JP2010126779A - Method for recovering nickel concentrate from used nickel hydride battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of processing for separating and recovering nickel concentrate efficiently used as a raw material in a step for producing metal nickel in good yield, from a nickel-containing material classified in a processing step of a used nickel hydride battery. <P>SOLUTION: The method includes following steps (1)-(3). Step (1): a nickel-containing material (B) with a nickel metallization ratio of ≥97.5% is prepared from a nickel-containing material (A). Step (2): a leaching solution containing nickel is obtained by adding the nickel-containing material (B) into a mineral acid solution with adjusted pH of 0-3, under a condition of solution temperature: 25-100°C to be served in leaching. Step (3): a cementation deposit containing nickel in a metal form is obtained by adding alkali into the leaching solution, under a condition of solution temperature: 25-100°C and while adjusting pH to 1-5, adding iron powder to be served in cementation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for recovering a nickel concentrate from a used nickel metal hydride battery, and more particularly, a metal that can be recycled as a battery material from a nickel-containing material that has been separated in a processing step of a used nickel metal hydride battery. The present invention relates to a processing method capable of separating and recovering a nickel concentrate suitable as a raw material for a step of producing nickel or a nickel compound in a high yield. This effectively recycles nickel from the used nickel metal hydride battery.

  In recent years, nickel metal hydride batteries have been used as storage batteries used in hybrid vehicles. Moreover, from the viewpoint of global environmental problems, it is considered that the ratio of hybrid vehicles to the entire vehicle will increase, and accompanying this, resource recycling of used nickel metal hydride batteries has become a problem. By the way, in the recycling of lead acid batteries, which has been the mainstream in the past as a storage battery for automobiles, it is easy to take out lead used as an electrode material as a metal, so only the recovered metal lead is used as a raw material for the lead acid battery. It can also be used for other purposes. For this reason, also in a nickel metal hydride battery, it is required to establish a method for recycling nickel, which is a main battery material, as a battery material.

  However, the nickel-metal hydride battery is composed of a positive electrode, a negative electrode, an electrode terminal and an electrolytic solution as functional members, and an electrode substrate, a separator, a case, and the like as structural members. More specifically, as the positive electrode active material, nickel hydroxide containing a trace amount of additive element, as the negative electrode active material, hydrogen storage alloy containing nickel, cobalt, rare earth element (Misch metal), etc., as the electrode substrate, a nickel plate, Nickel-plated iron plate, separator as plastic, electrolyte as potassium hydroxide aqueous solution, electrode terminal material as copper, iron-based metal, case as plastic, steel, etc. from various materials and components It is configured. That is, examples of the nickel-containing material to be recycled include a positive electrode active material made of nickel hydroxide, a negative electrode active material made of a hydrogen storage alloy containing nickel, and an electrode substrate made of a nickel plate or a nickel-plated iron plate.

  In this way, nickel-metal hydride batteries have a complex configuration and contain a wide variety of components that differ greatly in thermal, chemical and physical properties, so that they can be separated and recovered efficiently industrially. It was difficult. In other words, as a recycling method, there is generally a method in which a pure material is not separated but a material recovered in a certain mixture state is reused as a raw material, but this method is used in the case of a nickel metal hydride battery. But there was a cost problem. Furthermore, in nickel metal hydride batteries, it has been more difficult to recover nickel as a metal, such as recycling of lead metal in lead acid batteries. For example, since it is used as a raw material for nickel smelting, it is used as a raw material for a chlorine leaching-electrolytic extraction method which is one of nickel smelting methods. As a rare earth metal element to be mixed, the La grade is required to be about 50 ppm or less, and separation of the rare earth metal element is indispensable with the concentration of nickel.

