KR102536541B1 - Recovery method of nickel, positive material and secondary battery comprising the same - Google Patents

Abstract

A method for recovering nickel capable of recovering high-purity nickel at a high recovery rate is provided. One embodiment of the present invention is a method for recovering nickel using an electrolytic extraction device including an anode, a cathode spaced apart from the anode, and an electrolyte in which the anode and the cathode are immersed, (S1) containing nickel and a first impurity. obtaining a second impurity electrodeposited on the negative electrode and a second waste liquid not electrodeposited on the negative electrode by electrolyzing the first waste liquid to be deposited on the negative electrode; and (S2) adding aqueous ammonia to the second waste liquid to obtain a nickel sulfate-based compound, wherein the electrolyte solution includes the first waste liquid.

Description

Nickel recovery method, cathode material and secondary battery including the same

The present invention relates to a method for recovering nickel, and more particularly, to a method for recovering nickel, a positive electrode material containing nickel recovered therefrom, and a secondary battery including the same.

Nickel has recently been used in a larger amount than in the past as a cathode material for automobile secondary batteries, but most of them are dependent on foreign imports. In particular, due to the mutual relationship between the US and China, it is difficult to use nickel produced in China in order to enter the US automobile market, and various companies are making efforts to recover nickel resources through recycling. However, the recycling technology of nickel raw materials generated in most urban mines is limited to recovering through expensive solvent extraction processes after separating low-grade raw materials through dry/wet separation and leaching, and the production cost is high through various processes. There was a problem.

Therefore, it is necessary to find a way to efficiently recycle nickel from nickel-containing waste liquid compared to the prior art. In addition, as the proportion of nickel used as a raw material for cathode materials for secondary batteries gradually increases, the demand for nickel is rapidly increasing.

On the other hand, Korean Patent Registration No. 10-1467356 discloses "a method for recovering nickel from electroless nickel plating waste liquid". A separation and recovery method is disclosed. This method has a disadvantage in that the operation time is long and the production cost is high because the pH control and the adsorption and regeneration of the ion exchange resin must be repeated several times.

In addition, in Korean Patent Registration No. 10-2266892, "Method for recovering nickel sulfate from nickel-containing waste", pH is adjusted after leaching by adding sulfuric acid, and nickel hydroxide is added by adding a fluorine-based compound and then adding a pH adjusting agent. A method including several wet steps (step 8) of preparing and re-dissolving it in sulfuric acid is disclosed, but this process is also complicated and may cause environmental pollution by using a hydrogen fluoride-based compound. In addition, there is a disadvantage in that the production cost is high by using the evaporation concentration process.

In another Korean Patent Registration No. 10-1358961, "Method for producing high-purity nickel sulfate using continuous cooling crystallization", a method of removing impurities from an aqueous nickel sulfate solution through solvent extraction and recovering nickel through cooling crystallization through supersaturation is disclosed. has been initiated. This method also has a disadvantage in that the production cost is high because the solvent extraction process is performed, and the production cost is high due to the cooling crystal.

An object of the present invention is to provide a method for recovering nickel that can simultaneously increase the purity and recovery rate of nickel.

Another object of the present invention is to provide an economical nickel recovery method capable of reducing the process cost by simplifying the process.

Another object of the present invention is to provide a method for recovering nickel capable of reducing the amount of process waste and reducing the amount of chemicals used.

Another object of the present invention is to provide a cathode material containing nickel recovered by the nickel recovery method.

Another object of the present invention is to provide a secondary battery including the positive electrode material.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations indicated in the claims.

One embodiment of the present invention for achieving the above object is a method for recovering nickel using an electrolytic extraction device including an anode, a cathode spaced apart from the anode, and an electrolyte in which the anode and the cathode are immersed, (S1) nickel and electrolyzing the first waste liquid containing the first impurity to obtain a second impurity deposited on the negative electrode and a second waste liquid not deposited on the negative electrode. and (S2) adding aqueous ammonia to the second waste liquid to obtain a nickel sulfate-based compound, wherein the electrolyte solution includes the first waste liquid.

Specifically, the anode may include a body portion and a coating layer disposed on the body portion.

Specifically, the body portion may include at least one of titanium (Ti), nickel (Ni), and stainless steel, and the coating layer may include iridium (Ir), ruthenium (Ru), and platinum (Pt). ) may include at least one or more of them.

