JPS6330318A - Method for selectively separating and recovering gallium - Google Patents

Abstract

PURPOSE:To selectively separate and recover Ga with a simple operation and a high recovery efficiency by using a specific water soluble oligomer or polymer having chelate forming ability, and by contacting said oligomer or polymer with a Ga contg. solution through a film. CONSTITUTION:Said water soluble oligomer or polymer comprises those contg. N-nitrosohydroxyl amino group shown by the formula (wherein X is H, an inorg. or an org. NH4<+> ion, Na<+> ion or K<+> ion) which is obtd. by for example, reacting p-nitrobenzoyl chloride with polyethylene glycol, followed by reducing the nitro group in a neutral medium to form a nitroso compd. thereof. The Ga contg. solution (for example, Ga-Al mixture, etc.) is contacted with said oligomer or polymer through the film which penetrates especially, a metal ion or a hydrogen ion, etc., and does not penetrate said water soluble oligomer or polymer (such as a thin film of a cellulose etc.). Thus, the Ga metal is selectively separated and recovered with high recovery efficiency by a simple operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method for selectively separating and recovering gallium.

More specifically, the present invention relates to a method for selectively separating and recovering gallium in a solution that is present across a membrane using a specific water-soluble oligomer or polymer having chelate-forming ability.

Demand for gallium has been increasing significantly in recent years due to developments in the semiconductor field and the like. Unlike iron and copper, gallium does not exist in individual ores. Gallium is widely contained in small amounts in raw aluminum ore such as bauxite, coal smoke, zinc sulfide ore, and germanic ore. Therefore, there are various methods for separation and recovery. A lot of effort and money has been put into it. In other words, the development of a technology that can separate and recover gallium economically and efficiently using a simple process with few harmful effects is expected, and has great commercial value. In most cases, a gallium-aluminum mixed liquid containing a large amount of aluminum, called Bayer liquid, used when alumina is manufactured from bauxite by the Bayer process, is used as a raw material. The treatment of bauxite according to the Bayer method is
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.Next, the sodium aluminate is cooled and aluminum hydroxide is added as a seed to accelerate the hydrolysis reaction. Since most of the aluminum is precipitated as aluminum hydroxide, this is classified as F. At this time, most of the gallium remains in the V liquid. The P solution is evaporated and concentrated and reused for bauxite treatment. This f liquid is called Bayer's liquid and is essentially a raw material for gallium production.

Various methods have been implemented or proposed for separation and recovery of gallium using Bayer liquid.

In addition to the current method using mercury amalgam and the method of blowing carbon dioxide gas, recently there has been a method using solvent extraction using a chelate extractant made of an oxine derivative with increased hydrophobicity (Japanese Patent Laid-Open No. 51-32411, No. 53). -52289
No. 54-40212, No. 54-9972
Publication No. 6, Publication No. 59-92914, 9th issue 59-929
15, etc.), a liquid-liquid extraction method using a hydrophobic solvent extractant having an amidoxime group (Japanese Patent Application Laid-Open No. 1983-21)
9422, etc.), a method by adsorption separation using a chelate resin having an iminodiacetic acid group as a functional group (Japanese Unexamined Patent Application Publication No. 1986-
42737), adsorption separation method using a chelate resin having 7 midoxime and oxine as functional groups (JP-A-58-7412, JP-A No. 58-49620, 9th issue, JP-A No. 58-96831, JP-A No. 58-96831) 50024) and the like have been proposed.

However, each of these methods has various drawbacks. Disadvantages of the current method include mercury dissolution loss, mercury contamination, complicated operations, and low gallium recovery efficiency. Even recently proposed methods have many problems in actual use. jIIi In the method using an aqueous oxine conductor, the reagent is expensive, has low selectivity for gallium, has poor recovery efficiency, and has a noticeable functional deterioration due to elution of the reagent into an aqueous solution. Selectivity and elution of the extractant into the aqueous solution have also been pointed out as problems in the method using .

Further, the method using an iminodiacetic acid-based chelate resin has the drawbacks of low selectivity for gallium and the necessity of placing strict restrictions on the speed at which the chelate resin comes into contact with a solution containing gallium. Furthermore, methods using chelate resins having amidoxime or oxine as functional groups have the advantage of adsorbing gallium from alkaline solutions, but elution and recovery of gallium requires a high concentration of strong mineral acid or heating. .

In order to recover metallic gallium by electrolysis using the commonly practiced method, it must be returned to alkalinity, which complicates the process.Also, considering the general acid resistance and heat resistance of the chelate resin, it is difficult to recover metal gallium. The method cannot be said to be economically satisfactory either.

Due to these circumstances, even though the demand for metallic gallium has increased significantly with the development of the electronic industry such as the semiconductor sector, there is still no method of separation and recovery of gallium that is economically satisfactory on an industrial scale. Therefore, the present inventors conducted intensive studies to establish a new gallium separation method that overcomes the above-mentioned disadvantages, and found that a specific water-soluble oligomer or polymer with chelate-forming ability It has been discovered that gallium can be selectively adsorbed by bringing it into contact with a gallium-containing solution across a membrane, leading to the present invention.