  As a measure for this, for example, as a method for recovering metals from used nickel metal hydride batteries, after nickel metal hydride battery scraps are mechanically separated, they are dissolved in sulfuric acid, and first, rare earth elements are separated with sulfite, Further, the pH is raised, iron is neutralized and separated, and then a rare earth element, zinc, aluminum, manganese and the like are extracted into an organic phase by solvent extraction, and a nickel / cobalt alloy is recovered from the aqueous phase by electrolysis ( For example, see Patent Document 1). By applying this method, it is possible to separate and recover the nickel concentrate used as a raw material for the process of producing metallic nickel, but it is possible to use a metal such as a purification process by solvent extraction, a process of recovering nickel / cobalt alloy by electrolysis, etc. As a method for recovering the nickel concentrate used as a raw material for the process of producing nickel, there is a problem in cost and it cannot be used.

  As this solution, for example, it is used as a ferronickel smelting raw material. Normally, in the ferronickel smelting process, the electrolyte used in the nickel-metal hydride battery, the plastic used in the separator and the case are oxidized and decomposed in the firing process, and the nickel component is recovered as a ferronickel alloy in the reduction and melting process. Efficient collection. However, since ferronickel alloy is not easily dissolved in acid, it cannot be efficiently used as a raw material for a process for producing metallic nickel or a nickel compound.

  Under such circumstances, a used nickel metal hydride battery is subjected to mechanical separation for ensuring safety during storage, for example, removal of the electrolyte in the battery by firing, and further decomposition of the plastic if necessary. Are separated into respective members constituting the battery. Therefore, recovery of nickel from the nickel-containing material is required among the members separated in the processing steps of the used nickel-metal hydride battery as described above.

Japanese translation of PCT publication No. 10-510878 (first page, second page)

  An object of the present invention is to produce metallic nickel or a nickel compound that can be recycled as a battery material from a nickel-containing material separated in a processing step of a used nickel-metal hydride battery in view of the above-described problems of the prior art. An object of the present invention is to provide a treatment method capable of separating and recovering a nickel concentrate suitable as a raw material for the process in a high yield.

  In order to achieve the above object, the present inventors have conducted extensive research on a method for recovering nickel from the nickel-containing material separated in the processing step of the used nickel-metal hydride battery. A step of preparing a nickel-containing material having a specific nickel metallization rate, a step of subjecting the prepared nickel-containing material to leaching under specific conditions to obtain a leaching solution containing nickel, and in the obtained leaching solution The step of subjecting nickel to cementation under specific conditions to obtain a cementation deposit containing nickel in a metallic form was carried out in order, and contained nickel in a metallic form, excellent in acid solubility, and Nickel enrichment suitable as a raw material for the production process of metallic nickel or nickel compounds due to low content of rare earth elements other than cobalt and other impurity elements It found that can be separated and recovered in high yield, and completed the present invention.

That is, according to the first invention of the present invention, there is provided a method for recovering nickel from the nickel-containing material (A) separated in the processing step of the used nickel-metal hydride battery,
A method for recovering a nickel concentrate from a used nickel metal hydride battery comprising the following steps (1) to (3) is provided.
Step (1): A nickel-containing material (B) having a nickel metallization rate of 97.5% or more is prepared from the nickel-containing material (A).
Step (2): The nickel-containing material (B) is added to a mineral acid solution whose pH is adjusted to 0 to 3 under the condition of a liquid temperature: 25 to 100 ° C. and subjected to leaching, and contains nickel. Get a leachate to do.
Step (3): In the leachate, while adding alkali under conditions of liquid temperature: 25-100 ° C. and adjusting the pH to 1-5, iron powder is added and subjected to cementation, and nickel is added. Obtain cementation deposits in metallic form.

  According to a second aspect of the present invention, there is provided a method for recovering nickel concentrate from a used nickel-metal hydride battery according to the first aspect, wherein the mineral acid is sulfuric acid.

  According to the third invention of the present invention, in the first or second invention, in the step (2), the addition ratio of the nickel-containing material (B) is a solid-liquid ratio (nickel-containing material (B) / There is provided a method for recovering nickel concentrate from used nickel metal hydride batteries, characterized in that the mineral acid solution is 50 to 300 (g / L).

