JP7249317B2 - METHOD FOR SEPARATING METAL AND METAL SEPARATING DEVICE - Google Patents

Description

The present invention relates to a metal separation method and a metal separation apparatus.

In recent years, the demand for nickel and cobalt has increased as positive electrode materials for lithium ion batteries used in electric vehicle batteries and the like. From the viewpoint of effective utilization of resources, nickel and cobalt are being studied for their reuse by being recovered from the waste liquid generated in the manufacturing process of the positive electrode material.

However, when metals such as nickel and cobalt that have chemically similar properties are contained in an aqueous solution, it is not easy to separate these metals, and various methods have been investigated so far. . For example, in Patent Document 1, after both nickel and cobalt are adsorbed on an ion exchange resin, nickel and cobalt are eluted with a sulfuric acid solution, and then nickel and cobalt are separated using an organic solvent extraction method or the like. Proposed.

JP 2019-173063 A

However, in the method proposed in Patent Document 1, since both nickel and cobalt are adsorbed on the ion exchange resin, it is necessary to separately separate nickel and cobalt by an organic solvent extraction method or the like, and the process is complicated. In addition, the organic solvent extraction method has problems in terms of environmental load and cost. Such problems are not limited to nickel and cobalt, but also exist in other metals having chemically similar properties.

The present invention has been made in view of such problems, and provides a metal separation method and a metal separation apparatus capable of efficiently separating metals while reducing environmental load and cost. The challenge is to

A metal separation method according to the present invention comprises an aqueous solution containing at least one metal selected from Group A below (Group A metal) and at least one metal selected from Group B below (Group B metal). , a mixing step (1) of mixing the following acid and the following alkali to obtain a mixed solution containing an alkali complex of a group A metal and an acid complex of a group B metal; a separation step (2) in which the mixed solution is brought into contact with the ion exchange resin to separate the ion exchange resin adsorbing the group A metal alkali complex and the aqueous solution containing the group B metal acid complex; include.
Group A: nickel, copper, lead, zinc, and cadmium Group B: cobalt, iron, and manganic acid: carboxylic acid and its complex, a compound having a lactone structure, and at least one selected from the group consisting of gluconic acid Seed alkali: at least one selected from the group consisting of ammonia and amine compounds

The metal separation apparatus according to the present invention comprises an aqueous solution containing at least one metal selected from the following group A (group A metal) and at least one metal selected from the following group B (group B metal). , the following acid and the following alkali are mixed to obtain a mixed solution containing an alkali complex of a group A metal and an acid complex of a group B metal; a separation unit (12) for separating into an ion exchange resin adsorbing an alkali complex of a group A metal and an aqueous solution containing an acid complex of a group B metal by contacting the mixed solution with the ion exchange resin; a water reservoir (13) for storing the aqueous solution containing the group B metal acid complex separated by the separator (12).
Group A: nickel, copper, lead, zinc, and cadmium Group B: cobalt, iron, and manganic acid: carboxylic acid and its complex, a compound having a lactone structure, and at least one selected from the group consisting of gluconic acid Seed alkali: at least one selected from the group consisting of ammonia and amine compounds

Advantageous Effects of Invention According to the present invention, it is possible to provide a metal separation method and a metal separation apparatus that can efficiently separate metals while reducing environmental load and cost.

4 is a graph showing the results of measuring metal concentrations in Example 1 of Test 1. FIG. 4 is a graph showing the results of measuring metal concentration in Comparative Example 1 of Test 1. FIG. 4 is a graph showing the results of measuring metal concentrations in Comparative Example 2 of Test 1. FIG. 4 is a graph showing the results of measuring metal concentrations in Test 2. FIG.

Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

[Metal Separation Method]
A metal separation method according to the present embodiment includes an aqueous solution containing at least one metal selected from Group A (Group A metal) and at least one metal selected from Group B (Group B metal), A mixing step (1) of mixing an acid and an alkali to obtain a mixed solution containing an alkali complex of a group A metal and an acid complex of a group B metal, and the mixed solution obtained in the mixing step (1) and a separation step (2) of separating into an ion exchange resin adsorbing an alkali complex of a group A metal and an aqueous solution containing an acid complex of a group B metal by contacting the ion exchange resin with the ion exchange resin.

<Mixing step (1)>
In the mixing step (1), an aqueous solution containing a group A metal and a group B metal, an acid, and an alkali are mixed to obtain a mixture containing an alkali complex of the group A metal and an acid complex of the group B metal. to obtain a solution.

Group A metals are at least one metal selected from nickel, copper, lead, zinc, and cadmium. Also, the B group metal is at least one metal selected from cobalt, iron and manganese. Among these, when the Group A metal is nickel and the Group B metal is cobalt, these metals used as positive electrode materials for lithium ion batteries can be efficiently separated.

Acids preferentially bond with group B metals to form acid complexes. In addition, "preferentially" means that more group B metals than A group metals are bound to acid. That is, part of the group A metal may be bonded with acid. Moreover, all of the B group metals do not need to be combined with acid, and some of the B group metals may not be combined with acid.

The acid is at least one selected from the group consisting of carboxylic acids and their complexes, compounds having a lactone structure, and gluconic acid. Carboxylic acids include, for example, acetic acid, formic acid, propionic acid, citric acid, tartaric acid, and malic acid. Examples of compounds having a lactone structure include ascorbic acid. Among these, the acid is preferably a hydroxy acid such as citric acid, tartaric acid, or malic acid and a complex thereof, and more preferably citric acid, from the viewpoint of easily forming a complex.

Alkalis preferentially bond with group A metals to form alkali complexes. The term "preferentially" means that more group A metals than group B metals bind to alkali. That is, part of the B group metal may be bonded with alkali. Further, not all of the group A metals need to be bound with alkali, and some of the group A metals may not be bound with alkali.

The alkali is at least one selected from the group consisting of ammonia and amine compounds. Examples of amine compounds include monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylformamide and the like. Among these, the alkali is preferably ammonia from the viewpoint of easily forming a complex.

The pH of the obtained mixed solution is preferably 8.5 or more and 14 or less, more preferably 10 or more and 12 or less. When the pH of the mixed solution is within the above range, the alkali complex of the Group A metal is easily adsorbed on the ion exchange resin in the separation step (2) described later.

The mixed solution may contain other alkalis different from the above-mentioned alkalis in order to adjust the pH to the above range. Other alkalis are not particularly limited, and examples thereof include sodium hydroxide, calcium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, magnesium hydroxide, calcium oxide, magnesium oxide and the like.

<Separation step (2)>
In the separation step (2), the mixed solution obtained in the mixing step (1) and the ion exchange resin are brought into contact with each other to separate the ion exchange resin adsorbing the group A metal alkali complex and the group B metal acid complex. and an aqueous solution containing Alkali complexes of group A metals are easily adsorbed on ion exchange resins. On the other hand, since the acid complex of the group B metal is difficult to be adsorbed on the ion exchange resin, it flows out as an aqueous solution containing the acid complex of the group B metal. As a result, the ion exchange resin adsorbing the group A metal alkali complex and the aqueous solution containing the group B metal acid complex can be separated. It should be noted that the group A metal alkali complex need not be wholly adsorbed on the ion exchange resin, and a part thereof may be adsorbed on the ion exchange resin. The group A metal alkali complex preferably has a group A metal removal rate of 80% or more with an ion-exchange resin. Also, part of the acid complex of the group B metal may be adsorbed on the ion exchange resin.

As described above, in the method for separating metals according to the present embodiment, separation is performed in the separation step (2) into the ion exchange resin that has adsorbed the alkali complex of the group A metal and the aqueous solution containing the acid complex of the group B metal. Therefore, there is no need to separately use an organic solvent extraction method or the like. Therefore, in the metal separation method according to the present embodiment, the environmental load and cost can be reduced, and metals can be efficiently separated.

