JPS6219496B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is directed to materials containing trace amounts of Ga and In (sometimes in the form of solids, precipitates, or liquids) that contain gallium Ga and indium In at low concentrations, but also contain large amounts of metals other than gallium and indium. The present invention relates to a method for recovering metal Ga and metal In with good yield and from an economically advantageous method. 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,
In the case of precipitates, a method has been proposed in which the precipitate is dissolved with an acid to form a solution, and a solvent extraction method is applied to liquids with low concentrations of gallium and indium, and this method is attracting attention. For example, methods have been reported for concentrating gallium and indium by liquid-liquid extraction using organic solvents such as isopropyl ether, tributyl phosphate, methyl isobutyl ketone, or tertiary saturated fatty acids. ing. Among these, the method using isopropyl ether, tributyl phosphate, or methyl isobutyl ketone can be said to be an excellent method in that it can selectively extract gallium and indium, but it requires a high concentration of hydrochloric acid as the water phase condition during extraction. In particular, isopropyl ether and methyl isobutyl ketone have a problem in that they dissolve in a large amount in the aqueous phase and have a very short lifetime. In addition, the method using tertiary saturated fatty acids is advantageous in that the solvent is inexpensive and there are no restrictions on the type of acid or the concentration of gallium and indium, but it depends on the type and concentration of coexisting metal salts in the aqueous phase. However, there is a problem in that the extraction rate is significantly reduced. In addition, solvent extraction methods have the drawback that a common problem is that the solvent is entrained or dissolved in the residual liquid in the form of droplets. More specifically, the industrial recovery methods of Ga and In metals that have been proposed and implemented in the past include metal smelting smoke, various residues after main metal recovery, and hydrometallurgy during the hydrometallurgical process. Targets solutions, liquids and solids generated from other chemical processes,
When Ga and In, which are mixed in small amounts in this, are industrially extracted, there are cases where both Ga and In are in an economical content, and cases where one of them does not reach an economical content.
In general, the mainstream recovery methods have been as follows, depending on whether the material is mainly Ga or In (and depending on the form of the raw material to be treated). First, industrial extraction of metallic gallium was mainly carried out from aluminum smelting waste liquid or zinc smelting residue. In the case of waste liquid from aluminum smelting, alumina crystals are crystallized from a solution obtained by processing bauxite using the Bayer method, 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 sintered ore with sulfuric acid (in the case of wet zinc smelting method), or by adding a reducing agent and sintering 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. Dissolve the crude hydroxide with concentrated hydrochloric acid to obtain an approximately 6N hydrochloric acid solution, and concentrate gallium by performing liquid-liquid extraction from this solution using the above-mentioned solvent extraction method (using isopropyl ether or tributyl phosphate, etc.). methods have been adopted. However, the separation method using hydroxide requires extremely difficult filtration operations, and also requires very difficult filtration operations.
If a large amount of hydroxides, Al, etc. coexist, a large amount of these hydroxides will be produced, making the processing operation complicated, and the obtained gallium will also contain many other metals, making it difficult to expect separation of these metals. 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. The solvent extraction method (3) has the above-mentioned problem, and even if the solution to which it is applied is pretreated (neutralization method or concentrated alkali dissolution method) to concentrate gallium, it will not produce the same amount of gallium as zinc smelting residue. For materials containing 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.; A method has been implemented in which the resulting In-containing solution is treated with hydrogen sulfide and hydroxylated, and then In is precipitated by substitution with metal Zn or Al. However, in methods (1) and (2), Cu, Fe, Zn,
When large amounts of As, Al, etc. coexist, a large amount of precipitates are formed and the treatment operation becomes 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, although the solvent extraction method (4) has some advantages, it also has the problems mentioned above. For example, the method using isopropyl ether as a solvent is an excellent method because it can selectively extract In, but it requires hydrogen bromide as an aqueous phase condition during extraction, and the isopropyl ether aqueous phase The disadvantage is that the amount of dissolved material is large and the lifespan is short. There are various cases where other solvents are used, but even if they are effective for separating In from a certain metal, none are effective for separating In from all metals, and solutions containing various metals are effective. When separating and concentrating In from the metal, a large burden is placed on pretreatment in consideration of the properties of other metals. In addition, in the case of method (5), Cu, Fe, Zn,
This is because a trace amount of In is separated from a solution obtained by processing a substance containing large amounts of As, Al, etc.
The reality is that many separation methods have to be combined, and in the past, any method involved complicated and complicated steps, and there was no economical method. In particular, Ga
A commercial method that can efficiently separate and recover both In and In has not yet been established. The present invention was made with the aim of solving such conventional problems of Ga and In extraction.For this purpose, the present inventors have conducted various tests and researches, and as a result, the present invention has been developed as described in detail above. Ga and
When In is industrially extracted, virtually all the extracted raw materials can be used as target raw materials, and the problems mentioned above in various conventional methods can be solved all at once.
We were able to establish an industrial method for extracting Ga and In from materials containing trace amounts of Ga and In. Thus, the present invention can be applied to a liquid obtained by dissolving a solid substance containing small amounts of Ga and In with an acid, or a liquid generated from a metal smelting process or other chemical process.
A solution containing trace amounts of Ga and In is used as a treatment stock solution, and this treatment stock solution is converted to a pH that can selectively adsorb Ga and In.
a first step in which the liquid is passed through a layer of chelating ion exchange resin under a certain temperature; Adding an alkaline agent to the eluent from the second step
A third step of precipitating the In content by adjusting the pH to 10 or more, followed by solid-liquid separation; a dissolving step of dissolving the solid content obtained in the third step with an acid to obtain an acidic solution; In the In precipitation step, a metal less base than In is added to the solution obtained in the third step, and In is precipitated by displacement from this solution.Ga content is removed by adding acid to the liquid obtained in the third step and reverse neutralizing it. A reverse neutralization step in which solid-liquid separation is performed after precipitating Ga, and an electrolytic step in which the solid content obtained in the reverse neutralization step is dissolved with an alkali and the alkaline solution is used as an electrolyte to collect Ga. Ga and In from trace amounts of In
