JP2000204423A - Separation concentration of gallium and indium in solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separation concentrating method of Ga and In in a soln. capable of efficiently recovering Ga and In from a soln. contg. trace amounts of Ga and In at a low cost. SOLUTION: As a soln. contg. trace amounts of Ga and In, a soln. obtd. by two step neutralizing treatment in a zinc leaching residue treating stage of zinc refining is used, this soln. is heated to 70 to 150 deg.C soln. temp. while being violently stirred under the control of pH to 2 to 4 by using mineral acid or an alkali agent in the presence of iron (I, II) ions, sulfuric acid ions and univalent cations and is brought into reaction for 2 to 24 hr to produce jarosite, Ga and In are coprecipitated together with jarosite grains, and solid-liq. separation is executed therein to recover jarosite contg. Ga and In.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for separating and concentrating Ga and In, particularly Ga, from a solution containing Ga and In.

[0002]

2. Description of the Related Art Ga is a metal element obtained in trace amounts as a by-product of smelting zinc and aluminum, and is widely used in compound semiconductors. In the compound semiconductor field, 6N (99,99
High-purity Ga purified to GaAs, Ga
Used for P production, these are light emitting diodes, IC, L
It is used for SI and the like. On the other hand, like Ga, In is a metal element obtained in trace amounts as a smelting by-product of zinc and aluminum, and is mostly used for ITO, which is a transparent electrode film of liquid crystal.

[0003] Conventionally, Ga, I
Methods for selectively separating and concentrating n include an ion exchange method and a solvent extraction method. As an ion exchange method, for example, a method disclosed in JP-A-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 to selectively adsorb Ga and In, and then eluted with a mineral acid. Things.

[0004] On the other hand, the solvent extraction method involves adding a carboxylic acid-based or phosphoric acid-based chelate extractant to an organic solvent, converting the resultant into an organic phase, adjusting the pH of the aqueous phase, and vigorously contacting the organic phase. A method for selectively extracting Ga and In in an aqueous phase as a chelate in an organic phase is well known.

[0005]

However, the ion exchange method requires large-scale equipment such as a resin tower regardless of the amounts of Ga and In to be recovered. If a large amount of impurities such as iron and aluminum are present, if they are not removed beforehand, not only will the efficiency of resin separation deteriorate, but also problems such as blockage of the resin tower will occur.

[0006] In the solvent extraction method, an organic chelating agent and an organic solvent necessary for the reaction are often used. In addition to these running costs, a safety equipment is required from the viewpoint of safety. There was a problem that the cost became very high as an investment.

As described above, any of the conventional methods is difficult in terms of cost to tackle as a future business, and there has been a problem how to recover a small amount of Ga and In at low cost.

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned background, and has been developed to reduce the cost and efficiency of recovering Ga and In from a solution containing trace amounts of Ga and In. , In is provided.

[0009]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, focused on the jarosite method used for zinc leaching residue treatment in wet zinc smelting, The present inventors have found conditions for separating and concentrating Ga, In, in particular, Ga into a jarosite precipitate from a solution containing a trace amount of In, which has led to the present invention. A first step of adjusting the pH of the solution to 2 to 4 using a mineral acid or an alkali agent in the presence of iron (III) ions, sulfate ions and monovalent cations, and a first step. While stirring the solution,
１５０150 ° C., and reacted for 2-24 hours to form jarosite, and G
a, In: a second step of coprecipitating a and In, and a third step of solid-liquid separation of the reaction product obtained in the second step to recover jarosite containing Ga and In. In
Is a separation and concentration method.

In a second aspect of the present invention, in the method for separating and concentrating Ga and In in a solution according to the first aspect, in the second step, the jarosite particles separately formed may have a pulp concentration of 50 to 150 g / L. This is a method for separating and concentrating Ga and In in a solution, characterized in that they are added so as to be as follows.

According to a third invention, in the method for separating and concentrating Ga, In in a solution according to the first to third inventions, in the second step, the Ga, In recovered earlier in the third step is used.
Is added, and this addition treatment is repeated such that the content of Ga, In in the jarosite containing Ga, In obtained in the third step becomes 1 to 5%. G in solution characterized by performing
This is a method for separating and concentrating a and In.

