JP2012229481A - Method for separating and recovering valuable material from used lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering valuable materials from used lithium ion batteries by individually separating the valuable material included in the used lithium ion batteries.SOLUTION: The used lithium ion batteries are disassembled into powder materials comprising active materials and massive materials comprising iron, copper, and aluminum after organic materials, such as an electrolyte, are removed. The powder material is subjected to oxidizing roasting and reducing roasting, and graphite is removed. Then a crystal of a lithium complex oxide is decomposed, and a lithium component included therein is once converted into lithium hydroxide, and ultimately, the lithium component is recovered as lithium carbonate. Furthermore, cobalt and nickel are recovered as magnetic products by magnetic separation while oxides and hydroxides of manganese, iron, and the like are recovered as non-magnetic products.

Description

The present invention relates to used lithium ion batteries in which the positive electrode active material is various lithium composite oxides, aluminum and copper used in battery case materials and current collectors, and cobalt constituting the positive electrode active material, The present invention relates to a method of separately collecting valuable materials such as nickel and lithium.
The present invention also relates to a separation and recovery method capable of separating and recovering valuable materials even from a state where a plurality of types of used lithium ion batteries are mixed.

Methods for recovering valuable materials from used lithium ion batteries have been proposed in the past, but in most cases, the positive electrode active material is lithium cobaltate, and nickel-based or manganese other than cobalt-based materials are used. In the case of a cathode active material based on iron or iron phosphate, there are almost no proposals for the recovery method, and there is no proposal for the recovery of valuable materials from batteries in which they are mixed. The current situation is that nothing has been done.
For example, Patent Document 1 proposes a method for recovering lithium and cobalt from lithium cobaltate. However, the method described here is a case where only pure lithium cobaltate is used. It is not recovery from the battery. That is, in Patent Document 1, fluoride generated by hydrolysis of lithium hexafluorophosphate (LiPF ₆ ) used as an electrolyte in an actual waste battery and thermal decomposition of polyvinylidene fluoride (PVDF) used as a binder. The influence of lithium fluoride produced by hydrogen is not considered at all.
Patent Document 2 proposes a method for recovering copper and iron as valuable materials from a used lithium-manganese battery. However, the object is a case where the target is a lithium-manganese battery alone, and the recoverable value is recovered. There is no mention of recovery of lithium and manganese, which are copper and iron, which are considered to be more valuable than these.

In the future, lithium-ion batteries will be used in HV and EV batteries, and as their use increases, the percentage of expensive cobalt used will be low, or lithium-ion batteries that will not be used at all will increase. Therefore, it is expected that various types of lithium ion batteries will be used together.
In such a situation, the recovery of valuable materials from used lithium ion batteries must assume various positive electrode active materials or a mixture of them.
Especially in Japan, where resources are scarce, it is becoming increasingly necessary to collect valuable materials from various types of used lithium-ion batteries safely and simply and reuse them in preparation for such cases. It is thought to come.

JP 2004-11010 A JP 2000-313926 A

  In view of such a situation, the present invention is a mixture of lithium ion batteries of various types of positive electrode active materials, valuable materials such as copper, aluminum, cobalt, nickel, manganese, lithium, The present invention provides a method for safe and simple separation and collection.

The present invention
In a method of separating and collecting valuable materials from used lithium ion batteries,
After immersing used lithium ion batteries in water in which alkaline earth metal hydroxide is dissolved or suspended, the batteries are pre-roasted at a temperature of 400 ° C. or lower, the batteries are disassembled, and the product is A first step of separating with a sieve a bulk product containing at least one selected from copper, aluminum, and iron, and a powdered product containing positive and negative active materials;
After the powdery product obtained in the first step is oxidized and roasted at a temperature of 400 ° C. or higher, the second step is further reduced and roasted at a temperature of 400 to 750 ° C. in a reducing gas stream.
The reduced roasted product obtained in the second step is immersed in water or an aqueous solution in which an alkaline earth metal hydroxide is suspended, and then the lithium content is recovered from the filtrate obtained by filtration. 3 steps,
After the residue of filtration in the third step is suspended and dispersed in water, the suspension is recovered by magnetically separating metal cobalt and / or metal nickel by magnetic separation, while manganese and A fourth step of recovering at least one selected from iron oxides and hydroxides and other non-magnetic materials as non-magnetic deposits;
The present invention relates to a method for separating and recovering valuable materials of used lithium ion batteries.

According to the separation and recovery method of the present invention, valuable materials such as copper, aluminum, cobalt, nickel, manganese, and lithium can be safely separated from those in which lithium ion batteries of various types of positive electrode active materials are mixed. And it can be easily separated and collected.
Further, according to the method of the present invention, since no expensive chemicals are used, the separation and collection cost is low, and in addition, the separation and collection equipment is simple and can be easily enlarged.

