JP2866005B2 - Method for recovering valuable resources from discarded nickel-hydrogen storage alloy secondary batteries - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the use of a nickel / alkali / hydrogen storage alloy secondary battery (hereinafter abbreviated as Ni-MH battery in the present specification) having a hydrogen storage alloy in the negative electrode. When discarded, this discarded Ni-MH
The present invention relates to a method for recovering valuable resources from a battery. This Ni-M
When discharging / charging, the negative electrode of the H battery is MH + OH ⁻
反 応 H ₂ O + M + e ⁻ (where M is a hydrogen storage alloy), but the hydrogen gas generated during charging (in the direction of the arrow ←) is stored in the hydrogen storage alloy M and becomes M · H. Does not generate hydrogen polarization.

As a hydrogen storage alloy, a powder such as a LaNi ₅ -based alloy is used. This Ni-MH battery is attracting attention as a secondary battery used for a power source of an electric vehicle or the like, and a dramatic increase in production is expected in the future.

[0003]

2. Description of the Related Art A Ni-MH battery has a positive electrode in which porous metal nickel or fibrous metal nickel is filled with nickel hydroxide, and a nickel-plated iron punching plate, porous metal nickel, or the like, and a hydrogen storage alloy powder as a conductive material. , A negative electrode fixed together with a binder, a separator formed of polypropylene or the like, and these are housed in a steel container together with the electrolytic solution.

Since this Ni-MH battery does not use harmful cadmium as a member, unlike a nickel-cadmium battery, it does not cause serious pollution even when disposed. However, since nickel and hydrogen storage alloys are valuable resources, it is extremely important to recover these valuable resources from discarded Ni-MH batteries from the viewpoint of resource utilization.

[0005] Tohoku University, Institute of Materials Engineering, Bulletin 48 (19
(December 1992) On page 175, a study was started to separate and recover nickel and rare metal components from nickel scrap in nickel-hydrogen batteries using a gas phase reaction such as a halogenation volatilization method or a carbonyl method. Is described. However, no specific technical content is described.

JOM 1993, May, P32-
It describes the result of dissolving the entire waste of a nickel-hydrogen secondary battery in which a titanium-based hydrogen storage alloy is disposed on the negative electrode in an acid. That is, it is described that when the substance is dissolved in nitric acid and then the dissolved substance is further dissolved in hydrochloric acid, the nickel and titanium components can be dissolved in the acid. However, in this method, since the hydrogen storage alloy also becomes a solution, the value of the recovered material is low, and the post-treatment of the solution is expected to be complicated, so that it is difficult to provide an economical recovery method.

[0007]

As described above, Ni-
MH batteries include nickel, nickel hydroxide, hydrogen storage alloys, separators, synthetic resin films, steel containers, etc.
It is formed of various types of members having different physical and chemical properties. It is an object of the present invention to provide a method for recovering valuable materials having a high value from a waste of Ni-MH batteries composed of various kinds of members by a simple method.

[0008]

SUMMARY OF THE INVENTION The present invention provides:
(1) When recovering valuable resources from a discarded nickel-hydrogen storage alloy secondary battery having a powdered hydrogen storage alloy disposed on the negative electrode, the secondary battery is crushed, and the crushed pieces are treated in water. The powder portion is converted into a slurry, and then a non-slurried portion is separated into a slurry and the non-slurried portion is recovered as a steel material. The slurry is separated by specific gravity and / or floating separation into a crude hydrogen storage alloy portion and a crude nickel hydroxide portion. The crude hydrogen storage alloy part was washed and recovered as a hydrogen storage alloy, and the crude nickel hydroxide part was dissolved in acid to remove impurities to recover nickel compounds, which was discarded. This is a method of recovering valuable resources from a Ni-MH battery.

[0009] (2) The method for recovering valuable resources from the discarded Ni-MH battery according to (1), wherein the crushing is performed by cutting off contact with the atmosphere. And (3) the method of cutting off contact with the atmosphere is a method of forming a water film on a secondary battery to be broken.
This is a method of recovering valuable resources from the discarded Ni-MH battery of (2).

(4) A method of recovering valuable materials from the discarded Ni-MH battery of (2), wherein the method of cutting off contact with the atmosphere is a method of using an inert gas atmosphere. And (5) the method of recovering valuable resources from the discarded Ni-MH battery of (1), wherein the fracturing is fracturing using a biaxial twisting blade rotary crusher. And (6) the crushing is performed by using a low-speed vertical crusher.
This is a method of recovering valuable resources from the MH battery.

