KR20120031445A - Method for manufacturing high-purity nickel - Google Patents

Abstract

PURPOSE: A method for manufacturing high purity nickel is provided to effectively achieve high purity nickel by using electrolyte with a low density of impurities, less than 0.1mg/l. CONSTITUTION: A method for manufacturing high purity nickel comprises an electrolysis process using an electrolyte containing nickel. Impurities, such as iron, zinc, and copper, included in the electrolyte are removed in advance through electrolysis so that the impurity density of the electrolysis is 0.1mg/l or less.

Description

Manufacturing method of high purity nickel {METHOD FOR MANUFACTURING HIGH-PURITY NICKEL}

This invention relates to the method of manufacturing high purity nickel for lithium batteries by electrolytic extraction using a nickel containing solution.

Lithium nickelate or lithium nickel cobalt oxide of the positive electrode material used in the lithium battery is produced by firing a mixture of a predetermined amount of nickel oxide and lithium carbonate. At this time, impurities such as copper, zinc and iron other than cobalt elute into the electrolyte by repeated charge and discharge of the lithium ion battery, which adversely affects the performance and the life of the battery.

As shown in JP 2007-46157 A (Patent Document 1) as a method for producing high-purity nickel, anodolite is used at a pH 2? It is adjusted to 5, and impurities such as iron, cobalt, and copper contained in the anolite are added with an oxidizing agent to precipitate and remove the impurities as hydroxides, or to remove the impurities by preliminary electrolysis or Ni foil. Preparation by removing any impurities by combining any one method or two or more methods of removing the impurities by a substitution reaction, followed by removing the impurities using a filter, and then using the removed liquid as catholyte to manufacture the electrolyte. There is a way.

In such a method, anodolite was extracted during electrolysis, and the liquid was precipitated and removed as a hydroxide, or a preliminary electrolysis was required, resulting in a complicated device and inefficient.

In general, in the case of producing nickel metal from recycled raw materials, it is common to purify the solution by ion exchange, solvent extraction, or the like, and to carry out electrolytic collection or electrolytic purification again, which is described in JIS Standard H2104-1975. A scoop and one type of nickel foil are produced. The impurity concentration of the JIS standard scoop is iron: 0.02 mass% or less, that is, 200 mass ppm or less, copper: 0.005 mass% or less, that is, 50 mass ppm or less, and zinc is not specified. However, since the quality of nickel nickel for lithium batteries now requires more than the JIS standard H2104-1975 scoop, it is necessary to improve the quality.

Japanese Patent Application Laid-Open No. 2007-46157 "High purity nickel, high purity nickel target, and high purity nickel thin film"

Generally when this invention manufactures a nickel metal from a recycling raw material, a solution is refine | purified by ion exchange, solvent extraction, etc., and this is electrolytically collected again.

At this time, it aims at providing the electrolytic collection technique which manufactures high purity nickel metals, such as for lithium batteries more efficiently.

In order to solve the above problems, the iron, zinc, and copper impurities contained in the electrolyte are electrolyzed using an electrolyte having an impurity concentration of 0.1 mg / l or less in the electrolyte from which impurities are removed by electrolysis, thereby efficiently avoiding a complicated process. The knowledge that nickel can be manufactured was acquired.

Based on this knowledge, the present invention

(1) When electrolytically using a nickel-containing solution as an electrolyte, high-purity nickel electrolysis using an electrolyte solution in which each impurity concentration in the electrolyte solution in which impurities contained in the electrolyte are previously removed by electrolysis is 0.1 mg / L or less, respectively. Method of preparation.

(2) The manufacturing method of high purity nickel whose electrolyte solution which removed the impurity contained in the electrolyte solution as described in said (1) by electrolysis is a nickel sulfate solution, and whose nickel concentration is 70 g / L or more.

(3) The method for producing high-purity nickel, wherein the impurity contained in the electrolytic solution according to (1) or (2) is any one of iron, zinc, and copper, or is an electrolytic solution contained in two or more types of electrolytic solutions.

(4) In the electrolytic step of removing impurities contained in the electrolytic solution according to any one of (1) to (3), the current density during electrolysis is 0.05? Process for producing high purity nickel which is 7 A / dm 2.

(5) The method for producing high-purity nickel, wherein the pH of the electrolyte solution for removing the impurities according to any one of the above (1) to (4) is 1.0 or more and 5.0 or less.

