JP2015168858A - Cobalt extraction solution, cobalt solution, and cobalt collection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cobalt extraction solution capable of extracting cobalt safely at lower cost than cost in a conventional one.SOLUTION: The cobalt extraction solution comprises: an ionic liquid including a quarternary ammonium group; and an organic solvent existing in a state that being mixed with the ionic liquid, and having 60 or more of a kauri-butanol value.

Description

  The present invention relates to a cobalt extraction solution, a cobalt solution, and a cobalt recovery method.

  Cemented carbides with tungsten carbide as the main component, cobalt and nickel as binding metals, and carbides such as titanium, tantalum, and chromium added to improve performance are superior in hardness and wear resistance. Widely used in tools for metal processing.

  In such a tool using a cemented carbide, a tool that has become unusable due to chipping or wear during use or a chipped portion thereof is discarded as scrap called hard scrap.

  In addition, some of the cemented carbide powder generated during the manufacture of cemented carbide tools and grinding scraps generated by processing cemented carbide tools with grinding wheels will be discarded as scrap called soft scrap. Become.

  In the following description, the cemented carbide scrap is a used scrap of an alloy containing 50% by weight or more of tungsten carbide and having cobalt or nickel as a binder phase.

  These hard scraps and soft scraps contain a large amount of tungsten which is a rare metal. More than 60% of tungsten resources are used in carbide tools. Furthermore, the prices of ammonium paratungstate (APT) and tungsten oxide, which are intermediate materials for tungsten materials, have been rising in recent years, and establishment of a recycling technique for tungsten contained in carbide tools is desired.

  Therefore, a recycling method for cemented carbide tools that regenerates tungsten carbide from used cemented carbide tools has been proposed. Specifically, the zinc method, molten salt dissolution method, oxidation roasting-alkali dissolution method, etc. are known. (Patent Documents 1 and 2, Non-Patent Document 1).

  On the other hand, the residue produced when tungsten is recovered by the above method contains a large amount of cobalt, and its recovery is also desired. However, in addition to cobalt, the residue contains iron, manganese, nickel, copper, chromium, tantalum, tungsten, vanadium, etc. When reusing as a carbide material, The problem of cobalt purity arises.

  Therefore, a technique for separating, purifying, and recovering cobalt contained in the residue from recovering tungsten is desired.

  As a technique for separating cobalt from iron and nickel, a solvent extraction method (cited document 3) and a precipitation removing method using sulfide (patent document 4) have been reported.

  However, the solvent extraction method requires a large amount of a flammable hazardous material solvent, and requires explosion-proof equipment, so there are safety and cost problems. On the other hand, the precipitation removal method using sulfides requires the use of harmful sulfides, and there are problems in maintaining the environmental load and working environment.

  Therefore, a cobalt extraction method using an ionic liquid has been reported as a method for dealing with these problems. The ionic liquid here means a liquid which is a salt that becomes liquid at 100 ° C. or lower and is composed only of ions.

  The ionic liquid has a structure composed of a cation part and an anion part. Specific examples of the extraction method using an ionic liquid include an ionic liquid containing a quaternary phosphonium group in the cation portion (hereinafter referred to as a quaternary phosphonium ionic liquid) or an ionic liquid having a quaternary ammonium group (hereinafter referred to as quaternary ammonium). The ionic liquid is mixed with an organic solvent as necessary, and the viscosity is adjusted. Then, by contacting the ionic liquid with a solution containing cobalt and nickel, only cobalt is added to the ionic liquid. There is a method of extracting (Non-Patent Documents 2 and 3).

Japanese National Patent Publication No. 11-505801 International Publication No. 2010/104009 JP 2013-194269 A JP 2012-212375 A

Yasuhiko Tenmaya, Development project for high-efficiency recovery system for rare metals, etc., “Recovery of tungsten, etc. from waste carbide tools”, Metal Resource Report, Japan Petroleum Natural Gas / Metal Mineral Resources Organization, Vol. 38, no. 4, November 2008, pp. 407-413 Sil Wellens, Ben Thijs, Koen Binnemans. “An environmentally friendlier approach to hydrometallurgy: highly selective separation of cobalt from nickel by solvent extraction with undiluted phosphonium ionic liquids” Green Chemistry, 2012, 14, 1657 Patrycja Rybka et.al., Separation Science and Technology, 47, 1296-1302, 2012

  However, the techniques shown in Non-Patent Documents 2 and 3 have the following problems.