(7) The crushed fragments have a length of 5 to 20 mm.
A method for recovering valuable resources from the discarded Ni-MH battery according to the above (1), characterized in that the crushed fragments are treated in water to reduce the powder portion. The method of recovering valuable resources from the discarded Ni-MH battery of the above (1), characterized in that the method of forming a slurry is a method of applying rolling and / or ultrasonic vibration to the crushed fragments.

FIG. 1 is a flow sheet of the main process of the present invention. The present invention will be described based on FIG. First, cutting will be described. The outer surface of the discarded MH battery is covered with a steel container covered with a synthetic resin film, and the inside may have a pressure of several kg / cm ^{2 due to} residual hydrogen and the like.
In addition, the hydrogen storage alloy may oxidize partially when it comes into contact with air, or may ignite or explode in extreme cases.

In the present invention, the steel container is first broken to take out the internal organs. At this time, in cutting using a normal cutter, the cut portion is crushed and it is difficult to take out the contents. Therefore, it is preferable to use a deformed torsion rotary blade at the time of cutting. For example, a Ni-MH battery is cut into pieces having a length of 5 to 20 mm while spraying water using a biaxial torsion blade rotary crusher manufactured by Ujiie Seisakusho to cut off the contact between the atmosphere and the Ni-MH battery. Although crushed, there was no ignition or explosion as described above, and the contents could be easily taken out.

FIGS. 2A and 2B are explanatory views of an example of a two-shaft twisted blade rotary crusher, wherein FIG. 2A is an overall explanatory view and FIG. 2B is an explanatory view of a deformed twisted rotary blade. The deformed torsional rotary blades 1 and 2 are arranged in mesh with each other and roll inward. When the deformed torsional rotating blades 1 and 2 rotate, the Ni-MH battery to be crushed has its steel container portion cut by the rotating blades. By setting the blade width t and the pitch S of the blades of the deformed torsional rotary blades 1 and 2 to a desired size, the Ni-MH battery can be broken into desired fragments.

If the Ni-MH battery to be crushed is immersed in liquid nitrogen in advance and cooled to a low temperature, the steel container, which is the outer case of the Ni-MH battery, becomes brittle at low temperature and is easily broken. . In this case, a usual roll crusher, jaw crusher, or the like may be used.

This crushing can also be performed using a low-speed vertical crusher. 3A and 3B are explanatory views of an example of a low-speed vertical pulverizer, in which FIG. 3A is an explanatory view of a vertical section and FIG. 3B is an explanatory view of a horizontal cross section. Reference numeral 3 denotes a triangular block-shaped rotary blade, and a blade edge is formed at an end 3-1. Reference numeral 5 denotes a fixed blade protruding from the inner surface of the cylindrical wall. Rotary shaft 6
When the rotary blade 3 attached to the hopper 8 rotates, the steel container portion of the Ni-MH battery of the Ni-MH battery inserted into the hopper 8 is cut by the cutting edge 3-1 of the rotary blade 3 and the fixed blade 5. You. In the figure, reference numeral 4 denotes another rotary blade attached to the rotary shaft 6, which has the same function as the rotary blade 3. 7 is a screen in the figure.

According to the knowledge of the present inventors, the breaking size is 2
If it exceeds 0 mm, it is difficult to take out the contents. However, there is no particular advantage in shredding to less than 5 mm. For this reason, the length of the crushed fragments is preferably 5 to 20 mm. The crushed pieces should be stored in water. .

The crushed pieces are treated in water, and the underwater treatment is performed in order to take out a powder portion of the contents as a slurry from the crushed pieces of the Ni-MH battery. The crushed pieces are placed in an underwater ball mill and rolled, or a means such as applying ultrasonic vibration to water is applied to take out the powder portion as slurry. At this time, the binder and nickel hydroxide are also taken out as a slurry.

The primary separation in FIG. 1 is performed in order to separate a portion that does not turn into a slurry in the underwater treatment from the slurry. This separation is preferably performed by using a 200-mesh sieve and using a slurry below the sieve. With a sieve coarser than 200 mesh, the amount of impurities mixed into the slurry increases and the purity of the recovered material decreases. According to the knowledge of the present inventors, it is preferable to classify the sieve in order from a sieve having a larger sieve to a finer sieve, and to separate the sieve on the sieve as a portion which is not to be slurried successively, and to set the final sieve to 200 mesh. According to this method, breakage and wear of the 200-mesh sieve can be significantly prevented and reduced. This primary separation can also be performed using a hydrocyclone separator or a table ore separator.