According to a fourth aspect of the present invention, in the method for separating and concentrating Ga and In in a solution according to any one of the first to third aspects, the iron (III) ion concentration of the solution containing Ga and In is reduced to 0. 0.2 to 5 g / L and the sulfate ion concentration of 0.2
g / L or more, the monovalent cation concentration is 0.01 to 0.1.
The concentration of Ga, I in the solution is adjusted to mol / L.
n is a separation and concentration method.

According to a fifth aspect, in the method for separating and concentrating Ga and In in a solution according to any one of the first to fourth aspects, the monovalent cations are Na ⁺ , K ⁺ , and NH ₄ ⁺ Ga in a solution, characterized in that it is at least one of the following:
This is a method for separating and concentrating In.

[0014]

FIG. 1 is a flow chart 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 this embodiment, a solution obtained in a zinc leaching residue treatment step in wet zinc smelting is used as a solution containing Ga and In.

The method according to this embodiment includes the following steps: (1) Ga, I
a first step of adjusting the pH of the solution containing n to 2 to 4,
(2) a second step of reacting the solution obtained in the first step to coprecipitate Ga and In together with jarosite particles;
(3) The reaction product obtained in the second step is subjected to solid-liquid separation,
A third step of collecting jarosite containing Ga and In. Here, jarosite is a substance represented by a chemical formula: M: Fe ₃ (SO ₄ ) ₂ (OH) ₆ M: monovalent cation.

(1) First Step (pH Adjustment Step) 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 the two-stage neutralization step of the zinc leaching residue treatment step in the wet zinc smelting shown in FIG. That is, as shown in FIG. 1, in the zinc leaching residue treatment in the wet zinc smelting, the SO ₂ and the electrolytic tail solution are first added to the zinc leaching residue after returning to the calcined and adding sulfuric acid to perform zinc leaching. To perform SO ₂ leaching. By this SO ₂ leaching treatment, Pb,
Au, Ag, etc. are removed as residues.

Next, Pb, Au, and A are leached by SO ₂ leaching.
g, etc., is added to calcium carbonate (CaC
O ₃ ) is added to perform the first stage neutralization. Thereby, gypsum precipitates and free sulfuric acid is removed.

Next, zinc powder is added to the liquid that has been subjected to the one-stage neutralization, and dearsenic treatment is performed. During this dearsenic treatment, copper arsenide pulp is precipitated. Next, calcium carbonate is added to the liquid after the dearsenic treatment, and two-stage neutralization is performed. At the time of this two-stage neutralization, gypsum, Ga, In and the like are removed. The present invention provides a method for removing G which is removed during this two-stage neutralization.
An acid leaching solution of a two-stage neutralization residue containing a, In, etc. is used as a solution to be separated and concentrated. After two-stage neutralization,
O2 and steam are added to remove iron and remove hematite, and the remaining liquid is returned to the original leachate for similar treatment.

The solution containing Ga, In and the like obtained in the two-stage neutralization usually contains iron (II) ions, sulfate ions and monovalent cations. These components are constituents of jarosite, but iron (II) ions need to be converted to iron (III) ions by an oxidizing agent such as air, oxygen or permanganate ion. According to the present invention, jarosite, which is an iron oxide, is generated, and Ga and In are coprecipitated with the particles. That is, generally, when a precipitate of iron (III) ions precipitates from a liquid, Ga, In ions present in the weakly acidic solution are taken into the precipitate and separated from the liquid. Are known. The present invention provides Ga, I by using jarosite as a precipitate of iron (III) ions to be precipitated.
The inventors focused on the fact that n was selectively taken in and good separation and concentration could be achieved.

First, iron (III) ions, sulfate ions and Na ⁺ , K
It is necessary that monovalent cations such as ⁺ and NH ₄ ⁺ be contained in a predetermined ratio or more. Therefore, they are replenished or oxidized as necessary so that they are contained in a predetermined ratio. Air, oxygen or permanganate ions are suitable as oxidizing agents. The iron (III) ion concentration is
The solution is preferably 0.2 to 5 g / L. If it is lower than 0.2 g / L, the collection rate of Ga, In ions present in the solution is less than 60% by Ga ions. On the other hand, even if the amount is more than 5 g / L, the effect does not change and the cost is unnecessarily increased.

