JP2015170430A - Method of recovering valuable metal from lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in which a conventional recycling method being consistently a wet process is high in cost since it requires a waste water treatment, and it becomes too costly for manganese whose base metal price is cheap.SOLUTION: When a dry type heat decomposition process in which an organic substance such as a separator is vaporized and burnt by heating it under in-furnace fluidization, and a positive electrode material and a negative electrode material are separated by utilizing the vaporization expansion force of the organic substance and the collision shock force with a furnace wall due to the fluidization, and a rounding process in which, preferably, the separated positive electrode material and negative electrode material are made to collide with the furnace wall to round them under the promoted in-furnace fluidization are executed, the positive electrode material and the negative electrode material are separated from a cell to become round as illustrated. By efficiently utilizing already-existing organic substances, they can be removed and the positive electrode material and the negative electrode material can be separated. Also, a separation method using X-ray irradiation can be used by rounding.

Description

  The present invention relates to a method for recovering valuable metals from a lithium ion secondary battery, and more particularly to a method for recovering valuable metals using a dry process.

  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 come out, and the landfill site is approaching its limit, so it is no longer allowed to dispose of it as easily as in the past. There is a strong demand for the system.

  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. The constituent metals Al (aluminum) and Cu (copper) are separated and recovered, and the constituent metals of the positive electrode active material Ni (nickel) and Co (cobalt) are separated and recovered, respectively, and the remaining Li ( It has been proposed that lithium) be concentrated by solvent extraction and back extraction and then recovered as a lithium carbonate solid.

JP 2007-122885 A

However, the above method is consistently based on a wet process, requires wastewater treatment, and is expensive. In particular, recently, lithium ion secondary batteries using lithium manganate having a characteristic comparable to lithium cobaltate as a positive electrode active material have been developed, and manganese is cheaper than metal than cobalt, In the future, a dramatic market expansion of this type is expected.
Thus, in the conventional recovery method using the wet method as described above, manganese with a low price of metal cannot meet the cost.

  Therefore, an object of the present invention is to provide a novel and useful method for recovering valuable metals from a lithium ion secondary battery, which can utilize a part of the dry process.

  The present invention has been made to solve the above-mentioned problems, and the invention of claim 1 is a method for recovering valuable metals from a lithium ion secondary battery, wherein a lithium ion secondary having a blade member projecting and sheathed. Cutting process that exposes the inclusions by cutting the battery, and heats the cuttings in the fluidizer to diffuse and burn organic substances such as separators, and uses the vaporization expansion force of organic substances and the impact impact force of the furnace wall due to flow And it is a valuable metal collection | recovery method provided with the dry-type heating dismantling process which isolate | separates a positive electrode material and a negative electrode material, without making a metal melt | dissolve.

  A second aspect of the invention is a method for recovering valuable metals from a lithium ion secondary battery according to the first aspect, further comprising a rounding and compressing step of causing a positive electrode material and a negative electrode material separated in a fluid machine to collide against the machine wall and round. This is a valuable metal recovery method.

  According to a third aspect of the present invention, there is provided a method for recovering valuable metals from a lithium ion secondary battery according to the second aspect, wherein the positive electrode active material is separated from the separated positive electrode material by causing shearing in the fluidizer. It is a valuable metal collection | recovery method provided with the metal exposure process which exposes the metal which comprises a body.

  According to a fourth aspect of the present invention, there is provided a method for recovering a valuable metal from a lithium ion secondary battery according to any one of the first to third aspects, wherein in the cutting step, a positive electrode lead for bundling a plurality of positive electrode materials and a plurality of negative electrode materials In this valuable metal recovery method, the negative electrode leads for bundling each other are cut to separate the positive electrode material bundle and the negative electrode material bundle together.

  According to a fifth aspect of the present invention, in the method for recovering a valuable metal from the lithium ion secondary battery according to any one of the first to fourth aspects, the separated positive electrode material and negative electrode material are irradiated with X-rays, whereby each constituent metal is recovered. This is a valuable metal recovery method characterized in that the positive electrode material and the negative electrode material are separated by making a determination using the difference and sorting based on the determination result.

  According to a sixth aspect of the present invention, in the method for recovering valuable metals from the lithium ion secondary battery according to the fifth aspect, the material separated from the positive electrode material and the negative electrode material by sieving is taken out before the separation step. This is a valuable metal recovery method.

