JPH06340930A - Method for recovering valuable metal from nickel-hydrogen secondary battery - Google Patents

Abstract

PURPOSE:To provide a method by which a larger amt. of valuable metals can efficiently be recovered from a nickel-hydrogen secondary battery at a lower cost as compared with separation-purification-refining utilizing conventional chemical treatment and a valuable electrode material can be recycled. CONSTITUTION:A nickel-hydrogen secondary battery is crushed and alkali, org. materials and iron are separated. In a process (a), the resulting powder is fired. In a process (b), the powder is dissolved in a mineral acid and rare earth metal ions and nickel ions are precipitated, separated by filtration and fired. In a process (c), the powder is dissolved in a mineral acid, rare earth metal ions are precipitated as fluoride, separated by filtration and fired to obtain rare earth metal fluoride, and nickel ions are precipitated from the residual soln., separated by filtration and fired to obtain nickel oxide. One or more fired bodies obtd. through one of the processes (a)-(c) or the processes (a) and (c), (b) and (c) or (a)-(c) are treated by a molten salt electrolysis method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering effective metal from a nickel-hydrogen secondary battery, which is effective for recycling the nickel-hydrogen secondary battery.

[0002]

2. Description of the Related Art In recent years, the demand for secondary batteries has rapidly increased due to the portable electronic products. Further, nickel-metal hydride secondary batteries have been improved as a pollution-free battery for electric vehicles, and attention is focused on future demand expansion. As described above, the nickel-hydrogen secondary battery is superior in characteristics to the conventional nickel-cadmium battery and has less environmental problems. Therefore, the demand for the nickel-hydrogen secondary battery is expected to increase in the future.
However, a method for recovering an effective metal from a used nickel hydrogen secondary battery has not yet been established. This is because the cost is higher when using the conventional chemical treatment method than when using a new raw material. Therefore, the effectiveness of the nickel-hydrogen secondary battery, which is increasing in environmental demand, is effective. Development of a metal recovery method is desired.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to obtain an effective metal at a low cost and efficiently, and it is effective from a nickel-hydrogen secondary battery in terms of recycling and environment. To provide a metal recovery method.

[0004]

According to the present invention, a nickel-hydrogen secondary battery is crushed to remove an alkali content, and then an organic substance is separated by a wet specific gravity fractionation method, and an iron content is separated. After performing (a) at least the alkali content, the step of baking the components separated organic matter and iron, (b) at least the alkali content, after dissolving the components separated organic matter and iron in mineral acid, rare earth A step of precipitating metal ions and nickel ions and filtering and calcining the precipitate; (c) precipitating rare earth metal ions as fluorides after dissolving at least the components separated from the alkali content, organic material and iron content in mineral acid Then, the obtained precipitate is filtered and calcined to obtain a rare earth metal fluoride, while nickel ions are precipitated from the residual liquid obtained by filtering the precipitate, and the precipitate is filtered,
A step of firing to obtain nickel oxide, any one of the above steps (a) to (c), a combination of steps (a) and (c), (b)
Nickel hydrogen characterized in that the combination of the step and the step (c), or the calcined product obtained by all the steps of the steps (a) to (c) is treated by a molten salt electrolysis method using an electrolytic method molten salt bath. An effective metal recovery method from a secondary battery is provided.

The present invention will be described in more detail below.

In the recovery method of the present invention, first, nickel hydrogen 2
After crushing the secondary battery and removing the alkali content, a step of separating organic substances by a wet specific gravity fractionation method is performed. The nickel-hydrogen secondary battery can be crushed, for example, by using a crusher such as a biaxial shearing crusher, preferably into small pieces of 5 mm or less. The crushed pieces and the like are further washed to remove the alkali content.

In the wet specific gravity fractionation method, for example, a commercially available wet specific gravity sorter or the like is used to separate organic substances such as plastics and separators.