[Structure of the invention] Indicates an inorganic or organic ammonium ion or an alkali metal ion of sodium or potassium)
Provided is a method for selectively separating and recovering gallium from a gallium-containing solution, which comprises contacting a water-soluble oligomer or polymer that accommodates the N-nitrone hydroxylamino group represented by the above with the gallium-containing solution across a membrane. It's about doing.

As a water-soluble oligomer or polymer having an N-nitrosohydroxylamino group,

For example, water-soluble oligomers or polymers having a hydroxyl group at the end such as polyethylene glycol, polyvinyl alcohol, and polyhydroxyethyl methacrylate, and compounds having a nitro group such as nitrobenzoic acid, methyl nitrobenzoate, nitrobenzoyl chloride, and nitrophenyl isocyanate. A water-soluble oligomer or polymer obtained by reacting the nitro group with a neutral nitro group, followed by nitrosation or nitrosoammonium; such as polyethyleneimine or an ethylene oxide polymer having a 7-mino group at the terminal A water-soluble oligomer or polymer is reacted with a compound having a nitro group such as nitrobenzoic acid, methyl nitrobenzoate, nitrobenzoyl chloride, nitrophenyl isocyanate, etc. to neutralize the nitro group of the primary lever, and to roughly reduce the nitro group. water-soluble oligomers or polymers obtained through oxidation or nitroso-ammonium conversion; A water-soluble oligomer or polymer obtained by reacting a compound having a nitro group such as benzylamine, nitronaphthylamine, nitrophenyl isocyanate, etc., then reducing the nitro group with neutrality, and further nitrosation or nitron ammoniumization; A mixture consisting of water-soluble oligomers or polymers having N-nitrone hydroxylamino groups obtained by various methods; Water-soluble oligomers or polymers having N-nitrone hydroxylamino groups obtained by Katsura's method and polyvinylpyrrolidone; Sodium polyacrylate.

Examples include mixtures with water-soluble oligomers or polymers such as sodium polystyrene sulfonate and quaternized polyvinylpyridine. In addition, water-soluble oligomers or polymers having 7 N-nitrone hydroxylamino groups are nitroso-hydroxylamino groups that form water-soluble polymers such as ethylene oxide, ethyleneimine, hydroxyethyl methacrylate, and N-vinylpyrrolidone. It can also be obtained by introducing a group and polymerizing it by a conventional method, but as is known, N-nitrone phenylhydroxylamine or its salt having a functional N-nitrosohydroxylamino group can be used to terminate radical polymerization. Because it is effective as a drug (Japanese Patent Application Laid-Open No. 51-90
381, etc.), and the method using the polymer reaction described above is preferably employed. When the obtained water-soluble oligomer or polymer having an N-nitrosohydroxylamino group is made into an aqueous solution, it is desirable that the viscosity of this aqueous solution is not very high, so the polymer that becomes the source of the polymer reaction is relatively It is desirable to have a low degree of polymerization, and a molecular weight of 500-1.
0,000 preferably 1.000-5,000
are used.

The membrane used in the present invention is not particularly limited as long as it is a membrane that allows low molecular weight substances such as metal ions to pass through but does not allow large molecular weight water-soluble oligomers or polymers to pass through.For example, for ultrafiltration, diffusion, etc. Examples of membranes that have been reprinted for dialysis include cellulose, polyacrylonitrile, polymethyl methacrylate, polyethylene vinyl alcohol, polysulfone, and polyamide. The thickness of the film may be as long as it does not cause physical damage, and a thickness of about 30-50 #Lm is sufficient, and if a support material for the film is used in combination, a thickness of 11 cm can be used. Moreover, the shape of one pattern 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 the industrial aluminum manufacturing process
Examples include aluminum mixed liquid, aluminum alloy manufacturing waste liquid, and leachate of zinc sulfide ore, germanite, etc.
Considering the industrial scale and commercial value, it is called Bayer liquid, which is produced in the process of producing alumina by the Bayer process. A gallium-aluminum mixture liquid in which most of the aluminum content has been removed and the gallium concentration ratio is increased is preferably used.

In order to selectively separate and recover gallium from a gallium-containing solution according to the present invention, it is sufficient to simply bring the gallium-containing solution into contact with the specific water-soluble oligomer or polymer having chelate-forming ability through the membrane. There are no particular restrictions on the method of contact, for example, filling a cylindrical column with the oligomer or polymer,
A method is employed in which both ends of the column are closed with membranes and a solution containing gallium is passed through the column, or a method in which the aqueous solution of the oligomer or polymer and the solution containing gallium are brought into contact while being circulated through a hollow fiber membrane. . The amount of the oligomer or polymer used is appropriately selected depending on the gallium concentration in the solution. The operating temperature is 5 to 70°C, preferably 10 to 50°C. Further, the contact time is usually several minutes or more. Further, the solution containing gallium is preferably acidic, and particularly preferably has a pH of 0-2.