Examples of ion exchange resins include strongly acidic cation exchange resins, weakly acidic cation exchange resins, strongly basic anion exchange resins, weakly basic anion exchange resins, amphoteric ion exchange resins, and chelate resins. Among these, the ion-exchange resin is preferably a chelate resin from the viewpoint of easily adsorbing an alkali complex. The chelate resin is not particularly limited, and examples thereof include iminodiacetic acid-type chelate resin, N-methylglucamine-type chelate resin, aminophosphoric acid-type chelate resin, thiouric acid-type chelate resin, alkylamino group-type chelate resin, Examples include polyamine-type chelate resins, pyridine-type chelate resins, amidoxime-type chelate resins, Fe complex-type chelate resins, and the like.

In the separation step (2), the contact between the mixed solution and the ion exchange resin may be carried out by passing the mixed solution through a column packed with the ion exchange resin. The material of the column is not particularly limited, and examples thereof include resins such as vinyl chloride, polypropylene, polyethylene, eslon, polyacetal, fluororesin, polycarbonate and nylon; glass and the like. The column may be transparent, translucent, or opaque, but is preferably transparent from the viewpoint of making it possible to visually confirm changes in the ion-exchange resin and predict when to replace it. The size of the column is not particularly limited, and for example, a column with an inner diameter of 10 to 600 cm and a height of 50 to 200 cm can be used.

The rate at which the mixed solution is passed through the column is preferably 0.05 L/h or more and 20 L/h or less, and 0.1 L/h or more and 10 L/h or less, from the viewpoint of easily adsorbing the alkali complex. is more preferred.

<Group A metal recovery step (3)>
The metal separation method according to the present embodiment further includes a group A metal recovery step ( 3) may be included.

In the group A metal recovery step (3), for example, an acid such as hydrochloric acid or sulfuric acid is passed through the ion exchange resin that has adsorbed the group A metal alkali complex obtained in the separation step (2) to remove the group A metal. After obtaining an aqueous solution containing the group A metal hydroxide, an alkaline precipitation method can be used to recover the group A metal hydroxide.

<Group B metal recovery step (4)>
The metal separation method according to the present embodiment further comprises a group B metal recovery step (4) of recovering the group B metal from the aqueous solution containing the acid complex of the group B metal obtained in the separation step (2). may contain.

In the group B metal recovery step (4), for example, after adjusting the pH of the aqueous solution containing the group B metal acid complex so that the group B metal acid complex is adsorbed on the ion exchange resin, the group B metal acid complex is removed. It is adsorbed on an ion-exchange resin, and an acid such as hydrochloric acid or sulfuric acid is passed through the ion-exchange resin to obtain an aqueous solution containing a group B metal. can be recovered. Here, the pH of the aqueous solution containing the group B metal acid complex is preferably 4 or more and 6 or less from the viewpoint of making it easier for the ion exchange resin to adsorb the group B metal acid complex.

[Metal separation device]
The metal separation device according to the present embodiment comprises an aqueous solution containing at least one metal selected from Group A (Group A metal) and at least one metal selected from Group B (Group B metal); A mixing section (11) for mixing an acid and an alkali to obtain a mixed solution containing an alkali complex of a group A metal and an acid complex of a group B metal, and the mixed solution obtained in the mixing section (11) A separation unit (12) that separates an ion exchange resin that adsorbs an alkali complex of a group A metal and an aqueous solution containing an acid complex of a group B metal by bringing the ion exchange resin into contact with the separation unit (12), and the separation unit ( and a reservoir (13) for storing the aqueous solution containing the group B metal acid complex separated by 12).

In the mixing section (11), the mixing step (1) described above is performed. As the aqueous solution containing the group A metal and the group B metal, the acid and the alkali mixed in the mixing section (11), those described above can be used.