In the recovery method of the present invention, iron is then separated. The iron content can be separated by one or more kinds of separation methods selected from the group consisting of a magnetic separation method, a specific gravity separation method and a sieve separation method. As the magnetic separation method, for example, an electromagnetic magnet separator or the like, as the specific gravity separation method, for example, thickener, wet cyclone, etc., and as the sieve separation method, for example, a wet vibration sieve machine or the like can be used. It is also possible to combine them.

By separating such an alkali content, an organic substance and an iron content, nickel, nickel hydroxide, nickel rare earth metal alloy powder and the like can be recovered from a nickel hydrogen secondary battery.

In the recovery method of the present invention, after separating at least the alkali component, the organic substance and the iron component, the specific (a)
Any one of the steps (c), a combination of the steps (a) and (c), a combination of the steps (b) and (c), or all the combination steps of the steps (a) to (c) To do.

The specific step (a) is a step of firing a component such as a metal from which at least the alkali component, the organic substance and the iron component have been separated. The firing is preferably 200-
It may be carried out at 1000 ° C. for 2 to 10 hours, and nickel oxide, nickel rare earth metal oxide and the like are recovered by the step (a).

In the specific step (b), at least the components such as the metal from which the alkali content, the organic substance and the iron content are separated are dissolved in a mineral acid such as nitric acid or hydrochloric acid, and then rare earth metal ions and nickel ions are precipitated. Filtering the resulting precipitate,
This is the step of firing.

In order to precipitate the rare earth metal ions and nickel ions, for example, the components in which the alkali component, the organic substance and the iron component have been separated are dissolved in mineral acid, and then ammonium bicarbonate, an alkaline solution or a mixture thereof is added. The precipitation can be carried out by Examples of the alkaline solution include aqueous ammonia and caustic soda. The addition amount of the ammonium bicarbonate, the alkaline solution, or the mixture thereof is 1. The theoretical value of the amount necessary for precipitating the rare earth metal ion and the nickel ion in the components in which the alkali component, the organic substance and the iron component are separated. 0 to
It is preferably 1.2 times. Addition of such ammonium bicarbonate and / or alkaline solution precipitates the contained rare earth metal and nickel carbonates and / or hydroxides.

The precipitated carbonate and / or hydroxide can be filtered by a known filtration method. Further, in order to calcine the filtered precipitate, it is preferably 300-
The firing may be performed at 1000 ° C. for 2 to 10 hours. Nickel oxide, nickel rare earth metal oxide and the like are recovered by the step (b).

In the step (c), first, at least the components such as the metal in which the alkali content, the organic material and the iron content are separated are dissolved in a mineral acid such as nitric acid or hydrochloric acid, and then the rare earth metal ion is precipitated as a fluoride. Then, the obtained precipitate is filtered and calcined to obtain a rare earth metal fluoride (hereinafter referred to as RF ₃ ).
In order to precipitate the rare earth metal as a fluoride, it can be obtained by, for example, dissolving the components in which the alkali component, the organic substance and the iron component are separated, in mineral acid and then adding hydrofluoric acid and / or ammonium fluoride or the like. it can. The addition amount of the hydrofluoric acid and / or ammonium fluoride is 1.0, which is a theoretical value of the amount required to precipitate the rare earth metal ions in the components separated from the alkali component, the organic substance and the iron component.
It is preferably about 1.2 times. The precipitate obtained, which is a fluoride of rare earth metal ions, can be filtered by a known method, and the calcination is preferably performed at 200
RF for 2-10 hours at ~ 1000 ° C
You can get ₃ . The obtained RF ₃ can be directly used as one component of the molten salt bath for electrolysis in the molten salt electrolysis method described later.

