JPH06200336A - Separation of cobalt from nickel - Google Patents

Abstract

PURPOSE:To separate cobalt from nickel with high extraction efficiency and selectivity by using an emulsifiable liq. membrane having a specified structure and conditioned with a cationic surfactant. CONSTITUTION:The cationic surfactant has the basic structure of glutamic acid and has two hydrophobic groups and hydrophilic groups. The R<1> and R<2> of the hydrophobic group are 12-22C saturated or unsaturated hydrocarbonic group or preferably 14-18C alkyls or alkenyls, and dodecyls, tridecyls or tetradecyls are exemplified. A quaternary ammonium group is most suitable to the hydrophilic group. Meanwhile, chlorine and bromine are preferable as the halogen X as the counter anion of ammonium cation. When hydoxymethyl and hydroxyethyl are used as R<3>, an extraction rate is increased as compared with methyl and ethyl, and selectivity is improved.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for separating cobalt and nickel, and more particularly to an improved method for separating cobalt and nickel using an emulsion type liquid membrane prepared with a specific cationic surfactant.

[0002]

2. Description of the Related Art A solvent extraction method for extracting a metal from an aqueous phase using an organic solvent and a metal extractant is an essential method for separating a metal which is difficult to separate and purify by a usual method. . An emulsion liquid film to which a W / O / W type liquid film is applied, which is obtained by dispersing a water-in-oil (W / O) type emulsion called a so-called reverse phase in the aqueous phase in the solvent extraction method. The type extraction method has been attracting attention in recent years.

The W / O type emulsion used for separating metals is a mixture of a surfactant and a metal extractant dissolved in an aliphatic hydrocarbon and the like, and an aqueous sulfuric acid solution for back-extracting the metal, and the mixture is stirred and mixed. It is a state in which fine water droplet-shaped particles of a micron unit such as a sulfuric acid aqueous solution in which the organic phase prepared by the above is a continuous phase are dispersed, and each fine particle is stabilized by an appropriately selected surfactant. Therefore, it is not easily destroyed even by mechanical elastic force such as stirring. When this is added to an aqueous solution containing a metal and stirred and dispersed, the metal in the outer aqueous phase is extracted into the organic phase, and at the same time, the metal is back-extracted from the organic phase into the emulsion droplet aqueous phase. The metal in the water phase is concentrated in the water phase in the emulsion droplets. After extraction, the mixture is allowed to stand to separate into an external water phase and a W / O emulsion phase. Further, by demulsifying the W / O type emulsion, the aqueous phase in the emulsion in which the metal is concentrated can be separated.

As described above, the features of the metal extraction process using the W / O type emulsion are: (1) Since the liquid film of fine particles is used, the interface between the water phase and the organic phase is compared to the general extraction. The area is greatly increased, which improves the processing speed. (2) The extraction / back extraction is performed at the same time, so that the concentration efficiency is high and the apparatus can be downsized.
Due to these features, the metal extraction process using the W / O type emulsion is very effective as a method for removing harmful metals contained in a small amount of waste water. However, when this method is applied to the separation of metals, it is said that it is difficult to carry out the separation with a high selectivity, probably because of the influence of the surfactant or the like used in the preparation of the W / O emulsion.

Generally, it is necessary to select a surfactant having the following properties as a surfactant used for preparing a W / O emulsion. That is, (1) When the prepared W / O emulsion is dispersed in an aqueous solution containing a metal to extract the metal, a mechanical stirring operation is added to increase the extraction efficiency, and thus the W / O emulsion is stirred. It is not easily destroyed by, for example, (2) demulsification easily occurs when recovering concentrated metal components in the inner aqueous phase of the emulsion, (3) the liquid membrane phase is circulated in industrial processes. Since it is used repeatedly, it should be chemically stable and easy to manufacture.

As described above, the surfactants used in the preparation of W / O emulsions are required to have many functions, and therefore, those actually used are relatively limited. As a typical one, sorbitan monooleate (span 80, trade name, manufactured by ICI) and the cationic surfactant used in the present invention have a hydrophilic group portion different from the following general formula.