The separation step (2) described above is performed in the separation section (12) and the water storage section (13). In the separation section (12), the group A metal alkali complex was adsorbed on the ion exchange resin, and the aqueous solution containing the group B metal acid complex was stored in the water storage section (13), thereby adsorbing the group A metal alkali complex. It can be separated into an ion exchange resin and an aqueous solution containing an acid complex of a group B metal.

The metal separation apparatus according to the present embodiment may further include a group A metal recovery section (14) for recovering the group A metal from the ion exchange resin that has adsorbed the alkali complex of the group A metal. In the group A metal recovery section (14), the above-described group A metal recovery step (3) is performed.

The metal separation apparatus according to the present embodiment may further include a group B metal recovery unit (15) for recovering the group B metal from the aqueous solution containing the acid complex of the group B metal. In the group B metal recovery section (15), the above-described group B metal recovery step (4) is performed.

It should be noted that the metal separation method and the metal separation apparatus according to the present embodiment are not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present invention. In addition, the configurations, methods, etc. of the embodiments other than the above may be arbitrarily adopted and combined, and the configurations, methods, etc. according to one embodiment described above may be applied to the configurations, methods, etc. according to the other embodiments described above. You may

EXAMPLES The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[Test 1]
<Model liquid waste>
Model waste liquids A to C were prepared by the method shown below. Table 1 shows the concentration (analysis value) of each component of the model waste liquids A to C.

(Model waste liquid A)
(a) 606 g of sodium chloride was added to 3 L of distilled water and thoroughly stirred to dissolve.
(b) To the solution obtained in (a) above, 586 g of citric acid monohydrate was added and thoroughly stirred to dissolve.
(c) 8.3 g of nickel (II) chloride hexahydrate was added to the solution obtained in (b) above, and thoroughly stirred to dissolve.
(d) To the solution obtained in (c) above, 8.2 g of cobalt chloride was added and thoroughly stirred to dissolve.
(e) A 25 mass % sodium hydroxide solution was added to the solution obtained in (d) above to adjust the pH to 10.5.

(Model waste liquid B)
(a) 606 g of sodium chloride was added to 3 L of distilled water and thoroughly stirred to dissolve.
(b) 155 g of ammonium chloride was added to the solution obtained in (a) above and thoroughly stirred to dissolve.
(c) 8.3 g of nickel (II) chloride hexahydrate was added to the solution obtained in (b) above, and thoroughly stirred to dissolve.
(d) To the solution obtained in (c) above, 8.2 g of cobalt chloride was added and thoroughly stirred to dissolve.
(e) A 25 mass % sodium hydroxide solution was added to the solution obtained in (d) above to adjust the pH to 10.5.

(Model waste liquid C)
(a) 606 g of sodium chloride was added to 3 L of distilled water and thoroughly stirred to dissolve.
(b) 155 g of ammonium chloride was added to the solution obtained in (a) above and thoroughly stirred to dissolve.
(c) To the solution obtained in (b) above, 586 g of citric acid monohydrate was added and thoroughly stirred to dissolve.
(d) 8.3 g of nickel (II) chloride hexahydrate was added to the solution obtained in (c) above, and thoroughly stirred to dissolve.
(e) To the solution obtained in (d) above, 8.2 g of cobalt chloride was added and thoroughly stirred to dissolve.
(f) A 25 mass % sodium hydroxide solution was added to the solution obtained in (e) above to adjust the pH to 10.5.

In Table 1, "Ni" represents nickel concentration, "Co" represents cobalt concentration, "TOC" represents total organic carbon concentration, "NH4-N" represents ammonia nitrogen concentration, "CL" represents chloride ion concentration.