FIG. 1 is a flowchart showing an example of a specific procedure of a method for separating and recovering valuable materials of lithium ion batteries of the present invention.

Hereinafter, the present invention will be described in detail.
In the present invention, first, the batteries are configured by pre-roasting lithium ion batteries in which the positive electrode active material is a cobalt-based, nickel-based, manganese-based, iron phosphate-based, or the like. The organic substances are decomposed and burned, and removed from the system. The pre-roasted product is divided into a powdered product composed of the active material of the positive electrode and the negative electrode and a bulk product composed of a battery lid, a current collector, and the like by a sieve after disassembling the batteries. Collect aluminum, iron, etc. (First step)
The obtained powdery product is preferably mixed with an alkaline earth metal hydroxide and then roasted in a stream of moisture-containing oxidizing gas (hereinafter referred to as “oxidative roasting”) to form a negative electrode After burning the graphite of the material and the unburned portion remaining in the preliminary roasting, it is further roasted in an atmosphere of a reducing gas (hereinafter referred to as “reducing roasting”). (Second step)
The reduced roasted product thus obtained was immersed in an aqueous solution in which water or an alkaline earth metal hydroxide was suspended, and the lithium contained therein was converted into lithium hydroxide and dissolved in the aqueous solution. Thereafter, it is filtered and the lithium content is recovered from the filtrate, preferably as lithium carbonate. (Third step)
One filtration residue collects metallic cobalt and metallic nickel as magnetic deposits by magnetic separation, and collects oxides and hydroxides such as manganese and iron as non-magnetic deposits. (4th process)
The present invention focuses on the physicochemical characteristics of various materials constituting the lithium ion batteries, and makes the best use of the differences to separate and collect valuable materials.

In the “used lithium ion batteries” in the present invention, the positive electrode active materials are LiCoO ₂ , LiNiO ₂ , Li (Co · Ni) O ₂ , Li (Co · Ni · Mn) O ₂ , Li (Ni · Mn). ) ₁ of a rock salt type crystal structure such as O _2, a spinel type crystal structure such as LiMn ₂ O ₄ , Li (Mn · Ni) ₂ O ₄ , and an olivine type crystal structure such as LiFePO ₄ It is a state where two or more species are mixed. In the “used lithium ion batteries” in the present invention, the kind of material of the negative electrode active material is not particularly limited, but also includes defective products generated in the process of manufacturing the lithium ion batteries. About the defective article which generate | occur | produces in the manufacturing process of lithium ion batteries, it is also possible to collect | recover by incorporating in the middle of the collection | recovery flow in this invention according to the stage which generate | occur | produces.

[First step]
In the first step of the separation and recovery method of the present invention, used lithium ion batteries are pre-roasted at a temperature of 400 ° C. or lower after being immersed in water in which an alkaline earth metal hydroxide is dissolved or suspended. The battery is disassembled and the product is separated with a sieve into a bulk product containing at least one selected from copper, aluminum, and iron and a powder product containing positive and negative electrode active materials.

(Water immersion)
In the method of the present invention, first, the used batteries are immersed in water in which an alkaline earth metal hydroxide is dissolved or suspended to discharge electricity remaining in the batteries. The safety and stability of the recovery operation of valuable materials by this method is ensured.
In particular, in the method of the present invention, as the immersion water, an appropriate amount of alkaline earth metal hydroxide such as Ca (OH) ₂ or Mg (OH) ₂ previously dissolved or suspended in water is used. The reason is that it is necessary to shorten discharge time by increasing the electric conductivity of the immersion water and to remove harmful substances such as fluorine and phosphorus contained in the batteries.

That is, when LiPF _{6 of} the electrolyte constituting the batteries comes into contact with water, HF and LiH ₂ PO ₄ that are readily soluble in water are generated, and these further react with Ca (OH) ₂ or Mg (OH) _2. This is because CaF ₂ or MgF ₂ and Ca ₃ (PO ₄ ) ₂ or Mg ₃ (PO ₄ ) ₂ , which hardly dissolve in water, become a solid compound of fluorine and phosphorus.
In this way, since the solid compound of fluorine and phosphorus is suspended in the immersion water, if the water is removed after immersion in water, LiPF ₆ that decomposes at low temperatures can be safely and easily removed from the batteries in advance. It can be removed.
In this step, for example, it is desirable to perforate a battery case of a used battery or the like in advance so that when the battery is immersed in water, the water easily penetrates into the battery.