  According to a fourth invention of the present invention, in any one of the first to third inventions, in the step (3), the addition ratio of iron powder is the chemical equivalent of cementation reaction per nickel in the leachate. Provided is a method for recovering nickel concentrate from a used nickel metal hydride battery characterized in that it is 1.1 to 11 times.

  According to a fifth invention of the present invention, in any one of the first to fourth inventions, in the step (3), the reaction atmosphere is a non-oxidizing atmosphere. A method for recovering nickel concentrate from a battery is provided.

  According to a sixth invention of the present invention, in any one of the first to fifth inventions, cementation containing the unreacted iron powder obtained in place of the iron powder in the step (3). A method for recovering nickel concentrate from a used nickel metal hydride battery according to any one of claims 1 to 5 is provided.

  The method for recovering a nickel concentrate from a used nickel-metal hydride battery of the present invention contains nickel in a metal form from the nickel-containing material separated in the processing step of the used nickel-metal hydride battery, has excellent acid solubility, and Since the content of rare earth elements other than cobalt and other impurity elements is low, the nickel concentrate suitable as a raw material for the process of producing metallic nickel or nickel compounds that can be recycled as battery materials is separated and recovered in high yield. Its industrial value is extremely high. Furthermore, if the cementation deposit containing unreacted iron powder obtained by cementation is reused repeatedly instead of iron powder, nickel is concentrated in the recovered cementation deposit to improve the nickel quality. Since it can rise, it is more advantageous.

Hereinafter, the method for recovering the nickel concentrate from the used nickel metal hydride battery of the present invention will be described in detail.
The method for recovering a nickel concentrate from a used nickel-metal hydride battery according to the present invention is a method for recovering nickel from the nickel-containing material (A) separated in the processing step of the used nickel-metal hydride battery. (1) to (3) are included.
Step (1): A nickel-containing material (B) having a nickel metallization rate of 97.5% or more is prepared from the nickel-containing material (A).
Step (2): The nickel-containing material (B) is added to a mineral acid solution whose pH is adjusted to 0 to 3 under the condition of a liquid temperature: 25 to 100 ° C. and subjected to leaching, and contains nickel. Get a leachate to do.
Step (3): In the leachate, while adding alkali under conditions of liquid temperature: 25-100 ° C. and adjusting the pH to 1-5, iron powder is added and subjected to cementation, and nickel is added. Obtain cementation deposits in metallic form.

In the present invention, it is particularly important to prepare a nickel-containing material (B) having a nickel metallization rate of 97.5% or more from the nickel-containing material (A) separated in the processing step of the used nickel-metal hydride battery. It is. That is, when the nickel metallization rate of the nickel-containing material is less than 97.5%, nickel oxide cannot be leached in a high yield because the leaching of nickel oxide is insufficient in the acid leaching.
In addition, it is important to adopt the steps (2) and (3), thereby containing nickel in a metal form, excellent in acid solubility, and contents of rare earth elements other than cobalt and other impurity elements. Since the rareness is low, it is possible to separate and recover a nickel concentrate that is efficiently used as a raw material in a process for producing metallic nickel or a nickel compound that can be recycled as a battery material. That is, by the cementation reaction of step (3), nickel and cobalt are selectively metallized and separated from the rare earth element, iron, manganese, zinc, etc. dissolved from the nickel-containing material (B) in step (2). be able to.

(1) Step (1)
The step (1) is a step of preparing a nickel-containing material (B) having a nickel metallization rate of 97.5% or more from the nickel-containing material (A) separated in the processing step of the used nickel-metal hydride battery. is there.
The nickel-containing material (A) is a member containing nickel separated in the processing step of a used nickel-metal hydride battery, and the member is not particularly limited. At least one selected from a positive electrode active material, an electrode substrate, and a negative electrode active material separated from a battery is used. Furthermore, at least 1 sort (s) chosen from the positive electrode active material, electrode substrate, or negative electrode active material discharged | emitted as a waste material in the manufacturing process of a nickel metal hydride battery can also be used. In addition to nickel, the nickel-containing material (A) is usually any one of cobalt, rare earth elements, iron, manganese, zinc, and the like derived from the additive of the positive electrode active material, the electrode substrate, or the negative electrode active material. Is contained.

