JP3784187B2 - Separation and concentration of Ga and In in solution - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for separating and concentrating Ga, In, particularly Ga, from a solution containing Ga, In.
[0002]
[Prior art]
Ga is a metal element obtained in a trace amount as a smelting byproduct of zinc and aluminum, and is often used in compound semiconductors. In the compound semiconductor field, high-purity Ga refined to 6N (99,9999%) or more is used for GaAs and GaP production, and these are used for light-emitting diodes, ICs, LSIs, and the like. On the other hand, In, like Ga, is a metal element obtained in a trace amount as a smelting by-product of zinc and aluminum, and most of it is used in ITO which is a transparent electrode film of liquid crystal.
[0003]
Conventional methods for selectively separating and concentrating Ga and In from a solution containing Ga and In include an ion exchange method and a solvent extraction method. As an ion exchange method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 59-193230 is known. In this method, a solution containing a small amount of Ga and In is passed through a chelating ion exchange resin layer under an appropriate pH, and Ga and In are selectively adsorbed, and then these are eluted using a mineral acid. Is.
[0004]
On the other hand, as a solvent extraction method, a carboxylic acid-based or phosphate-based chelate extraction agent is contained in an organic solvent, and this is used as an organic phase, and the pH of the aqueous phase is adjusted, and the aqueous phase is vigorously brought into contact with the organic phase. A method of selectively extracting Ga and In as a chelate in an organic phase is well known.
[0005]
[Problems to be solved by the invention]
However, the ion exchange method requires a large facility such as a resin tower regardless of the amount of Ga and In to be recovered. Further, when a large amount of impurities such as iron and aluminum are present, if not removed in advance, not only the resin separation efficiency is deteriorated, but also problems such as clogging of the resin tower occur.
[0006]
In addition, in the solvent extraction method, organic chelating agents and organic solvents necessary for the reaction are often used, and in addition to these running costs, exposure prevention equipment is obligated for safety reasons. However, there was a problem that the cost was high.
[0007]
Thus, any of the conventional methods is difficult in terms of cost to tackle as a future business, and how to collect a small amount of Ga and In at a low cost is a problem.
[0008]
The present invention has been made under the above-described background, and it is possible to efficiently recover Ga and In at low cost from a solution containing a small amount of Ga and In. An object is to provide a separation and concentration method.
[0009]
[Means for Solving the Problems]
As a result of diligent research to achieve the above object, the present inventors have focused on the jarosite method used for zinc leaching residue treatment in wet zinc smelting, and from a solution containing a small amount of Ga, In, Ga, In, The inventors have found a condition for separating and concentrating In, particularly Ga, into a jarosite precipitate from a solution, and have reached the present invention.
A first step of adjusting the pH of the solution containing Ga, In to 2 to 4 using a mineral acid or an alkaline agent in the presence of iron (III) ions, sulfate ions, and monovalent cations;
While stirring the solution obtained in the first step, the liquid temperature is heated to 70 to 150 ° C. and reacted for 2 to 24 hours to generate jarosite and co-precipitate Ga and In together with the jarosite particles. Two steps,
And a third step of recovering jarosite containing Ga and In by solid-liquid separation of the reaction product obtained in the second step, and a method of separating and concentrating Ga and In in a solution.
[0010]
The second invention is
In the method for separating and concentrating Ga and In in the solution according to the first invention,
In the second step, it is a method for separating and concentrating Ga and In in a solution, wherein jarosite particles produced separately are added so that the pulp concentration is 50 to 150 g / L.
[0011]
The third invention is
In the method for separating and concentrating Ga and In in the solutions according to the first to third inventions,
In the second step, at least a part of the jarosite containing Ga and In previously collected in the third step is added, and Ga and In in the jarosite containing Ga and In obtained in the third step. In this method, Ga and In are separated and concentrated in a solution.
[0012]
The fourth invention is:
In the method for separating and concentrating Ga and In in a solution according to any one of the first to third inventions,
The solution containing Ga and In has an iron (III) ion concentration of 0.2-5 g / L, a sulfate ion concentration of 0.2 g / L or more, and a monovalent cation concentration of 0.01-0. It is a method for separating and concentrating Ga and In in a solution characterized by adjusting to 1 mol / L.
[0013]
The fifth invention is:
In the method for separating and concentrating Ga and In in a solution according to any one of the first to fourth inventions,
A method for separating and concentrating Ga and In in a solution, wherein the monovalent cation is at least one of Na ⁺ , K ⁺ and NH ₄ ⁺ .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a flowchart showing a schematic configuration of a method for separating and concentrating Ga and In in a solution according to an embodiment of the present invention. Hereinafter, a method for separating and concentrating Ga and In in a solution according to an embodiment of the present invention will be described with reference to FIG. In addition, this embodiment is an example using the solution obtained by the zinc leaching residue processing process in wet zinc smelting as a solution containing Ga and In.
[0015]
In the method of this embodiment, (1) the first step of adjusting the pH of the solution containing Ga, In to 2 to 4, (2) the solution obtained in the first step is reacted to form the jarosite particles. A second step of co-precipitation of Ga and In, and (3) a third step of recovering jarosite containing Ga and In by solid-liquid separation of the reaction product obtained in the second step.