  First, the quaternary phosphonium-based ionic liquid is much more expensive than the quaternary ammonium-based ionic liquid, and there was a problem in terms of cost when used for recovering cobalt from used carbide tools and the like. .

  Although quaternary ammonium-based ionic liquids are less expensive than phosphonium-based ionic liquids, they have higher solubility in water than quaternary phosphonium-based ionic liquids, so that when used for cobalt extraction from an aqueous solution containing cobalt, ionic liquids Was dissolved in the aqueous solution, and there was a problem that it was difficult to separate cobalt.

  Thus, all of the conventional cobalt recovery technologies have problems, and there is no technology that combines cost and recovery efficiency.

  This invention is made | formed in view of the said subject, The objective is to provide the solution for cobalt extraction which can extract cobalt more efficiently cheaply than before.

  In order to solve the above-described problems, the present inventor has studied a composition of an ionic liquid that can be more efficiently and efficiently extracted with cobalt than a conventional ionic liquid and that is cheaper than a phosphonium-based ionic liquid.

  In particular, the present inventor examined whether it is possible to reduce the solubility of quaternary ammonium-based ionic liquids in water.

  As a result, by mixing a certain organic solvent in the quaternary ammonium-based ionic liquid, it has been found that the solubility in water can be greatly reduced, and ions can be extracted from an aqueous solution containing cobalt, It came to make this invention.

  That is, the first aspect of the present invention is a cobalt extraction solution having an ionic liquid containing a quaternary ammonium group and an organic solvent having a kauributanol value of 60 or more, which is present in a mixed state with the ionic liquid. is there.

  A second aspect of the present invention includes the cobalt extraction solution according to the first aspect and an aqueous solution of an acid containing cobalt and chlorine dissolved in the cobalt extraction solution. It is a cobalt solution in which cobalt is dissolved.

  In the third aspect of the present invention, an aqueous solution of an acid containing cobalt and chlorine is present in a state of being mixed with an ionic liquid containing a quaternary ammonium group and the ionic liquid, and has an organic solvent having a kauributanol value of 60 or more. A cobalt recovery method comprising: dissolving in a cobalt extraction solution, and separating and recovering cobalt by dissolving the cobalt in the cobalt extraction solution.

  According to the present invention, it is possible to provide a cobalt extraction solution that is cheaper and more efficient than conventional ones.

It is a flowchart which shows an example of the cobalt extraction method of this embodiment. FIG. 4 is a graph showing the relationship between the mixing ratio of TOMAC (tri-octhyl-methyl-ammnoiumu-chloride) and an organic solvent and the viscosity. It is a figure which shows the relationship between the mixing ratio of TOMAC, an organic solvent, Co extraction ability, and Co-Ni separation ability. It is a flowchart of the cobalt extraction method of an Example.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments suitable for the invention will be described in detail with reference to the drawings.

<Principle of this embodiment>
First, the principle of cobalt extraction of this embodiment will be briefly described.

  In this embodiment, an ionic liquid is used to separate cobalt from an aqueous solution containing nickel and cobalt.

  Specifically, first, an aqueous solution containing nickel, cobalt, and chlorine is prepared.

Specifically, a compound containing nickel and cobalt is dissolved in an acid containing chlorine such as hydrochloric acid to cause the reaction shown in Formula 1.
CoO + 2HCl → CoCl ₂ + H ₂ O… Formula 1
Since the produced cobalt chloride is water-soluble, an aqueous cobalt solution can be obtained.

  Next, an aqueous solution containing nickel, cobalt, and chlorine is brought into contact with an ionic liquid having a chloride ion as an anion portion.

  At this time, cobalt in the aqueous solution is combined with chlorine and extracted into the ionic liquid as a chloride complex.

  On the other hand, since nickel does not form a chloride complex, it remains in the aqueous solution and is separated from cobalt. This is the principle of cobalt extraction of this embodiment.

Thus, the reaction in which cobalt is extracted into an ionic liquid is shown below.
_{^{Co 2+ + 4Cl - → CoCl 4}} 2- ... Equation 2
^{_{2I.L. - Cl + CoCl 4 2- →}} (IL) 2 -CoCl 4 + Cl - (IL: the cationic portion of the ionic liquid) Equation 3

Moreover, the extraction ability and separation ability of cobalt are defined as follows.
Extraction capacity: Amount of cobalt extractable into ionic liquid per unit volume (g / dm ³ = kg / m ³ ).
Separation ability: The amount of cobalt extracted in an ionic liquid per unit volume divided by the amount of nickel extracted (g / g).

