction reaction using Si is an exothermic reaction,
It becomes a heat source and the required energy can be reduced. In the method for recovering valuable metal from the metal oxide containing an alkali metal according to claim 2 and the dependent claims 3 and 4, since the metal oxide containing an alkali metal is used, the melting point of the slag is reduced. The slag can maintain high fluidity even when CaO having a high melting point is added. Therefore, slag having high basicity and high fluidity can be produced. Then, by introducing the iron material, the reducibility is increased, and the valuable metal can be more efficiently recovered as an iron alloy. Since the reducing agent contains one or more of FeSi, Si, CaSi, and SiC, these are oxidized and
The step of generating O ₂ and separately adding SiO ₂ can be omitted. Further, since the reduction reaction using Si is an exothermic reaction, the reduction reaction becomes a heat source and required energy can be reduced.

[0020] In the method of recovering valuable metal from a metal oxide containing an alkali metal according to claim 3, metal oxides containing alkali _{metals, Li n Co m O x,} Na n Co
_{m O x, K n Co m} O x, Li n Ni m O x, Na n N
_{i m O x, K n Ni} m O x, Li n Mn m O x, Na n
Mn _m O _x, because it contains any one or more of K _n Mn _m O _x, these include Co, contains valuable metals such as Ni, it is possible to these recovery. Claim 4
In the method for recovering valuable metals from a metal oxide containing an alkali metal as described above, the slag-making agent is CaO, Ca (OH)
_{2. Since} any one or more of CaCO ₃ is contained, a high basicity can be maintained, and reduction can be promoted.

[Brief description of the drawings]

FIG. 1 is a process explanatory diagram of a method for recovering valuable metal from a metal oxide containing an alkali metal according to one embodiment of the present invention.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-10-155871 (JP, A) JP-A-5-320779 (JP, A) JP-A-49-84915 (JP, A) JP-A-1- 247535 (JP, A) JP 42-18906 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22B 5/00-9/22 H01M 10/54

Claims (4)

(57) [Claims] 1. A method of adding a reducing agent and a slag-making agent to a metal oxide containing an alkali metal generated in a process of manufacturing a secondary battery, melting the metal oxide, and reducing and settling any one of Co, Ni, and Mn.
Or a method for recovering a valuable metal from a metal oxide containing an alkali metal which recovers a valuable metal composed of two or more, wherein the reducing agent contains any one or more of FeSi, Si, CaSi, and SiC. A method for recovering valuable metal from a metal oxide containing an alkali metal, characterized by comprising: 2. An iron material, a metal oxide containing an alkali metal,
A metal oxide containing an alkali metal for recovering a valuable metal composed of one or more of Co, Ni, and Mn that is reduced and precipitated by charging a reducing agent and a slag-making agent into a furnace, and is reduced and precipitated as an iron alloy. A method for recovering valuable metal from a product, wherein the reducing agent contains one or more of FeSi, Si, CaSi, and SiC, and is a valuable metal from a metal oxide containing an alkali metal. Collection method. 3. A method of recovering valuable metal from a metal oxide containing an alkali metal according to claim 1 or 2, wherein the metal oxide containing the alkali metal, Li _n Co _m O _{x,
Na n Co m O x, K} n Co m O x, Li n Ni m O
_{x, Na n Ni m O x} , K n Ni m O x, Li n Mn m
Any one of O _x , Na _n Mn _m O _x , and K _n Mn _m O _x
Or a method for recovering valuable metal from a metal oxide containing an alkali metal, characterized by containing two or more. 4. The method for recovering valuable metal from a metal oxide containing an alkali metal according to claim 1, wherein the slag-making agent is CaO, Ca (OH) ₂ , C
A method for recovering a valuable metal from a metal oxide containing an alkali metal, wherein the valuable metal contains any one or two or more of aCO ₃ .