JP2016121383A - Method for producing aluminum-copper alloy from lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that: when the current collector (aluminum foil) on a positive electrode material side and the curent collector (copper foil) on a negative electrode material side are separated by dry process and without melting, a material having a high metal content ratio of aluminum and copper (aluminum-copper grain-state material) is produced in a mixed state; even though they can be utilized as an additive material for steel or the like, and as lithium is contained even by only a little, they cannot be utilized as the additive material for aluminum alloy.SOLUTION: In the method for producing aluminum-copper alloy from lithium ion secondary battery, when charging and melting the aluminum-copper grain-state material into a furnace, the lithium component is removed from the metal side; as a concrete technique, a molten salt layer is provided on top of the lower hot-melt, and the aluminum-copper grain-state material is charged thereinto; the aluminum and copper are warmed and melt, and go out from the molten salt layer and migrate and mix into the lower hot-melt, but the lithium component is separated and adsorbed to the molten salt layer to remain therein; also, as the molten salt layer blocks between the air and molten metal side, the amount of slag is less, and the yield is good, therefore the recycling without waste is possible; and when the molten salt layer is a salt bath layer, it is more preferable, as the lithium combines with chloride and stably remains in the salt bath layer side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for recovering valuable metals contained in a lithium ion secondary battery, and particularly relates to a method for recovering aluminum and copper by focusing on a current collector.

  Currently used lithium ion secondary batteries include a bag or case-shaped outer package in which a negative electrode material, a positive electrode material, a separator, and an electrolytic solution are sealed, and the positive electrode active material is lithium. It is a metal composite oxide.

Lithium ion secondary batteries have been used for a long time as secondary batteries for various portable devices because of their light weight and high electric capacity, but recently there has been a dramatic increase in demand for automobiles.
Therefore, in the future, a large amount of used products will be generated, and the landfill site is approaching its limit, so it is no longer allowed to dispose of it as easily as in the past. However, there is a strong demand for recycling that can increase the recovery rate of valuable metals and that can be used in a wide range at a low cost.

  In response to this, in Patent Document 1, as a method of recovering valuable metals, the battery is disassembled, the disassembled material is washed with alcohol or water to remove the electrolytic solution, and then wet is used to collect the current collector. It has been proposed that the constituent metals are separated and recovered, and the remaining lithium (Li) in the aqueous solution is concentrated by solvent extraction and back extraction and then recovered as a lithium carbonate solid.

JP 2007-122885 A JP 2012-193424 A

The above traditional methods are consistently wet processes, require wastewater treatment and are expensive. Recently, lithium ion secondary batteries using lithium manganate, which has characteristics comparable to lithium cobaltate, have been developed as the positive electrode active material, and manganese is cheaper than cobalt. However, the above-mentioned wet recovery method cannot be profitable.
Therefore, a method using a dry process has been sought, and Patent Document 2 proposes, as one of them, a method for recovering a manganese-based alloy using the dry process, which is suitable for profitability as an Mn-Ni alloy. It is possible to collect in

The current collector on the positive electrode material side is made of aluminum foil, and the current collector on the negative electrode material side is made of copper foil. When these are separated from the battery without melting by a dry method, The one with a high metal content comes out. In particular, when it is separated and then applied to a peeling machine, a metal with a higher metal content appears.
These are assumed to be used as they are or after briquetting or press forming, and are currently expected to be used as additives for copper, such as steel, but then the ratio of components that can be effectively used is high. It is not an active resource recycling of things.
Also, it can be used as an additive for casting aluminum alloys from the mixed components of aluminum and copper. However, if even a small amount of lithium, for example, 100 ppm, is included, the hot water flow becomes worse. It cannot be used as a material.

  Therefore, the present invention is capable of producing aluminum / copper alloy bullion substantially free of lithium from a lithium ion secondary battery with a high yield, and is open to use as an additive for aluminum alloy. It is an object of the present invention to provide a method for producing an aluminum / copper alloy from a useful lithium ion secondary battery.