Specifically, the first impurity may include at least one of iron (Fe), copper (Cu), aluminum (Al), cobalt (Co), tin (Sn), antimony (Sb), and chromium (Cr). .

Specifically, the second impurity may include at least one of copper (Cu), aluminum (Al), tin (Sn), antimony (Sb), and chromium (Cr).

Specifically, the electrolytic extraction device may be operated under current conditions of 1.32 to 1.85 A·hr/g and power conditions of 1.30 to 2.50 kWh.

According to another embodiment of the present invention, the content of the ammonia water may be 1.0 to 1.3 equivalent ratio compared to the nickel.

Specifically, the nickel sulfate-based compound may be any one selected from the group consisting of nickel sulfate, nickel ammonium sulfate, and combinations thereof.

Another embodiment of the present invention for achieving the above object provides a cathode material containing nickel recovered by a nickel recovery method.

Another embodiment of the present invention for achieving the above object provides a secondary battery including the positive electrode material.

The solution to the above problems does not enumerate all the features of the present invention. Various features of the present invention and the advantages and effects thereof will be understood in more detail with reference to the following specific examples.

According to one aspect of the present invention, a method of economically recovering nickel in the form of a compound from waste liquid containing impurities can be implemented. Through this, it is possible to reduce the amount of waste liquid discharged from the process and the amount of chemicals used, as well as to provide the effect of lowering the treatment cost by simplifying the process.

In addition to the above effects, specific effects of the present invention will be described together while explaining specific details for carrying out the present invention.

1 is an electrolytic extraction device used in a method for recovering nickel according to an embodiment of the present invention.
2 is a method for recovering nickel nickel according to another embodiment of the present invention.

Embodiments of the present invention to be described below are provided to more clearly explain the present invention to those skilled in the art, and the scope of the present invention is not limited by the following examples, Embodiments may be modified in many different forms.

In this specification, a range of values expressed using the term 'to' indicates a range of numbers including the values described before and after the term as the lower limit value and the upper limit value, respectively.

Terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. Terms in the singular form used herein may include plural forms unless the context clearly indicates otherwise. Also, as used herein, the terms "comprise" and/or "comprising" specify the presence of the stated shape, step, number, operation, member, element, and/or group thereof. and does not exclude the presence or addition of one or more other shapes, steps, numbers, operations, elements, elements and/or groups thereof. In addition, the term “connection” used in this specification means not only direct connection of certain members, but also a concept including indirect connection by intervening other members between the members.

In addition, when a member is said to be located “on” another member in the present specification, this includes not only a case where a member is in contact with another member, but also a case where another member exists between the two members. As used herein, the term “and/or” includes any one and all combinations of one or more of the listed items. In addition, terms of degree such as "about" and "substantially" used in the present specification are used in a range of values or degrees or meanings close thereto, taking into account inherent manufacturing and material tolerances, and are used to help the understanding of the present application. Exact or absolute figures provided for this purpose are used to prevent undue exploitation by infringers of the stated disclosure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The size or thickness of areas or parts shown in the accompanying drawings may be slightly exaggerated for clarity of the specification and convenience of description. Like reference numbers indicate like elements throughout the detailed description.

One embodiment of the present invention is a method for recovering nickel using an electrolytic extraction device including an anode, a cathode spaced apart from the anode, and an electrolyte in which the anode and the cathode are immersed, (S1) containing nickel and a first impurity. obtaining a second impurity electrodeposited on the negative electrode and a second waste liquid not electrodeposited on the negative electrode by electrolyzing the first waste liquid to be deposited on the negative electrode; and (S2) adding aqueous ammonia to the second waste liquid to obtain a nickel sulfate-based compound, wherein the electrolyte solution includes the first waste liquid. According to one aspect of the present invention, the second impurity may be electrodeposited on the negative electrode by electrolyzing the first waste liquid containing nickel and the first impurity. By adding ammonia water to the second waste liquid from which the second impurities are removed, the ammonia water may combine with nickel ions present in the second waste liquid to form a precipitate. Thereafter, when the precipitate is filtered from a mixture of ammonia water and the second waste liquid and then dried, a high-purity nickel sulfate-based compound having a high recovery rate can be obtained. According to another aspect of the present invention, it is possible not only to reduce the amount of waste liquid and the amount of chemicals used, but also to provide an advantage of lowering the unit cost of the process by simplifying the process.

