KR101445443B1 - Solvent extraction method of aluminum - Google Patents

Abstract

An object of the present invention is to provide a solvent extraction method of aluminum capable of separating and recovering aluminum with high efficiency from a solution containing aluminum.
The present invention is a method for extracting aluminum from a solution containing aluminum in an acidic solution of sulfuric acid, comprising an extraction step of extracting and separating aluminum using an organic solvent containing mono-2-ethylhexyl 2-ethylhexylphosphonate.

Description

SOLVENT EXTRACTION METHOD OF ALUMINUM "

The present invention relates to a solvent extraction method of aluminum.

Lithium-ion batteries are rapidly expanding applications for hybrid vehicles, and production of large-sized batteries is expected to increase sharply due to high capacity of the units. In addition, in order to expand the demand for lithium ion batteries, it is required to establish a method for recovering valuable metals from lithium ion batteries.

This lithium ion battery is mainly composed of a positive electrode, a negative electrode, a separator, and a housing. The positive electrode is formed of a positive electrode active material including manganese, cobalt, nickel, lithium, and a conductive material such as carbon black, As shown in Fig. The positive electrode material is composed of an aluminum foil having a thickness of about 15 micrometers and a binder layer containing a positive electrode active material, and an outer surface of the aluminum foil is coated with a black positive electrode active material.

As a recycling method of a lithium ion battery, there is proposed a method of incinerating and crushing a used lithium ion battery, acid leaching using the raw material after the selection, and extracting and separating each metal by solvent extraction from the obtained leaching solution . However, if the raw material contains aluminum as the positive electrode material as an impurity, aluminum is leached by acid leaching, which adversely affects extraction separation in solvent extraction. Therefore, when aluminum is contained in the leached liquid obtained by acid-leaching the raw material, it is necessary to remove aluminum.

As a method for removing aluminum in the acidic solution, neutralization method, aluminum sulfate method, solvent extraction method, and the like have been proposed. As a neutralization method, there has been proposed a method in which a neutralizing agent such as sodium hydroxide is added to neutralize the pH in the range of 6 to 8, as disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-33984) . As the aluminum sulfate method, as described in Patent Document 2 (Japanese Patent Application Laid-Open No. 1-153517), the SO ₄ / Al molar ratio is set to 3/2 to 9/2, Thereby precipitating aluminum sulfate.

As a method for extracting aluminum using solvent extraction, extraction and separation of aluminum by acidic phosphate ester has been reported as disclosed in Patent Document 3 (Japanese Patent Application Laid-Open No. 63-25217), and 99% Or more can be extracted.

Japanese Patent Application Laid-Open No. 2004-33984 Japanese Patent Application Laid-Open No. 1-153517 Japanese Patent Application Laid-Open No. 63-25217

In the recycled lithium ion battery, the raw material having a high aluminum content is present. There is a problem that when the raw material having a high aluminum content is leached, aluminum is contained at a high concentration in the leaching solution. The metal to be recovered in the recycling of the lithium ion battery is manganese, cobalt, nickel, lithium, and aluminum needs to be separated as an impurity.

However, in the neutralization method described in Patent Document 1 or 2, precipitated aluminum hydroxide is gelled to deteriorate the filtration property, and there is also a problem that cobalt and nickel in the liquid are also precipitated by air-hole action at the time of neutralization. There is a problem that a large amount of sulfuric acid is required also in the aluminum sulfate method.

On the other hand, in the solvent extraction method described in Patent Document 3, although aluminum can be recovered, there is no report on the separation method of aluminum and other metals.

Accordingly, it is an object of the present invention to provide a method of extracting aluminum from a solution containing aluminum, manganese, and other metals, which can separate and recover aluminum with high efficiency.

As a result of diligent studies for solving the above problems, it has been found out that, by using a solvent extraction method and selecting an appropriate organic solvent as a solvent to be used for extraction, the extraction efficiency of the organic solvent is different depending on the metal to be extracted, Aluminum can be separated and extracted with high efficiency.

According to one aspect of the present invention, which is completed on the basis of the above knowledge, the present invention provides a process for producing a sulfuric acid-containing solution containing aluminum by extraction and separation of aluminum using an organic solvent containing mono-2-ethylhexyl 2-ethylhexylphosphonate And a solvent extraction step of extracting aluminum from the solution.

