JP3079287B2 - How to recover valuable resources from used lithium batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for recovering valuable resources from a used lithium battery. Lithium batteries are used as power sources for mobile phones, PHSs, video cameras, notebook computers, and the like because of their features such as small size, light weight, and high energy density per volume.

The main components of a lithium battery are an aluminum case, a negative electrode plate made of copper foil, a positive electrode plate made of aluminum foil coated with lithium metal oxide (metal: Mo, Co, Ni, Sn, etc.), polyethylene, etc. And the like. Mo, Co, contained in lithium metal oxide
Since Ni and the like are valuable metals, some recovery methods have been proposed.

[0003]

2. Description of the Related Art According to Japanese Patent Application Laid-Open No. 6-322452, a crushed product of a used lithium secondary battery, which is separated by magnetic separation from magnetic materials such as metallic nickel, is roasted in a non-oxidizing atmosphere. Or reduction roasting in a reducing atmosphere and subjecting the resulting roasted product to magnetic separation have been proposed.
Roasting in a non-oxidizing atmosphere in the above method is a step for reducing the metal oxide by a carbonaceous substance contained as separator, carbon of the negative electrode material, etc.,
The last magnetic separation is a process for separating nickel and cobalt from copper and the like.

According to Japanese Patent Application Laid-Open No. 6-346160,
It has been proposed that a used lithium secondary battery is roasted to remove a binder, a solvent, and the like, and the roasted product is crushed and sieved to use the sieved material as a raw material for smelting.

[0005]

Problems to be Solved by the Invention JP-A-6-322, cited above.
In Japanese Patent No. 452, a used lithium secondary battery is directly crushed, but this crushing is more difficult than crushing of a roasted product. Furthermore, since the crushed material is directly magnetically separated without roasting in order to reduce the burden of roasting, magnetic separation for separating a non-magnetic material and a magnetic material is performed twice before and after roasting. Next, in the method disclosed in JP-A-6-346160, the recovery of nickel and cobalt is left to the smelting process, so that there is room for improvement in terms of thermal energy. In addition, the aluminum of the case and the copper of the negative electrode are both recovered as non-magnetic substances in the conventional method, so that it is difficult to use the recovered substances as raw materials for non-ferrous smelting.

[0006]

DISCLOSURE OF THE INVENTION The present invention is used in such a manner that it can be easily pulverized, and that magnetic and non-magnetic substances can be sufficiently separated by a single magnetic separation, and that aluminum and copper can also be sufficiently separated. The purpose is to recover valuable metals from used lithium batteries. The used lithium batteries contained in the aluminum case are roasted together with the aluminum case, and the obtained roasted product is pulverized and magnetically separated by magnetic separation. By separating the non-magnetic material from the non-magnetic material, and applying a magnetic field from a magnet to the non-magnetic material that has generated the eddy current, the non-magnetic material is repelled from the magnet. Another object of the present invention is to provide a method for recovering valuable resources from a used lithium battery, which is characterized in that it is separated into crushed powder. Hereinafter, the method of the present invention will be described in detail.

The weight of 15 lithium batteries is about 300 g, in which about 50 g of Co and about 30 to 40 Cu are contained.
g and Al are contained in about 90 to 100 g. First, in the method of the present invention, a spent lithium battery is roasted together with an aluminum case to decompose organic substances such as polypropylene and n-methyl-2-pyrrolidone.
Combustion, volatilization, and generation of CO as a reducing gas. If the roasting temperature is too low, the reduction of lithium metal oxide by the CO gas generated by decomposition of organic substances becomes insufficient and the burden of crushing increases, while if it is too high, the roasted material melts and solidifies, making it difficult to crush it. 550 ℃
The following is preferred, and more preferably 500 to 550 ° C.

[0008] The heating furnace for roasting is not limited,
It can be performed in a stationary furnace such as an electric furnace or a heavy oil furnace. In this case, a direct heating furnace under a stoker can be used. One batch of used lithium batteries is stacked on a stoker, and a flue of combustion exhaust gas is provided from the upper part of the furnace, and roasting is performed while appropriately discharging combustion gas. When the used lithium battery is roasted without being crushed, the above-described combustion of organic substances and generation of CO gas occur inside the battery, and the reduction of oxide proceeds in the space in the battery case. This roasting reduces most of iron oxide, nickel oxide, cobalt oxide and the like, while copper foil, aluminum case and the like maintain the metal form. The obtained roasted product contains about 70 to 90% by weight of a metal powder, a lump, a net,
Foil, plate, or these partially maintain the bonding structure in the battery. In addition to metals, some unburned carbon and organic substances are also included.