  As described above, in the treatment process of the used nickel metal hydride battery, when the firing process is performed at the time of separation of each member, the form of nickel in the nickel-containing material (A) is changed depending on the firing condition, and the metallization rate is increased. fluctuate. That is, the atmosphere formed at the time of firing varies depending on the gas composition to be charged, the carbon produced by the decomposition of the plastic in the battery, the iron-based member, etc., and thereby the positive electrode active material contained in the nickel-containing material (A). The oxidation state of nickel hydroxide constituting the nickel, nickel in the hydrogen storage alloy constituting the negative electrode active material, or nickel constituting the electrode substrate changes. Note that the nickel plate that normally constitutes the positive electrode substrate and the nickel-plated iron plate that constitutes the negative electrode substrate are difficult to oxidize, but in particular, the powdered positive electrode active material and the negative electrode active material are easily oxidized.

  Here, the method for preparing the nickel-containing material (B) is not particularly limited, but the nickel metallization rate is determined from the nickel-containing material (A) separated in the processing step of the used nickel-metal hydride battery. Means for selecting nickel-containing material satisfying desired nickel oxidation state of 97.5% or more by analytical method, or used nickel-metal hydride battery, or fractionated nickel-containing material to obtain desired nickel oxidation state Is used for roasting in a reducing atmosphere. The method for roasting in a reducing atmosphere is not particularly limited, and conditions for reducing nickel oxide to metallic nickel are used. Moreover, as an analysis method for measuring the oxidation state (nickel metalization rate) of nickel, a method by fluorescent X-ray analysis is preferable because it is simple.

(2) Step (2)
Step (2): The nickel-containing material (B) is added to a mineral acid solution having a pH adjusted to 0 to 3 under a liquid temperature of 25 to 100 ° C., and subjected to leaching. It is a step of obtaining a leachate containing.
The mineral acid is not particularly limited, and at least one selected from sulfuric acid, hydrochloric acid, or nitric acid is used, but sulfuric acid is preferable because of cost, handling properties, and subsequent cementation reaction.

  In the step (2), the leaching of the nickel-containing material (B) may be performed by leaching the positive electrode active material, the electrode substrate, or the negative electrode active material simultaneously or individually. In the case of leaching individually, rare earth elements can be concentrated in the leaching residue of the negative electrode active material depending on the leaching conditions.

  The liquid temperature used in the above step (2) is 25 to 100 ° C., and 75 to 85 ° C. is preferable in consideration of the reaction rate, the water evaporation amount, and the energy efficiency. That is, when the liquid temperature exceeds 100 ° C., the liquid phase boils, so that reaction control becomes difficult.

  As pH used at the said process (2), it is 0-3, and 0-1 are preferable when reaction rate etc. are considered. That is, when the pH is less than 0, pH adjustment becomes difficult. On the other hand, when the pH exceeds 3, leaching of nickel is insufficient.

  Although it does not specifically limit as an addition rate of the nickel containing material (B) used at the said process (2), 50-300 (g / in solid-liquid ratio (nickel containing material (B) / mineral acid solution)). L) is preferred. That is, when the solid-liquid ratio is less than 50 (g / L), the amount of leachate increases, so that the processing efficiency in the next step deteriorates. On the other hand, when the solid-liquid ratio exceeds 300 (g / L), problems such as deterioration of the stirring state and saturation of the leaching component in the liquid occur.

  The leaching method is not particularly limited, and a general means is used. However, stirring is performed to shorten the reaction time, and air blowing or hydrogen peroxide is used to efficiently leach nickel. It is preferable to add an oxidizing agent such as Further, the method for separating the leachate and the leach residue after leaching is not particularly limited, and a general filtering means is used. In addition, since the rare earth element derived from a negative electrode active material is concentrated in the leaching residue, it can be processed separately.