(Preliminary roasting)
Subsequently, batteries immersed in water are pre-roasted at a temperature of 400 ° C. or lower, and organic substances such as polyethylene and N-methylpyrrolidone in the batteries that are thermally decomposed at a relatively low temperature are gasified and combusted. And remove it outside the system.
In this preliminary roasting, a large amount of organic substances are decomposed and burned, so that the environmental atmosphere surrounding the batteries being roasted is locally rich in H ₂ , CO and C, and the roasting temperature is 400. If the temperature exceeds ℃, the reduction of cobalt salt and nickel constituting the positive electrode active materials such as LiCoO ₂ and LiNiO ₂ will start and the possibility of decomposition of the rock salt type crystals increases. In that case, one lithium becomes LiOH or Li ₂ O, which is combined with fluorine or phosphorus remaining in the organic substance to produce LiF or Li ₃ PO _4, and the recovery rate of lithium in the subsequent process is lowered. This is not preferable.
Therefore, in the method of the present invention, the preliminary roasting temperature is limited to a range where the upper limit is 400 ° C. at which cobalt or nickel is hardly reduced, and is preferably 300 to 350 ° C.

In this way, organic substances that decompose at a high temperature exceeding 400 ° C. and contain harmful substances, such as polyvinylidene fluoride used as a binder for positive and negative electrodes of batteries, remain in the batteries. However, most of the organic substances can be removed out of the system with almost no loss of lithium.
In the method of the present invention, an organic substance such as polyvinylidene fluoride that does not decompose at the preliminary roasting temperature can be treated in a subsequent step.
Further, the atmosphere at the time of this preliminary roasting is preferably oxidizing but is not particularly limited in the present invention.

(Disassembly of batteries)
Disassembly of used lithium ion batteries after pre-roasting can be performed using a crushing facility including a crusher so that the particle size after disassembly does not become excessively fine and is about 50 mm or less. The battery case and the inside thereof are preferably separated. If it is the above crushing facilities, there will be no restriction | limiting in particular about the kind of crusher, What kind of thing can be used.

(Sieving)
The dismantled product after preliminary roasting obtained in this way is made into a lump product containing copper, aluminum, iron and a powdery product containing positive and negative active materials using a sieve such as a vibrating sieve or a rotary sieve. Sorted. That is, lump products such as copper foil, aluminum foil, and iron pieces constituting the battery case and current collector are used as sieve products on the sieve mesh, and active materials constituting the positive and negative electrodes are used as sieve products. Separate each under the sieve mesh.
In this case, the mesh opening of the sieve is preferably about 2.0 mm or less from the viewpoint of subsequent handling, but is not particularly limited in the present invention.
The sieved product taken out here can be collected separately for each material as copper, aluminum, iron, etc. by a known sorting operation such as specific gravity sorting or magnetic force sorting.

[Second step]
In the second step of the present invention, the powdery product obtained in the first step is oxidized and roasted at a temperature of 400 ° C. or higher, and further reduced and roasted at a temperature of 400 to 750 ° C. in a reducing gas stream. It is a process to do.
That is, the powdery product that is an unsieved product by sieving is mainly composed of a lithium composite oxide such as cobalt, nickel, manganese, and iron phosphate as a positive electrode active material and graphite as a negative electrode active material. In addition, organic substances and burners that were not decomposed by the preliminary roasting in the first step are also included, and the volume of these organic substances, burners, and carbon-based substances such as graphite is lithium composite oxide. Therefore, the presence of these substances becomes extremely inconvenient when recovering valuable materials in the lithium composite oxide in the subsequent steps.

(Oxidation roasting)
Therefore, in the present invention, the powdery product is oxidized and roasted at a temperature of 400 ° C. or higher. In this case, the oxidation roasting is performed by adding and mixing an appropriate amount of an alkaline earth metal hydroxide such as Ca (OH) ₂ and Mg (OH) _{2 to} the above powdered product, etc. It is preferable to carry out at a temperature of 400 ° C. or higher in an oxidizing gas stream.
Here, the reason for using the alkaline earth metal hydroxide and the oxidizing gas containing moisture is to preserve the working environment and prevent pollution by making fluorine and phosphorus produced by oxidation roasting into solid compounds. Because. Moreover, there is no restriction | limiting in particular in the range with the said effect about the flow volume of the airflow of the oxidizing gas containing a water | moisture content.

In oxidation roasting, combustion of the debris generated in the previous pre-roasting and decomposition and combustion of organic substances not decomposed by pre-roasting occur at a temperature of 400 ° C. or higher. At that time, harmful fluorine substances contained in polyvinylidene fluoride and the like are generated. In the method of the present invention, they can be reacted with moisture and hydroxides of alkaline earth metals to form CaF ₂ or MgF ₂ that is hardly soluble in water and solidified to prevent release into the atmosphere.