The non-slurried portion separated by the primary separation is composed of a punching plate, nickel fiber, steel container, electrode terminal, debris such as an organic separator, a synthetic resin, or the like. In the present invention, the non-slurried portion is used as a raw material for steel, for example, ferronickel. Ferronickel is an alloy used for manufacturing stainless steel, which is manufactured by heating and melting nickel ore, carbon and a solvent at about 1500 ° C. or higher, containing about 30% of nickel and the balance mainly consisting of iron.

The nickel and iron contained in the non-slurried portion are contained in this alloy during the production process of ferronickel and become raw materials for producing stainless steel. Other components contained in the portion not to be slurried are lost during the production process of ferronickel or contained in slag and discarded. The non-slurried part separated by primary separation is used as a nickel source when manufacturing stainless steel,
It can also be used directly.

The slurry separated by the primary separation contains a hydrogen storage alloy, nickel hydroxide powder, a binder and a conductive material, and is diluted alkaline. In the present invention, this slurry is secondarily separated and separated into a crude hydrogen storage alloy part containing a hydrogen storage alloy and a crude nickel hydroxide part containing nickel hydroxide. In the secondary separation, since the crude hydrogen storage alloy part has a specific gravity larger than that of the crude nickel hydroxide part, it can be separated by a known specific gravity separation method or a floating separation method. For example, a known water-flow type table ore separator or jig ore separator can be used for the secondary separation.

The crude hydrogen storage alloy obtained by the secondary separation is
Washing treatment with an organic solvent such as alcohols, ketones, kerosene or water or a washing solution obtained by adding a surfactant to water,
The organic binder and the like are removed and dried to obtain a purified hydrogen storage alloy powder. In addition, when drying in vacuum at about 80 ° C., the hydrogen occluded by the hydrogen storage alloy is removed. The purified hydrogen storage alloy powder can be reused as it is alone or mixed with a new hydrogen storage alloy manufactured separately. Further, it can be charged into a high-temperature melting facility for producing a lump of hydrogen storage alloy and reused as a lump of hydrogen storage alloy.

The crude nickel hydroxide part obtained by the secondary separation is a slurry mainly composed of nickel hydroxide and containing a binder, a conductive material and a part of a hydrogen storage alloy. This is done by washing and filtering if necessary to separate the excess alkaline solution,
The solution is dissolved using any one of hydrochloric acid, sulfuric acid, and nitric acid, or a mixture thereof, and then filtered to separate the solution into an insoluble portion.

The solution contains nickel ions, small amounts of rare earth ions, cobalt ions, zinc ions and the like. When the rare earth ion is treated with oxalic acid while maintaining the pH at 1.5 to 2.0, it forms a precipitate and can be separated from the solution by filtration. The solution from which the precipitate of rare earth ions has been removed is neutralized with a caustic alkali solution to obtain nickel hydroxide containing cobalt and zinc. When the solution from which the rare earth ion precipitate has been removed is extracted with a solvent, nickel, cobalt, and zinc can be separated from each other, and can be recovered as the respective hydroxides and carbonates.

[0026]

Embodiment 1 AA type discarded Ni-MH battery 6
kg, good cutter with 5mm distance between teeth (trade name, Ujiie Seisakusho Co., Ltd., 3-horsepower 2-axis twisted blade rotary crusher)
Then, it was broken while spraying water from the rotating tooth portion.

The shredded product was transferred to a stainless steel ball mill having an internal volume of 30 liters (containing 50 stainless steel balls having a diameter of 30 mm) and sprayed together with about 15 liters of water and 60 rp. m for 1 hour.

The sieves are 3.0 mm, 0.5 mm, 0.075
mm sieve, the sieve mesh of 3.0 mm on top,
The contents of the ball mill were transferred in a three-tier manner with the 0.5 mm one inside and the 0.075 mm one below. Further, 5 liters of water was added from above to wash. The top of each sieve (the part that was not slurried) was collected and dried, but weighed 1.75 kg, and steel fragments, nickel fragments, and synthetic resin fragments were visually observed.

