JPH0617228B2 - Selective separation and recovery method of gallium - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for selectively separating and recovering gallium.

More specifically, it relates to a method for selectively separating and recovering gallium in a solution existing across a membrane by using a specific water-soluble oligomer or polymer having a chelate-forming ability.

[Prior Art] Demand for gallium has been significantly increasing in recent years due to the development of the semiconductor field and the like. Unlike iron and copper, gallium does not have a single ore. Since gallium is widely contained little by little in raw aluminum ore bauxite, coal smoke ash, zinc sulphide ore, germane ore, etc., various efforts have been made for separation and recovery, and much effort and cost have been spent. . In other words, it is expected to develop a technology that can efficiently and economically separate and recover gallium with a simple process, with few adverse effects, and has great commercial value. Now, in the production of gallium currently being carried out on an industrial scale,
In most cases, the raw material is a gallium-aluminum mixed liquid containing a large amount of aluminum, which is called a Buyer liquid when alumina is produced from bauxite by the Bayer method. In the treatment of bauxite by the Bayer method, first, raw ore is thermally decomposed with an aqueous sodium hydroxide solution to prepare a sodium aluminate solution. At this time,
Most of the gallium is transferred to the sodium aluminate solution. Then, the sodium aluminate is cooled, and aluminum hydroxide is added as seeds to accelerate the hydrolysis reaction. Most of the aluminum precipitates as aluminum hydroxide, so this is excluded. At this time, most of gallium remains in the liquid. The liquid is evaporated and concentrated and reused for bauxite treatment. This liquid is called a Bayer liquid and is substantially a raw material for producing gallium.

Various methods have been implemented or proposed for separating and recovering gallium using a Bayer solution. In addition to the current method using mercury amalgam and blowing carbon dioxide gas, recently, a method using solvent extraction using a chelate extractant composed of an oxine derivative having improved hydrophobicity (Japanese Patent Laid-Open No. 51-3
No. 2411, No. 53-52289, No. 54-
No. 40212, No. 54-99726, and No. 59.
-50024, 59-92914, and 5
9-92915, etc.) has been proposed.

However, each of these methods has various drawbacks. Disadvantages of the conventional method are dissolution loss of mercury, pollution by mercury, loss of caustic alkali in an aqueous solution of sodium aluminate due to carbon dioxide, and low gallium recovery efficiency. In addition, even in the recently proposed solvent extraction method using a hydrophobic oxine derivative, the following structural formula Kelex 100 (manufactured by Schering) and its similar compounds are used, and the reagent is effective, and the selectivity to gallium in strong basicity is low, and the recovery efficiency is poor, and the reagent is used in an aqueous solution. It has been pointed out that problems such as functional deterioration due to elution and contamination of the buyer's solution are involved.

Due to such circumstances, although the demand for metallic gallium has expanded remarkably with the development of the electronic industry field such as the semiconductor sector, the separation and recovery of gallium that is still economically satisfactory on an industrial scale. No method is established. Therefore, as a result of intensive studies to establish a novel method for separating and recovering gallium overcoming the above inconvenience, the present inventors have found that a specific water-soluble oligomer or polymer having a chelate-forming ability separates gallium from the membrane. The inventors have found that the gallium in a strongly basic aqueous solution is selectively adsorbed by contacting with a solution containing the same, and have reached the present invention.

[Means for Solving Problems] The present invention has (However, R represents an alkyl group having 1 to 5 carbon atoms.) A water-soluble oligomer or polymer having a substituted hydroxyquinoline represented by the following formula is used, and a solution containing gallium separated by a membrane, particularly a Bayer solution Another object of the present invention is to provide a method for selectively separating and recovering gallium from a solution, which is characterized in that it is brought into contact with a strongly basic aqueous solution as described above.