In the examples and comparative examples, the nickel concentration was measured by JIS K 0102-59.1 dimethylglyoxime absorptiometry, and the cobalt concentration was measured by JIS K 0102-60.1 nitroso R salt absorptiometry. , the ammonia nitrogen concentration was determined using the JIS K 0102-42.3 neutralization titration method. However, for the ammonia nitrogen concentration, a value converted from ammonium ion to ammonia nitrogen was used.

<Ion exchange resin>
As the ion exchange resin, an iminodiacetic acid type chelate resin (MC-700, manufactured by Sumika Chemtex Co., Ltd.) was used. 100 mL of the chelate resin was packed in a 200 mL graduated cylinder (column) made of resin, and pure water was filled up to the level of the retained liquid.

<Example 1>
In Example 1, the model waste liquid C was passed through the column, and the concentrations of nickel and cobalt in the effluent sampled over time were measured. The measurement results are shown in Table 2 and FIG. The speed at which the waste liquid was passed through the column was 200 mL/hour (SV=2). That is, an amount twice as much as the internal volume of 100 mL of the column is passed for one hour.

As can be seen from the results in Table 2 and FIG. 1, when the supply amount was 0.8 L, nickel was 5 mg/L and cobalt was 86 mg/L. Also, when the supply amount was 17.6 L, nickel was 5.2 mg/L and cobalt was 95 mg/L. That is, in Example 1 using the model waste liquid C that satisfies the constituent requirements of the present invention, nickel is adsorbed on the ion exchange resin, but cobalt flows out without being adsorbed on the ion exchange resin. Therefore, nickel and cobalt can be separated.

<Comparative Example 1>
Except for using the model waste liquid A instead of the model waste liquid C, the liquid was passed through the column in the same manner as in Example 1. The measurement results are shown in Table 2 and FIG.

As can be seen from the results in Table 2 and FIG. 2, when the supply amount was 4.3 L, nickel was 59 mg/L and cobalt was 90 mg/L. Also, when the supply amount was 17.6 L, nickel was 24 mg/L and cobalt was 81 mg/L. That is, in Comparative Example 1 using the model waste liquid A containing no alkali, both nickel and cobalt flowed out without being adsorbed by the ion exchange resin. Therefore, nickel and cobalt cannot be separated.

<Comparative Example 2>
Except for using the model waste liquid B instead of the model waste liquid C, the liquid was passed through the column in the same manner as in Example 1. The measurement results are shown in Table 2 and FIG.

As can be seen from the results in Table 2 and FIG. 3, nickel and cobalt were almost 0 mg/L at any feeding amount. That is, in Comparative Example 2 using model waste liquid B containing no acid, both nickel and cobalt are adsorbed on the ion exchange resin. Therefore, nickel and cobalt cannot be separated.

[Test 2]
A model waste liquid D was prepared by the method shown below. The model waste liquid D is assumed to be an aqueous solution that flows out without being adsorbed by the ion exchange resin in Example 1 of Test 1. The concentration of cobalt in model waste liquid D was 100 mg/L.
(a) 606 g of sodium chloride was added to 3 L of distilled water and thoroughly stirred to dissolve.
(b) 155 g of ammonium chloride was added to the solution obtained in (a) above and thoroughly stirred to dissolve.
(c) To the solution obtained in (b) above, 586 g of citric acid monohydrate was added and thoroughly stirred to dissolve.
(d) To the solution obtained in (c) above, 16.3 g of cobalt chloride was added and thoroughly stirred to dissolve.
(e) A 25% by mass sodium hydroxide solution was added to the solution obtained in (d) to adjust the pH to 4, 6 and 8, respectively.

The model effluent D adjusted to pH 4, 6, and 8 was passed through the same column as in test 1, and the concentration of cobalt in the effluent sampled over time was measured. The measurement results are shown in Table 3 and FIG. The speed at which the waste liquid was passed through the column was the same as in Test 1.