[0007]

[Chemical 2]

(In the formula, R and R'may be the same or different from each other and represent a saturated or unsaturated hydrocarbon group having 8 to 20 carbon atoms, and m and n represent integers of 1 to 10). , X represents a halogen atom) (Japanese Patent Laid-Open No. 1-224038) and the like, but the extraction efficiency and selectivity are not satisfactory. An object of the present invention is to provide a method for separating cobalt and chromium with high extraction efficiency and selectivity by using an emulsion liquid film type extraction method.

[0009]

[Means for Solving the Problems] The present inventors have established W / O / W
As a result of intensive research to develop a method capable of separating metals with high selectivity in an emulsion liquid membrane type extraction method applying a liquid membrane, a cationic surfactant having a specific structure The inventors have found that cobalt and nickel can be easily separated by using, and have completed the present invention. That is, the present invention includes: 1) General formula (I)

[0010]

[Chemical 3]

(In the formula, R ¹ and R ^{2, which} may be the same or different, each represents a saturated or unsaturated hydrocarbon group having 12 to 22 carbon atoms, and R ³ is methyl, ethyl, hydroxymethyl or hydroxyethyl. Group, and X represents halogen), and a method for separating cobalt and nickel, characterized by using an emulsion type liquid membrane prepared with at least one cationic surfactant represented by the formula:

2) The water-insoluble phase containing the metal extractant and the water phase containing the metal ion condensing agent are emulsified in the presence of the cationic surfactant represented by the above-mentioned general formula (I) to obtain an oil. After forming a water (W / O) type emulsion, the emulsion is dispersed in an aqueous solution containing cobalt ions and nickel ions, which is a phase to be extracted, and the cobalt ions are extracted with the emulsion to be concentrated in the aqueous phase of the emulsion. After
Separation and demulsification of the emulsion, and separation of the cobalt ion-concentrated aqueous phase from the water-insoluble phase, and 3) R ¹ in the general formula (I) And R ² is an alkyl group or an alkenyl group having 12 or more carbon atoms, and R ³ is a hydroxymethyl or hydroxyethyl group.
The method for separating cobalt and nickel described in 1.

The present invention will be described in detail below. The cationic surfactant represented by the general formula (I) used in the present invention has a basic structure of glutamic acid and has two hydrophobic groups and two hydrophilic groups. These hydrophobic groups are W
/ O greatly contributes to the preparation of the emulsion and the improvement of the stability of the emulsion. The cationic surfactant represented by the general formula (I) may be used alone or in combination of two or more.

In the general formula (I), R ¹ and R ² relating to the two hydrophobic groups are saturated or unsaturated hydrocarbon groups having 12 to 22 carbon atoms, preferably alkyl or alkenyl having 14 to 18 carbon atoms. It is a base. Here, R ¹ and R ² may be the same or different, but the same group is preferable from the viewpoint of easy production. In addition to a straight chain, a branched hydrocarbon group may be used. Specific examples include dodecyl (lauryl), tridecyl, tetradecyl (myristyl), pentadecyl, hexadecyl (cetyl), heptadecyl,
Octadecyl (stearyl), an oleyl group, etc. are mentioned.

As the hydrophilic group, a quaternary ammonium group is most suitable for improving the separation selectivity between cobalt and nickel. Further, examples of the halogen X in the general formula (I) which is the counter anion of the ammonium cation include fluorine, chlorine, bromine and iodine, but chlorine and bromine are preferable. R ³ is a methyl group, an ethyl group, a hydroxymethyl group or a hydroxyethyl group. Compared to the methyl group and the ethyl group, the hydroxymethyl group and the hydroxyethyl group have a high extraction treatment rate and also an improved selectivity. Therefore, it is preferable.

The surfactant used in the present invention is a compound derived from glutamic acid, and it is considered that the stability of the liquid film constituting the emulsion can be improved by the three-dimensional structure of rigid glutamine. The surfactant used in the present invention can be easily synthesized from glutamic acid by a known method. For example, it can be easily produced by diesterifying glutamic acid with a long-chain alcohol, acylating an amino group with monochloroacetic acid chloride, and then quaternizing with a tertiary amine according to the following reaction scheme.