  The present invention has been made to solve the above-mentioned problems, and the invention of claim 1 is directed to an aluminum / copper alloy manufacturing method from a lithium ion secondary battery, wherein an aluminum-based positive electrode current collector is derived from an aluminum source. And a method of alloying by a melting method in which a lithium component is not substantially contained in the alloy when the copper-based negative electrode current source is introduced into a furnace as a copper source and dissolved. It is.

  The invention according to claim 2 is the method for producing an aluminum / copper alloy from the lithium ion secondary battery according to claim 1, wherein the molten salt layer is cut off from the atmosphere when dissolved. .

  A third aspect of the invention is a method for producing an aluminum / copper alloy from a lithium ion secondary battery according to the second aspect, wherein the molten salt layer is formed of chloride.

  According to a fourth aspect of the present invention, in the method for producing an aluminum / copper alloy from the lithium ion secondary battery according to the third aspect, a mixture containing a salt as a chloride is used.

  According to a fifth aspect of the present invention, in the method for producing an aluminum / copper alloy from the lithium ion secondary battery according to any one of the first to fourth aspects, an aluminum-based or a mixed system of aluminum and copper is prepared in advance. The method is characterized in that an aluminum source and a copper source are put on the top.

  The invention of claim 6 is the method for producing an aluminum / copper alloy from the lithium ion secondary battery according to claim 5, wherein the aluminum source and the copper source are added while the molten metal is being stirred. It is.

  According to the method of the present invention, an aluminum / copper alloy substantially free of lithium can be produced from a lithium ion secondary battery with good yield.

It is a perspective view of the lithium ion secondary battery (laminate cell) used for embodiment of this invention. It is a flowchart of the whole valuable metal collection | recovery method including the method which concerns on embodiment. It is a figure which shows the method based on embodiment which forms a part of FIG. It is a schematic diagram of the melting pot furnace and stirring apparatus used with the method which concerns on embodiment. It is a photograph which shows the thing with the high Al * Cu metal ratio produced with the punching board of the material A3004P used in the Example, and the high-speed rotation type peeling machine.

(Processing object)
The processing target is a lithium ion secondary battery.
Lithium ion secondary batteries are enclosed in a bag or case-shaped exterior body, mainly in a state where a positive electrode material, a negative electrode material, and a separator are stacked with an electrolyte solution interposed therebetween.
The exterior body is made of metal, and the main metal is aluminum.
The positive electrode material mainly includes a sheet-like positive electrode current collector and a positive electrode active material fixed thereto. In the current mainstream, the positive electrode current collector is made of an aluminum foil, and the positive electrode active material is a lithium-containing composite metal oxide. The negative electrode material is mainly composed of a sheet-like negative electrode current collector and a negative electrode active material fixed thereto. In the current mainstream, the negative electrode current collector is made of copper or a copper alloy foil, and the negative electrode active material is made of a carbon material such as graphite that can occlude and release lithium.

  FIG. 1 shows an example of a lithium ion secondary battery 1 (about 30 cm × about 30 cm) in the form of a laminate cell, and an outer package 3 is formed of an aluminum bag. In the exterior body 3, the laminated body 5 is accommodated, and is laminated | stacked alternately like a positive electrode material, a separator, a negative electrode material, a separator, and a positive electrode material. The lithium ion secondary battery 1 has a structure in which a positive electrode is usually bundled with an aluminum plate and a negative electrode is a nickel plate with a nickel plate on the surface.

Recycle the above. FIG. 2 is a schematic resource flow of the lithium ion secondary battery.
≪Heat demolition process≫
The lithium ion secondary battery is inserted into a rotary heating furnace as it is, and while it is rotating, the flame of the burner is blown and burned at first, but when the temperature in the furnace reaches 500 ° C or higher, the electrolyte quickly vaporizes and burns Even if the burner is stopped using the as an ignition source, self-combustion starts in a chain. Then, the heating dismantling process is started, and the positive electrode material and the negative electrode material are separated and disassembled.
At that time, the peeled positive electrode active material and negative electrode graphite fall through the punching inner wall of the furnace.
≪Fluy separation process≫
The material is divided into a coarse material having a high metal content ratio of aluminum and copper discharged from the furnace and a fine material in which lithium-containing composite metal oxide and graphite are mixed.
A sieve top with a high metal content of aluminum and copper is subjected to further processing.
Incidentally, the sieving material is recycled as a Mn—Ni alloy ingot product by the smelting reduction method.