<Configuration of this embodiment>
Next, the structure of the cobalt extraction solution used for cobalt extraction in this embodiment will be described.

  As described above, the cobalt extraction solution of this embodiment separates cobalt by contacting with an aqueous solution containing cobalt and chlorine, and is in a state of being mixed with an ionic liquid containing a quaternary ammonium group and the ionic liquid. And has an organic solvent having a Kauributanol value (hereinafter referred to as KB value) of 60 or more.

  The KB value here refers to the number of milliliters of a sample when a certain amount of Kauri resin butanol solution is placed in an Erlenmeyer flask, placed on a standard type paper, a sample is added, and turbidity occurs and the typeface cannot be read. is there.

(Ionic liquid)
The ionic liquid is a liquid that extracts cobalt by contacting with an aqueous solution containing cobalt and chlorine. In this embodiment, an ionic liquid containing a quaternary ammonium-based ionic liquid having a chloride ion as an anion portion is used.

  This is because the quaternary ammonium-based ionic liquid is a very inexpensive ionic liquid as compared with other ionic liquids such as a quaternary phosphonium-based ionic liquid.

  Quaternary ammonium-based ionic liquids include tri-octthyl-methyl-ammnoiumu-chloride (TOMAC) or di-octadethyl-di-methyl-ammonium chloride (di-octadethyl-di-). methyl-ammoniumu-chloride) is exemplified, but not necessarily limited thereto.

(Organic solvent)
The organic solvent of the present embodiment lowers the solubility of an ionic liquid containing a quaternary ammonium group in water and adjusts physical properties such as viscosity, and an organic solvent having a KB value of 60 or more is used.

Here, the reason for using an organic solvent having a KB value of 60 or more will be described.
As described above, the quaternary ammonium-based ionic liquid having chloride ions as an anion portion is an ionic liquid that is very inexpensive as compared with other ionic liquids.

  However, in studies on extraction of metal ions, quaternary phosphonium ionic liquids that are very expensive compared to quaternary ammonium ionic liquids have been mainly used.

  This is because the phosphonium-based ionic liquid does not dissolve in water and the viscosity is low.

  On the other hand, an inexpensive ammonium-based ionic liquid has a problem of being mixed with water by about 10% by volume and a problem of high viscosity. In particular, when cobalt is extracted, the viscosity becomes very high and the separability from water is poor, so that it cannot pass through, for example, a continuous extraction tower. For this reason, in spite of using an ionic liquid with high extraction efficiency, processing can be performed only in a batch system with low efficiency. Since dissolution of the ionic liquid in water discharges the ionic liquid, which is an expensive extractant, out of the system, it is necessary to recover and decompose the ionic liquid. There is also a problem that the separation ability of cobalt and nickel is lower than that of phosphonium-based ionic liquids.

  In contrast, the present inventors have found that an organic solvent having a KB value of 60 or more is mixed with a quaternary ammonium-based ionic liquid, and in the mixed state, the solubility in water is decreased and the viscosity is also decreased. The above organic solvent is used.

  Examples of the organic solvent having a KB value of 60 or more include alkylbenzene derivatives and toluene. For example, by adding about 10% by volume of an alkylbenzene derivative (trade name Solvesso 150) having a KB value of 80 to a quaternary ammonium-based ionic liquid, the viscosity of the solvent can be lowered to 1/10 or less. In addition, the separability from water is improved, and the phenomenon that the quaternary ammonium ionic liquid dissolves in water does not occur (before mixing with an organic solvent, the quaternary ammonium ionic liquid is 3% by weight in water. It dissolves to a certain extent, but this is 0.01% or less). Thereby, the loss (dissolution in water) of the quaternary ammonium ionic liquid in the extraction process can be suppressed. The upper limit of the KB value is not particularly limited, but it is difficult to produce an industrially available organic solvent having a KB value exceeding 110.

  The reason why the dissolution in water can be suppressed by mixing and mixing the organic solvent and the quaternary ammonium-based ionic liquid is that the quaternary ammonium-based ionic liquid is preferentially dissolved in the hydrophobic organic solvent so that it can be dissolved in water. This is probably because dissolution did not occur.