Hereinafter, the configuration of the present invention will be described in more detail with reference to the drawings.

1. Nickel recovery method

1 is an electrolytic extraction device used in a method for recovering nickel according to an embodiment of the present invention.

Referring to FIG. 1, the electrolytic collecting device 100 according to the present invention may include an electrolytic bath 10, and the electrolytic bath 10 includes an electrolytic cell 20 and a power supply 30 for supplying power. can include

The electrolytic cell 20 according to the present invention may include an anode 40 , a cathode 50 and an electrolyte solution 60 .

The anode 40 according to the present invention is an electrode where an oxidation reaction occurs on its surface, and electrons can be provided to the cathode via a wire connected to the anode.

The anode 40 according to the present invention may be an insoluble electrode. When the anode is an insoluble electrode, it may be a physically, thermally and electrochemically stable electrode.

The positive electrode 40 according to the present invention is spaced apart from the negative electrode 50 and may be immersed in the electrolyte solution 60.

According to one embodiment of the present invention, the anode 40 may include a body portion and a coating layer disposed on the body portion. According to one embodiment of the present invention, by including the body portion and the coating layer in the anode, a physically, thermally and electrochemically stable electrode can be implemented and electrical conductivity can be improved.

For example, the body portion may include at least one of titanium (Ti), nickel (Ni), and stainless steel, and the coating layer may include iridium (Ir), ruthenium (Ru), and platinum (Pt). ) may include at least one or more of them. For example, the stainless steel may be STS444 or STS316L. Specifically, the coating layer may include a 1-based material such as iridium (Ir), ruthenium (Ru), or platinum (Pt), or a ternary material such as iridium (Ir), ruthenium (Ru), and platinum (Pt). can do. However, the technical idea of the present invention is not limited thereto, and as a material for the anode, a material capable of conducting electricity while having appropriate resistance and having acid resistance may be used.

For example, the thickness of the body part may be 1 to 2 mm, and the thickness of the coating layer may be 5 to 20 μm.

The negative electrode 50 according to the present invention may be an electrode in which a reduction reaction in which metal ions in the first waste liquid receive electrons provided from the positive electrode and are converted into second impurities 70 occurs. As the reduction reaction of metal ions in the first waste liquid proceeds, second impurities may be electrodeposited on the surface of the negative electrode.

The negative electrode 50 according to the present invention is spaced apart from the positive electrode 40 and may be immersed in the electrolyte solution 60. The positive electrode 40 and the negative electrode 50 may be electrically connected to each other through a conductive wire.

For example, the negative electrode 50 may include at least one of titanium (Ti), stainless steel, and nickel (Ni). However, the technical idea of the present invention is not limited thereto, and as a material for the negative electrode, a material that can conduct electricity while having appropriate resistance and has acid resistance can be used.

The electrolyte solution 60 according to the present invention includes a first waste solution. Specifically, the first waste liquid includes nickel and first impurities. By electrolyzing the first waste liquid containing nickel and the first impurity with an electrolytic collector, the second impurity 70 may be separated and electrodeposited on the cathode.

A method for recovering nickel according to an embodiment of the present invention is a method for recovering nickel using the electrolytic extraction device.

Step (S1): Electrolyzing the first waste liquid to obtain a second impurity and a second waste liquid;

A method for recovering nickel according to the present invention includes the steps of (S1) electrolyzing a first waste liquid containing nickel and a first impurity to obtain a second impurity deposited on the cathode and a second waste liquid not deposited on the cathode. include

Specifically, the first waste liquid (electrolyte) containing the nickel and the first impurities can be electrolyzed to effectively remove the impurity metal present in the first waste liquid by electrodeposition and separation on the negative electrode.

For example, based on the total weight of the first waste liquid according to the present invention, the content of nickel may be 2% by weight or more, specifically 1.5 to 10% by weight. For example, the nickel content may be analyzed using ICP (Inductively Coupled Plasma) or IC (Ion Chromatography) analysis equipment.

Specifically, the first impurity may include at least one of iron (Fe), copper (Cu), aluminum (Al), cobalt (Co), tin (Sn), antimony (Sb), and chromium (Cr). there is. For example, the content of the first impurity may be an amount excluding nickel from the total weight of the first waste liquid.