Next, the roasted material is crushed. This crushing has various forms as described above, and the roasted material having various dimensions is adjusted to an appropriate size, and the one that maintains the structure of the battery is refined to a powder form, and the next primary magnetic separation is performed. This is an operation that makes it easier to separate the material and the non-magnetic material. As a crusher,
Although not limited, a uniaxial crusher or the like can be preferably used. Crushing is JIS Z 880
It is preferable to carry out the process so that the size of one standard sieve is 5 mesh or less. In the form in the pulverized product, cobalt is mainly in powder form, and aluminum and copper are mainly in plate, foil and flake form. Therefore, if the magnetic separation is performed in the following steps, the separation can be achieved in principle by one magnetic separation. In the crushing after roasting according to the method of the present invention, the load of crushing is reduced because the batteries which have been crushed to some extent and whose weight is reduced by roasting instead of directly crushing the batteries themselves are reduced. In addition, most of the roasted products are metal, and there are almost no carbon and organic substances that are difficult to crush, and the parts are physically decomposed due to thermal expansion. You.

In the next step, magnetic separation is performed. This is a step for separating a roasted metal lithium salt and a roasted iron such as a case, which are magnetic substances, from non-magnetic substances. Preferably, the magnetic material separated by performing magnetic separation with a magnetic field strength of 1100 G or more contains 43 to 50% of Co and 1 to 3% of Al. The non-magnetic material is mainly composed of aluminum, contains a small amount of copper, and is accompanied by a small amount of cobalt.

The eddy current generated in a non-ferrous metal to which a high-frequency magnetic field has been applied is proportional to the conductivity of the metal. On the other hand, if a permanent magnet is arranged near the non-ferrous metal material separately from the high-frequency magnetic field generation source, the powder is repelled by the repulsive action of the eddy current with the magnetic field from the permanent magnet. The repulsion distance increases as the conductivity of the metal increases and as the specific gravity decreases. When copper and aluminum are compared, the former has a conductivity about 1.54 times that of the former, and the specific gravity is about 3.2 times that of the former. Taken together, aluminum has a greater repulsion distance than copper. In FIG. 1 schematically showing this process, 1 is a non-ferrous metal powder, 2 is a coil for generating an eddy current, 3 is a permanent magnet, and 4 is a copper crushed powder in a natural falling state (that is, a separated material for a small repulsion distance). 5) Similarly, 5 is a crushed aluminum powder in a naturally falling state (that is, a separated product having a large repulsion distance). Note that the cobalt powder, which is a ferromagnetic material, is ejected together with the crushed copper powder 4. In the above method, the alternating magnetic field has a frequency of 100 to 200 Hz and an intensity of 1000 to 100 Hz.
3000G is preferable, and as the permanent magnet, an Sm-Co-based magnet can be preferably used. The crushed aluminum powder 5 which is a isolate having a long repulsion distance contains 80 to 90% of Al, and the balance is mainly Cu, while the crushed copper powder 4 which is a isolate having a short repulsion distance has a C of 30 to 40%.
u, the balance being mainly Co, with a small amount of Al,
It also contains Sn. Therefore, the crushed aluminum powder 5 is used as an aluminum raw material, and the crushed copper powder 4 is used as a copper raw material when the amount of Co is small.

When the amount of Co in the crushed copper powder 4 which is a separated product having a short repulsion distance is large, for example, 10% or more, cobalt powder can be separated and recovered by magnetically separating the crushed copper powder. The above description regarding Co is exactly the same even if it is replaced with Ni. That is, since Ni is a magnetic substance, it can be recovered in the same manner as Co.

Hereinafter, the present invention will be described more specifically with reference to a flowchart for carrying out the present invention. A used lithium battery is used as a raw material 10, and for example, 400 kg is charged into a roasting furnace 11 such as an electric furnace or a heavy oil furnace. When the roasted valuable metal content reaches several tons, the crusher 12 crushes it to a size suitable for magnetic separation. The crushed pieces are passed through a portable conveyor 15 by a primary magnetic separator 16 having a conveyor and an electromagnet as elements, and the magnetic material is stored in a magnetic material container bag 17. The non-magnetic material is transferred to the eddy current sorter 18, where the eddy current is separated from the eddy current by a magnetic field from a magnet. The separated aluminum crushed powder 5 is stored in an aluminum powder container bag 19. The crushed copper powder 4 is separated by the secondary magnetic separator 20 to store the separated materials in the magnetic material container bag 21 and the nonmagnetic material container bag 22, respectively. Reference numeral 13 denotes a dust collecting facility, and 14 denotes a suction fan.

