JPS6219498B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is directed to materials containing trace amounts of Ga and In (sometimes solid or precipitated, sometimes liquid This invention relates to a method for separating and extracting both metallic Ga and metallic In with good yield and economically advantageous. Gallium and indium may be distributed at low concentrations in sludge, smoke, or liquids from various metal smelting processes and other chemical processing processes, and these sludges and liquids may contain gallium. It also plays a major role as a source of indium. However, compared to low concentrations of gallium and indium, this type of sludge and liquid contains extremely large amounts of metals other than gallium and indium, such as
It usually contains Fe, Al, Zn, As, Na and other metals. As a method of extracting gallium and indium from such gallium and indium sources,
An overview of the commercial methods that have been proposed and implemented so far is as follows. First, industrial extraction of metallic gallium has mainly been carried out from aluminum smelting waste liquid or zinc smelting residue. In the case of waste water from aluminum smelting, alumina crystals are crystallized from a solution obtained by processing bauxite using the Bayer process, and the filtrate after filtering out the alumina crystals is a sodium aluminate solution. (1) A method of separating trace amounts of gallium contained in this solution in the form of crude hydroxide by blowing carbon dioxide into this solution (or neutralizing it by adding an alkali agent), (2) This method A method has been implemented in which gallium is electrolyzed in a solution using a mercury cathode, and gallium is separated as a mixture with metallic mercury. In addition, in the case of zinc smelting residue, zinc leaching residue is produced by leaching zinc burnt ore with sulfuric acid (in the case of wet zinc smelting method), or by adding a reducing agent and burning zinc concentrate to distill zinc. (3) Neutralize the gallium-containing solution obtained by acid leaching or alkali leaching of this residue in a strong acid or reducing atmosphere to obtain a gallium-containing solution containing the generated gallium. A method has been used in which crude hydroxide is dissolved in concentrated hydrochloric acid to obtain a hydrochloric acid solution, and gallium is concentrated by performing liquid-liquid extraction from this solution using a solvent extraction method. However, the separation method using hydroxide (1) requires a very difficult filtration operation, and also requires a very difficult filtration operation.
When large amounts of Cu, Al, etc. coexist,
These hydroxides are produced in large quantities, making the processing operations complicated, and the resulting gallium also contains many other metals, making separation of these metals difficult. In addition, with the electrolysis method using a mercury cathode (2), in addition to the basic problem that this method cannot be used in solutions with low gallium concentration or solutions containing organic substances, due to the drop in current efficiency, there is also a loss of mercury. must also be taken into account. In the solvent extraction method (3), the solution to which this is applied is pretreated (neutralization method or concentrated alkali dissolution method).
Unless the gallium is concentrated, it will not be effective.
For materials such as zinc smelting residues, which contain large amounts of Fe, Al, Cu, Zn, etc., such pretreatment requires a large burden, making it difficult to use them industrially. On the other hand, industrial extraction of indium involves the use of weakly acidic solutions containing trace amounts of In generated from various processes. (3) Adding metals such as Zn, Cd, Al, etc. to this weakly acidic solution to precipitate In as a hydroxide; (4) Solvent extraction method from this weakly acidic solution. Therefore, there are methods to recover In, etc.; After treating the resulting In-containing solution with hydrogen sulfide and hydroxide,
A method of substituting and precipitating In with metal Zn or Al has been implemented. However, in methods (1) and (2), Cu, Fe, Zn,
If large amounts of As, Al, etc. coexist, a large amount of precipitates will be formed and the processing operations will be complicated, making it impossible to expect separation from other metals. Furthermore, in method (3), if a metal more noble than the additive metal coexists, it is impossible to separate the metal and In. In this respect, the solvent extraction method (4) has some advantages, as it can selectively separate In depending on the solvent used.
Although it is effective for separating In from a certain metal, it is not effective for separating In from all metals, and when separating and concentrating In from a solution containing various metals, other metals are used. Considering the nature of the process, a large burden will be placed on preprocessing. In addition, in the case of method (5), a trace amount of In is separated from a solution obtained by processing a substance containing a large amount of Cu, Fe, Zn, As, Al, etc., so there are many separation methods. It is no exaggeration to say that there was no economical method, as all conventional methods had complicated and complicated processes. In particular, from raw materials containing trace amounts of Ga and In as well as relatively large amounts of other metals,