Provide a method to recover In. [First step] In the first step, a solution obtained by dissolving a solid substance containing a small amount of Ga and In with an acid, or a solution containing a small amount of Ga and In generated in a liquid form from metal smelting process or other chemical process is processed into a raw solution. This is a step in which this treated stock solution is passed through a layer of chelating ion exchange resin under 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 hydrometallurgy and chemical processes whose main purpose is not to collect Ga or In, but it also contains Ga and In.
Liquids that also contain small amounts of In and In, such as electrolytic solutions for electrolytic refining of main metals, or liquids in which most of the main substances have been removed but contain large amounts of other metal ions and also contain small amounts of Ga and In. This refers to things similar to secondary liquids and waste liquids. The present invention targets these substances containing trace amounts of Ga and In (some solid, some liquid) that occur in various places.
If it is in solid form, it is 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 small amount of Ga and In is a liquid obtained by dissolving a solid substance containing a small amount of Ga and In with an acid, or a liquid containing a small amount of Ga and In is generated in liquid form from metal smelting process or other chemical process, but both Ga and In are 0.1 to 1 ( g/)
It is a liquid in which 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. . 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 alkali metal or hydrogen, R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 3 carbon atoms, and a chelate resin obtained by three-dimensionally crosslinking a phenol compound, a phenol, and an aldehyde. Can be used. Such a resin itself has been used as an ion exchange resin capable of reducing the iron ion concentration in an acidic electrogalvanizing bath, for example, in Japanese Patent Application Laid-open No. 121241/1983, and as an ion exchange resin that can reduce the concentration of iron ions in an acidic electrogalvanizing bath.
- Known as a commercially available resin from Unitika Co., Ltd. under the registered trademark of 50. 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. The contact temperature to the resin at this time 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 at pH values of 1.0 to 4.0. In addition, Figure 2 shows that an acidic sulfuric acid solution containing trace amounts of gallium and indium containing 10 to 20 (g/) of zinc, iron, and aluminum each was adjusted to pH 2.8, and sodium hydrogen sulfite was 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 this mixed solution is selectively adsorbed by the resin. [Second Step] The second step is a step in which the resin subjected to the first step is treated with a mineral acid to melt the resin-adsorbed substance. As mentioned above, Ga is added to this resin in the first step.
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, it is preferable to use a concentration of 1 to 6N, preferably 2 to 3N. This elution results in
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 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 has a concentration of 1 to 6N, preferably 3 to 4N in the case of sulfuric acid, and 1 to 6N and preferably 2 to 3N in the case of hydrochloric acid. The concentration of Ga and In in this eluent ranges from 0.1 to 50
(g/) can be achieved. The amount of metal ions other than Ga and In in this eluent is extremely small, and Ga and In
Only In is 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. It can be seen from the figure that Ga and In are selectively adsorbed by this resin, and that Ga and In are concentrated in the eluent, while 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. [Third step] The third step is a step in which an alkaline agent is added to the eluent obtained in the second step to adjust the pH to 10 or higher to precipitate the In component, and then solid-liquid separation is performed. be. This alkaline agent includes calcium hydroxide,
One or more of sodium hydroxide, calcium carbonate, aqueous ammonia, etc. can be used. That is, in the third step of the present invention, an alkaline agent is added to the eluent from the second step to adjust its PH value.
By adjusting the concentration to 10 or more, In is precipitated as a hydroxide, while Ga is dissolved in the liquid, and by performing solid-liquid separation in that state, In and Ga are separated. The solid content obtained in the third step is dissolved in an acid to form an acidic liquid, and then a metal less noble than In is added thereto to precipitate In by displacement from this solution. As a result, metallic In can be extracted in high yield. That is, after the precipitate in the third step is filtered, it is dissolved in mineral acid, such as sulfuric acid or hydrochloric acid, at a pH of 2.0 or less, and a metal less noble than In, such as zinc powder or aluminum plate, is added to In in this acidic solution. Indium sponge is obtained by adding 1 to 3 equivalents. The collected sponge In can be melted and cast into an anode as needed, and then electrorefined to produce high-purity In metal. On the other hand, the liquid obtained in the third step is reverse neutralized by adding acid to adjust the pH to 5 to 8 to precipitate the Ga component, followed by solid-liquid separation. The solid content is dissolved with an alkali, and the metal content is collected using this alkaline solution as an electrolyte. That is, the filtrate from the third step is prepared by adding an acid such as sulfuric acid and reverse neutralizing it until the pH becomes about 5 to 8 to precipitate the Ga content, and after solid-liquid separation, the obtained solid content Add an alkali such as sodium hydroxide to adjust the pH to 10 or higher, and use the resulting alkaline solution as an electrolyte to electrolytically extract the Ga component. The characteristic phenomenon utilized in the present invention is that Ga ions dissolved in the mineral acid eluent used in the second step
This is a phenomenon in which Ga precipitates are redissolved during the neutralization process of In ions in the third step. This relationship is shown in FIG. In other words, if the pH value of the eluent is lower than 4, if the pH is gradually raised from this low pH value by adding alkali, Ga will precipitate once, but from around PH value exceeding 8 (preferably 10 ) This Ga starts to dissolve again, whereas In does not dissolve again. In the present invention, this phenomenon is utilized to separate Ga and In in a mineral acid eluent. As explained above, the present invention provides an economical and high-yield Ga, which can be used to expand the range of raw materials to be processed, as an alternative to the industrial production methods of Ga and In, which have had various problems in the past. In recovery methods are provided. Examples are given below, but the chelating ion exchange resin used in the examples is Uniselect.
A resin commercially available from Unitika Co., Ltd. under the registered trademark UR-50 (a compound of the above general formula in which M, R ₁ and R ₂ are all hydrogen, phenol as the phenol and formaldehyde as the aldehyde) It is a resin obtained by three-dimensional cross-linking. Example 1 In this example, as the composition is shown in Table 1,
An example is shown in which Ga and In are separated and recovered from materials produced in the zinc smelting process that contain large amounts of Zn, Al, and Fe and trace amounts of Ga and In.