Used in the present invention (However, R represents an alkyl group having 1 to 5 carbon atoms.) Examples of the water-soluble oligomer or polymer having a substituted hydroxyquinoline in the molecule include polyethylene glycol, polyvinyl alcohol,
Polyhydroxyethyl methacrylate, copoly N-vinylpyrrolidone-hydroxyethyl methacrylate,
Water-soluble oligomer or polymer having a hydroxyl group such as copoly N-vinylpyrrolidone-vinyl alcohol, carboxyethyl cellulose, hydroxypropyl cellulose, amylose, amylopectin, or water-soluble such as polyethyleneimine or ethylene oxide polymer having an amino group at the end. 2-methyl-5-chloromethyl-8-hydroxyquinoline, 2-propyl-5-chloromethyl-8
-Hydroxyquinoline, 2-ethyl-7-chloromethyl-8-hydroxyquinoline, 2-amyl-7-chloromethyl 8-hydroxyquinoline and the like water-soluble oligomers or polymers; carboxyl groups or acid chlorides at the terminals 2-Methyl-5-aminomethyl-8-hydroxyquinoline, 2-butyl-7-aminomethyl-8-hydroxyquinoline, 2-propyl-5-containing water-soluble oligomers or polymers such as ethylene oxide polymers having groups. Water-soluble oligomers or polymers obtained by reacting amino-8-hydroxyquinoline, 2-amyl-7-amino-8-hydroxyquinoline, etc .; Water-soluble oligomers having the substituted hydroxyquinoline obtained by various methods Or polymer A mixture of a water-soluble oligomer or polymer having the above-mentioned substituted hydroxyquinoline obtained by various methods with a water-soluble oligomer or polymer such as polyvinylpyrrolidone, sodium polyacrylate, sodium polystyrenesulfonate, or quaternized polyvinylpyridine. A mixture may be mentioned. The reaction of the water-soluble oligomer or polymer having a hydroxyl group or an amino group with the chloromethylated substituted hydroxyquinoline is carried out according to a known method, for example, in the presence of a catalyst such as aluminum chloride, zinc chloride, sodium hydride,
Dimethylformamide, dimethylacetamide, N-methylpyrrolidone, chloroform, methylene chloride, dioxane, nitrobenzene and the like are used as solvents at room temperature to 10
It can be obtained by reacting at 0 ° C for several hours to several tens of hours. When the obtained oligomer or polymer having the substituted hydroxyquinoline is used as an aqueous solution, it is desired that the viscosity of the aqueous solution is not so high. Therefore, it is desirable that the original polymer has a relatively low degree of polymerization. Those of 500-20,000, preferably 1,000-10,000 are used.

In the present invention, the membrane used to separate the water-soluble oligomer or polymer having a substituted hydroxyquinoline from the solution containing gallium is permeable to low-molecular substances such as metal ions, but is permeable to water-soluble oligomers or polymers. There is no particular limitation as long as it is a film that does not. For example, thin films of cellulosics, polyacrylonitrile, polymethylmethacrylate, polyethylene vinyl alcohol, polysulfone, polyamide, etc., which are commercially available for ultrafiltration and diffusion dialysis, can be mentioned. The film thickness should be such that it does not physically break, 30-50μ
A thickness of about m is sufficient, and a thinner film can be used if a support material is used in combination with the film. Further, the shape of the membrane may be either a flat membrane or a hollow fiber membrane.

The gallium-containing solution in the present invention is not particularly limited as long as it is a gallium-containing solution. For example,
Gallium obtained in industrial aluminum production process
Aluminum mixed liquid, aluminum alloy manufacturing effluent, or leaching liquid such as zinc sulfide ore and germane stone,
Considering the industrial scale and the commercial value, a gallium-aluminum mixed liquid having a high gallium concentration ratio, which is referred to as a Bayer liquid produced in the alumina production process by the Bayer method, is used to remove most of the aluminum content. Used.

To selectively separate and recover gallium from the gallium-containing solution according to the present invention, simply contact the gallium-containing solution with the specific water-soluble oligomer or polymer having a chelate-forming ability through the membrane. Of course, the contact method is not particularly limited. For example, a method in which a cylindrical column is filled with the above-mentioned oligomer or polymer, both ends of the column are sealed with a membrane, and a solution containing gallium is passed, or an aqueous solution of the above-mentioned oligomer or polymer and a solution containing gallium are hollow fibers. A method of contacting while circulating through a membrane or the like is adopted. The amount of the above-mentioned oligomer or polymer used is appropriately selected depending on the gallium concentration in the solution. The working temperature is 5-100 ° C, preferably 10-80 ° C. A contact time of several minutes is sufficient.

As described above, the water-soluble oligomer or polymer having gallium adsorbed therein according to the present invention can be eluted by contacting with an aqueous solution of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid or the like in the range of 1 to 2 N. The eluent may be used as it is, or may be treated with an alkali to form an aqueous solution of sodium galmate, for example, and a known method such as electrolysis may be used to obtain metallic gallium. Further, the water-soluble oligomer or polymer in which gallium is eluted can repeatedly adsorb gallium according to the above operation.