A commercial method for separating and recovering both Ga and In has not yet been established. The present invention was made with the aim of solving such problems in the conventional separation and collection of Ga and In metals.For this purpose, the present inventors have conducted various tests and researches, and hereby, the above-mentioned findings have been made. Substantially all the raw materials used in the conventional industrial extraction of Ga or In as described in detail can be used as the target raw materials, and the problems described above in various conventional methods can be solved at once. We were able to establish a commercial separation and collection method for metallic Ga and In from materials containing trace amounts of Ga and In. Thus, the present invention is capable of dissolving trace amounts of Ga and In and relatively large amounts of other materials obtained by dissolving solid materials containing trace amounts of Ga and In with acids, or generated in liquid form from metal smelting and other chemical processes. A first step in which a solution containing metals is used as a treatment stock solution, and this treatment stock solution is passed through a layer of chelating ion exchange resin at a pH value that allows selective adsorption of Ga and In. A second step of treating the resin with a mineral acid to elute the resin-adsorbed substance; a metal In precipitation step in which the In dissolved in the obtained eluent is precipitated by replacing the metal In with a metal less noble than In. Process: First, the pH of the liquid after collecting the metal In in the metal In precipitation step is set to 10 or higher to separate and remove the solid content produced, and then the pH is adjusted to 5 to 8 to separate and recover the produced solid content. Metal Ga is obtained by electrowinning from an alkaline solution in which the solid content is dissolved.
Metallic Ga from materials containing trace amounts of Ga and In through Ga electrowinning process
Provides a method for separating and collecting In and In. [First step] This first step is performed using a liquid obtained by dissolving a solid material containing trace amounts of Ga and In with an acid, or using Ga generated in liquid form from a metal smelting process or other chemical process.
In this step, a solution containing a small amount of In is used as a treatment stock solution, and this treatment stock solution is passed through a layer of chelating ion exchange resin at a pH value that allows selective adsorption of Ga and In. Here, solid substances containing small amounts of Ga and In include raw material minerals themselves such as bauxite, germanite, and zinc ore, or smoke ash generated from the smelting process of these or other minerals.
Refers to smelting residues, coal ash, etc., including Zn, Fe,
At least two or more of Al, As, Ni, Cd, etc. are Ga
It refers to a group of substances that contain tens to hundreds of times or more than Ga and In, and not only those that have traditionally been used as sources for collecting Ga and In, but also those that cannot be economically extracted using conventional techniques. Ga, In
This also includes those containing trace amounts of. It is also generated in liquid form from metal smelting and other chemical processes.
A liquid containing trace amounts of Ga and In is used in metal smelting and chemical processes whose main purpose is not to collect Ga or In, but it also contains the main substances, such as Ga, In, etc.
Liquids that also contain trace amounts of In, such as electrolytic solutions for electrolytic refining of main metals, or liquids that have almost all of the main substances removed but contain large amounts of other metal ions and trace amounts of Ga and In. It refers to things similar to secondary liquids and waste liquids. The present invention targets these materials containing small amounts of Ga and In (some solid and some liquid) that are generated in various places. treated with acid. As this acid, it is preferable to use sulfuric acid, which is inexpensive. At that time, one step of leaching is performed at normal temperature and pressure so that the free sulfuric acid concentration after leaching with sulfuric acid is 10 (g/) or more, and the leachate (treated stock solution in the present invention) is collected by filtration. good. The processing stock solution used in the present invention is thus prepared.
A liquid containing a trace amount of Ga and In dissolved in an acid, or a liquid containing a trace amount of Ga or In generated from a metal smelting process or other chemical process. g/
), and metal ions other than Ga and In, for example, metal ions such as Zn, Fe, Al, As, Ni, Cd, etc. coexist singly or in total at 2 to 70 (g/) or more. be. In the first step, this treatment stock solution is mixed with Ga and In.
The solution is passed through a layer of chelating ion exchange resin at a pH value that allows selective adsorption. The chelating ion exchange resin used here has the general formula, for example: However, M is an alkali metal or hydrogen, and R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 3 carbon atoms. A chelate resin obtained by three-dimensionally crosslinking the phenol compound represented by the above with phenols and aldehydes can be used. Such resin itself is known as an ion exchange resin capable of reducing the concentration of iron ions in acidic electrogalvanizing baths, for example, in Japanese Patent Application Laid-Open No. 54-121241, and is also known as an ion exchange resin that can reduce the concentration of iron ions in acidic electrogalvanizing baths. It is commercially available from the company. Such a chelating ion exchange resin (particularly a chelating ion exchange resin having an aminocarboxylic acid group) can be used to remove liquids containing extremely large amounts of various metal ions other than Ga and In.
It has been found that it has the ability to selectively adsorb Ga and In. In this case, the pH value of the treated stock solution is adjusted to 1.0 to 4.0, preferably 2.0 to 3.0. As mentioned above, when using sulfuric acid leachate as a processing stock solution, it is possible to obtain a solution that satisfies this PH value as is, and the processing stock solution is originally used as an acidic solution with this PH value during the metal smelting process. This is especially true when obtained from chemical processes such as
There is no need to adjust the PH value. If trivalent iron ions coexist in this treatment stock solution, it is preferable to reduce them to divalent iron ions in advance using a reducing agent such as sulfur dioxide gas or sodium bisulfite. When passing the treatment stock solution through the resin, the exchange tower filled with the resin should be fed at a rate such that the space velocity (hereinafter sometimes simply referred to as SV) is 5.0 or less, preferably 0.5 to 1.5. Pass the liquid through. As a result, only Ga and In in the treatment stock solution are selectively adsorbed to this resin. At that time, the contact temperature to the resin is 10 to 50℃, preferably
A temperature of 35 to 45°C is suitable. Figure 1 shows the relationship between the PH value of the treated stock solution and the amount of Ga and In adsorbed onto the resin. The data when passing fluid is as follows.