  A seventh aspect of the present invention is a method for recovering valuable metals from a lithium ion secondary battery according to the fifth or sixth aspect, wherein the method comprises a positive electrode material containing lithium manganate as a positive electrode active material, and is classified. The pulverized positive electrode material is further crushed and separated, separated into a larger aluminum side and a smaller metal oxide side for sieving, and the metal oxide side is subjected to a smelting reduction treatment and recovered as a manganese-based alloy. This is a valuable metal recovery method.

According to the valuable metal recovery method of the present invention, the step of separating the positive electrode material and the negative electrode material can be realized by a dry method.
Therefore, valuable metals can be recovered by a method with high cost performance.

1 is a perspective view of a lithium ion secondary battery (laminate cell) according to an embodiment of the present invention. It is sectional drawing of FIG. It is explanatory drawing of the cutting process of FIG. It is explanatory drawing of the apparatus used for the heating demolition / rounding / compression / sizing process of FIG. It is an image figure of the change of the lithium ion secondary battery in the apparatus of FIG. It is a photograph figure which shows the state after the process in FIG. It is a flowchart of the whole valuable metal collection | recovery method concerning embodiment of this invention.

(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 composed of an aluminum foil, the positive electrode active material is a lithium-containing composite metal oxide, and PO ₄ is contained as a general formula. LiA _x B _1-x PO ₄ (A is at least one element selected from Mn, Co, Ni, B is Na, Mg, Sc, Y, Fe, Cu, Zn, Al, Cr, Pb, Sb, B And at least one element selected from the above. The positive electrode active material naturally includes a material containing rare metal and not containing PO ₄ .
The positive electrode active material is made by adding a conductive assistant such as carbon black and a binder such as polytetrafluoroethylene (PTFE), and suspending it in a solvent such as water or N-methylpyrrolidone to form a slurry. It is applied and fixed to.
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. The negative electrode active material is powdered, dispersed in a solvent similar to the above to form a slurry, and applied to a current collector to be fixed.

The separator is typically made of a resin film such as polyethylene.
The electrolytic solution includes a non-aqueous solvent and a solute. Typical non-aqueous solvents are carbonates such as diethyl carbonate and ethylene carbonate, and typical solutes are lithium hexafluorophosphate. Some non-aqueous electrolytes contain a polymer material such as polyvinylidene fluoride.
A typical electrode lead (tag) to be bonded to the current collector is an aluminum sheet on the positive electrode side and a nickel sheet on a copper sheet on the negative electrode side.

  As described above, the metals included in the current collector and the metal oxide are integrated with the organic matter constituting the separator and the electrolyte, and valuable metals to be collected include aluminum, copper, cobalt, Not only nickel but also manganese is envisaged.

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 outer package 3, as shown in FIG. 2, the positive electrode material 5, the separator 7, the negative electrode material 9, the separator 7, and the positive electrode material 5 are alternately stacked. One end side of each branch lead 11 is fixed to each positive electrode material 5 (strictly, a positive electrode current collector), and the other end side of each branch lead 11 is fixed to a strip-shaped main lead 13. An adhesive is interposed. Thus, the plurality of positive electrode materials 5 are in a bundled state. Similarly, the negative electrode material 9 side is also bundled together.
As shown in FIG. 1, the main lead 13 extends outward from the outer package 3 for energization, and functions as a tag. The electrolyte solution is not shown for the convenience of visual recognition.

What was described above is subjected to the following processing steps.
(Processing process)
≪Cutting process≫
FIG. 3 is an explanatory diagram of the cutting of the lithium ion secondary battery 1, and it is recommended to cut along the planned cutting line L. By cutting along the planned cutting line L1, the fixed portion between the branch lead 11 and the main lead 13 is separated from the positive electrode material 5 and the negative electrode material 9 side as well as the main lead 13 side as shown in FIG. Therefore, the bundle of the positive electrode material 5 and the negative electrode material 9 is unwound. Further, by cutting along the planned cutting line L2, the size is suitable for the separation process described later. The cutting line L2 is also in a direction perpendicular to the cutting line L1, and among the cuts C1, C2, and C3, the cuts C2 and C3 on which the positive electrode material 5 and the negative electrode material 9 are stacked are the same. Since both sides have cut ends, it is easy to break apart.
By this cutting step, the organic matter such as the separator 7 is exposed, and can be brought into contact with air. In addition, since the electrolytic solution is immersed in a separator or the like, even if it is cut, the electrolytic solution is hardly dropped and separated.