[0016]
(1) 1st process (pH adjustment process)
This step is a step of adjusting the pH to 2 to 4 by adding an alkali agent or a mineral acid to a solution containing Ga and In. Here, the solution containing Ga and In is obtained, for example, in a two-step neutralization step of the zinc leaching residue treatment step in the wet zinc smelting shown in FIG. That is, as shown in FIG. 1, the zinc leach residue processing in wet zinc smelting, zinc leach residue after the zinc leaching by adding sulfuric acid to return to burn ore, firstly, the SO ₂ and the electrolyte tail solution To perform SO ₂ leaching. By this SO ₂ leaching treatment, Pb, Au, Ag, etc. are removed as residues from the zinc leaching residue.
[0017]
Next, first stage neutralization is performed by adding calcium carbonate (CaCO ₃ ) to the liquid from which Pb, Au, Ag, and the like have been removed by SO ₂ leaching. Thereby, gypsum precipitates and free sulfuric acid is removed.
[0018]
Next, a zinc powder is added to the liquid that has been neutralized by one stage to perform a dearsenic treatment. During this dearsenic treatment, copper arsenide pulp is deposited. Next, calcium carbonate is added to the liquid after the dearsenic treatment, and two-stage neutralization is performed. In the two-stage neutralization, gypsum, Ga, In and the like are removed. In the present invention, the acid leaching solution of the two-stage neutralization residue containing Ga, In and the like removed during the two-stage neutralization is used as a solution to be separated and concentrated. After the two-stage neutralization, O2 and steam are added to remove iron to remove it as hematite, and the remaining liquid is returned to the initial leachate and subjected to the same treatment.
[0019]
The solution containing Ga, In and the like obtained during the two-step neutralization usually contains iron (II) ions, sulfate ions, and monovalent cations. Although these components are constituent elements of jarosite, iron (II) ions must be converted to iron (III) ions by an oxidizing agent such as air, oxygen or permanganate ions. In the present invention, jarosite, which is an iron oxide, is generated, and Ga and In are coprecipitated with the particles. That is, generally, Ga and In ions present in a weakly acidic solution may be taken into the precipitate and separated from the liquid when the precipitate of iron (III) ions is precipitated from the liquid. Are known. This invention pays attention to the fact that Ga and In are selectively taken in and good separation and concentration can be achieved by using jarosite as the precipitate of iron (III) ions to be precipitated.
[0020]
First, it is necessary that a monovalent cation such as iron (III) ion, sulfate ion and Na ⁺ , K ⁺ , NH ₄ ⁺ which are constituent elements of jarosite is contained in a predetermined ratio or more in the solution. . Accordingly, replenishment or oxidation is performed as necessary so that these are included in a predetermined ratio. As the oxidizing agent, air, oxygen or permanganate ions are suitable. The iron (III) ion concentration is preferably 0.2 to 5 g / L in solution. When it is lower than 0.2 g / L, the collection rate of Ga and In ions existing in the solution is less than 60% by Ga ions. On the other hand, even if it exceeds 5 g / L, the effect does not change, and the cost is increased.
[0021]
The sulfate ion concentration may be 0.2 g / L or more, and the monovalent cation may be 0.01 to 0.1 mol / L corresponding to 5 to 10 times the theoretical amount of the above chemical formula.
[0022]
Furthermore, the pH of the solution is important in order to produce jarosite precipitates. The pH of the solution is preferably 2-4. In the region where the pH is higher than 4, impurities such as aluminum and zinc other than Ga and In ions are precipitated together with the iron precipitate, so that Ga and In cannot be separated from these impurities. On the other hand, if the pH is less than 2, a part of iron-only precipitate is generated, and Ga and In cannot be co-precipitated.
[0023]
The formation of jarosite is due to heat aging. That is, the solution temperature is heated to 70 to 150 ° C. while vigorously stirring the solution. In this state, the reaction and aging are performed for 2 to 24 hours, more preferably for 10 to 24 hours. If the temperature in this case is low, jarosite will not be formed, and iron (III) hydroxide will be produced, leading to deterioration of filterability. Even at 150 ° C. or higher, iron precipitates other than jarosite are generated. Moreover, since normal pressure heating is possible if liquid temperature is 70-100 degreeC, it is preferable also at the point of apparatus cost. Moreover, when the reaction time is short, the coprecipitation rate of Ga into jarosite becomes insufficient. On the other hand, even if the reaction time exceeds 24 hours, the aging does not proceed any further.
[0024]
Moreover, when the jarosite particle | grains produced | generated separately in the reaction tank are added by 50-150 g / L by pulp concentration, the production | generation of jarosite will be completed in a shorter reaction time (2-6 hours). In the addition of jarosite, jarosite particles that are separately generated in advance are added only for the first time when the processing operation is started. After the processing operation is started and jarosite is recovered through the third step, a part of the jarosite recovered in the third step is returned and added. This addition is repeated so that the Ga and In contents in the jarosite containing Ga and In obtained in the third step are 1 to 5%, respectively.