In addition, water is dissolved in the quaternary ammonium ionic liquid in the same manner as the quaternary ammonium ionic liquid is dissolved in water. The nickel contained in the water cannot be separated by the extraction process, and the ionic liquid needs to be washed after the extraction. However, mixing the quaternary ammonium ionic liquid with an organic solvent and mixing it also reduces the amount of water dissolved into the quaternary ammonium ionic liquid, thereby reducing the amount of nickel mixed in and the ability to separate cobalt and nickel. Can be improved.
The above is an explanation of the reason for using an organic solvent having a KB value of 60 or more.

  The cobalt extraction solution preferably contains an organic solvent in a volume ratio of 2% to 50%, and more preferably 5% to 15%. This is because the effect of containing the organic solvent cannot be obtained when the content of the organic solvent is less than 2%. On the other hand, if it exceeds 50%, the organic solvent does not participate in the extraction of Co, and therefore, the Co extraction ability decreases.

  The cobalt extraction solution preferably contains an organic solvent so that the viscosity is 0.02 Pa · s or more and 0.5 Pa · s or less. This is because, in order to prepare a solution having a viscosity of less than 0.02 Pa · s, it is necessary to contain a large amount of an organic solvent, and Co extraction ability is reduced. Further, when the viscosity exceeds 0.5 Pa · s, it is difficult to perform a process using a continuous extraction apparatus during Co extraction. As the content of the organic solvent increases, the viscosity of the cobalt extraction solution decreases. However, as described above, if the content is too large, the Co extractability decreases, so the content of the organic solvent reduces both the viscosity and the extractability. It is necessary to set in consideration.

<Cobalt extraction method>
Next, a cobalt extraction method using the cobalt extraction solution according to the present embodiment will be described with reference to FIG.

  Here, tungsten scrap is generated by subjecting cemented carbide scrap containing tungsten, cobalt, nickel, iron to oxidation roasting and alkali extraction treatment or molten salt dissolution treatment, and filtering the produced sodium tungstate aqueous solution. A method for recovering an aqueous cobalt solution from the residue is exemplified.

  First, an acid such as hydrochloric acid or sulfuric acid is brought into contact with the tungsten extraction residue, and cobalt is leached into an aqueous solution as cobalt chloride or cobalt sulfate to form an acidic aqueous solution (S1 in FIG. 1). Considering later treatment, hydrochloric acid is preferred as the acid type. However, when chlorine is replenished later with sodium chloride or the like, the acid is not necessarily limited to hydrochloric acid as long as it is a strong acid, and may be sulfuric acid or the like.

  The acid concentration is preferably 1 N or more and 10 N or less, more preferably 2 N or more and 5 N or less.

  This is because when the acid concentration exceeds 10N, the removal rate of manganese and copper during the ion exchange treatment described later decreases. On the other hand, when the acid concentration is less than 1 N, the cobalt concentration in the leachate (the aqueous solution in which cobalt is leached) is lowered, resulting in a decrease in processing efficiency and an increase in cost.

  Next, hydrogen peroxide is added to the aqueous solution. This is because iron in the residue is oxidized to trivalent. The specific addition amount is about 0.5 times mol or more and 3 times mol or less of iron. It is equivalent to 0.5 times mole of iron, and all iron can be oxidized.

  If the amount of hydrogen peroxide added exceeds 3 times the amount of iron, oxygen is generated due to decomposition of excess hydrogen peroxide, which causes bubbles to enter the resin tube during ion exchange described later, which is not desirable. On the other hand, when the addition amount of hydrogen peroxide is less than 0.5 times mole of iron, unoxidized iron remains in the solution, which is not desirable. Immediately after the addition of hydrogen peroxide, iron is oxidized.

  Next, the pH of the aqueous solution is adjusted to 1 or more and 6 or less using an alkali such as sodium hydroxide or calcium hydroxide to precipitate iron, and the precipitated iron is removed by filtration or the like (S2 in FIG. 1). .

  As a specific alkali, a hydroxide composed of a monovalent cation is preferable, and sodium hydroxide is preferable in view of cost. This is because when finally extracted Co is used as a raw material for a cemented carbide tool, it is necessary to add oxalic acid to a Co aqueous solution to precipitate, but when a hydroxide composed of a divalent cation is used in S2, This is because hydroxide is precipitated together with cobalt during oxalic acid precipitation, and is easily contained as an impurity. However, in the case of directly reducing Co, it is not necessary to limit the alkali to a hydroxide composed of a monovalent cation. Calcium hydroxide, magnesium hydroxide, potassium hydroxide, strontium hydroxide, hydroxide Cobalt or the like can be used. However, carbonates such as sodium carbonate are undesirable because they produce cobalt carbonate, and ammonia is undesirable because a cobalt-ammine complex is produced and cobalt cannot be extracted into an ionic liquid.