(6) The high purity nickel according to any one of (1) to (5) above, wherein the nickel concentration at the end of electrolytic collection is 50 g / l or more when the electrolytic collection is performed using an electrolytic solution in which impurities contained in the electrolytic solution are removed by electrolysis. Manufacturing method.

(7) The method for producing high-purity nickel according to the above (6), wherein the current density in the electrolytic picking step is 0.5 to 10 A / dm 2.

(8) The manufacturing method of high purity nickel whose pH of the electrolyte solution of the electrolytic collection process as described in said (6) or (7) is 1.0 or more and 5.0 or less.

(9) The electrolytic cell used in the electrolytic collection process in any one of said (6)-(8) divides an anode and a cathode by a diaphragm, and cathode-containing electrolyte solution whose impurity concentration contained in electrolyte solution is 0.1 mg / L or less A method for producing high purity nickel, which is placed intermittently or continuously on the side.

From the above, according to the present invention,

(1) High purity nickel can be manufactured effectively without using complicated process or apparatus.

1 shows a processing flow in the present invention.

From the studies of nickel plating and nickel alloy plating, impurities of copper, zinc and iron contained in the nickel electrolyte are preferentially electrodeposited over nickel. In electrolytic extraction using DSE in the anode, nickel carbonate or the like is dissolved to replenish the reduced nickel, and commercially available nickel carbonate contains impurities such as copper, zinc and iron. For this reason, in order to replenish the reduced nickel, when nickel carbonate is replenished continuously or intermittently, impurities are also replenished in the electrolyte solution. For this reason, the impurities are also vaccinated in the nickel electrodeposition, and nickel of high purity cannot be obtained.

In this invention, it is the manufacturing method of high purity nickel using electrolytic solution whose impurity concentration in electrolyte solution is 0.1 mg / L or less, without supplying nickel electrolytically degraded with nickel carbonate.

(Removal of impurities by electrolysis)

The electrolytic solution is circulated with a pump using a 5 L square electrolyzer, SUS, Ti, etc. for the anode, and SUS and Ti for the cathode.

As electrolytic conditions, liquid temperature 20? 70 ° C., pH 1.0? 5.0, current density 0.05? It is carried out at 7 A / dm 2.

The nickel concentration is set to an initial concentration such that the concentration of nickel is 70 g / l or more at the end of the electrolysis to remove impurities.

If the nickel concentration at the end of the electrolysis is less than 70 g / L, since only electrolytic concentration of nickel at a concentration of 50 g / L or higher can be delivered in the electrolytic collection of nickel in the next step, it is not preferable because the high-purity nickel obtained is less.

It is not preferable because nickel sulfate precipitates at a nickel concentration of 130 g / l or more.

Although liquid temperature is sufficient as room temperature (20 degreeC) or more, in 70 degreeC or more, resin used for an electrolytic cell tends to deteriorate, and it is unpreferable. More preferably, 40? 60 ° C.

PH of electrolyte solution is adjusted continuously or intermittently. If pH is lower than 1.0, since SUS used for a cathode elutes, it is not preferable.

On the other hand, when the pH is higher than 5.0, nickel hydroxide is generated and precipitation is not preferable. In the management of the electrolyte, the pH is 1.0? 2.5 is more preferable.

The current density is no problem at 10 A / dm 2 or less. However, if the current density exceeds 7 A / dm 2, the decrease in the nickel concentration in the electrolyte increases, so that the current density is 0.05? The range is 7 A / dm 2. Considering the reduction of nickel in the electrolyte, 0.05? The range of 1.0 A / dm <2> is more preferable.

The electrolysis time depends on the impurity concentration in the electrolytic solution and hardly depends on the current density. It is thought that the reason that it hardly depends on the current density is because impurity electrodeposition is in the region of diffusion domination because the impurity concentration is low.

Therefore, impurities can be generally removed at 0.01-0.2 mg / (dm &lt; 2 &gt; x time) when electrolytically carried out at a current density of 0.05 A / dm &lt; 2 &gt;

Therefore, the time required for removing impurities can be determined by the initial impurity concentration, the electrolyte amount, the cathode area and the time.

By satisfy | filling the above electrolytic conditions, the impurity concentration in electrolyte solution can be reduced to 0.1 mg / L or less of each element, respectively.

(Method for producing high purity nickel)

By using a 5 L square electrolyzer and using DSE for the anode, SUS, Ti, etc. for the cathode, the electrolyte can be circulated by a pump without performing separation between the anode and the cathode with a diaphragm or the like to perform electrolysis.