[0017]

[Chemical 4]

The oil phase used in the preparation of the W / O emulsion is a liquid that is not uniformly dissolved in water, for example, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons,
Specific examples include mineral oil, paraffin oil, kerosene, light oil, naphtha, perchlorethylene, benzene, toluene, xylene, hexane, heptane, cyclohexane and the like. Also, a mixture of these may be used.

An extractant for metal extraction is dissolved in these oil layers. The extractant used here may basically be one that is soluble in aliphatic hydrocarbons, aromatic hydrocarbons, and halogenated hydrocarbons. Specifically, 2-ethylhexylphosphonic acid-mono-2-ethylhexylate (P
C-88A, trade name, manufactured by Daihachi Chemical Co., Ltd., bis-
(2,4,4-Trimethylpentyl) phosphinic acid (C
YANEX272, product name, Mitsui Cyanamid Co., Ltd.
Manufactured by Henkel), 2-hydroxy-5-alkylbenzaldehyde oxime (LIX860, trade name, manufactured by Henkel), 2-hydroxy-5-alkylacetophenone oxime (LIX84, trade name, manufactured by Henkel), and the like.

The metal extractant is used at a concentration of 1 to 30000 mol / m ^{3 based on} the volume of the W / O emulsion. W
The aqueous phase used for preparing the / O emulsion is for back-extracting and concentrating the metal extracted in the emulsion oil phase, and an aqueous solution of a mineral acid such as hydrochloric acid, sulfuric acid, nitric acid is used. . The concentration of the mineral acid is 50 to 10,000 mol / m ³ , and an organic acid, salt or the like may be added as appropriate.

The ratio of the oil phase to the water phase can be widely varied within the range in which the W / O emulsion can be stably present.
Aqueous phase = 30: 70 to 95: 5 (volume ratio).
The W / O type emulsion is prepared by rapidly stirring the above oil phase and water phase in the presence of the cationic surfactant used in the present invention. Here, various homomixers, emulsifiers and the like can be used for high speed stirring.
The concentration of the surfactant is in the range of 1 to 100 mol / m ^{3 based} on the volume of the emulsion, more preferably 5 to
It is in the range of 50 mol / m ³ .

Extraction and separation of cobalt and nickel are carried out by adding the prepared W / O type emulsion to an aqueous solution containing cobalt and nickel and stirring and dispersing. For example, when 2-hydroxy-5-alkylacetophenone oxime (LIX860) is used as the metal extractant, cobalt is extracted and back-extracted to be concentrated in the inner aqueous phase of the W / O emulsion, and nickel is converted to the outer aqueous phase. You will be left behind. The amount of W / O emulsion added varies depending on the concentrations and amounts of cobalt and nickel, but usually W / O
O emulsion: aqueous metal solution = 1: 20 to 20: 1.

After completion of the extraction separation, the external water phase and the W / O type emulsion phase are separated. Separation is carried out by utilizing the difference in specific gravity, but usually it can be separated only by leaving it still. For demulsification of the emulsion after separation, an electrical method of applying a voltage and a method of adding an oil-in-water (O / W) type surfactant are used. In the former case, the applied voltage is effective in either direct current or alternating current, and a voltage of 0.1 to 50 KV is usually used. The oil phase after demulsification can be continuously used for the next emulsification and extraction process as it is. In the latter method, a surfactant having a hydrophilic-lipophilic balance (HLB) value of 8 to 14 is preferable. By the above operation, for example, 2-hydroxy-
5-Alkylacetophenone oxime (LIX860)
When nickel is used, nickel is concentrated in the outer water phase and cobalt is concentrated in the water phase obtained by the demulsification of the W / O type emulsion at a high concentration.