≪Crushing separation process≫
The high-fluid metal content ratio of aluminum and copper is crushed and separated by a high-speed rotary impact peeler, that is, separated from the fluid and separated again to further remove the positive electrode active material and carbon powder, thereby further increasing the metal content ratio. A further higher sieve of 0.25 mm or more comes out in a mixed state as aluminum and copper granules. This is used as the object to be processed in the present invention and is recycled.
By the way, the sieving material at this stage is also recycled as a Mn—Ni alloy ingot product by the above-described melt reduction method.

Next, the alloy manufacturing method of the present invention using the granular material to be treated will be described in detail with reference to FIG.
FIG. 3 shows the processing contents of this alloy manufacturing method in a time series.
In FIG. 4, reference numeral 7 denotes a melting pot furnace, the upper surface of the melting pot furnace 7 is opened, and a pot (pot) 9 is accommodated. The heat source is a gas burner. Reference numeral 11 denotes a stirring device, and a flat spatula 15 is attached to the lower portion of the support shaft 13 of the stirring device 11. The support shaft 13 rotates around the axis, and when it rotates, the spatula 15 rotates around the axis in the pot 9 to stir the molten metal.

First, an aluminum material is put into the pot 9 of the melting pot furnace 7 and melted to make a hot water. This aluminum material is a stamped plate made of A3004P material. The mixing ratio of the aluminum / copper granular material and the sewage is set according to the component specifications of the aluminum copper alloy product.
Chloride is added as a molten metal covering melting agent (= flux) on the lower hot water. The chloride is preferably a mixture of NaCl and KCl at a mass ratio of 1: 1. This is because the melting point is low, and it is easy to melt and form a stable salt bath layer (= molten salt layer) on the sewage. As the chloride used at that time, a salt having a low melting point and no harmful gas generation or a mixture thereof is also effective. When the salt bath layer is formed, the hot water is covered and the salt bath layer is shielded from the atmosphere (oxygen). If the thickness of the salt bath layer is too thick, heat loss will occur, or the dissolved metal will be transferred to the bottom of the hot metal side, but if it is too thin, the coating of the particulate matter will be insufficient. When the granular material is 30 mm or less, about 5 to 40 mm is preferable, and about 20 to 40 mm is more preferable.
This completes the preliminary process.
If the pot 9 is stirred, the hot water temperature is kept uniform. This agitation also works as described below.

In this state, a material with a high metal content ratio disassembled and separated from the lithium ion secondary battery that is the object to be treated is put into the pot 9. When stirring starts, not only the bottom water but also the salt bath layer on the upper layer side will be in a flow state, so that the charged particulate matter is quickly drawn into the salt bath layer from the outermost layer and covered. The Therefore, oxidation of aluminum that is easily oxidized is also prevented.
In the salt bath layer, the metal, that is, aluminum and copper are warmed and dissolved, and then move out of the salt bath layer and into the hot water to be mixed. At that time, lithium adhering to the active material side of the positive electrode and lithium derived from the electrolyte are easily adsorbed even in the molten salt layer, but in the case of the salt bath layer, in particular, they combine with the chloride, so the lithium metal composite oxidation Smoothly leaves the product and the lithium organic compound side and is left behind on the salt bath layer side.
In this way, molten aluminum and copper are formed and increased in the pot 9, while lithium is slagged and accumulated in the salt bath layer.

When the molten metal is taken out from the pot 9 and cooled, it becomes an ingot of aluminum / copper alloy. The obtained bullion has a good yield and contains almost no lithium, and can be used as an additive for an aluminum alloy.
The aluminum / copper alloy is preferably a product containing 33% copper, which is the eutectic point from the viewpoint of the purpose of the copper additive, but the copper blending ratio is set according to demand.