It can be seen that both Ga and In are well adsorbed when the pH value is 1.0 to 4.0. In addition, Figure 2 shows that an acidic sulfuric acid solution containing a trace amount of gallium or indium containing 10 to 20 (g/) each of zinc, iron, and aluminum is adjusted to pH 2.8, and sodium hydrogen sulfite is added to reduce the solution. This figure shows the relationship between the amount of liquid passed through the chelating ion exchange resin at S.V1.0 after maintaining its properties and the flow point. It can be seen that the mixed solution is selectively adsorbed by the resin. [Second Step] The second step is a step of treating the resin that has undergone the first step with a mineral acid to elute the resin-adsorbed substance. As mentioned above, in the first step, this resin contains:
Ga and In ions are selectively adsorbed from other metal ions. This can be easily eluted using mineral acids such as sulfuric acid or hydrochloric acid. In the case of sulfuric acid, 1 to 6N, preferably 3 to 6N
4N, in the case of hydrochloric acid, 1 to 6N, preferably 2 to 3N
It is recommended to use one with a concentration of By this elution, it is possible to obtain a Ga- and In-containing solution that has a low concentration of metal ions other than Ga and In, and contains Ga and In, respectively, on the order of 0.01 to 1 (g/) or more. Once this eluent has been obtained, adjust the pH value of this eluent to 1.0 to 4.0, preferably 2.0 to 3.0, in the same way as in the previous adsorption step from the treated stock solution (first step), and then adjust the pH value as necessary. Accordingly, trivalent iron ions are reduced to divalent iron ions using a reducing agent, and S.V5. 0 or less, preferably S.V 1.0 to 3.0, Ga and In are adsorbed onto this resin again, and this is eluted by repeating the process of eluting with mineral acid again. The concentration of metal ions other than Ga and In in the liquid can be further reduced. As in the previous case, the mineral acid used for this repeated elution is, for example, sulfuric acid, 1 to 6N, preferably 3 to 6N.
4N, in the case of hydrochloric acid, 1 to 6N, preferably 2 to 3N
The concentration of Ga and In in this eluent can be extremely high, such as 0.1 to 50 (g/). and,
The amount of metal ions other than Ga and In in this eluent is extremely small, and only Ga and In are separated and concentrated. Figure 3 shows the pH of the eluent obtained in the case of Figure 2.
The figure shows the relationship between the amount of liquid passed and the flow point when the liquid was passed through the layer of the chelating ion exchange resin at S.V2.0 after adjusting the value to 2.8. From the same figure, Ga, In
It is selectively adsorbed to this resin, and the eluent contains
It can be seen that as Ga and In are concentrated, the concentrations of other metal ions are reduced. FIG. 4 shows an elution curve when gallium and indium adsorbed on the resin are eluted from the eluent with 2N hydrochloric acid. Next, in the method of the present invention, an indium sponge is collected by displacing and precipitating In dissolved in the eluent obtained in the second step using a metal less base than In. . That is, depending on the acid concentration of the eluent, it may be adjusted to a mineral acid such as sulfuric acid or hydrochloric acid to a pH of 2.0 or less, and powdered or plate-shaped In such as zinc or aluminum may be added to this acidic solution.
An indium sponge is obtained by adding 1 to 3 equivalents of a base metal to In. At that time, before this displacement precipitation, more specifically, before pH adjustment, metals other than indium are precipitated by blowing hydrogen sulfide gas into the liquid, and these are filtered out from the liquid. If the formulation is adopted, the liquid can be purified easily, thereby increasing the purity of the indium sponge in the displacement precipitation process. This collected spongy indium can be melted and cast into an anode as required, and then subjected to electrolytic refining to obtain In metal of even higher purity. First, an alkaline agent is added to the tail liquid after In substitution precipitation to raise the pH to 10 or more, to generate a precipitate of metals other than Ga such as iron, which is filtered out. ~8 to form a precipitate of Ga hydroxide, which was filtered out and then re-neutralized.
Ga hydroxide is dissolved in sodium hydroxide and used as a Ga electrolyte.
Gather Ga. Figure 5 shows the relationship between the pH of the liquid and the precipitation rate of Ga hydroxide. Ga precipitates well when the pH value is in the range of 4 to 8, but even if the pH value is low or high, Ga It can be seen that it dissolves.
Therefore, for example, when iron ions coexist (as shown in the figure, iron precipitates at a pH value of 5 or higher), an alkaline agent is added to the eluent to raise the pH value to 10 or higher. Therefore, after forming a precipitate of iron hydroxide (if Ga precipitates once and redissolving it in the process) and filtering it out, for example, sulfuric acid is added to the liquid to reverse neutralize it to a pH value of 5 to 8. By doing so, a precipitate of Ga hydroxide is generated and the precipitate is filtered out, thereby making it possible to separate and remove iron ions entrained in the eluent and to concentrate Ga. As a result, as shown in Examples below, highly purified metallic Ga can be collected at an extremely high yield. As explained above, the present invention provides an economical and high-yield method for Ga and In that can be used to expand the range of raw materials that can be processed, instead of the conventional separation and collection methods for Ga and In that have had various problems. Commercial separation and collection methods are provided. The present invention will now be described in more detail with reference to Examples. The chelating ion exchange resin used in the Examples is Uniselect UR-50 (registered trademark of Unitika Co., Ltd.). In addition, this thing is
It is obtained by three-dimensionally crosslinking a compound of the above general formula in which M, R ₁ and R ₂ are all hydrogen with phenol as the phenol and formaldehyde as the aldehyde. Example This example has the composition shown in Table 1.
Ga
An example of separate recovery of In and In is shown below.