  The precipitated iron is removed by filtration. On the other hand, if the pH exceeds 6, cobalt is precipitated as a hydroxide and the recovery rate of cobalt is lowered, which is not desirable. On the other hand, if the pH is lower than 1, the precipitation of iron does not proceed completely, the iron removal rate is lowered, and the removal rate of manganese and copper by subsequent ion exchange is also lowered, which is not desirable.

  Next, chloride is added to the aqueous solution so that the chloride ion concentration is at least twice that of cobalt. This is for efficiently extracting cobalt into the ionic liquid.

  In addition, when hydrochloric acid is used for the cobalt leaching process (the process of S1 in FIG. 1), the addition of chloride here is not essential.

  Next, the aqueous solution is brought into contact with the ion exchange resin to remove manganese and copper (S3 in FIG. 1).

  Specifically, it is desirable to immerse a chelate-type anion exchange resin having a volume of 1/100 or more of the aqueous solution in the aqueous solution for 10 minutes or more, or to fill the column with the ion exchange resin and then pass the aqueous solution.

  When the resin volume is less than 1/100 of the aqueous solution volume, the removal rate of manganese and copper decreases, which is not desirable.

  Moreover, when the immersion time of resin is less than 10 minutes, since the removal rate of manganese and copper falls, it is not desirable.

  In addition, when the liquid is passed after filling the column, the space velocity (Space Velocity, SV) is passed at a speed of 0.1 or more and 10 or less.

  When the space velocity at the time of filling the column is less than 0.1, it is not desirable because the processing takes time and is not realistic.

  Moreover, when the space velocity at the time of filling a column exceeds 10, the breakage of manganese and copper is accelerated and the regeneration frequency of the ion exchange resin is increased, which is not desirable.

  Next, an ionic liquid previously mixed with an organic solvent is brought into contact with the aqueous solution to extract and dissolve Co into the ionic liquid to separate it from nickel (S4 in FIG. 1). The contact method is the same as a general solvent extraction process, and may be a batch type or a continuous type. Nickel is recovered because it remains in the aqueous solution.

  In addition, the chlorine concentration at the time of contact between the ionic liquid and the aqueous solution is desirably 2 to 10 times the molar concentration of the cobalt concentration.

  This means that when the chlorine concentration exceeds 10 times the molar concentration of the cobalt concentration, general chlorides such as sodium chloride and calcium chloride are close to the upper limit to dissolve in water, and it takes a very long time to dissolve. This is because a precipitate remains and it is difficult to separate the quaternary ammonium-based ionic liquid from the precipitate.

  Further, when the chlorine concentration is less than twice the molar concentration of the cobalt concentration, it is difficult to produce a cobalt chloride complex, and the extractability is reduced.

  Finally, a solution from which cobalt is extracted (herein referred to as a cobalt solution) is brought into contact with water such as pure water (S5 in FIG. 1).

Since pure water does not contain chloride ions, the cobalt chloride complex is decomposed and cobalt is back-extracted to the pure water side. The lower the pure water temperature, the more efficiently cobalt can be extracted.
The above is the cobalt extraction method of this embodiment.

As described above, the cobalt extraction solution of the present embodiment has an ionic liquid containing a quaternary ammonium group and an organic solvent having a Kauri-butanol value of 60 or more that exists in a state of being mixed with the ionic liquid.
Therefore, cobalt extraction that is cheaper and more efficient than the prior art is possible.

  Hereinafter, based on an Example, this invention is demonstrated concretely.

Example 1
Quaternary ammonium-based ionic liquid was brought into contact with various organic solvents, and the viscosity of the mixed solution was measured as the possibility of mixing and the change in physical properties when mixed.

  Specifically, first, TOMAC was prepared as a quaternary ammonium-based ionic liquid.

  Next, an organic solvent having a KB value of 30 to 100 was prepared as an organic solvent, and TOMAC and the organic solvent were brought into contact with each other. In addition, the relationship between the used organic solvent and KB value is as follows.