In the specific step (c), while obtaining the RF ₃ , nickel ions are precipitated from the residual liquid after filtration for precipitating the rare earth metal ions as fluorides, and the resulting precipitates are obtained. It is a process of filtering and firing. To precipitate the nickel ions, ammonium carbonate and / or an alkaline solution or the like is added to the residual liquid after the filtration to obtain a precipitate such as nickel carbonate and / or hydroxide. it can. Examples of the alkaline solution include aqueous ammonia and caustic soda. The addition amount of the ammonium bicarbonate and / or the alkaline solution is preferably 1.0 to 1.2 times the theoretical value of the amount necessary for precipitating nickel ions in the residual liquid. Next, nickel oxide is recovered by filtering and calcining the obtained precipitate. The filtration and calcination can be performed under the same conditions as the above-mentioned filtration and calcination for obtaining RF ₃ .

In the step (c), RF ₃ and nickel oxide are recovered. Either RF ₃ or nickel oxide obtained can be supplied to the molten salt electrolysis method described later. Both can be provided.

The steps (a) to (c) can be carried out independently and then subjected to the following molten salt electrolysis method.
(a) step and (c) step combination step, the (b) step and (c)
It is also possible to carry out the molten salt electrolysis method after performing the combination step of the steps and all the combination steps of the steps (a) to (c).
In this case, when the step (c) is performed, the RF ₃ obtained in the step (c) can be used as one component of the molten salt bath for electrolysis in the molten salt electrolysis method. In addition, (c) process, (a)
And / or step (b), the nickel oxide obtained by filtering and calcining the precipitate such as nickel carbonate and / or hydroxide in the step (c) is added to the above (a) )
And / or the composition may be adjusted to the same composition as the nickel rare earth metal oxide obtained in the step (b) and then subjected to the molten salt electrolysis method described later.

In the recovery method of the present invention, nickel hydrogen 2 is obtained by treating the calcined product obtained in at least one of the steps (a) to (c) by a molten salt electrolysis method using an electrolytic method molten salt bath. Effective metals such as misch metal and alloys of misch metal and nickel can be recovered from the secondary battery.

The molten salt electrolysis method can be performed by a known method. Specifically, for example, as a molten salt bath for electrolysis, RF ₃ , lithium fluoride (hereinafter referred to as LiF) and barium fluoride (hereinafter referred to as barium fluoride) are used. A mixed salt of BaF ₂ ) or the like can be used. In the molten salt bath for electrolysis, (a) to
This can be carried out by a method in which the calcined product obtained in at least one step of step (c) is charged and electrolysis is performed while melting in a temperature range of preferably 700 to 1400 ° C. Mixing ratio of each component in the molten salt bath for electrolysis, that is, RF ₃ : L
iF: BaF ₂ has a weight ratio of 1: 0.1 to 0.4: 0.
It is preferable to set it to 08 to 0.3. Also the above
In addition to the fired product obtained from the steps (a) to (c), a new rare earth metal oxide such as a misch metal raw material can be further mixed in the molten salt bath for electrolysis. By mixing a new rare earth metal oxide, the content of the rare earth metal in the obtained alloy is increased, the melting point is lowered, and the molten salt electrolytic treatment is facilitated, which is preferable. The mixing ratio of the new rare earth metal oxide is 0. 0 by weight ratio with respect to the burned material 1 such as the metal oxide recovered by the firing in the steps (a) to (c).
3-13 are preferable. By such a molten salt electrolysis method,
An effective metal can be obtained.

The effective metal obtained by the present invention can be regenerated into a nickel-hydrogen battery electrode alloy or the like after melting in an ordinary argon atmosphere or a vacuum high-frequency melting furnace after the alloy composition is blended. In this case, the inclusion of a small amount of metal such as cobalt, aluminum or manganese added to the electrode material has no influence on the characteristics of the regenerated electrode material and is not particularly limited.

[0022]

According to the method for recovering the nickel-hydrogen secondary battery of the present invention, the effective metal can be efficiently recovered from the nickel-hydrogen secondary battery, which makes it possible to effectively recycle the electrode material and to use the usual chemistry. It is possible to collect a large amount at a low cost as compared with separation, refining and refining using a chemical treatment method.