In the method of the present invention, by performing oxidation roasting at a temperature of 400 ° C. or higher, graphite is further combusted, and at the same time, the crystals of the iron phosphate-based lithium composite oxide can be decomposed. In particular, by setting the temperature to 500 ° C. or higher, it is preferable that graphite burns easily, and crystals of the iron phosphate-based lithium composite oxide can be easily decomposed. Further, at that time, harmful phosphorus compounds are formed, which, like the above-mentioned fluorine, react with moisture and hydroxides of alkaline earth metals to form Ca ₃ (PO ₄ ) ₂ and It becomes a solid compound hardly soluble in water such as CaHPO ₄ or Mg ₃ (PO ₄ ) ₂ and MgHPO _4, and has the effect of preventing the release of harmful substances into the atmosphere.

The above various chemical reactions are preferably carried out at a high temperature in terms of reaction rate, but the upper limit temperature of oxidation roasting in this case can be arbitrarily determined in consideration of the equipment specifications and economics. Since it can do, it is not specifically limited in the method of this invention.
The amount of the alkaline earth metal hydroxide added to and mixed with the powdery product in the method of the present invention is the chemical amount when fluorine or phosphorus contained in the powdery product reacts with the alkaline earth metal. It is sufficient that the amount is equal to or more than the amount that satisfies the equivalent, and even if it is excessive, there is no problem in the subsequent process.
In addition, the amount of water added to the oxidizing gas used for the oxidizing roasting atmosphere gas is such that the fluorine or phosphorus contained in the powdery product is more than the chemical equivalent amount to hydrogen fluoride or phosphoric acid. The addition method may be a method of spraying water separately from the oxidizing gas ventilated in the oxidation roasting furnace.

(Reduction roasting)
Subsequently, the oxidized roasted product is subjected to reduction roasting at a temperature of 400 ° C. to 750 ° C. in a reducing gas atmosphere.
The purpose of this reduction roasting is to reduce cobalt and nickel contained in the powdered product to metal, and manganese and iron to divalent to trivalent oxides (MnO, Mn ₃ O ₄ , FeO 2), Accordingly, the crystal structure of the rock salt type and spinel type lithium composite oxide is decomposed to react lithium with Li ₂ O, LiOH, or Li ₂ CO ₃ .

  As the type of reducing gas used for the reduction roasting, any one of hydrogen, carbon monoxide, hydrocarbon and ammonia can be used as long as it is a mixed gas of two or more. Particularly, hydrogen and / or Or ammonia is preferred. The reason is that in the case of hydrogen or ammonia, the reducing power is stronger than other carbon-based gases, so the temperature of reduction roasting can be lowered, and the time required for reduction can also be shortened. Because. In the case of carbon monoxide and hydrocarbon gases, metallic cobalt and metallic nickel produced by reductive roasting may act as a catalyst for inducing the carbon solution reaction, and fine carbon particles may be deposited. However, in the method of the present invention, the generated carbon can be treated without any problem in the subsequent steps, and therefore, in the present invention, the above carbon-based gas can also be used.

The reason why the reduction roasting temperature is defined in the range of 400 ° C. to 750 ° C. in the present invention depends on the type of reducing gas used in the method of the present invention, and the reduction start temperature of lithium composite oxide and the generation This is because the types of lithium compounds are different.
That is, when the reducing gas is hydrogen, the reduction starts from about 400 ° C., and the products are Li ₂ O and LiOH, but when carbon monoxide is used, the reduction starts from about 600 ° C. The product is Li ₂ CO ₃ , and the melting points of Li ₂ O, LiOH, and Li ₂ CO ₃ of these products are 1700 ° C., 450 ° C., and 750 ° C., respectively, and the temperature at which the reduction is performed is higher than the melting point. Then, the roasted product is partially liquefied and hinders the progress of the reduction reaction.

Also, one of the metallic cobalt and metallic nickel produced by this reduction reaction is in the form of a very fine powder and therefore has a very high activity. Such highly active metal powder easily oxidizes in the presence of oxygen even at room temperature, and metal cobalt and metal nickel obtained by reductive roasting may easily become oxides after generation. In this case, the ferromagnetic properties of the metal cobalt and nickel may be lost, and magnetic force selection in the subsequent process may not be possible.
Therefore, in carrying out the method of the present invention, it is preferable that the obtained roasted product is cooled and held in an inert gas environment such as nitrogen or argon when the reduction roasting is completed.