Specifically, the electrolytic extraction device may be operated under current conditions of 1.30 to 2.40 A hr/g and power conditions of 1.30 to 3.00 kWh, and more specifically, current conditions of 1.32 to 2.38 A hr/g and 1.30 to 2.50 kWh. It may be operated under a power condition of kWh, and more specifically, it may be operated under a current condition of 1.32 to 1.85 A hr/g and a power condition of 1.30 to 2.50 kWh. When the current conditions and power conditions of the electrolytic extraction device are satisfied within the above numerical range, copper and other impurities can be effectively electrodeposited and separated from the cathode, the purity of nickel in the second waste liquid can be increased, and in terms of power consumption, The efficiency of the treatment process can be improved.

The second impurity according to the present invention may be electrodeposited in the form of metal fine powder at the cathode by obtaining electrons from the metal ions in the electrolyte solution by the electrolytic extraction device. For example, the second impurity may include at least one of copper (Cu), aluminum (Al), tin (Sn), antimony (Sb), and chromium (Cr), and specifically include copper (Cu). can do. Copper (Cu) having a low reduction potential may be obtained as an electrolytic residue, and iron (Fe), nickel (Ni), and chromium (Cr) having a relatively high reduction potential may remain as an electrolyte waste solution.

That is, by separating copper having a low reduction potential from the first waste liquid, the concentration of copper in the second waste liquid may be 20 mg/L or less, specifically 10 to 20 mg/L. As the concentration of copper in the second waste liquid is lowered within the above range, high-purity nickel may be recovered with a high recovery rate. For example, the concentration of copper in the first waste liquid may be 800 to 1,000 mg/L.

(S2) step: obtaining a nickel sulfate-based compound by adding aqueous ammonia to the second waste liquid;

The nickel recovery method according to the present invention includes (S2) adding ammonia water to the second waste liquid to obtain a nickel sulfate-based compound. Specifically, the step (S2) may include obtaining a mixture including a precipitate and a residual liquid by adding aqueous ammonia to the second waste liquid. More specifically, the step (S2) may include a step of obtaining a nickel sulfate-based compound by drying the crystals obtained by filtering the mixture in a conventional manner.

Ammonia water according to the present invention may form a precipitate by combining with nickel ions in the second waste liquid. In this case, most of other impurities including iron (Fe) may be present in the residual solution according to the ionization tendency.

The content of ammonia water according to the present invention may be 1.0 to 1.3 equivalent ratio compared to the nickel, and may be specifically 1.0 to 1.2 equivalent ratio. When the content of the ammonia water satisfies the above numerical range, the purity and recovery rate of nickel can be simultaneously increased and the content of impurities can be minimized.

According to another embodiment of the present invention, the pH of the mixture of the second waste liquid and ammonia water may be 1.5 to 2.2, specifically 1.6 to 1.8. When the pH of the mixture is within the above range, most nickel ions may be precipitated in the form of crystals. For example, as a method for analyzing the pH of a mixture of the second waste liquid and ammonia water, a pH meter commercially available in the art may be used.

The nickel sulfate-based compound according to the present invention may be any one selected from the group consisting of nickel sulfate, nickel ammonium sulfate, and combinations thereof. The nickel sulfate-based compound may be recovered in a crystalline form.

The purity of the nickel sulfate-based compound according to the present invention may be 92% or more, specifically 98% or more, and more specifically 99% or more.

The recovery rate of the nickel sulfate-based compound according to the present invention may be 87% or more, specifically 90% or more.

2 is a method for recovering nickel according to another embodiment of the present invention.

Referring to FIG. 2 , a method for recovering nickel according to another embodiment of the present invention includes electrolyzing a first waste liquid containing nickel and a first impurity to obtain a second impurity and a second waste liquid (S10); Injecting aqueous ammonia into the second waste liquid to separate a crystalline nickel sulfate-based compound (S20); and filtering and drying the crystalline nickel sulfate-based compound to obtain a high-purity nickel sulfate-based compound (S30).

2. Cathode material and secondary battery including the same

Another embodiment of the present invention may provide a cathode material containing nickel recovered by the nickel recovery method. For example, the cathode material may include a cathode active material containing nickel. According to one example, the cathode active material containing nickel may be Li _x1 NiO ₂ (0.5<x1<1.3), Li _x2 (Ni _a1 Co _b1 Mn _c1 )O ₂ (0.5<x2<1.3, 0<a1<1, 0<b1<1, 0<c1<1, a1+b1+c1=1), Li _x3 Ni _1-y1 Co _y1 O ₂ (0.5<x3<1.3, 0<y1<1), Li _x4 Ni _{1- y2} Mn _y2 O ₂ (0.5<x4<1.3, O≤y2<1), Li _x5 (Ni _a2 Co _b2 Mn _c2 )O ₄ (0.5<x5<1.3, 0<a2<2, 0<b2<2, 0<c2<2, a2+b2+c2=2), and Li _x6 Mn _2-z1 Ni _z1 O ₄ (0.5<x6<1.3, 0<z1<2). .