In the electrolysis of high purity nickel, in order to prevent impurities from being carried into the electrolytic solution, diffusion of nickel reduced by electrolysis in the form of nickel carbonate or the like is not performed.

As electrolytic conditions, the nickel concentration before electrolysis is 70? Electrolysis is terminated when nickel concentration is 50 g / l or more using 120 g / l. Moreover, liquid temperature 20? 70 ° C., pH 1.0-5.0, current density 0.5? It is carried out at 10 A / dm 2.

If the nickel concentration is 50 g / l or less, nodule is likely to occur, and the anode and the cathode are in contact, which is not preferable. It is not preferable because nickel sulfate precipitates at a nickel concentration of 130 g / l or more.

Although liquid temperature is sufficient as room temperature or more, resin used for an electrolytic cell will deteriorate easily at 70 degreeC or more, and is unpreferable. More preferably, 40? 60 ° C.

The pH of the electrolyte is adjusted continuously or intermittently. When pH is less than 1.0, hydrogen gas generation | occurrence | production in a cathode increases, and current efficiency of nickel falls, and it is inefficient.

On the other hand, when the pH is higher than 5.0, nickel hydroxide is generated and precipitation is not preferable.

In terms of the current efficiency of nickel, the pH is 2.5? 4.0 is more preferable. If the current density exceeds 10 A / dm 2, nodule is generated, which is not preferable because the anode and the cathode are in contact.

If the current density is less than 0.5 A / dm 2, the productivity is poor, so the current density is 0.5? The range of 10 A / dm <2> is preferable, More preferably, it is 1.5? 5 A / dm 2.

On the other hand, electrolysis can also be carried out by circulating the cathode and anolite using separate pumps using an electrolytic cell using a diaphragm and using DSE for the anode, SUS, Ti, etc. for the cathode. In the case of an electrolytic cell using a diaphragm, the pH slightly increases due to the generation of hydrogen gas generated at the cathode side.

On the other hand, on the anode side, a decrease in pH due to generation of oxygen gas and generation of hydrogen ions occurs due to hydrolysis. Since the decrease in pH at the anode side is greater than the rise in pH at the cathode side, the electrolyte on the anode side can be used for pH adjustment of the electrolyte on the cathode side, and the pH adjuster can be reduced.

Next, the Example of this invention is described. In addition, this embodiment is an example to the last, It is not limited to this example. That is, all the aspects or modifications except an Example are included within the scope of the technical idea of this invention.

1, one aspect of the processing flow of this invention is shown. According to the above processing flow, an embodiment of the present invention is shown below.

Example

(Examples 1-9) Examples of Impurity Removal by Electrolysis

Electrolyte was performed by using an electrolytic cell in which the anolyte and the catholyte were not separated by a diaphragm, using DSE for the anode, and SUS for the cathode, and anodic and cathode areas of 0.5 dm 2, and circulating the electrolytic solution by a pump. The electrolyte solution amount was 5.0 L and circulated at 250 ml / min. As electrolyte conditions, the electrolyte solution containing the impurity shown in Table 1 was used. As shown in Table 2, the impurity concentration in the electrolytic solution after the completion of the electrolysis was lowered to 0.1 mg / l or less as the copper, zinc and iron concentrations as impurities.

(Comparative Examples 1-4) Comparative Example of Impurity Removal by Electrolysis

It carried out by the electrolytic conditions shown in Table 1 as a comparative test. In Comparative Example 1, the nodule occurred in the electrodeposited material because the current density was as high as 12.5 A / dm 2. In Comparative Example 2, the nickel concentration at the end of electrolysis was 70 g / L or less, and the nickel concentration of the next step was not satisfied. In Comparative Example 3, precipitation of nickel hydroxide occurred in the electrolytic solution due to high pH. In Comparative Example 4, impurities were removed by electrolysis from the same impurity concentration as in Example 5, but the impurity concentration in the electrolyte solution did not become 0.1 mg / L or less because the electrolysis time was short.

(Examples 9-16) Example of Preparation of High Purity Nickel

Using an electrolytic cell in which the anolyte and the catholyte were separated by a diaphragm, using DSE for the anode and SUS for the cathode, the anode and cathode areas were 0.5 d㎡, and the anode side and the cathode side liquids were circulated individually by a pump. Electrolysis was carried out. The amount of the electrolytic solution was 2.5 L for both the anode side liquid and the cathode side liquid, and each liquid was circulated at 250 ml / min by a pump. As electrolytic conditions, it implemented using the electrolyte solution which removed the impurity shown in Table 3 by electrolysis. As shown in Table 3, copper, zinc, and iron impurities were able to obtain high purity nickel of 3 ppm or less. Moreover, the external appearance and electrolyte solution of the electrodeposited body were also favorable.