The solvent extraction method of aluminum of the present invention is, in one embodiment, the aluminum sulfate-containing leach solution obtained by recycling lithium ion batteries in the sulfuric acid acidic solution.

In another embodiment of the present invention, the acidic solution of sulfuric acid includes at least one of manganese, cobalt, nickel and lithium as a metal other than aluminum.

In a method of extracting aluminum from a solvent according to another embodiment of the present invention, the extraction step is performed under conditions of an equilibrium pH of 1. 8 or more and 3 or less.

According to another embodiment of the present invention, the sulfuric acid solution is a sulfuric acid solution containing at least 0.001 to 20 g / L of aluminum and 0.001 to 30 g / L of manganese.

In another embodiment of the present invention, the extraction process of aluminum is performed under conditions of an equilibrium pH of not less than 2 and not more than 2.5.

According to the present invention, it is possible to provide a method of extracting aluminum from a solvent capable of separating and recovering aluminum from a solution containing aluminum, manganese and other metals with high efficiency. Thus, for example, in the recycling of lithium ion batteries, aluminum contained in the leachate leached with raw materials can be separated without substantially losing other metals (manganese, cobalt, nickel, lithium).

1 is a graph showing the pH-extraction rate curves of manganese, cobalt, nickel, lithium and aluminum when mono-2-ethylhexyl 2-ethylhexylphosphonate is used as an extractant in the solvent extraction method according to the embodiment of the present invention FIG.
2 is a view showing a pH-reverse extraction rate curve when aluminum is back-extracted from a solvent in which aluminum is extracted, in a solvent extraction method according to an embodiment of the present invention.

The solvent extraction method for aluminum according to the embodiment of the present invention can be suitably used for a method for recovering valuable metals from a lithium ion battery main body that has been used. In more detail, the positive electrode material contained in a lithium ion battery is treated A method of extracting and separating aluminum as an impurity by solvent extraction from a solution which is generated at the time of extraction. Hereinafter, the case where the aluminum in the leach solution in the recycling of the lithium ion battery is extracted and separated by solvent extraction will be described as an example. However, the present invention is not limited to the following examples. Of course it is available.

<Target liquid>

The aluminum solvent extraction method according to the embodiment of the present invention can treat the aluminum-containing leached solution obtained in the lithium ion battery recycle. That is, the liquid to be treated is a sulfuric acid solution containing manganese, cobalt, nickel, lithium or other metals, which are metals to be recycled in addition to aluminum. This treatment liquid contains, for example, 0.001 to 300 g / L of sulfuric acid, 0.001 to 20 g / L of aluminum, 0.001 to 30 g / L of manganese, 0.001 to 30 g / L of cobalt, 0.001 to 30 g / To 30 g / L of lithium is contained.

Aluminum is extracted and separated from this leach solution by a solvent extraction method. The extractant is mono-2-ethylhexyl 2-ethylhexylphosphonate. The extractant is diluted with a hydrocarbon-based solvent and adjusted, and the sulfuric acid solution containing aluminum is mixed to perform solvent extraction of aluminum. The mixing ratio of the mono-2-ethylhexyl 2-ethylhexylphosphonate and the solvent is preferably 1: 3. As the hydrocarbon solvent, aromatic solvents, paraffin solvents, naphthene solvents and the like can be used. Of these, naphthenic solvents are preferable.

Fig. 1 shows the relationship between the equilibrium pH at the time of solvent extraction and the extraction rate of each element. The equilibrium pH at the time of extracting aluminum is preferably adjusted to be 1.8 or more, preferably 2 or more, and 3 or less, preferably 2.5 or less, more preferably 2.3, by adding a neutralizing agent. As the neutralizing agent, sodium hydroxide, sodium carbonate and the like can be used. When the equilibrium pH is not less than 1 and not more than 3, the metal other than aluminum such as cobalt, nickel, and lithium is contained in the solution, thereby suppressing the extraction of metals other than aluminum with aluminum. As a result, , And can be selectively extracted. Particularly, when manganese is contained in the solution, the manganese is inhibited from being extracted together with aluminum by setting the equilibrium pH to 2 or more and 2.5 or less, preferably 2.3 or less. As a result, aluminum is more efficiently and selectively extracted It is preferable.