  By the above step (2), a nickel leaching rate of 99% or more can be obtained. Thereby, a leachate having a nickel concentration of 40 to 120 g / L is obtained. At the same time, a cobalt leaching rate of 99% or more can be obtained.

(3) Step (3)
In the step (3), in the leachate, an alkali is added under the condition of a liquid temperature: 25 to 100 ° C., and the pH is adjusted to 1 to 5, while iron powder is added and subjected to cementation. A step of obtaining cementation deposits containing nickel in metallic form. Here, nickel contained in the leachate is recovered in a metallic state and separated from the rare earth element.

  The step (3) is to perform a cementation reaction (showing the case where the substituent is iron) shown in the following reaction formula (1) using a metal powder. As the metal powder used for cementation, Metals such as iron, aluminum, and zinc, which have a higher ionization tendency than nickel, are used. In the method of the present invention, iron powder is used in consideration of cost, handling properties, drainage treatment, and the like. As a result, most of cobalt as well as nickel is reduced and contained in the cementation deposit, but rare earth elements remain in the liquid because they are not reduced.

Reaction formula (1): Ni ²⁺ + Fe → Ni + Fe ²⁺

  As a liquid temperature used at the said process (3), it is 25-100 degreeC, and 60-80 degreeC is preferable when the reaction rate and solubility are considered. That is, in the cementation reaction, the reaction proceeds at a temperature higher than normal temperature and the higher the temperature, on the other hand, when the liquid temperature exceeds 100 ° C., the liquid phase boils and the reaction control becomes difficult.

  As pH used at the said process (3), it is 1-5, and 2-4 are preferable when reaction rate etc. are considered. That is, when the pH is less than 1, the consumption of mineral acid and iron is increased, which is uneconomical. On the other hand, when the pH exceeds 5, problems such as a slow reaction rate and contamination of cementation deposits due to the formation of hydroxides occur. Here, an alkali such as sodium hydroxide is used as the pH adjuster.

  Although it does not specifically limit as an addition rate of the iron powder used at the said process (3), It is a chemical equivalent of the cementation reaction shown by the said Reaction formula (1), and 1.1 ~ per nickel in the said leaching solution It is preferably 11 times. That is, when the addition ratio of the iron powder is less than 1.1 times, the reaction is not completed even if the iron powder is completely dissolved, and unrecovered nickel in the liquid is generated. On the other hand, when the addition ratio of the iron powder exceeds 11 times, the stirring state deteriorates.

  The cementation method is not particularly limited, and a general means is used. However, stirring is preferably performed in order to shorten the reaction time, and divalent iron is reduced to 3 by oxidation from the atmosphere. The reaction atmosphere is preferably adjusted to a non-oxidizing atmosphere because it may be oxidized to valent iron to produce a hydroxide, and therefore purging with an inert gas such as nitrogen is performed.

In the above cementation method, the end point of the cementation reaction that sufficiently separates nickel in the liquid can be easily determined by observing that the color of the liquid phase changes from green to blue.
Moreover, the cementation deposit after the cementation reaction is separated and collected from the final solution using a general filtration means or magnetic force, and a cementation deposit containing nickel in a metal form is obtained. Here, the collected cementation deposit can remove the final liquid water adhering to the repulp washing, the water washing and the like.

  In the above step (3), the cementation deposit is usually made of sponge-like metallic nickel and unreacted iron powder. Therefore, cementation deposit containing unreacted iron powder instead of iron powder. It is preferable to reuse the product. At that time, by repeatedly using the cementation deposit 2 to 4 times, nickel can be concentrated in the recovered cementation deposit and the nickel quality can be increased.

  The cementation residue separated and recovered in the above step (3) contains nickel in a metal form, has good solubility in an acidic solution, has a sufficiently high nickel quality, and is other than cobalt. The process of producing metallic nickel or a nickel compound that can be recycled as a battery material since the rare earth element content and other impurity element content of the battery are sufficiently reduced, particularly the rare earth element content is reduced to 50 ppm or less. For example, it is suitable in terms of solubility and quality as a raw material for the above-described chlorine leaching-electrolytic collection method or the like.