The sieved portion (slurry) was separated into a portion having a large specific gravity and a portion having a small specific gravity while adding water using a batch type table ore separator. A portion having a large specific gravity (crude hydrogen storage alloy portion) was dispersed in acetone and then allowed to stand to separate acetone containing suspended matters. The sedimentation section was dried at 40 ° C. in a vacuum to obtain 2.2 kg of a hydrogen storage alloy. This hydrogen storage alloy had a carbon content of 0.01% and an oxygen content of 0.2%, and was of a grade that could be sufficiently reused.

The portion having a small specific gravity (crude nickel hydroxide portion) separated by the above table ore separator is allowed to stand, the supernatant liquid is removed, and 35% hydrochloric acid is added to the sediment.
The reaction was carried out by heating to 0 ° C. for 2 hours. The pH at the end of the reaction was 1.2. The solution was filtered to remove the precipitate,
Oxalic acid was added to the filtrate, and the pH was adjusted to 1.8 to 80 ° C.
After keeping for a time, the precipitate (rare earth oxalate) was filtered off. A 10% sodium hydroxide solution was added to the filtrate, and nickel hydroxide was precipitated and separated by filtration. The precipitate was washed with water and dried to obtain 1.8 kg of nickel hydroxide.

[0031]

The waste of the Ni-MH battery is nickel,
Although it is formed of various kinds of members having different physical and chemical properties, such as a hydrogen storage alloy, a binder, a synthetic resin film, and steel, according to the present invention, a valuable material having a high value can be efficiently converted by a simple method. Can be collected well.

[Brief description of the drawings]

FIG. 1 is a flow sheet of an important process of the present invention.

FIG. 2 is a schematic explanatory view of a two-axis twist blade rotary crusher.

FIG. 3 is a schematic explanatory view of a low-speed vertical crusher.

[Explanation of symbols]

1: Deformed twist rotary blade 2: Deformed twist rotary blade
3: triangular block-shaped rotary blade, 4: triangular block-shaped rotary blade, 5: fixed blade, 6: rotary shaft.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoji Mizumi 5-9-6 Tokodai, Tsukuba City, Ibaraki Prefecture Japan Tsukuba Research Laboratories Co., Ltd. (72) Inventor Honda Tsugutoku Nihonbashi Koami, Chuo-ku, Tokyo No. 8-4, Nippon Heavy Industries, Ltd. (56) References JP-A-6-207227 (JP, A) JP-A-6-340930 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) C22B 7/00 H01M 10/54

Claims (8)

(57) [Claims] When recovering valuable resources from a discarded nickel-hydrogen storage alloy secondary battery having a powdered hydrogen storage alloy disposed on the negative electrode, the secondary battery is crushed and crushed pieces are treated in water. Then, the powder part is converted into a slurry, then the non-slurried part is separated into a slurry and the non-slurried part is recovered as a steel raw material. The slurry is separated from the crude hydrogen storage alloy part and the crude nickel hydroxide by specific gravity separation or floating separation. The crude hydrogen storage alloy part is washed and recovered as a hydrogen storage alloy, and the crude nickel hydroxide part is dissolved in acid to remove impurities and recover nickel compounds. And recovering valuable resources from the nickel-hydrogen storage alloy secondary battery. 2. The method for recovering valuable resources from a discarded nickel-hydrogen storage alloy secondary battery according to claim 1, wherein the crushing is performed by cutting off contact with the atmosphere. 3. The method according to claim 1, wherein the method of cutting off the contact with the atmosphere is a method of forming a water film on a secondary battery to be broken.
A method for recovering valuable resources from the discarded nickel-hydrogen storage alloy secondary battery according to claim 2. 4. A method for recovering valuable resources from a discarded nickel-hydrogen storage alloy secondary battery according to claim 2, wherein the method of cutting off contact with the atmosphere is a method of using an inert gas atmosphere. Method. 5. The method according to claim 1, wherein the crushing is performed using a twin-screw rotary blade rotary crusher. Method. 6. The scrap nickel according to claim 1, wherein the crushing is performed using a low-speed vertical crusher.
A method of recovering valuable resources from a hydrogen storage alloy secondary battery. 7. A method for recovering valuable resources from a discarded nickel-hydrogen storage alloy secondary battery according to claim 1, wherein the fragment is a fragment having a length in the range of 5 to 20 mm. . 8. The method according to claim 1, wherein the method of treating the crushed pieces in water to turn the powder portion into a slurry is a method of applying rolling and / or ultrasonic vibration to the crushed pieces. And recovering valuable resources from the nickel-hydrogen storage alloy battery.