[Third step]
The third step in the method of the present invention is obtained by immersing the reduced roasted product obtained in the second step in an aqueous solution in which water or an alkaline earth metal hydroxide is suspended, followed by filtration. In this step, the lithium content is recovered from the filtrate.
(Hydroxylation reaction)
The reduced roasted product obtained in the second step is immersed in water or an aqueous solution in which an appropriate amount of a hydroxide of an alkaline earth metal such as Ca (OH) ₂ or Mg (OH) ₂ is suspended. Then, Li ₂ CO ₃ contained in the reduced roasted product or an aqueous solution in which water or an alkaline earth metal hydroxide is suspended is changed to LiOH having higher solubility in water, and then it is added to the above water or aqueous solution. Dissolve in
In this case, if the lithium content in the reduced roasted product is LiOH in its entirety, a simple water is sufficient, but if a part or much of the lithium content is Li ₂ CO ₃ , the alkaline earth metal water An aqueous solution in which the oxide is suspended is used.

The reason for limiting the alkaline substance that changes Li ₂ CO ₃ to LiOH by this hydroxylation reaction to hydroxides of alkaline earth metals such as Ca (OH) ₂ and Mg (OH) ₂ is that by-product CaCO ₃ and Since MgCO ₃ hardly dissolves in water, it can be easily separated from LiOH dissolved in an aqueous solution by filtration. In the case of NaOH or KOH, which is an alkali metal hydroxide, it is soluble in water. This is because Na ₂ CO ₃ and K ₂ CO ₃ of this form are formed as a by-product and cannot be separated by filtration.
In this hydroxylation reaction, some of the oxides of divalent or trivalent manganese and iron produced by the reduction roasting in the second step react with Ca (OH) ₂ or Mg (OH) _2. Thus, Mn (OH) ₂ and Fe (OH) ₂ are obtained, but these products are hardly soluble in water, so that there is no problem in the subsequent filtration operation.

When the positive electrode active material is an iron phosphate-based material, the phosphorus content contained therein reacts with a suspended aqueous solution such as Ca (OH) ₂ or Mg (OH) ₂ and is hardly soluble in water. , Ca ₃ (PO ₄ ) ₂ or CaHPO ₄ , Mg ₃ (PO ₄ ) ₂ or MgHPO ₄ , this can also be transferred to the residue side during filtration, which can be a problem in the subsequent process Absent.
Furthermore, when the reduced roasted product contains a fluorine component, it similarly changes to CaF ₂ or MgF ₂ which hardly dissolves in water, so that it can be moved to the residue side during filtration.
Therefore, the amount of the alkaline earth metal hydroxide used in the hydroxylation reaction may be an amount satisfying the chemical equivalents related to the various chemical reactions.
Thus, if the aqueous solution is filtered, high purity LiOH can be transferred to the filtrate side, and when recovering lithium from the filtrate, when recovering lithium as LiOH, The water may be simply evaporated as it is, and the carbonation reaction in the next step can be omitted.

(Carbonation reaction)
In the fractional collection method of the present invention, carbon dioxide gas is blown into the filtrate obtained by the hydroxylation reaction, and LiOH obtained by the hydroxylation reaction is converted to Li ₂ CO ₃ having a solubility in water smaller than that of LiOH. If it is filtered again after analysis, high purity Li ₂ CO ₃ can be recovered as the residue.
In this filtrate, a maximum of about 1.3% by mass of Li ₂ CO ₃ is dissolved and remains. Therefore, the water in the filtrate is evaporated to recover Li ₂ CO ₃ in the filtrate, If the filtrate is recycled and used as part of the water in the hydroxylation reaction in the previous step, the lithium recovery rate will be extremely high.
Further, this carbonation reaction can be performed by using carbonate such as sodium carbonate in addition to carbon dioxide gas. In this case, Na content or the like may remain as impurities in the Li ₂ CO _{3 to be} recovered. Therefore, it is preferable to use carbon dioxide gas in the method of the present invention.

[Fourth process]
In the fourth step of the method of the present invention, after the residue of the filtration in the third step is suspended and dispersed in water, the suspension is magnetically separated to magnetically deposit metallic cobalt and / or metallic nickel. On the other hand, at least one selected from oxides and hydroxides of manganese and iron, and other non-magnetic materials is recovered as a non-magnetized material.

(Suspension treatment)
Water is added to the filtration residue obtained by the filtration operation after the hydroxylation reaction, and suspended and dispersed to prepare a suspension having an appropriate concentration.
In this case, the suspension is prepared by using an appropriate pulverizer and a dispersing agent so that impurities made of metal cobalt and / or metal nickel are not involved in the magnetic separation in the next step. desirable.

(Magnetic sorting)
The suspension is subjected to a magnetic separator, and a magnetic material selected from ferromagnetic metallic cobalt and metallic nickel is magnetically deposited, such as manganese and iron oxides and hydroxides, and alkaline earth metal compounds and impurities. Separated and recovered as other non-magnetic products.
Magnetic selection in the method of the present invention can be easily performed by using a permanent magnet such as a general ferrite magnet or alnico magnet, or an electric magnet.