  Organic solvent with a KB value of 30: Isopar C (isoparaffinic solvent manufactured by ExxonMobil), organic solvent with a KB value of 40: Exol DSP80 (Naphthenic solvent manufactured by ExxonMobil), organic solvent with a KB value of 60: cyclohexane, organic with a KB value of 80 Solvent: Solvesso 150 (an aromatic solvent manufactured by ExxonMobil), organic solvent having a KB value of 100: toluene. The results are shown in Table 1.

  As is clear from Table 1, the organic solvent having a KB value of less than 60 was not mixed with TOMAC and separated into two phases. On the other hand, it was confirmed that a solvent having a KB value of 60 or more is miscible with TOMAC.

  Next, among the above organic solvents, Solvesso 150 was prepared as a solvent having a KB value of 60 or more and mixed with TOMAC at various ratios, and the influence of the mixing ratio on the viscosity of the mixed solution was measured. The results are shown in FIG.

  As shown in FIG. 2, it was confirmed that when the mixing ratio of the organic solvent was increased, the viscosity of the mixed solution decreased almost linearly. Therefore, it has been found that the addition of an organic solvent to TOMAC affects its physical properties.

(Example 2)
A solution in which a quaternary ammonium-based ionic liquid and an organic solvent were mixed (cobalt extraction solution) was brought into contact with Co and a Ni aqueous solution, and Co extraction ability and separation ability were evaluated. The specific procedure is as follows.

  First, TOMAC as a quaternary ammonium-based ionic liquid and Solvesso 150 as an organic solvent were prepared, and TOMAC and an organic solvent were mixed at a mixing ratio of 0 to 60 vol% to prepare a cobalt extraction solution.

Next, Co and Ni were dissolved in 4 mol / L hydrochloric acid to prepare a Co and Ni aqueous solution (Co: 43 g / dm ³ , Ni: 1.0 g / dm ³ ). Note that g / dm ³ = kg / m ³ (the same applies hereinafter).

  Next, Co, Ni aqueous solution and cobalt extraction solution are placed in a separatory funnel and brought into contact by shaking for 10 minutes, Co is transferred to the cobalt extraction solution to extract Co, and Ni remains in the aqueous solution. I let you.

  Next, the Co and Ni concentrations of the aqueous solution before and after extraction were quantitatively analyzed by ICP-AES, and the Co extraction ability and the separation ability between Co and Ni were calculated from the concentration difference of each element before and after extraction. The results are shown in FIG.

  As shown in FIG. 3, the Co extractability decreased as the volume ratio of Solvesso 150 increased. This is probably because Solvesso150 in the solvent does not participate in the extraction of Co.

  On the other hand, the larger the volume ratio of Solvesso 150, the better the separation between Co and Ni. This is presumably because the higher the ratio of Solvesso 150, the more hydrophobic the cobalt extraction solution, and the more the Ni-containing aqueous solution was prevented from dissolving into the cobalt extraction solution.

(Example 3)
Co was extracted from the compound (cobalt residue) containing cobalt, copper, chromium, manganese, iron and nickel by the procedure shown in FIG. 4 by the Co extraction method according to this embodiment. The specific procedure is as follows.

First, 130 g of cobalt residue was dissolved in 1000 ml of hydrochloric acid as an acid (concentration 2 mol / l) to obtain an acid leaching solution (S11 in the figure). The concentration (mg / dm ³ ) of the metal component in the acid leaching solution is as follows. Cu: 1, Cr: 150, Mn: 27, Fe: 1460, Ni: 500).

  Next, 2 ml of hydrogen peroxide (concentration 0.59 mol / l) and sodium hydroxide (concentration 8 mol / l) were added to the acid leaching solution to adjust the pH to 3, and iron was precipitated and collected (S12 in the figure). ).

  Next, the acid leaching solution from which iron was removed was brought into contact with an ion exchange resin (50 ml), and Mn and Cu were adsorbed on the ion exchange resin and removed from the acid leaching solution (S13 in the figure).

  Next, the acid leaching solution from which Mn and Cu have been removed is brought into contact with a cobalt extraction solution (mixing ratio 10: 1) in which TOMAC as an ionic liquid and Solvesso 150 as an organic solvent are mixed, and cobalt in the cobalt extraction solution The ionic liquid was extracted (S14 in the figure).

  Finally, the cobalt extraction solution was brought into contact with pure water, and cobalt was back-extracted into the pure water (S15 in the figure).