[0023]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[0024]

Example 1 A used nickel-hydrogen secondary battery (containing 82 g of a positive electrode material and 151 g of a negative electrode material necessary for recovery) was crushed into small pieces of 5 mm or less by a biaxial shearing crusher, and then put into a container with a stirrer. The mixture was charged, stirred while flowing water, and the alkaline content was removed by overflow. Then, after removing the organic substance by a wet specific gravity sorter, the residual metal was removed by a wet electromagnetic vibrating sieve to remove iron, and filtered to recover nickel and nickel rare earth metal powder.

Next, the recovered nickel and nickel rare earth metal powders are fired in an electric furnace at 800 ° C. for 2 hours and converted into metal 1
94 g of metal oxide was obtained with a yield of 83.3%. The obtained metal oxide was electrolyzed at 1000 ° C. while being put into a molten salt bath for electrolysis containing RF ₃ 65% by weight, LiF 20% by weight and BaF ₂ 15% by weight. The metal obtained is 145.3
The yield from the metal oxide was 74.9%. The composition of the obtained metal oxide is 28.
The content was 9%, nickel 65.2%, cobalt 3.6%, aluminum 0.6% and manganese 1.7%.

[0026]

Example 2 A used nickel hydrogen secondary battery (containing 840 g of a positive electrode material and a negative electrode material necessary for recovery) was crushed into small pieces of 5 mm or less by a biaxial shearing crusher, and then the same as in Example 1. The alkali content, the organic substance and the iron content were removed and filtered to recover nickel and nickel rare earth metal powder.

Next, the recovered nickel and nickel rare earth metal powder are dissolved in nitric acid, and then ammonium fluoride 220 is added.
A rare earth metal is precipitated as a fluoride by adding a g-containing aqueous solution, filtered, and calcined at 700 ° C. to obtain 396 g of RF ₃ .
Obtained. On the other hand, the rare earth metal is precipitated as a fluoride,
1130 g of ammonium bicarbonate and 20
2275 ml of% ammonia water was added to precipitate nickel ions as nickel carbonate, which was filtered and calcined at 800 ° C. to obtain 728 g of nickel oxide. Yield 84.1
%Met.

Next, LiF and BaF ₂ were added to the obtained RF _3.
Was mixed, and a molten salt bath for electrolysis having a composition ratio of 65:20:15 by weight was prepared. When 100 g of a misch metal raw material was charged as a rare earth metal oxide into an electrolytic furnace using this bath, an electrolytic treatment was performed at 900 ° C., and 78.6 g of misch metal was obtained.

[0029]

Example 3 RF ₃ obtained by processing in the same manner as in Example 2
Then, LiF and BaF ₂ were mixed, and a molten salt bath for electrolysis having a composition ratio in terms of weight of 65:20:15 was prepared.
A rare earth metal nickel alloy was obtained at a yield of 75.5% when electrolytically treated at 1050 ° C. while introducing the metal oxide obtained by the same treatment as in Example 1 into the electrolytic furnace using this bath. .

[0030]

Example 4 A mixture of 700 g of nickel oxide obtained by treating in the same manner as in Example 2 and 1000 g of a misch metal raw material as a rare earth metal oxide was mixed with 65% by weight of RF ₃ , 20% by weight of LiF and 15% of BaF _2. The electrolytic treatment was performed at 950 ° C. while charging the electrolytic solution in a molten salt bath for electrolysis of wt%. The obtained metal was 1310 g, and the metal composition was 60% by weight of rare earth metal and 40% by weight of nickel.
The yield of nickel from nickel oxide was 92%.

[0031]

Example 5 A used nickel-hydrogen secondary battery (containing 840 g of a positive electrode material and a negative electrode material necessary for recovery) was crushed into small pieces of 5 mm or less by a biaxial shearing crusher, and then the same as in Example 1. The alkali content, the organic substance and the iron content were removed and filtered to recover nickel and nickel rare earth metal powder.