Thus, the obtained mixture of high-purity metallic cobalt and metallic nickel can separate cobalt and nickel by methods such as known acid dissolution methods and solvent extraction methods, and can further increase the purity.
In addition, nonmagnetic materials such as manganese and iron oxides and hydroxides are likely to be effective raw materials in other fields.

  EXAMPLES Hereinafter, although a reference example and an Example demonstrate this invention concretely, this invention is not limited to the following examples.

[Reference Example 1] <Recovery of lithium and cobalt from LiCoO ₂ reagent>
Using the reagent LiCoO ₂ , the steps after “reduction roasting” in the fractional recovery method of the present invention were carried out to separate and recover lithium and cobalt.
Table 1 shows the chemical composition of the LiCoO ₂ reagent used here.

First, 100.0 g of the above LiCoO ₂ reagent is placed in a stainless steel dish and left in an externally heated tubular furnace (stainless steel furnace core tube) having a sufficient soaking area, and hydrogen is 2 liters / min. It was reduced and roasted at 500 ° C. for 90 minutes in an air stream, and then cooled to room temperature in a nitrogen atmosphere to obtain 81.2 g of a lightly sintered product.
As a result of examining the composition by X-ray diffraction, it was confirmed that cobalt was completely reduced to metal Co, and lithium was changed to LiOH and Li ₂ O.

Subsequently, the entire amount of the product was immersed in 400 ml of water and sufficiently stirred. Carbon dioxide was blown into the filtrate obtained by filtering it at a flow rate of 1 liter / min for 20 minutes, followed by drying by heating. As a result, 26.9 g of Li ₂ CO ₃ having a purity of 99.6% was recovered. In this case, the recovery rate of lithium was 72%.
In addition, 500 ml of water is added to one of the filtration residues after the reduction roasting, and the suspension is stirred by an ultrasonic crusher, and then magnetically separated by a ferrite magnet. Was solidified and 59.4 g of a dried product was obtained.
The magnetized product was confirmed to be metallic cobalt by X-ray analysis, and its purity was 98.5%. In this case, the recovery rate of cobalt was 98%.
Furthermore, 500 ml of water was added to 50.0 g of this dried magnetically adsorbed product to suspend it, and then filtered again. The residue was dried and the purity of cobalt was measured. As a result, the quality was 99.85. %Met.

[Reference Example 2] <Recovery of Lithium, Cobalt, Nickel and Manganese from Li (Co / Ni / Mn) O ₂ Reagent>
Using the reagent Li (Co · Ni · Mn) O ₂ , the steps after “reduction roasting” were carried out in the same manner as in Reference Example 1 to separate and recover lithium and cobalt, nickel and manganese. .
Table 2 shows the chemical composition of the Li (Co • Ni • Mn) O ₂ reagent used here.

First, 100.0 g of the Li (Co / Ni / Mn) O ₂ reagent was reduced and roasted at 680 ° C. for 150 minutes in a 2 liter / min flow of carbon monoxide in the tubular furnace, and then cooled to room temperature in a nitrogen atmosphere. did.
As a result, 107.8 g was obtained in a state where the upper layer portion of the product was covered with black powder and the product itself was not sintered at all.
As a result of examining each form by X-ray diffraction, lithium changed to Li ₂ CO ₃ , cobalt changed to Co, nickel changed to Ni, manganese changed to Mn ₂ O ₃ , and the rock salt type crystal structure was completely Disassembled. The black powder was graphite precipitated by the carbon solution reaction.

Subsequently, the entire amount of the roasted product was immersed in a solution in which 70 g of slaked lime reagent was suspended in 1 liter of water, and a hydroxylation reaction was performed by stirring for 30 minutes.
The suspension after the reaction was filtered, and carbonation gas was blown into the filtrate at a flow rate of 1 liter / min for 20 minutes to perform a carbonation reaction, and then the filtrate was heated and dried to have a purity of 99.1%. 26.1 g of Li ₂ CO ₃ was recovered.
In this case, the recovery rate of lithium was 69%.
On the other hand, after adding 1 liter of water to the filtration residue after the reduction roasting and making it into a suspension with a rotary crusher, magnetic selection was carried out using an alnico magnet to recover 40.8 g of a dried product of magnetized material. .
Table 3 shows the chemical composition of the magnetic deposit.

In this case, the recovery rates of cobalt and nickel were both 99%.
Moreover, the suspension which was not magnetized by the magnetic separation was filtered, the residue was recovered, and 117.0 g was obtained as a dried product.
Table 4 shows the chemical composition of the residue.

この場合のマンガンの回収率は、９８％であった。

In this case, the recovery rate of manganese was 98%.