≪Heating and dismantling process (→ Tomozukuri process) → Rounding process → Compression process → Sizing process) (Fig. 4)
In the case of continuous processing, for example, using two fluidizers, the material processed in the previous stage is charged in the subsequent stage and processed. FIG. 4 is a specific example thereof. The front stage is a rotary heating furnace 21, a so-called rotary kiln, in which the axial direction is inclined with respect to the horizontal direction, and an inlet 23 and a burner 25 provided on one end side in the axial direction are provided with a discharge port 27 provided on the opposite side in the axial direction. It is arranged higher. A plurality of rectangular plate-like blade members are attached to the furnace wall, and the blade members project inward. The blade members are inclined and project from the vertical direction, and are disposed in a spiral shape with their positions shifted sequentially.
The rotary heating furnace 21 is connected to a subsequent rotary granulator 31 via a chute 29. The rotary granulator 31 has a double wall structure, and the inner wall 33 is formed of a punching plate. Also in this granulator 31, the axial direction is inclined from the horizontal direction, and the inlet 35 provided on one end side in the axial direction is disposed higher than the discharge port 37 provided on the opposite side in the axial direction. A drop port 39 is provided on the outlet 37 side, and one end side of the transfer conveyor 41 (screw conveyor) faces the lower side. A recovery box 43 faces the other end side of the conveyor 41.

The rotary heating furnace 21 and the granulator 31 can be configured with substantially the same size. If the use of the punching inner wall 33 is abandoned, the rotary heating furnace 21 can also serve as the granulator 31.
However, in this case, batch processing is performed.
In the present invention, the whole of FIG. 4 constitutes a heating demolition / compression / size control apparatus.

Processing using the rotary heating furnace 21 and the like will be described.
When all the cut pieces C1 to C3 are charged into the rotary heating furnace 21 and heated by blowing the flame of the burner 25 while rotating, the heating and disassembling process is started.
The organic matter diffuses and burns when heated, and eventually disappears, but expands when the organic matter vaporizes. The organic matter constitutes the separator 7 and the electrolytic solution, and exists around the inner surface side of the outer package 3 and between the positive electrode material 5 and the negative electrode material 9. The seal portion is peeled off and separated, and a force acts in a direction to separate the stacked positive electrode material 5 and negative electrode material 9.
In addition, since the furnace body rotates about the axis, the cut object C is lifted by the blade member in the furnace, and when it reaches a certain level, the action of spontaneous fall is repeated. It collides with a wall and receives an impact. Therefore, the positive electrode material 5 and the negative electrode material 9 are separated and disassembled under these combined actions.

  At the time of disassembly, if the metal constituting the outer package or current collector melts, it adheres strongly to the oxide and carbon, so it cannot be separated without wet treatment, but as described above, it can be cut to remove the organic matter. Because it is exposed and heated, the heat of the organic matter also circulates to the surface side, and by utilizing the impact under flow, it can be disassembled without melting, and from the current collector to the oxide and Carbon floats up and is easy to peel off.

When a rotary heating furnace is used, a shearing effect can also be expected. Therefore, granular oxide begins to peel off from the surface of the positive electrode material 5 that is disassembled and exposed, and powdery powder from the surface of the negative electrode material 9 As the carbon begins to peel off, the metal constituting the substrate begins to be exposed.
Further, the sharp tip of the positive electrode material 5 or the like comes out and collides with the furnace wall, but since it is heated and has good malleability, it is compressed and rounded by the collision. That is, the rough rounding process also proceeds in parallel.

Thereafter, when the rotary granulator 31 is charged, it is further rounded and compressed to form a lump with a certain size.
When the rotational speed is increased from the beginning, this rounding action is applied before complete separation, so that the positive electrode material 5 and the negative electrode material 9 that have been separated are joined together in a state of being bitten together by this rounding action. Since it becomes a lump of a certain size, that is, granulated, it is necessary to change the processing conditions every time as described above, but the rotary heating furnace 21 and the rotary granulator Thus, efficient continuous processing is realized. Further, the completely separated granular oxide or powdery carbon passes through the punching inner wall 33, falls from the dropping port 39, is carried on the conveyor 41, and is collected in the collection box 43.

Through the above steps, the cut product C2 changes as shown in FIG.
In addition, each positive electrode material and negative electrode material do not change uniformly in time, and other cut products C2 have already entered the rounding process even while a certain cut product C2 is in the heat dismantling process.