[0014]

As described above, the process sequence in the present invention has the following features. (A) By performing roasting before crushing required for magnetic separation, reduction by generated gas and decomposition of battery parts due to thermal expansion are brought about. Thus, the roasting is advantageously used in the crushing and subsequent steps. Further, (b) the magnetic separation is performed before the selection by the eddy current and the magnet, so that the mixing of the magnetic metal such as Co into the crushed copper powder is reduced. Hereinafter, the present invention will be described in more detail by a valuable metal recovery method performed on a laboratory scale.

[0015]

EXAMPLES The metal composition of a used lithium battery as a raw material was as follows.

[0016]

[Table 1]

When 323 g of the raw material was roasted in a small kiln at 550 ° C. for 30 minutes, the weight was reduced by 54 g, but the metal composition was not changed. Next, magnetic selection (magnetic field 1100G)
Was performed to obtain 92 g of a magnetic substance and 175 g of a nonmagnetic substance. The respective compositions are as shown in Tables 2 and 3. The loss due to magnetic separation was 0.6 g.

[0018]

[Table 2]

[0019]

[Table 3]

Subsequently, the non-magnetic material is subjected to an alternating magnetic field (120 H
(2000 g), using a magnetic coil and a rare earth permanent magnet to separate into crushed aluminum powder (93 g) and crushed copper powder (82 g). The compositions are shown in Tables 4 and 5.

[0021]

[Table 4]

[0022]

[Table 5]

The crushed copper powder was similarly subjected to magnetic separation, and a magnetic substance (20 g) shown in Table 6 and a non-magnetic substance (62 g) shown in Table 7 were obtained.
I got

[0024]

[Table 6]

[0025]

[Table 7]

As described above, according to the present invention, cobalt is recovered as a magnetic material for primary magnetic separation, and in some cases, crushed copper powder separated by eddy current separation is recovered as magnetic material for secondary magnetic separation. can do. Copper is recovered as a segregated material with less repulsion when the non-magnetic material of the primary magnetic separation is further separated by eddy current, while aluminum is recovered as a strongly repelled separated material when the non-magnetic material of the primary magnetic separation is further separated by eddy current. Is done.

[0027]

(1) It is possible to recover valuable resources by crushing a used lithium battery once. (2) Since the used lithium battery is not crushed from its original form, but crushed what has already been powdered by roasting, the burden of crushing is reduced. (3) Since the recovered cobalt content has a purity of 35% or more, it can be used as a cobalt raw material. Although a small amount of aluminum accompanies, it is easily removed by oxidation. (4) Copper and aluminum can be separated, the copper content being a raw material for copper smelting in converters, flash smelting furnaces and the like, and the aluminum content being a raw material to be melted in an electrolytic furnace and the like. (5) In summary, the running cost when implementing the method of the present invention is low. The recovered materials are also very valuable and suitable for sale to material manufacturers, steel manufacturers and non-ferrous smelters.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for separating copper crushed powder and aluminum powder by eddy current.

FIG. 2 is a flow sheet of a method for carrying out the method of the present invention.

[Explanation of symbols]

 2 Magnetic field generating coil 3 Permanent magnet 4 Copper crushed powder 5 Aluminum crushed powder 10 Raw material 11 Roasting furnace 12 Crusher 17 Primary magnetic separator 18 Eddy current separator 20 Secondary magnetic separator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-245126 (JP, A) JP-A-51-52561 (JP, A) West German Patent Application Publication No. 4424825 (DE, A1) US Patent 5,352,270 (US , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 10/54 B03C 1/00-1/30 B09B 5/00 C22B 7/00

Claims (1)

(57) [Claims] 1. A used lithium battery contained in an aluminum case is roasted together with the aluminum case, and the obtained roasted product is crushed, magnetically separated and separated into a magnetic material and a non-magnetic material. By applying a magnetic field from a magnet to the non-magnetic material that has generated the eddy current and repelling the magnet from the magnetic material, the powder is separated into crushed powder mainly composed of aluminum and crushed powder mainly composed of copper, A method for recovering valuable resources from a used lithium battery, wherein the crushed powder mainly composed of copper is separated into a magnetic substance mainly composed of cobalt and a non-magnetic substance mainly composed of copper by magnetic separation.