[Reference Example 3] <Recovery of lithium and manganese from LiMn ₂ O ₄ reagent>
Using the reagent LiMn ₂ O ₄ , the steps after “reduction roasting” were carried out in the same manner as in Reference Example 1 to separate and recover lithium and manganese.
Table 5 shows the chemical composition of the LiMn ₂ O ₄ reagent used here.

First, 100.0 g of the LiMn ₂ O ₄ reagent was reduced and roasted at 650 ° C. for 120 minutes in a 1 liter / min hydrogen stream in the tubular furnace, and then cooled to room temperature in a nitrogen atmosphere.
As a result, 87.5 g of a roasted product in a slightly sintered state was obtained.
As a result of X-ray diffraction, manganese was changed to Mn ₂ O ₃ and MnO, and the spinel crystal structure was completely decomposed.
To this baked product, 500 ml of water was added and stirred for 30 minutes to completely dissolve LiOH, followed by filtration.

Subsequently, the filtrate was heated to evaporate water, and 7.1 g of LiOH having a purity of 99.6% was recovered. In this case, the recovery rate of lithium was 54%. One filtration residue was dried as it was to obtain 84.5 g.
Table 6 shows the chemical composition of the dried product.

In this case, the recovery rate of manganese was 98%.
[Reference Example 4] <Recovery of lithium and iron from LiFePO ₄ reagent>
Using the reagent LiFePO ₄ , the steps after “oxidation roasting” in the method of the present invention were carried out to separate and recover lithium and iron.
Table 7 shows the chemical composition of the LiFePO ₄ reagent used here.

First, 100.0 g of the above LiFePO ₄ reagent was mixed with 70.0 g of Ca (OH) ₂ and oxidized and roasted at 700 ° C. for 90 minutes in an air stream of 2 liters / min in which the hot water phase was passed through the tubular furnace. 175.1 g of the product was obtained.
This oxidized roasted product was confirmed to be CaHPO ₄ and Fe ₂ O ₃ by X-ray diffraction, and it was found that the olivine type crystal structure was completely decomposed.
From this, it can be inferred that this oxidation roasting caused the following chemical reaction with air, water, and Ca (OH) ₂ .
12LiFePO ₄ + 3O ₂ → 4Li ₃ Fe ₂ (PO ₄ ) ₃ + 2Fe ₂ O ₃
Li ₃ Fe ₂ (PO ₄ ) ₃ + 6H ₂ O → 3LiOH + Fe ₂ O ₃ + 3H ₃ PO ₄
H ₃ PO ₄ + Ca (OH) ₂ → CaHPO ₄ + 2H ₂ O

Subsequently, the whole amount was reduced and roasted at 650 ° C. for 60 minutes in an air stream of 1 liter / min of hydrogen to obtain 169.1 g of the product.
In the X-ray diffraction, no change was observed in CaHPO ₄ and only Fe ₂ O ₃ was changed to FeO.

Next, the reduced roasted product is immersed in a solution obtained by suspending 20.0 g of a Ca (OH) ₂ reagent in 1 liter of water, and stirred for 30 minutes to carry out a hydroxylation reaction. The turbid solution was filtered.
Carbonate gas was blown into the filtrate at a flow rate of 1 liter / min for 20 minutes to carry out a carbonation reaction, followed by heating and drying to obtain 13.8 g of Li ₂ CO ₃ having a purity of 98.3%.
The lithium recovery rate at this time was 60%.
On the other hand, after adding 1 liter of water to the filtration residue after the above hydroxylation reaction and sufficiently stirring to make a suspension, magnetic separation is performed using an alnico magnet to confirm that there is no magnetic deposit, and the suspension The liquid was filtered again and the solid content was recovered to obtain 180.9 g of a dried product.
Table 8 shows the chemical composition of the dried product.

この場合の鉄の回収率は９７％であった。

In this case, the iron recovery rate was 97%.

[Example 1] <Recovery of valuable materials from used batteries>
[First step]
[Water immersion]
After 100.0 kg of used lithium-ion battery mainly used in mobile phones and personal computers is immersed in water in which some Ca (OH) ₂ is suspended for about 2 days, the electricity remaining in the battery is discharged. The sample was thoroughly drained and used as a sample for this experiment.
[Preliminary roasting]
The used battery after water immersion was heated for 5 hours at 300 to 350 ° C. in an open type rotary electric heating furnace, and pre-baked.
The weight of the battery after the preliminary roasting was 69.6 kg (weight loss rate: 30.4%).

[Battery dismantling]
The entire amount of the pre-roasted battery was disassembled with a batch-type shredder facility.
[Sieving of dismantled products]
Table 9 shows the result of sieving the dismantled product with a vibrating sieve (mesh opening: 1 mm). Of these, the +1 mm product is taken out of the system as a mixture of metals such as iron, copper, and aluminum, and is -1 mm. The product was transferred to the subsequent second step.