[Effects of the Invention] Therefore, according to the present invention described in detail above, in comparison with the method using a hydrophobic chelating agent substantially consisting of Kelex100 as well as the conventional method, (However, R represents an alkyl group having 1 to 5 carbon atoms.) A water-soluble oligomer or polymer having a substituted hydroxyquinoline is represented by gallium even in a strongly basic aqueous solution such as Bayer's solution. Is highly selective and has great practical value. Also in terms of operation, a wide range of operation methods such as column flow method and liquid / liquid contact method through a membrane can be adopted. Moreover, since the solvent is water in the liquid / liquid contact method, conventional kerosene etc. can be used as a solvent. There is an advantage that gallium can be efficiently separated and recovered, such as not requiring special consideration to the organic solvent as seen in the liquid / liquid extraction method.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to the examples below.

Example 1 With a number average molecular weight of 4,000 polyethylene glycol and dioxane as a solvent, 2-methyl-5-chloromethyl-8-hydroxyquinoline was reacted in the presence of sodium hydride to have 2-methyl-8-hydroxyquinoline at the end. A water-soluble oligomer was obtained. 30 g of this oligomer was charged into a cylindrical glass column having a diameter of 20 mm, and both ends of the column were sealed with a cellophane film having a thickness of 50 μm.
100 ml of a 3N sodium hydroxide aqueous solution containing 200 ppm and aluminum 40,000 ppm (aluminum / gallium concentration ratio = 200) was repeatedly passed at room temperature for 2 hours. Then, 50 ml of water was passed for 10 minutes, and then 100 ml of a 2N hydrochloric acid aqueous solution was passed for 30 minutes at room temperature to obtain an eluate recovery solution of gallium. As a result of measuring the metal ion concentration in the recovered liquid, gallium 130ppm, aluminum 270ppm
(Aluminum / gallium concentration ratio, 2.077) and gallium were selectively separated.

The results are shown in Table 1 below.

Example 2 Polyethylene glycol having the same number average molecular weight of 4,000 as in Example 1 was used as a material for obtaining a water-soluble oligomer having a chelate-forming ability, and 2-ethyl-7-chloroethyl-8-hydroxyquinoline was used as a reaction reagent. The procedure was the same as in Example 1 except for the above.

Example 3 The procedure of Example 1 was repeated, except that polyethylene glycol having a number average molecular weight of 6,000 was used as the material for obtaining the water-soluble oligomer having a chelate-forming ability.

Example 4 2-Methyl-5 in the presence of zinc chloride using polyethyleneimine having a number average molecular weight of 4,000-5,000 and dioxane as a solvent
Example 1 using a water-soluble oligomer obtained by reacting -chloromethyl-8-hydroxyquinoline
It carried out similarly to.

Example 5 Example 1 was repeated except that copoly N-vinylpyrrolidone-hydroxyethyl methacrylate having a number average molecular weight of 10,000 was used as a material for obtaining a water-soluble oligomer having a chelate-forming ability.

Example 6 As in Example 1, except that a 30 μm copolyacrylonitrile-N-vinylpyrrolidone film (8-2, molar ratio) was used as a film separating the water-soluble oligomer having a chelate-forming ability and the solution containing gallium. I did.

Comparative Examples 1 and 2 As an extractant for Comparative Example 1, 4 g of 8-hydroxyquinoline was dissolved in 10 g of decanol and 80 ml of chloroform, and as an extractant for Comparative Example 2, Kelex 100 (manufactured by Schering) 8
g was dissolved in 10 g of decanol and 80 ml of kerosene,
I adjusted each. To these, 100 ml of the strongly basic gallium-aluminum mixed aqueous solution used in Example 1 was added, and the mixture was vigorously shaken at room temperature for 2 hours, and then the aqueous layer and the oil layer were separated. Next, 100 ml of 2N hydrochloric acid aqueous solution was added to the oil layer, and the mixture was vigorously mixed at room temperature for 30 minutes to measure the metal ion concentration in the hydrochloric acid aqueous solution.

Claims (4)

[Claims] 1. In the molecule (However, R represents an alkyl group having 1 to 5 carbon atoms.) A water-soluble oligomer or polymer having a substituted hydroxyquinoline represented by the formula is used, and the film is contacted with a solution containing gallium. Method for selective separation and recovery of gallium. 2. A membrane that separates a water-soluble oligomer or polymer from a solution containing gallium, which is a membrane that is permeable to ions such as metal ions, hydroxide ions and hydrogen ions, but is impermeable to water-soluble oligomers and polymers. The method for selectively separating and recovering gallium according to claim 1, wherein: 3. The method for selectively separating and recovering gallium according to claim 1, wherein the solution containing gallium is a strongly basic aqueous solution. 4. The method for selectively separating and recovering gallium according to claim 1, wherein the solution containing gallium is an aqueous solution of sodium aluminate in the alumina production process by the Bayer method.