As can be seen from the results in Table 3 and FIG. 4, when the supply amount is 1.1 L, pH 4: 0 mg / L, pH 6: 0 mg / L, pH 8: 45 mg / L, and when the supply amount is 3.8 L, pH4: 9.6 mg/L, pH6: 0 mg/L, pH8: 51 mg/L, and when the supply amount is 5.6 L, pH4: 100 mg/L, pH6: 4.4 mg/L, pH8: 54 mg/L Met. That is, when the model waste liquid D has a pH of 4 or more and 6 or less, cobalt is likely to be adsorbed on the ion exchange resin.

Claims (13)

An aqueous solution containing at least one metal selected from Group A below (Group A metal) and at least one metal selected from Group B below (Group B metal), an acid below, and an alkali below. a mixing step (1) of mixing to obtain a mixed solution containing an alkali complex of a group A metal and an acid complex of a group B metal;
By bringing the mixed solution obtained in the mixing step (1) into contact with the ion exchange resin, the ion exchange resin adsorbing the group A metal alkali complex and the aqueous solution containing the group B metal acid complex are separated. A separation step (2) to
A method of separating metals, including
Group A: nickel, copper, lead, zinc, and cadmium Group B: cobalt, iron, and manganic acid: carboxylic acid and its complex, a compound having a lactone structure, and at least one selected from the group consisting of gluconic acid Seed alkali: at least one selected from the group consisting of ammonia and amine compounds 2. The method according to claim 1, further comprising a group A metal recovery step (3) of recovering the group A metal from the ion exchange resin that adsorbs the alkali complex of the group A metal obtained in the separation step (2). Metal separation method. 3. The metal according to claim 1, further comprising a group B metal recovery step (4) for recovering the group B metal from the aqueous solution containing the acid complex of the group B metal obtained in the separation step (2). separation method. The method for separating metals according to any one of claims 1 to 3, wherein the ion exchange resin is a chelate resin. The method for separating metals according to any one of claims 1 to 4, wherein the mixed solution obtained in the mixing step (1) has a pH of 8.5 or more and 14 or less. The method for separating metals according to any one of claims 1 to 5, wherein the acid is a hydroxy acid and its complexes. The method for separating metals according to any one of claims 1 to 6, wherein the acid is citric acid. The method for separating metals according to any one of claims 1 to 7, wherein the alkali is ammonia. The method for separating metals according to any one of claims 1 to 8, wherein the group A metal is nickel and the group B metal is cobalt. In the separation step (2), the mixed solution is brought into contact with the ion exchange resin by passing the mixed solution through a column filled with the ion exchange resin,
The method for separating metals according to any one of claims 1 to 9, wherein the mixed solution is passed through the column at a rate of 0.05 L/h or more and 20 L/h or less. An aqueous solution containing at least one metal selected from Group A below (Group A metal) and at least one metal selected from Group B below (Group B metal), an acid below, and an alkali below. a mixing part (11) for mixing to obtain a mixed solution containing an alkali complex of a group A metal and an acid complex of a group B metal;
By bringing the mixed solution obtained in the mixing section (11) into contact with the ion exchange resin, the ion exchange resin adsorbing the group A metal alkali complex and the aqueous solution containing the group B metal acid complex are separated. a separation unit (12) for
a water storage part (13) for storing the aqueous solution containing the acid complex of the group B metal separated by the separation part (12);
Separating equipment for metals, including
Group A: nickel, copper, lead, zinc, and cadmium Group B: cobalt, iron, and manganic acid: carboxylic acid and its complex, a compound having a lactone structure, and at least one selected from the group consisting of gluconic acid Seed alkali: at least one selected from the group consisting of ammonia and amine compounds 12. The metal separation device according to claim 11, further comprising a group A metal recovery unit (14) for recovering the group A metal from the ion exchange resin that has adsorbed the alkali complex of the group A metal. 13. The metal separating apparatus according to claim 11 or 12, further comprising a group B metal recovery unit (15) for recovering the group B metal from an aqueous solution containing an acid complex of the group B metal.

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