  Hereinafter, the present invention will be described in more detail by way of examples and comparative examples of the present invention, but the present invention is not limited to these examples. The metal used in the examples and comparative examples was analyzed by ICP emission analysis.

Example 1
(1) Step (1)
Using a member separated from the sintered product of the used nickel metal hydride battery, this was analyzed, and as a leaching material, a positive electrode active material having a nickel metallization rate of 97.7% and a mixture of the positive electrode substrate and the negative electrode active material Selected.

(2) Step (2)
Using the mixture of the positive electrode active material and the positive electrode substrate and the negative electrode active material, these were individually subjected to leaching, and the leaching rate was determined.
For leaching, a reaction vessel equipped with a stirring blade and an air blowing device was used. 20 g of the leaching raw material was added to 200 mL of sulfuric acid solution adjusted to pH 0.5 at a solid / liquid ratio of 100 (g / L), and subjected to leaching for 4 hours while adjusting the liquid temperature to 80 ° C. A leachate was obtained. The air blowing rate was 1 L / min.
Here, the composition of the mixture of the positive electrode active material and the positive electrode substrate is Ni: 77.5 mass%, Co: 5.40 mass%, La: <0.01 mass%, and as a result, the leaching rate is Ni : 99.9%, and Co: 99.9%.
The composition of the negative electrode active material was Ni: 45.5% by mass, Co: 3.53% by mass, and La: 14.5% by mass. As a result, the leaching rate was Ni: 99.9%, Co : 99.9% and La: 55.9% by mass.

(3) Step (3)
The negative electrode active material was leached under the same conditions as in the above step (2), and the resulting leachate was used for cementation to obtain cementation deposits. Here, the composition of the leachate was Ni: 77.0 g / L, Co: 3.34 g / L, and La: 0.62 g / L.
For cementation, a reaction vessel equipped with stirring blades and purged with nitrogen was used. In 300 mL of the leachate, while adding sodium hydroxide to adjust the pH to 3.0, iron powder was added at a solid-liquid ratio of 500 (g / L) and stirred at a liquid temperature of 70 ° C. for 8 hours. A cementation deposit was obtained and a concentrate (C) containing nickel in metallic form was recovered.
In addition, as an iron powder, a composition is total iron: 96.7 mass%, metallic iron: 92.5 mass%, FeO: 5.4 mass%, and a particle size distribution is 425-300 micrometers: 0.7 mass. %, 300-250 μm: 5.2 mass%, 250-150 μm: 30.5 mass%, 150-106 μm: 22.3 mass%, 106-75 μm: 18.5 mass%, −75 μm: 22.8 mass% The one made by Dowa Iron Powder Industry Co., Ltd. was used.
As a result, a cementation deposit having a composition of Ni: 16.3 mass%, Co: 0.15 mass%, and La: 26 ppm was obtained. Here, the recoveries were Ni: 99.0% and Co: 28.5%.

(Example 2)
Using a negative electrode active material with a nickel metallization rate of 97.7%, leaching was performed under the same conditions as in Example 1 to obtain a leaching solution. Next, iron powder was added to the obtained leachate under the same conditions as in Example 1 to perform cementation, and a cementation deposit containing unreacted iron powder was obtained. Thereafter, in the cementation of the leachate obtained under the same conditions, the cementation deposit containing the unreacted iron powder was repeatedly used instead of the iron powder. The number of repetitions was 3. The leachate concentrations were Ni: 46.6 g / L, Co: 3.36 g / L, and La: 14.2 g / L.
As a result, the Ni quality of cementation materials increased with the increase in the number of repetitions. Initial Ni quality: 9.3 mass%, Ni quality after the first repetition: 21.0 mass%, Ni quality after the second repetition: 29.1 mass%, and Ni quality after the third repetition: It was 35.3 mass%.