  FIG. 6 is a photograph showing the state of the lithium ion secondary battery 1 after processing. As shown in this figure, the positive electrode material 5 and the negative electrode material 9 are separated, and each becomes a rounded lump.

As the furnace operating conditions of the rotary heating furnace 21, the burner 25 is ignited while the blower is operated, and the atmosphere in the furnace reaches 250 to 300 ° C. with respect to the rotary heating furnace (length: 5 m, diameter: 700 mm). Then, insert the cut material and let it burn. When the self-combustion starts, the burner 25 is stopped and the self-combustion is continued as it is. The rotation speed and the residence time vary depending on the total charge amount and the relative amount of organic matter. However, if the cut material C is charged at 300 kg / hour in continuous processing, the recommended condition is that the rotation speed is 3. The residence time is 6 minutes and 30 seconds at 6 times / minute. In addition, although the temperature has risen to 800 ° C. or higher due to diffusion combustion of organic matter, the heat is efficiently used for disassembling the positive electrode material 5 and the negative electrode material 9.
In the rotary granulator 31 of the same size, the recommended conditions are a rotation speed of 4.6 rotations / minute and a residence time of 5 minutes and 40 seconds.

≪Fluid separation process≫
The mixture of the positive electrode material 5 and the negative electrode material 9 discharged from the rotary granulator 31 is divided into 20 mm up, 20 mm to 0.25 mm, and less than 0.25 mm under.
Moreover, what has accumulated in the collection box 43 through the punching inner wall 33 of the rotary granulator 31 is added to 20 mm to 0.25 mm.
By dividing the fluid in advance in this way, it is possible to improve the efficiency of separation described later.

≪Separation process≫
A 20 mm up one is automatically sorted by a sorter.
The sorter currently assumed to be used irradiates the transmitted X-rays on what is transported on the conveyor, and the aluminum (on the positive electrode material 5 side) from the difference in shade (atomic density) of the shadow of the image Metal) and copper (metal) on the negative electrode material 9 side are discriminated, and based on the discrimination result, an air stream is blown from one side of the light and shade to the one side of the light and dark, and the rest is dropped as it is, so that it is separated. Yes.
If a joint action is expected, a color sensor (CCD camera) may be used instead of transmitted X-rays, and the color difference (aluminum is silver and copper is black) may be discriminated.

≪Crushing separation process≫
The separated material is primarily crushed by a single-shaft high-speed shredder, and is secondarily crushed by a hammer impact type crushing apparatus, and sieved to 0.5 mm up and 0.5 mm under.
Thereby, the positive electrode material 5 side is separated into an aluminum raw material (final product) and a positive electrode active material, and each is recovered. Further, the negative electrode material 9 side is separated into a copper raw material (final product) and carbon powder, and each is recovered.

≪Alloying process by melting reduction≫
The positive electrode active material separated and recovered as described above contains Mn, Ni, Co and the like, and the subsequent separation and recovery steps differ depending on the respective ratios. When Mn is dominant, it is recommended in terms of cost to make a (Mn + Ni) alloy ingot product by a melt reduction method after briquetting.

In the above, attention is paid to the positive electrode material 5 and the negative electrode material 9, but for the other materials, first, those of 20 mm to 0.25 mm are used in the same manner in the above-mentioned ‘crushing and separating step’, and (Al + Cu ) Separated into alloy and carbon powder and recovered respectively.
Moreover, the thing below 0.25 mm under is similarly provided to above-mentioned << alloying process by melting reduction >>.

Regarding the materials separated and recovered above, the aluminum raw material is aluminum material (aluminum melting raw material, deoxidizing material, reducing agent, etc.), the copper raw material is copper material (mine copper raw material, Cu additive for steel making, Cu for Al alloy) Additives etc.), carbon powder is assumed to be an auxiliary agent, (Al + Cu) alloy is assumed to be a Cu mother alloy for Al alloying, and (Mn + Ni) alloy is assumed to be an additive for producing stainless steel.
In this way, the lithium ion secondary battery can be recycled without waste.
FIG. 7 is an overall flow diagram of recycling by the above-described steps.

  In the above, the application of the smelting reduction method is shown for the positive electrode active material, but when the amount of Ni and Co is relatively large, it may be possible to separate and recover each by wet, A method in a form commensurate with the value of the metal may be selected as appropriate.