As described above, the embodiments of the present invention have been described in detail. However, the specific configuration is not limited to these embodiments, and the invention can be changed even if there is a design change without departing from the gist of the present invention. include.
For example, if a low frequency induction furnace is used as a melting furnace, an automatic stirring action of the molten metal works, so that a separate stirring device is not necessary.

The pot 9 is for aluminum 500 kg, the height is 865 mm, the upper end diameter is 876 mm, the bottom diameter is 350 mm, and the capacity is 326L.
Each material, including the material shown in FIG. 5, was added to this and alloyed under the following conditions.
FIG. 5 shows a photograph of a granular material with a high metal content ratio that was disassembled and separated from a punched plate of a material A3004P and a lithium ion secondary battery and was produced by a high-speed rotation type peeling machine.

Example 1

In the table, the oxidation reaction sedative was potassium chloride, which was used in combination to suppress the oxidation reaction when the granular material was charged. In addition, the granular raw materials were charged in small portions.
By doing so, the amount of slag produced was suppressed to some extent.
In addition, the presence of a significant amount of LiCl.LiCO ₂ .LiClO ₄ has been confirmed from the result of fluorescence x-ray diffraction, and the slag is derived from lithium of lithium metal composite oxide and electrolyte solution contained in the positive electrode active material. It was demonstrated that it was separated from the lithium compound.

(Example 2)

The whole amount of the granular raw material was charged at once, but it dissolved smoothly and no oxidation reaction occurred.
The presence of a significant amount of LiCl·LiCO ₂ · LiClO ₄ is confirmed from the result of fluorescence x-ray diffraction, and the slag is lithium of a lithium metal composite oxide contained in the positive electrode active material and the lithium compound derived from the electrolytic solution Proved to be separated from
Yield was also significantly improved.
From this result, it was confirmed that when the salt bath layer has a certain thickness, the effect is remarkably enhanced.
In addition, the bare metal was close to a nearly eutectic composition.

(Comparative Example 1)
For comparison with Example 2, an experiment without flux, that is, no salt bath layer was performed and compared, and the results were as follows.

  From the above results, it was clearly demonstrated that not only the yield is good but also lithium can be separated from the metal side by forming the molten salt layer by the alloying method of the present invention.

  By using the method of the present invention, used lithium ion secondary batteries and those produced at the manufacturing stage are recycled in a method that can be used extensively, with a high ratio of components and cost performance that can be used effectively without making them waste. it can.

1. Lithium ion secondary battery (cell)
3 ... Exterior body 5 ... Laminated body 7 ... Melting pot furnace 9 ... Pot 11 ... Stirrer 13 ... Support shaft 15 ... Spatula

Claims (6)

In the method for producing aluminum / copper alloy from lithium ion secondary battery,
Dissolving method in which lithium component is not substantially contained in the alloy when the aluminum-based positive electrode current collector is used as the aluminum source, and the copper-based negative electrode current collector is derived from the copper source as it is introduced into the furnace. A method characterized in that alloying is performed. The method for producing an aluminum / copper alloy from a lithium ion secondary battery according to claim 1,
A method of cutting off from the atmosphere with a molten salt layer when dissolving. In the method for producing an aluminum / copper alloy from the lithium ion secondary battery according to claim 2,
Forming a molten salt layer with chloride; In the aluminum and copper alloy manufacturing method from the lithium ion secondary battery according to claim 3,
A method characterized in that a mixture containing salts as chloride is used. In the aluminum and copper alloy manufacturing method from the lithium ion secondary battery according to any one of claims 1 to 4,
A method characterized in that an aluminum-based or a mixed system of aluminum and copper is preliminarily made, and an aluminum source and a copper source are put thereon. In the aluminum and copper alloy manufacturing method from the lithium ion secondary battery according to claim 5,
A method characterized in that an aluminum source and a copper source are added while stirring the sewer.

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