(Comparative Example 1)
(1) Step (1)
Using a member separated from the sintered product of the used nickel metal hydride battery, this was analyzed, and as a leaching raw material, a mixture of a positive electrode active material having a nickel metallization rate of 90.0% and a positive electrode substrate and a nickel metallization rate was 65% of the negative electrode active material was selected.
(2) Step (2)
Using the mixture of the positive electrode active material and positive electrode substrate and the negative electrode active material, these were individually subjected to leaching under the same conditions as in Example 1 to obtain the leaching rate.
Here, the composition of the mixture of the positive electrode active material and the positive electrode substrate is Ni: 76.5% by mass, Co: 4.60% by mass, La: 0.12% by mass, and as a result, the leaching rate is Ni: It was 88.0%, and Co: 87.1%.
The composition of the negative electrode active material was Ni: 38.6% by mass, Co: 3.20% by mass, and La: 12.1% by mass. As a result, the leaching rate was Ni: 63.1%, Co : 68.4% and La: 17.9% by mass.

  As described above, in Example 1, a positive electrode active material having a nickel metallization ratio of 97.5% or more and a mixture of a positive electrode substrate and a negative electrode active material are prepared from the members separated from the sintered product of the used nickel metal hydride battery. This was leached, the nickel in the obtained leachate was subjected to cementation, and it was carried out according to the method of the present invention, so that nickel was leached in high yield and efficient as a raw material for the process of producing metallic nickel. It can be seen that the nickel concentrate used in can be recovered. On the other hand, in Comparative Example 1, since the nickel metallization rate is low, it can be seen that satisfactory results cannot be obtained in leaching.

  As is clear from the above, the method for recovering the nickel concentrate from the used nickel metal hydride battery of the present invention contains nickel in a metal form from the nickel-containing material separated in the processing step of the used nickel metal hydride battery, Because it has excellent acid solubility and low rare earth element content, it can separate and recover nickel concentrate suitable as a raw material for the production process of metallic nickel in high yield, and simultaneously recover coexisting cobalt at the same time as nickel. Therefore, it is suitable as a technique for recovering valuable metals such as nickel used in the field of recycling used nickel-metal hydride batteries. In particular, in the case of a member containing a rare earth element, a nickel concentrate from which these are separated is obtained, which is advantageous.

Claims (6)

A method of recovering nickel from nickel-containing material (A) separated in a processing step of a used nickel metal hydride battery,
A method for recovering nickel concentrate from a used nickel metal hydride battery, comprising the following steps (1) to (3):
Step (1): A nickel-containing material (B) having a nickel metallization rate of 97.5% or more is prepared from the nickel-containing material (A).
Step (2): The nickel-containing material (B) is added to a mineral acid solution whose pH is adjusted to 0 to 3 under the condition of a liquid temperature: 25 to 100 ° C. and subjected to leaching, and contains nickel. Get a leachate to do.
Step (3): In the leachate, while adding alkali under conditions of liquid temperature: 25-100 ° C. and adjusting the pH to 1-5, iron powder is added and subjected to cementation, and nickel is added. Obtain cementation deposits in metallic form.   The method for recovering a nickel concentrate from a used nickel metal hydride battery according to claim 1, wherein the mineral acid is sulfuric acid.   In the step (2), the addition ratio of the nickel-containing material (B) is 50 to 300 (g / L) in a solid-liquid ratio (nickel-containing material (B) / mineral acid solution). Item 3. A method for recovering nickel concentrate from a used nickel metal hydride battery according to item 1 or 2.   In the said process (3), the addition ratio of an iron powder is 1.1-11 times per nickel in the said leaching liquid with the chemical equivalent of a cementation reaction, The any one of Claims 1-3 characterized by the above-mentioned. Of recovering nickel concentrate from used nickel metal hydride batteries.   The method for recovering a nickel concentrate from a used nickel-metal hydride battery according to any one of claims 1 to 4, wherein in the step (3), the reaction atmosphere is a non-oxidizing atmosphere.   The used (1) according to any one of claims 1 to 5, wherein in the step (3), the cementation deposit containing the obtained unreacted iron powder is reused instead of the iron powder. A method for recovering nickel concentrate from a nickel metal hydride battery.