According to one embodiment of the present invention, the nickel sulfate-based compound obtained by the nickel recovery method may be converted into a cathode active material containing the nickel through a solvent extraction method.

Another embodiment of the present invention may provide a secondary battery including the positive electrode material. For example, the secondary battery may be a cylindrical, prismatic, or pouch-shaped secondary battery, but is not particularly limited as long as it corresponds to a charge/discharge device.

Another embodiment of the present invention may provide a battery module including the secondary battery as a unit cell and a battery pack including the same. The battery pack, for example, a power tool (Power Tool); electric vehicles, including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); Alternatively, it may be used as a power source for one or more medium- or large-sized devices selected from the group consisting of power storage systems.

Hereinafter, an embodiment of the present invention will be described in detail so that those skilled in the art can easily practice it, but this is only one example, and the scope of the present invention is Not limited.

[Production Example: Nickel recovery method]

Example 1: Removal of impurities through electrolytic extraction process

The electrolytic sampling device includes an anode made of a body portion made of Ti (thickness: 2 mm) and a coating layer containing iridium (Ir) coated on the body portion (thickness: 20 μm); A negative electrode, which is a plate made of Ti; and an electrolyte solution (first waste solution) in which the anode and the cathode are immersed. In this case, the first waste liquid is an electrolyte at time 0 in Table 1 below and has a total volume of 10 L.

Table 1 below shows the behavior of nickel (Ni) and first impurities (Fe, Cu) over time when the applied current amount is different. With the temperature maintained at a constant temperature of 30℃, changes in nickel (Ni) to be recovered, iron (Fe) and copper (Cu) to be removed are measured with ICP (Inductively Coupled Plasma) analysis equipment over time according to the change in the amount of applied current. did

Applied current amount element 0 hours 6 hours 12 hours 1.32A hr/g Ni(g/L) 37.90 37.14 36.76 Fe(g/L) 4.82 4.77 4.72 Cu (g/L) 0.80 0.48 0.24 1.85 A hr/g Ni(g/L) 37.90 36.01 35.63 Fe(g/L) 4.82 4.72 4.67 Cu (g/L) 0.80 0.33 0.02 2.38 A hr/g Ni(g/L) 37.90 33.73 28.43 Fe(g/L) 4.82 4.53 4.43 Cu (g/L) 0.80 0.24 0.00

Referring to Table 1, a significant amount of Cu remains after 12 hours under the current condition of 1.32 A hr / g, and Cu does not remain after 12 hours under the current condition of 2.38 A hr / g, but nickel ( Since the Ni) recovery rate is low, it can be confirmed that it is preferable to perform electrolytic sampling under the current condition of less than 2.38 A·hr/g.

In the case of iron (Fe) under the above conditions, the removal rate increased from 2% to 8% as the amount of applied current increased from 1.32 A hr/g to 2.38 A hr/g, but the recovery rate of nickel (Ni) Given this, it may be preferable to perform the current condition at 1.85 A·hr/g. In addition, in the case of iron (Fe), since it is separated and discharged as the third waste liquid in Example 2 to be described later, it can be seen that the removal rate in the electrolytic extraction process has little effect.

Example 2: Recovery of nickel through addition of ammonia water

A second waste liquid was obtained through the electrolytic sampling process performed under the current condition of 1.85 A·hr/g in Example 1.

Table 2 below shows the final pH of a mixture of the second waste liquid and the ammonia water according to the equivalent weight of the ammonia water by adding ammonia water (NH ₃ ratio = 25%) to the second waste liquid at room temperature. A pH meter was used as a method for analyzing the pH of the mixture in which the second waste liquid and ammonia water were mixed.