Next, the recovered nickel and nickel rare earth metal powder were dissolved in nitric acid, the insoluble matter was filtered, and 1273 g of ammonium bicarbonate and 2561 ml of 20% ammonia water were added to the residual liquid after filtration to remove nickel and rare earth elements. Of mixed carbonates were precipitated and filtered off. The resulting precipitate is 80
When baked at 0 ° C. for 10 hours, 1051 g of nickel rare earth metal oxide was obtained with a yield of 80.7%. The obtained nickel rare earth metal oxide was electrolyzed at 1020 ° C. while being placed in a molten salt bath for electrolysis having the same composition as in Example 1.
The obtained metal was 722 g, and the yield from the metal oxide was 85.6%. The composition of the rare earth metal 2
9.6% by weight, nickel 66.7% by weight, cobalt 3.
It was 7%.

[0033]

Example 6 RF ₃ obtained by processing in the same manner as in Example 2
Then, LiF and BaF ₂ were mixed, and a molten salt bath for electrolysis having a composition ratio in terms of weight of 65:20:15 was prepared.
While the nickel rare earth metal oxide obtained by the same treatment as in Example 5 was charged into an electrolysis furnace using this bath, 105
Upon electrolytic treatment at 0 ° C., a rare earth metal nickel alloy was obtained with a yield of 87.3%.

[0034]

Example 7 RF ₃ obtained by processing in the same manner as in Example 2
Then, LiF and BaF ₂ were mixed, and a molten salt bath for electrolysis having a composition ratio in terms of weight of 65:20:15 was prepared.
While mixing 100 g of metal oxide obtained by the same treatment as in Example 1 and 100 g of nickel rare earth metal oxide obtained by the same treatment as in Example 5, in an electrolytic furnace using this bath. Electrolysis was performed at 1000 ° C. The obtained rare earth metal nickel alloy was 138.6 g, and the yield was 86.4%. The composition is rare earth metal 2
9.2% by weight, nickel 65.9% by weight, cobalt 3.
7 wt%, aluminum 0.3 wt%, manganese 0.9
% By weight.

[0035]

Example 8 150 g of a metal oxide obtained by the same treatment as in Example 1 and 200 g of a misch metal raw material as a rare earth metal oxide were mixed, and RF ₃ 65% by weight, Li
Electrolysis treatment was carried out at 950 ° C. while pouring into a molten salt bath for electrolysis containing 20% by weight of F and 15% by weight of BaF ₂ . The amount of the obtained metal was 268.6 g, and the metal composition thereof was the rare earth metal 7
0.6% by weight, nickel 27.0% by weight, cobalt 1.
5% by weight, 0.2% by weight of aluminum, 0.7 of manganese
% By weight.

Claims (2)

[Claims] 1. A nickel-hydrogen secondary battery is crushed to remove an alkali content, followed by a step of separating an organic substance by a wet specific gravity fractionation method, and a step of separating an iron content, and (a) at least the above. Calcining the component in which the alkali component, the organic substance and the iron component have been separated, (b) at least the component in which the alkali component, the organic substance and the iron component have been separated are dissolved in mineral acid, and then a rare earth metal ion and a nickel ion are precipitated, A step of filtering and calcining the precipitate, (c) dissolving at least the components separated from the alkali content, organic substance and iron content in mineral acid, precipitating rare earth metal ions as fluorides, and filtering and calcining the resulting precipitate. To obtain a rare earth metal fluoride while precipitating nickel ions from the residual liquid obtained by filtering the precipitate, filtering the precipitate, and calcining to obtain nickel oxide, steps (a) to (c) above. of Zureka 1 step, (a) step and (c)
A combination of steps, a combination of steps (b) and (c), or
(a) ~ (c) the fired product obtained by all the steps,
Electrolytic method A method for recovering an effective metal from a nickel-hydrogen secondary battery, characterized by treating by a molten salt electrolytic method using a molten salt bath. 2. The method for recovering an effective metal from a nickel-hydrogen secondary battery according to claim 1, wherein a rare earth metal oxide is further added to the electrolytic molten salt bath in addition to the fired product.