(Selection test)
Under the conditions shown in the above embodiment, a «cutting step», a «heating and disassembling step (→ tapping step) → a rounding step → a sizing step)» and a «sorting step» are performed, and a sample of the positive electrode material When a sorting test was conducted by selecting a sample of the negative electrode material, and assuming that the quality required for the sorted product was about 95%, the copper material was classified as 97.8% for the copper sorting, and the recovery rate was 94.7%. It was confirmed that the positive electrode material (aluminum) can be sorted with an accuracy of 98.1% and a recovery rate of 95.0%.
For comparison, when the cell was not cut (no cutting) and only the lead (tab) side was cut (lead cutting), the same test was performed. The negative electrode material (copper) can be sorted with an accuracy of 94.5% grade and a recovery rate of 88.7%. The aluminum sorting can sort the positive electrode material (aluminum) with an accuracy of 96.1% grade and a recovery rate of 87.4%. Was confirmed. In lead cutting, the negative electrode material (copper) can be selected with an accuracy of 96.3% and a recovery rate of 89.4% in the copper selection, and the positive electrode material (aluminum) in the aluminum selection of 96.6% and the recovery rate. It was confirmed that sorting can be performed with an accuracy of 90.2%.

  If the method of this invention is utilized, a lithium ion secondary battery can be recycled by a system with high cost performance, without making it a waste.

1. Lithium ion secondary battery (cell)
3 ... Exterior body 5 ... Positive electrode material 7 ... Separator 9 ... Negative electrode material 11 ... Branch lead 13 ... Main lead C1-3 ... Cut

The present invention has been made to solve the above-mentioned problems, and the invention of claim 1 is a method for recovering valuable metals from a lithium ion secondary battery, wherein the inclusion is exposed by cutting the lithium ion secondary battery. The cutting process to be performed, and the cut material is heated and diffused and burned in a fluid machine with a blade member protruding and sheathed, and the vaporization expansion force of the organic material and the impact impact force between the furnace wall due to the flow are utilized And it is a valuable metal collection | recovery method provided with the dry-type heating dismantling process which isolate | separates a positive electrode material and a negative electrode material, without making a metal melt | dissolve.

Claims (7)

In the method of recovering valuable metals from lithium ion secondary batteries,
A cutting step of cutting the sheathed lithium ion secondary battery with the blade member protruding to expose the inclusion;
The cut material is heated in a fluidizer to diffuse and burn organic substances such as separators, and by utilizing the vaporization expansion force of the organic substance and the impact force of the collision with the furnace wall due to the flow, the positive electrode material and the negative electrode material without melting the metal A valuable metal recovery method comprising: a dry heating and dismantling step for separating the two. In the method for recovering valuable metals from the lithium ion secondary battery according to claim 1,
A valuable metal recovery method, comprising: a rounding step in which a positive electrode material and a negative electrode material separated in a fluid machine collide with the machine wall and round. In the method for recovering valuable metals from the lithium ion secondary battery according to claim 2,
A valuable metal recovery method comprising a metal exposure step of causing shearing in a fluidizer, peeling a positive electrode active material from a separated positive electrode material, and exposing a metal constituting a positive electrode current collector. In the method for recovering valuable metals from the lithium ion secondary battery according to any one of claims 1 to 3,
In the cutting step, the positive electrode lead for bundling a plurality of positive electrode materials and the negative electrode lead for bundling a plurality of negative electrode materials are respectively cut to separate the positive electrode material bundle and the negative electrode material bundle together. Valuable metal recovery method. In the method for recovering valuable metals from the lithium ion secondary battery according to any one of claims 1 to 4,
It is characterized by discriminating between the positive electrode material and the negative electrode material by irradiating X-rays to the separated positive electrode material and the negative electrode material using the difference between the respective constituent metals, and sorting based on the determination result. To recover valuable metals. In the method for recovering valuable metals from the lithium ion secondary battery according to claim 5,
A valuable metal recovery method, wherein a material separated from a positive electrode material and a negative electrode material is removed by sieving before the separation step. In the method for recovering valuable metals from the lithium ion secondary battery according to claim 5 or 6,
Metal materials with a positive electrode material containing lithium manganate as a positive electrode active material are treated, and the separated positive electrode material is further crushed and separated, and separated into a larger aluminum side and a smaller metal oxide side for sieving. A valuable metal recovery method, comprising subjecting an object side to a smelting reduction treatment and recovering it as a manganese-based alloy.