[0025]
In the third step, after completion of the reaction in the second step, solid-liquid separation is performed with a thickener or the like, and the liquid is drained, and jarosite containing Ga and In is recovered. The recovered jarosite is partly returned to the second step as described above, and sent to the alkali leaching or SO2 reduction leaching step.
[0026]
Example 1
As a solution containing Ga and In, gypsum in the zinc leaching residue treatment step of zinc smelting was leached, and a solution after removing most of In beforehand was used. The main components were Ga 100 mg / L, In 100 mg / L, Zn 30 g / L as impurities, and A1 15 g / L.
[0027]
Since this solution was 1 g / L of sulfuric acid acid, 2.5 g / L (0.06 mol / L) of monovalent cation K ⁺ was added without adding sulfate ion, and iron (III) Ions were added in two cases, 0.2 g / L and 4.0 g / L, and each was inserted into a reactor equipped with a stirrer.
[0028]
The above two solutions were adjusted to pH 2.7 with charcoal cal and then stirred vigorously to raise the liquid temperature to 90 ° C. and reacted in this state for 24 hours. After completion of the reaction, filtration was performed, and precipitation, Ga, In, and impurities such as aluminum and zinc were quantified, and a precipitation rate was determined for each. The results are shown in Table 1 in FIG.
[0029]
(Example 2)
When the same solution as in Example 1 was used, the iron (III) ion was set to 2 g / L, and a monovalent cation, K ^+, was added at 0.3 g / L (0.008 mol / L); The same operation as Example 1 was performed about the case where 0.0 g / L (0.08 mol / L) was added. The precipitation rate for each is shown in Table 2 of FIG.
[0030]
Example 3
To the same solution as in Example 1, 0.5 g / L of iron (III) ions and 0.7 g / L (0.018 mol / L) of K ⁺ were added and inserted into a reaction vessel equipped with a stirrer. After adjusting the pH of this solution to 2.7 with charcoal, add 102 g / L of jarosite particles, which had been separately produced, at a pulp concentration, raise the liquid temperature to 90 ° C., and react for 4 hours in this state. It was. After completion of the reaction, filtration was performed, and precipitation, Ga, In, and impurities such as aluminum and zinc were quantified, and a precipitation rate was determined for each. The results are shown in Table 3 in FIG.
[0031]
【The invention's effect】
As described in detail above, in the present invention, a solution containing Ga and In is adjusted to a pH of 2 to 2 using a mineral acid or an alkaline agent in the presence of iron (III) ions, sulfate ions and monovalent cations. The first step adjusted to 4 and the solution obtained in the first step is heated to 70 to 150 ° C. while vigorously stirring and reacted for 2 to 24 hours to form jarosite. In a solution having a second step of co-precipitation of Ga and In together with particles, and a third step of recovering jarosite containing Ga and In by solid-liquid separation of the reaction product obtained in the second step This is a method for separating and concentrating Ga and In, and enables Ga and In to be efficiently recovered from a solution containing a small amount of Ga and In at a low cost.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a schematic configuration of a method for separating and concentrating Ga and In in a solution according to an embodiment of the present invention.
FIG. 2 is a table summarizing precipitation rates and the like of examples.

Claims (5)

A first step of adjusting the pH of the solution containing Ga, In to 2 to 4 using a mineral acid or an alkaline agent in the presence of iron (III) ions, sulfate ions, and monovalent cations;
While stirring the solution obtained in the first step, the liquid temperature is heated to 70 to 150 ° C. and reacted for 2 to 24 hours to generate jarosite and co-precipitate Ga and In together with the jarosite particles. Two steps,
A method for separating and concentrating Ga and In in a solution, comprising solid-liquid separation of the reaction product obtained in the second step and recovering jarosite containing Ga and In. In the method for separating and concentrating Ga and In in the solution according to claim 1,
Separating and concentrating Ga and In in a solution, wherein in the second step, jarosite particles produced separately are added so that the pulp concentration is 50 to 150 g / L. In the method for separating and concentrating Ga and In in the solution according to claim 1 or 2,
In the second step, at least a part of the jarosite containing Ga and In previously collected in the third step is added, and Ga and In in the jarosite containing Ga and In obtained in the third step. A method for separating and concentrating Ga and In in a solution, wherein the addition treatment is repeated so that the content of 1 is 5%. In the method for separating and concentrating Ga and In in the solution according to any one of claims 1 to 3,
The solution containing Ga and In has an iron (III) ion concentration of 0.2-5 g / L, a sulfate ion concentration of 0.2 g / L or more, and a monovalent cation concentration of 0.01-0. A method for separating and concentrating Ga and In in a solution, wherein the concentration is adjusted to 1 mol / L. In the method for separating and concentrating Ga and In in the solution according to any one of claims 1 to 4,
A method for separating and concentrating Ga and In in a solution, wherein the monovalent cation is at least one of Na ⁺ , K ⁺ and NH ₄ ⁺ .

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