[Table] Sulfuric acid was added to 480 kg of the raw material shown in Table 1 so that the free acid concentration in the liquid after leaching treatment was 80 (g/), and the composition of the leachate is shown in Table 2. 1.5 m ³ was gotten.

[Table] After adjusting the oxidation-reduction potential by blowing hydrogen sulfide gas into 1.5 m ³ of the leachate shown in Table 2, it was further neutralized with calcium carbonate to adjust the pH value to 2.0, and the total volume including washing water was 1.92 m ³ The composition of the liquid in this case is shown in Table 3.

[Table] Concentration of coexisting metal ions in solution. However, composition ratio =

Claims (1)

[Claims] 1. A liquid obtained by dissolving a solid substance containing a trace amount of Ga and In with an acid, or a liquid containing a trace amount of Ga and In generated in a liquid form from a metal smelting process or other chemical process is used as a processing stock solution, and this The first step is to pass the treated stock solution through a layer of chelating ion exchange resin under a pH value that allows Ga and In to be selectively adsorbed.The second step is to pass the treated solution through a layer of chelating ion exchange resin under a pH value that allows Ga and In to be selectively adsorbed. The second step is to elute the resin-adsorbed substances by treatment, and an alkaline agent is added to the eluent from the second step.
A third step of precipitating the In content by adjusting the pH to 10 or more, followed by solid-liquid separation; a dissolving step of dissolving the solid content obtained in the third step with an acid to obtain an acidic solution; An In precipitation step in which a metal less base than In is added to the solution obtained in the third step, and In is precipitated by displacement from this solution.Ga content is removed by adding an acid to the liquid obtained in the third step and reverse neutralizing it. A reverse neutralization step in which solid-liquid separation is performed after precipitation, and an electrolytic step in which the solid content obtained in the reverse neutralization step is dissolved with an alkali and the alkaline solution is used as an electrolyte to collect Ga. A method for recovering Ga and In from trace amounts of substances. 2. The method according to claim 1, wherein in the dissolving step, an acidic solution having a pH of less than 5 is obtained. 3. Claim 1: In the reverse neutralization step, the pH is adjusted to 5 to 8 to precipitate the Ga component.
or the method described in paragraph 2.