  Table 2 shows the results of quantitative analysis by ICP-AES of the metal concentration in the aqueous solution in each procedure.

  As is clear from Table 2, the metal was sequentially removed in each procedure, and finally Co was purified.

  As mentioned above, although this invention was demonstrated based on embodiment and an Example, this invention is not limited to above-described embodiment.

  It is natural for those skilled in the art to come up with various modifications and improvements within the scope of the present invention, and it is understood that these also belong to the scope of the present invention.

Claims (20)

An ionic liquid containing a quaternary ammonium group;
An organic solvent present in admixture with the ionic liquid and having a Kauributanol value of 60 or more;
A solution for extracting cobalt.   The solution for cobalt extraction according to claim 1, comprising the organic solvent in a volume ratio of 2% or more and 50% or less.   The solution for cobalt extraction according to claim 1 or 2, comprising the organic solvent in a volume ratio of 5% or more and 15% or less.   The solution for cobalt extraction according to any one of claims 1 to 3, wherein the organic solvent is an alkylbenzene derivative or toluene.   The ionic liquid may be tri-octthyl-methyl-ammonium chloride (TOMAC) or di-octadethyl-di-methyl-ammonium chloride (di-octadethyl-di-methyl-ammoniumu). Cobalt extraction solution according to any one of claims 1 to 4, which is -chloride).   The solution for cobalt extraction according to any one of claims 1 to 5, wherein the viscosity is 0.02 Pa · s or more and 0.5 Pa · s or less.   The solution for cobalt extraction according to any one of claims 1 to 6, wherein the solubility in water is 0.01% or less. Cobalt extraction solution according to any one of claims 1 to 7,
An aqueous solution of an acid containing cobalt and chlorine, dissolved in the cobalt extraction solution;
Have
A cobalt solution in which cobalt is dissolved in the cobalt extraction solution.   An aqueous solution of an acid containing cobalt and chlorine is present in a state where it is mixed with an ionic liquid containing a quaternary ammonium group and the ionic liquid, and dissolved in a cobalt extraction solution having an organic solvent having a kauributanol value of 60 or more, A cobalt recovery method comprising: separating and recovering cobalt by dissolving cobalt in the cobalt extraction solution. (A) A compound containing cobalt is dissolved in an acid to form an acidic aqueous solution,
(B) The acid is dissolved in the cobalt extraction solution to extract cobalt into the cobalt extraction solution,
(C) bringing the cobalt extraction solution into contact with water and back-extracting and collecting cobalt into the water;
The cobalt recovery method according to claim 9, comprising:   The cobalt recovery method according to claim 9 or 10, wherein the cobalt extraction solution contains the organic solvent in a volume ratio of 2% to 50%.   The cobalt recovery method according to any one of claims 9 to 11, wherein the cobalt extraction solution contains the organic solvent in a volume ratio of 5% or more and 15% or less.   The cobalt recovery method according to any one of claims 9 to 12, wherein the organic solvent is an alkylbenzene derivative or toluene.   The ionic liquid may be tri-octthyl-methyl-ammonium chloride (TOMAC) or di-octadethyl-di-methyl-ammonium chloride (di-octadethyl-di-methyl-ammoniumu). The method for recovering cobalt according to any one of claims 9 to 13, which is -chloride). The compound comprises nickel;
(B)
Dissolving the acidic aqueous solution in the cobalt extraction solution to extract cobalt into the cobalt extraction solution, and recovering nickel remaining in the acidic aqueous solution;
The cobalt recovery method according to claim 10, comprising: The compound includes at least one of manganese and copper,
(D) separating manganese and copper from the acidic aqueous solution by contacting the acidic aqueous solution with a chelate resin;
The cobalt recovery method according to claim 10, comprising: The compound comprises iron;
(E) removing iron from the acidic aqueous solution;
The cobalt recovery method according to claim 10, comprising: Said (e) is
Hydrogen peroxide is added to the acidic aqueous solution to oxidize iron,
Adjusting the pH of the acidic aqueous solution to 1 or more and 6 or less to precipitate iron;
Removing the precipitated iron by filtration;
The cobalt recovery method according to claim 17, comprising:   The cobalt recovery method according to claim 10, wherein (a) includes adding a chloride to the acidic aqueous solution.   The said compound contains the residue after collect | recovering tungsten from the cemented carbide scrap containing tungsten and cobalt, The cobalt collection method of Claim 10 characterized by the above-mentioned.

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