[0024]

The cobalt and nickel which can be separated according to the present invention are so-called rare metals,
It is used as a raw material for functional materials in various fields, but the current situation is that its supply side is fragile. As a supply source, recently, copper and iron, nickel and cobalt,
Attention has been paid to manganese nodules, which include chromium and are present in large amounts in the deep sea floor such as the Pacific Ocean. The present invention is highly significant as a method for rapidly separating cobalt and nickel from these ores with high selectivity, and is a treatment difficult to achieve by the conventional solvent extraction method and the conventional emulsion liquid film method. Contribution to the mining sector is extremely large, such as reduction of separation cost due to improved efficiency.

[0025]

EXAMPLES The present invention will be described in more detail with reference to Production Examples, Examples and Comparative Examples, but the present invention is not limited to the following description.

Production Example 1: R ¹ = R in the general formula (I)
Preparation of ₂ = oleyl group, R ³ = methyl group cationic surfactant (hereinafter abbreviated as GEQA)

[0027]

[Chemical 5]

20 g (0.136 mol) of glutamic acid was dissolved in 600 ml of toluene, and 80.9 g of oleyl alcohol was dissolved.
(0.299 mol) and p-toluenesulfonic acid monohydrate (25.4 g, 0.13 mol) were added, a Dean Stark trap was attached, and the mixture was stirred under reflux for 4 hours for esterification reaction. The reaction solution is concentrated and then tetrahydrofuran (TH
F) Dissolved in 1000 ml, 41.2 g of triethylamine (0.40
8 mol), chloroacetic acid chloride 18.5 g (0.163 mol)
Was added and stirred for 6 hours. After the reaction, undissolved substances were filtered and the resulting solution was concentrated to give a chloroform solution, and then 1N hydrochloric acid,
The mixture was washed successively with 5% aqueous sodium hydrogen carbonate and water, dried over anhydrous magnesium sulfate, and concentrated to give a gum-like crude amide. The crude amide compound was dissolved again using 600 ml of THF, 12.0 g (0.20 mol) of trimethylamine was added to the solution, and the mixture was refluxed for 4 hours. The reaction solution was concentrated, made into a chloroform solution, washed with 1N hydrochloric acid solution and 5% saline solution, and then concentrated.
The crude reaction product was made into a chloroform solution and then purified by silica gel chromatography to obtain 41.5 g (yield 52%) of the title compound.

[0029] IR (neat) 1730cm ^-1 (ester), 1650 cm ^-1 (amide).

Production Example 2: R ¹ = R in the general formula (I)
Preparation of ₂ = oleyl group, R ³ = hydroxyethyl group cationic surfactant (hereinafter abbreviated as GEQA-OH)

[0031]

[Chemical 6]

50 g of the crude amide compound produced in the same manner as in Production Example 1 was dissolved in 300 ml of THF, 7.0 g of dimethylaminoethanol was added to this solution, and the mixture was refluxed for 6 hours.
After the reaction, the same purification operation as in Production Example 1 was performed to obtain 35 g of the title compound.

[0033] IR (neat) 3350cm-1 (hydroxyl), 1735 cm ^-1 (ester), 1650 cm ^-1 (amide).

Production Example 3: The following formula

[0035]

[Chemical 7]

A cationic surfactant represented by
Abbreviated as GE. ) Preparation of glutamic acid 20 g, oleyl alcohol 80 g, p-
40 g (0.21 mol) of toluenesulfonic acid monohydrate and 600 ml of toluene were mixed and refluxed for 5 hours using a Dean Stark trap. After the reaction, toluene is distilled off,
The residue was dissolved in ether, washed with 5% aqueous sodium hydrogen carbonate three times and then concentrated. A small amount of hydrochloric acid was added and recrystallized with acetone to obtain 78.1 g (yield: 76%) of hydrochloride of glutamic acid diester. 64 g (0.1 mol) of the hydrochloride and 19.5 g (0.11 mol) of glucono-δ-lactone were dissolved in 800 ml of ethanol and heated under reflux for 2 hours. After the reaction, the mixture was concentrated, and the residue was recrystallized from acetone to obtain the title compound. Melting point: 73 to 75 ° C; IR (nujol): 1710 cm ^-1 (ester), 1640 cm ^-1 (amide).