[Table] Sulfuric acid was added to the raw materials shown in Table 1 to obtain a leachate whose composition is shown in Table 2.

[Table] Neutralize the leachate in Table 2 with calcium carbonate to make the pH
After setting the value to 2.0 and filtering it, add an alkaline agent to the solution again to adjust the pH value to 2.5, and add sodium bisulfite to maintain the reducing property of the solution.
This solution was passed through a column packed with a chelating ion exchange resin at S.V 1.0, thereby selectively adsorbing gallium and indium onto the resin. Next, 3N sulfuric acid was used to elute the gallium and indium adsorbed on the resin. The composition of the obtained eluent (referred to as the separation liquid) is shown in Table 3.

[Table] Hydrogen sulfide gas was blown into the separated liquid shown in Table 3, and the resulting precipitate was filtered off. Zinc powder was added in an amount of 2 equivalents to indium to obtain an indium sponge. The collected indium sponge was melted to make an indium anode, and electrolytically purified to obtain metallic indium with a purity of 99.9% or higher. On the other hand, an alkali agent was added to the liquid obtained by separating the indium sponge to make the pH higher than 10, and the formed precipitate was filtered off. Sulfuric acid was added to the filtrate to reverse neutralize it, and the formed gallium hydroxide was collected by filtration. . Sodium hydroxide is added and dissolved in this gallium hydroxide, and this is used as an electrolyte to perform electrowinning of Ga, and the purity is determined.
More than 99.9% metallic gallium was obtained.

[Brief explanation of the drawing]

Figure 1 is a diagram of the relationship between the PH value of the treatment solution and the adsorption amount of Ga and In for the chelating ion exchange resin.
The figure contains high concentrations of zinc, iron and aluminum
After adjusting the pH of a dilute solution of Ga and In and maintaining its reducing properties, a certain amount of the solution is passed through a chelating ion exchange resin, and the relationship between the amount of solution passed and the flow point is shown in Figure 3.
After adjusting the pH of the eluent and maintaining reducing properties, a certain amount of the eluent is passed through a chelating ion exchange resin, and the relationship between the flow rate and flow point is shown in Figure 4. A diagram of the relationship between the elution amount and Ga and In concentration in the elution curve when ion exchange resin is eluted with 2N hydrochloric acid. Figure 5 is a diagram of the relationship between the pH value of the liquid and the hydrolysis of gallium and trivalent iron. It is.

Claims (1)

[Claims] 1. Trace amounts of Ga and In and relatively large amounts obtained by dissolving a solid material containing trace amounts of Ga and In with an acid, or generated in liquid form from a metal smelting process or other chemical process. A solution containing other metals is used as a treatment stock solution, and this treatment stock solution is used as a treatment stock solution for Ga and In.
The first step is to pass the liquid through a layer of chelating ion exchange resin under a pH value that allows selective adsorption of Step, A metal In precipitation step in which In dissolved in the obtained eluent is precipitated by replacing the metal In with a metal less noble than In, A metal In precipitation step in which the metal In is collected in the above metal In precipitation step, and the liquid is First, the solid content generated at a pH of 10 or higher is separated and removed, then the solid content generated at a pH of 5 to 8 is separated and recovered, and the metal Ga is obtained by electrowinning from an alkaline solution in which the solid content is dissolved.
Metallic Ga from materials containing trace amounts of Ga and In through Ga electrowinning process
and In separation collection method.