Therefore, by such a simple operation, gallium can be selectively separated and recovered from a solution containing gallium. Gallium can be eluted by further contacting the water-soluble oligomer or polymer with gallium adsorbed with a highly concentrated mineral acid or alkaline aqueous solution.

In particular, for mixing with an alkaline aqueous solution, the concentration of the alkaline aqueous solution can be selected from a wide range, such as a sodium galmate solution having an appropriate concentration, which can be easily adjusted. In this way, metallic gallium can be obtained from the eluted gallium eluent by a known method.

[Effects of the Invention] The present invention has higher selectivity for gallium than conventional methods. For example, as shown in Example 1, gallium 200 PP
By treating an aqueous solution (aluminum/gallium = 200) containing aluminum and 40,000 PP11 according to the present invention, gallium 120 PP■, aluminum [13ppm (aluminum/gallium = 0.89)
2) A solution with a high gallium ratio can be obtained.

In addition, the separation and recovery operation is simple, and a wide range of operating methods can be adopted, such as the column flow method and the liquid/liquid contact method through a membrane. In addition, there is no need to pay special consideration to organic solvents, which was seen in the liquid/liquid extraction method using kerosene as a solvent.
Adsorbed gallium can be easily eluted with an alkaline aqueous solution, and the eluent can be used directly as an electrolyte, which has the advantage that gallium can be separated and recovered more efficiently than conventional methods.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that the present invention is not limited to the following examples.

[Examples of the present invention] Example 1 Adding P to polyethylene glycol having an average molecular weight of 2,000
After reacting -nitrobenzoyl chloride and adding the product to a solution whose pH was adjusted to 6 with ammonium chloride, Zn powder was further added and reduced, and ammonia gas was blown in to form n-butyl nitrite. In addition, a water-soluble oligomer having an ammonium salt of N-nitron phenylhydroxylamine at the end was prepared. This oligomer 1
0g into a glass cylindrical column and both ends with a thickness of 50I
Gallium 200 PP11 and Aluminum 4G sealed with Lm cellophane film and XA adjusted to PH, 1
, 000 200 ml of an aqueous solution containing PP11 (aluminum/gallium = 200) was passed through the solution repeatedly at room temperature for 2 hours to selectively separate gallium.
malf' 50m of sodium hydroxide aqueous solution at room temperature
The solution was passed for 5 minutes to obtain a gallium elution and recovery solution. 01jl
When the metal ion concentration in the collected liquid was measured, it was found that aluminum 83PP11. Gallium 120 PP resin (aluminum/gallium = 0.892) was obtained, and gallium was selectively separated.

These results are shown in Table 1 below.

Example 2 The same procedure as in Example 1 was carried out except that polyethyleneimine having an average molecular weight of 4,000 to 5,000 was used as the material for obtaining a water-soluble oligomer having chelate-forming ability.

Example 3 The same procedure as in Example 1 was carried out except that polyhydroxyethyl methacrylate having an average molecular weight of 3,000 was used as the water-soluble oligomer material having chelate-forming ability.

Example 4 The same procedure as in Example 1 was carried out, except that polyethylene oxide having carboxyl-terminated terminals was used as the water-soluble oligomer material having chelate-forming ability, and p-nitrobenzylamine was reacted therewith.

Example 5 The same procedure as in Example 1 was carried out except that a cellulose acetate membrane with a thickness of 50 pm was used as the membrane separating the water-soluble oligomer having chelate-forming ability and the solution containing gallium.

Example 6 Example except that a 30 Bm thick 7crylonitrile-N-vinylpyrrolidone copolymer membrane (8-2, molar ratio) was used as the membrane separating the water-soluble oligomer having chelate-forming ability and the solution containing gallium. It was operated in the same manner as in 1.

Comparative Examples 1-3 Instead of using the water-soluble oligomers with ammonium salts of N-nitrophenylhydroxylamine used in Examples 1-3, polyethylene glycol with an average molecular weight of 2.000 was used to prepare them. The same procedure as in Example 1 was carried out using polyethyleneimine having an average molecular weight of 4,0QO-5,000 and polyhydroxyethyl methacrylate having an average molecular weight of 3,000.

Table 1

Claims (3)

[Claims] (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However,
represents a hydrogen atom, an inorganic or organic ammonium ion, or an alkali metal ion such as sodium or potassium. 1. A method for selective separation and recovery of gallium, which comprises bringing a water-soluble oligomer or polymer having an N-nitrosohydroxylamino group represented by the following formula into contact with a solution containing gallium through a membrane. (2) A patent claim characterized in that the membrane separating the water-soluble oligomer or polymer and the solution containing gallium is a membrane that allows ions such as metal ions and hydrogen ions to pass through but not the water-soluble oligomer or polymer. The method for selective separation and recovery of gallium according to item 1. (3) The method for selective separation and recovery of gallium according to claim 1, wherein the solution containing gallium is an acidic aqueous solution.