  The chemical composition of the -1 mm product is shown in Table 10, among which Fe, Al, and Cu are metal powders mixed during battery disassembly, and P and F are P and F in organic materials. Is the amount remaining in the battery without moving to the water side in the water immersion step.

[Second step]
[Oxidation roasting]
-1 mm under sieve product 30.0 kg mixed with 3.0 kg of Ca (OH) ₂ and rolled with air containing moderate moisture while rolling in an open type rotary roasting furnace. 6Hr roasting was performed at a temperature range of 550 to 600 ° C. to obtain 20.8 kg of oxidized roasted product.
The chemical composition of the oxidized roasted product is shown in Table 11. From this result, it can be seen that most of C is burned and removed.

[Reduction roasting]
Subsequently, 20.0 kg of the oxidized roasted product is roasted at 500 ° C. in a H ₂ stream for 6 hours in a closed type electric heating furnace, then cooled to room temperature in a N ₂ stream and reduced. 16.3 kg of roasted product was obtained.
Table 12 shows the chemical composition of the reduced roasted product.

[Third step]
[Hydroxylation reaction]
80 liters of water was added to 10.0 kg of the reduced roasted product and stirred, followed by filtration to separate a filtrate (first filtrate) and a residue (first residue).
Further, 40 liters of water was added to the residue and stirred, and then filtered again to divide it into a filtrate (second filtrate) and a residue (second residue).
Here, the 1st filtrate and the 2nd filtrate were mixed, and it was set as the filtrate in this hydroxylation reaction process.

[Carbonation reaction]
Carbon dioxide gas was blown into the filtrate obtained by the above hydroxylation reaction at 10 liter / min for 120 minutes, and then the filtrate was heated to evaporate water and recover 2.67 kg of Li ₂ CO ₃ having a purity of 98.9%. did.
In this case, the recovery rate of lithium was 87% on the basis of the reduced roasted product.

[Fourth process]
[Suspension treatment]
60 liters of water was added to the second filtration residue after the hydroxylation reaction, and the residue was crushed with a batch type wet ball mill to prepare a suspension.

[Magnetic sorting]
The suspension was subjected to magnetic separation with a magnetic separator having a magnetic flux density of 2000 Gauss while further watering to obtain 4.75 kg of a dried product of the magnetic deposit.
The chemical composition is shown in Table 13.

尚、この場合のコバルト及びニッケルの回収率は、還元焙焼品基準でそれぞれ９３％と９５％であった。

In this case, the recoveries of cobalt and nickel were 93% and 95%, respectively, on a reduced roasted product basis.

[Non-magnetic deposit filtration]
The suspension of non-magnetized material in the magnetic separation was filtered again, and the residue was recovered and dried to obtain 3.80 kg of dried non-magnetized material.
The chemical composition is shown in Table 14.

  As is clear from this result, harmful phosphorus and fluorine become a compound with calcium and remain in the non-magnetized material.

Claims (4)

In a method of separating and collecting valuable materials from used lithium ion batteries,
After immersing used lithium ion batteries in water in which alkaline earth metal hydroxide is dissolved or suspended, the batteries are pre-roasted at a temperature of 400 ° C. or lower, the batteries are disassembled, and the product is A first step of separating with a sieve a bulk product containing at least one selected from copper, aluminum, and iron, and a powdered product containing positive and negative active materials;
After the powdery product obtained in the first step is oxidized and roasted at a temperature of 400 ° C. or higher, the second step is further reduced and roasted at a temperature of 400 to 750 ° C. in a reducing gas stream.
The reduced roasted product obtained in the second step is immersed in an aqueous solution in which water or a hydroxide of an alkaline earth metal is suspended, and then the lithium content is recovered from the filtrate obtained by filtration. 3 steps,
After the residue of filtration in the third step is suspended and dispersed in water, the suspension is recovered by magnetically separating metal cobalt and / or metal nickel by magnetic separation, while manganese and A fourth step of recovering at least one selected from iron oxides and hydroxides and other non-magnetic materials as non-magnetic deposits;
A method for separating and recovering valuable materials of used lithium ion batteries, comprising:   The fraction collection method according to claim 1, wherein in the third step, carbon dioxide gas is reacted with the filtrate after filtration to recover a lithium content as lithium carbonate.   3. The oxidation roasting in the second step is performed by adding an alkaline earth metal hydroxide to a powdered product and mixing at a temperature of 400 ° C. or higher in a stream of oxidizing gas containing moisture. 4. Separation collection method.   The fractionated recovery method according to any one of claims 1 to 3, wherein the reducing gas in the reduction roasting in the second step is at least one selected from hydrogen, carbon monoxide, hydrocarbons and ammonia.

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