In the extraction process, the aluminum-extracted solvent is back-extracted with an acidic solution. As the acidic solution, a sulfuric acid solution, a hydrochloric acid solution, or the like is used. Fig. 2 shows the relationship between the equilibrium pH at the time of back extraction and the extraction rate of aluminum. The equilibrium pH at the time of back extraction is preferably adjusted to a range of 0 to 0.5. If the pH is higher than 0.5, back extraction of aluminum is incomplete and aluminum may remain in the solvent. When the pH is lower than 0, the acid concentration is high and the subsequent treatment becomes difficult.

[Example]

Hereinafter, embodiments of the present invention will be described, but the embodiments are for illustrative purposes and are not intended to limit the invention.

(Embodiment 1)

(H ₂ SO ₄ concentration of 10 g / L) containing various metals and mono-2-ethylhexyl 2-ethylhexylphosphonate (Daihatsu Kagaku Co., Ltd. product name: PC-88A) described in Table 1 were dissolved in a naphthenic solvent (Shellsol D70, manufactured by Shellsol D70) diluted to 25 vol% was mixed and stirred so as to have an organic phase / water = 1 (volume ratio), and aluminum was extracted while adjusting to an equilibrium pH of 2.3 with sodium hydroxide. Table 2 shows the extraction rates of the respective elements.

(Second Embodiment)

A sulfuric acid solution (H ₂ SO ₄ concentration 10 g / L) containing various metals listed in Table 1 was extracted at an equilibrium pH of 2.7 as in the first embodiment. Table 3 shows the extraction ratios of the respective elements.

(Third Embodiment)

A sulfuric acid solution (H ₂ SO ₄ concentration: 10 g / L) containing various metals listed in Table 1 was extracted at an equilibrium pH of 1.9 as in the first embodiment. Table 4 shows the extraction rates of the respective elements.

(Fourth to 18th embodiments)

Aluminum was extracted from the sulfuric acid solution (H ₂ SO ₄ concentration 10 g / L) containing various metals listed in Table 1 at the following equilibrium pH in the same manner as in Example 1, The relationship between the equilibrium pH and the extraction rate of each element is shown in Fig.

According to the first to eighteenth embodiments, it can be seen that aluminum is extracted with higher efficiency than other metals. Particularly, when the equilibrium pH is in the range of 1 to 3, the extraction ability is different depending on the metal to be extracted, and aluminum is selectively extracted. It can also be seen that aluminum is significantly more selectively extracted than manganese when the equilibrium pH is between 2 and 2.5, especially between 2 and 2.3.

(Reference example)

In order to back-extract aluminum extracted in the solvent in the first embodiment, back extraction was performed at an organic phase / water = 1 (volume ratio) and an equilibrium pH of 0.48 using a sulfuric acid solution (H ₂ SO ₄ concentration 20 g / L) Respectively. Table 5 shows the extrusion rate of aluminum from the solvent. From Table 6, it can be seen that 93% of the aluminum contained in the solvent is back-extracted, and the equilibrium pH of 0.5 or less is necessary to back-extract aluminum in the solvent.

Claims (7)

An organic solvent containing mono-2-ethylhexyl 2-ethylhexylphosphonate in an acidic solution of sulfuric acid containing at least one of manganese, cobalt, nickel and lithium as a metal other than aluminum and aluminum, aluminum Wherein the extraction step is carried out under conditions of an equilibrium pH of 1.8 or more and 3 or less. The method according to claim 1, wherein the acidic sulfuric acid solution is an aluminum-containing leaching solution obtained by recycling lithium ion batteries. delete delete The solvent extraction method according to claim 1 or 2, wherein the sulfuric acid solution is an acidic sulfuric acid solution containing at least 0.001 to 20 g / L of aluminum and 0.001 to 30 g / L of manganese. The solvent extraction method according to claim 2, wherein the extraction step is conducted under conditions of an equilibrium pH of not less than 2 and not more than 2.5. The method according to claim 5, wherein the extraction step is carried out under conditions of an equilibrium pH of not less than 2 and not more than 2.5.

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