Meanwhile, in Table 2 below, the equivalent weight of ammonia water was set based on nickel (Ni) remaining in the second waste liquid.

division Example 2-1 Example 2-2 Example 2-3 Example 2-4 Equivalent weight of ammonia water (compared to Ni) 1 equivalent 1.1 equivalent 1.2 equivalents 1.3 equivalents Final pH of the mixture 1.6 1.8 2.0 2.1 Final pH of the mixture: pH of the mixture of the second waste liquid and ammonia water

[Experimental Example 1: Purity of nickel and recovery rate of nickel according to the input amount of ammonia water]

Table 3 below shows the purity, recovery rate, and concentration of impurities (Cu, Fe) of nickel according to the equivalent weight of ammonia water.

1) Purity of nickel

The purity of nickel was calculated by the content of nickel contained in the crystalline nickel sulfate-based compound excluding impurities analyzed by ICP (Inductively Coupled Plasma).

2) Recovery rate of nickel

The recovery rate of nickel was calculated by Equation 1 below using ICP (Inductively Coupled 　plasma) analysis equipment.

[Equation 1]

Nickel recovery rate (%) = {[(concentration of nickel in the second waste liquid before adding ammonia water)-(concentration of nickel remaining in the mixture of the second waste liquid and ammonia water mixture)]/(before adding ammonia water) 2 Concentration of nickel in waste liquid)} X 100

3) Impurity concentration measurement method

Concentrations of impurities (Cu, Fe) were measured with ICP (Inductively Coupled 　plasma) analysis equipment.

division Example 2-1 Example 2-2 Example 2-3 Example 2-4 Equivalent weight of ammonia water (compared to Ni) 1.0 equivalent 1.1 equivalent 1.2 equivalents 1.3 equivalents Ni purity (%) 99.92 99.83 98.55 92.43 Ni recovery rate (%) 87.66 90.15 92.99 99.99 Cu (mg/L) 21 70 150 241 Fe (mg/L) 412 1,546 3,432 4,625 Total (mg/L) 433 1,616 3,582 4,866

Referring to Table 3, it can be seen that copper (Cu) and iron (Fe) are precipitated in a larger amount as the amount of ammonia water is increased and contaminated with impurities.

Summarizing the above experimental results, when the ammonia water input is adjusted to 1.0 to 1.3 equivalent ratio, specifically 1.0 to 1.2 equivalent ratio, and more specifically 1.1 equivalent ratio to nickel, the purity and recovery of nickel can be simultaneously increased, and the impurities (Cu, Fe) It can be confirmed that the content can be minimized.

It was also confirmed that the input amount of ammonia water could be adjusted up to 1.3 equivalents depending on the purity of nickel (Ni).

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also present. It falls within the scope of the right of invention.

10: Electrolyzer
20: electrolysis cell
30: power supply
40: anode
50: cathode
60: electrolyte
70: second impurity
100: electrolytic extraction device

Claims (10)

A method for recovering nickel using an electrolytic extraction device including an anode, a cathode spaced apart from the anode, and an electrolyte in which the anode and the cathode are immersed,
(S1) electrolyzing the first waste liquid containing nickel and the first impurities to obtain second impurities electrodeposited on the negative electrode and a second waste liquid not electrodeposited on the negative electrode; and
(S2) adding aqueous ammonia to the second waste liquid; including,
The electrolyte solution includes the first waste liquid,
In step (S2), the pH of the mixture of the second waste liquid and ammonia water is 1.5 to 2.2,
The electrolytic collection device,
Operated under current conditions of 1.85 A hr/g and power conditions of 1.30 to 2.50 kWh,
The content of the ammonia water is 1.1 equivalent ratio to the nickel,
The anode is
Comprising a body portion and a coating layer disposed on the body portion,
Nickel recovery method.
delete According to claim 1,
The body part,
Including at least one or more of titanium (Ti), nickel (Ni), and stainless steel,
The coating layer,
Including at least one or more of iridium (Ir), ruthenium (Ru) and platinum (Pt),
Nickel recovery method.
According to claim 1,
The first impurity is
Containing at least one or more of iron (Fe), copper (Cu), aluminum (Al), cobalt (Co), tin (Sn), antimony (Sb) and chromium (Cr),
Nickel recovery method.
According to claim 1,
The second impurity is
containing at least one of copper (Cu), aluminum (Al), tin (Sn), antimony (Sb) and chromium (Cr)
Nickel recovery method.
delete delete delete A cathode material containing nickel recovered by the nickel recovery method according to any one of claims 1 and 3 to 5.
A secondary battery comprising the positive electrode material according to claim 9.

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