Example 1 50 mol / m ³ of LIX860 in n-heptane, Production Example 1
20 mol / m ^{3 of} the cationic surfactant GEQA obtained in
After preparing the organic phase by dissolving it at a concentration of
0 ml and 50 ml of the organic phase were emulsified by an ultrasonic irradiation emulsifying device to prepare a W / O emulsion. The test solution is pH adjusted with 0.1 N acetic acid and 0.1 N sodium acetate.
A solution of cobalt ion (Co ²⁺ ) and nickel ion (Ni ²⁺ ) mixed at a concentration of 10 mol / m ³ was used in a solution adjusted to 5.5.

To 700 ml of this test solution, 100 ml of the above W / O emulsion was added, and the temperature was maintained at 30 ° C.
Agitation was performed at a speed of rpm. 3 minutes from the start of stirring, 5
Minutes, 10 minutes, 20 minutes, and 30 minutes later, the concentrations of cobalt and nickel contained in the outer water phase and the emulsion inner water phase are quantified by atomic absorption spectrometry, and the extent of extraction from the outer water phase to the emulsion inner water phase The extraction rate indicating whether or not it was calculated was calculated. The results of the extraction ratios of nickel and cobalt over time are shown in FIG. It can be seen from FIG. 1 that the extraction rate of cobalt is much higher than that of nickel, and cobalt is selectively extracted.

Comparative Example 1 Sorbitan monooleate (span 8
No. 0, trade name, manufactured by ICI), GE obtained in Production Example 3 and the following formula described in JP-A 1-224038.

[0040]

[Chemical 8]

The amphoteric surfactant represented by (GEQAP
Using A), a separation experiment was performed in the same manner as in Example 1 to calculate the extraction rates of nickel and cobalt. The results are shown in Fig. 1. When the GEQA of the present invention is used,
It can be seen that it is superior in both extraction rate and selectivity to using GE and GEQAPA as surfactants. When the span 80 was used, the extraction rate and selectivity were both below GEQAPA.

Example 2 Using the surfactant GEQA-OH obtained in Production Example 2, a separation experiment was conducted under the same conditions as in Example 1. The results are shown in Figure 2. It was confirmed that the use of GEQA-OH was superior to the use of GEQA in terms of extraction rate and selectivity, and the structure of the hydrophilic group of the surfactant greatly affects the separation. It became clear.

[0043]

[Brief description of drawings]

FIG. 1 is a diagram showing changes over time in the extraction rates of nickel and cobalt in Example 1 and Comparative Example 1.

FIG. 2 is a diagram showing a change with time of an extraction rate of nickel and cobalt in Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hikotada Tsuboi, 1900 Togo, Mobara-shi, Chiba Mitsui Saiana Mid Co., Ltd. (72) Inventor Shigemitsu Nagao 1900, Togo, Mobara-shi, Chiba Mitsui Siana Mid Co., Ltd.

Claims (3)

[Claims] 1. A compound represented by the general formula (I): (In the formula, R ¹ and R ^{2, which} may be the same or different, each represents a saturated or unsaturated hydrocarbon group having 12 to 22 carbon atoms, and R ³ represents a methyl, ethyl, hydroxymethyl or hydroxyethyl group. , X represents halogen), and a method for separating cobalt and nickel, characterized in that an emulsion type liquid membrane prepared with at least one kind of cationic surfactant represented by the formula (1) is used. 2. An aqueous insoluble phase containing a metal extractant and an aqueous phase containing a metal ion concentrating agent are emulsified in the presence of the cationic surfactant represented by the general formula (I) according to claim 1. After forming a water-in-oil (W / O) emulsion, the emulsion is dispersed in an aqueous solution containing cobalt ions and nickel ions, which is a phase to be extracted, and the cobalt ions are extracted with the emulsion to obtain the inner water of the emulsion. The method according to claim 1, characterized in that the emulsion is separated, demulsified, and the aqueous phase enriched with cobalt ions is separated from the water-insoluble phase after being concentrated into a phase. 3. R ¹ and R ² in the general formula (I) have 1 carbon atoms.
2 to 22 alkyl or alkenyl groups, R ³
The separation method according to claim 1 or 2, wherein is a hydroxymethyl or hydroxyethyl group.