Comparative Example 5-10 Comparative Example of Manufacturing High Purity Nickel

It carried out by the electrolytic conditions shown in Table 3 as a comparative test. In the comparative example 5, since the electrolyte solution which did not remove copper, zinc, and iron impurities by electrolysis was used, the impurity concentration in electrodeposited nickel is high. In the comparative example 6, since current density is low as 0.2 A / dm <2>, electrolysis time is long and productivity is bad. Since the comparative example 7 had a high current density of 12.5 A / dm <2>, nodule generate | occur | produced in the electrodeposited material. In Comparative Example 8, since the pH was low at 0.25-0.75, the current efficiency of nickel electrodeposition was low at 32%, resulting in poor productivity. In Comparative Example 9, since the pH was high, precipitation occurred in the electrolytic solution. Since the comparative example 10 used the electrolytic solution which removed the copper, zinc, and iron impurities by electrolysis but did not remove the impurities to 1 ppm or less, the impurity concentration in electrodeposited nickel is high.

(Example 17-23) Example of manufacturing high purity nickel

Using an electrolytic cell that does not separate the anolyte and the catholyte, using DSE for the anode and SUS for the cathode, the anode and cathode areas were 0.5 dm2, and the electrolytic solution was circulated with a pump to perform electrolysis. The electrolyte solution amount was 5.0 L and circulated at 250 ml / min. As electrolytic conditions, it implemented using the electrolyte solution which removed the impurity shown in Table 5 by electrolysis. As shown in Table 6, the copper, zinc, and iron impurities were able to obtain high purity nickel of 3 ppm or less. Moreover, the external appearance and electrolyte solution of the electrodeposited body were also favorable.

Comparative Example 11-14 Comparative Example of Preparation of High Purity Nickel

It carried out by the electrolytic conditions shown in Table 5 as a comparative test. In the comparative example 11, since current density is low as 0.1 A / dm <2>, electrolysis time is long and productivity is bad. Since the comparative example 12 had a high current density of 12.5 A / dm <2>, nodule generate | occur | produced in the electrodeposited material. In Comparative Example 13, since the pH was low at 0.25-0.75, the current efficiency of nickel electrodeposition was as low as 32%, resulting in poor productivity. In Comparative Example 14, since the pH was high, precipitation occurred in the electrolytic solution.

Claims (9)

When electrolytically using a nickel-containing solution as an electrolytic solution, the impurities contained in the electrolytic solution are electrolyzed using an electrolytic solution in which each impurity concentration in the electrolytic solution from which impurities have been previously removed by electrolysis is 0.1 mg / L or less, respectively. Method for producing nickel. The method of claim 1,
An electrolytic solution from which impurities contained in an electrolytic solution are removed by electrolysis is a nickel sulfate solution, and the nickel concentration is 70 g / L or more. The method according to claim 1 or 2,
The impurity contained in electrolyte solution is any one of iron, zinc, and copper, or the electrolyte solution contained in two or more types of electrolyte solution, The manufacturing method of the high purity nickel characterized by the above-mentioned. The method according to claim 1 or 2,
In the electrolytic step of removing impurities contained in the electrolytic solution, the current density during electrolysis is 0.05? 7 A / dm 2 A method for producing high purity nickel, characterized in that. The method according to claim 1 or 2,
PH of electrolyte solution which removes an impurity by electrolysis is 1.0-5.0, The manufacturing method of high purity nickel characterized by the above-mentioned. The method according to claim 1 or 2,
A method for producing high purity nickel, wherein the nickel concentration at the end of electrolytic collection is 50 g / l or more when electrolytic collection is performed using an electrolytic solution in which impurities contained in the electrolytic solution are removed by electrolysis. The method according to claim 6,
The current density in the electrowinning process is 0.5? It is 10 A / dm <2>, The manufacturing method of high purity nickel characterized by the above-mentioned. The method according to claim 6,
PH of electrolyte solution of an electrolytic collection process is 1.0 or more and 5.0 or less, The manufacturing method of high purity nickel characterized by the above-mentioned. The method according to claim 6,
The electrolytic cell used in the electrolytic collection step divides the anode and the cathode into a diaphragm, and the electrolyte is intermittently or continuously placed in the cathode side with an electrolyte having an impurity concentration of 0.1 mg / L or less in the electrolyte. Manufacturing method.

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