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 which is 5 to 10 times the theoretical amount of the above chemical formula. .

In addition, the pH of the solution is important for the formation of jarosite precipitates. The pH of the solution is 2
To 4 are preferable. In the region where the pH is higher than 4, Ga, In
Since impurities other than ions, such as aluminum and zinc, also precipitate together with the iron precipitate, Ga and In cannot be separated from these impurities. On the other hand, if the pH is less than 2, a precipitate of only iron is partially formed, and Ga and In cannot be coprecipitated.

The generation of jarosite is due to heat aging. That is, while stirring the solution vigorously,
Heat to 0-150 ° C. In this state, the reaction and aging are performed for 2 to 24 hours, more preferably 10 to 24 hours. If the temperature in this case is low, jarosite will not be formed, and iron (III) hydroxide will be generated, leading to deterioration in filterability. Even at 150 ° C. or more, iron precipitates other than jarosite are formed. Further, if the liquid temperature is 70 to 100 ° C., normal pressure heating is possible, which is also preferable from the viewpoint of apparatus cost. Further, if the reaction time is short, the co-precipitation rate of Ga in jarosite becomes insufficient. On the other hand, if the reaction time exceeds 24 hours, aging does not proceed any longer.

Further, when jarosite particles separately produced are added to the reaction tank at a pulp concentration of 50 to 150 g / L,
The jarosite formation is completed in a shorter reaction time (2-6 hours). For the addition of jarosite, jarosite particles separately generated in advance are added only at the first time of starting the processing operation. 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 repeatedly performed so that the content of Ga and In in the jarosite containing Ga and In obtained in the third step becomes 1 to 5%, respectively.

In the third step, after the completion of the reaction in the second step, solid-liquid separation is performed using a thickener or the like, and the liquid is drained and the jarosite containing Ga and In is recovered. The collected jarosite is returned to the second step, as described above, and then sent to an alkali leaching or SO2 reduction leaching step.

(Example 1) As a solution containing Ga and In, gypsum in a zinc leaching residue treatment step of zinc smelting was leached, and a solution after removing most of In in advance was used. The main components are Ga 100 mg / L, In 100
mg / L, Zn 30 g / L as impurities, A1 15
g / L.

Since this solution was acidic with 1 g / L of sulfuric acid, no sulfate ion was added, but K ⁺ , a monovalent cation, was added at 2.5 g / L (0.06 mol / L), and iron was added. (II
I) Ions were added for two types, 0.2 g / L and 4.0 g / L, and each was inserted into a reaction vessel equipped with a stirrer.

After adjusting the pH of the above two solutions to 2.7 with charcoal, the solution was stirred vigorously, the temperature of the solution was raised to 90 ° C., and the mixture was reacted in this state for 24 hours. After the completion of the reaction, filtration was performed, Ga and In in the precipitate and the filtrate, and aluminum and zinc as impurities were quantified, and the precipitation rate was determined for each. The results are shown in Table 1 of FIG.

(Example 2) Using the same solution as in Example 1, the iron (III) ion was changed to 2 g / L, and the monovalent cation K ⁺ was changed to 0.3 g / L (0.008 mol / L). L)
The same operation as in Example 1 was performed for the case where the addition was performed and the case where 3.0 g / L (0.08 mol / L) was added.
The precipitation rate for each is shown in Table 2 of FIG.

Example 3 In the same solution as in Example 1, 0.5 g / L of iron (III) ion and 0.7 g / L of K ⁺ were added.
(0.018 mol / L) and inserted into a reaction vessel equipped with a stirrer. After adjusting the pH of the solution to 2.7 with charcoal, jarosite particles separately formed were added at a pulp concentration of 102 g / L, the liquid temperature was raised to 90 ° C., and a reaction was performed for 4 hours in this state. Was. After the completion of the reaction, filtration was performed, Ga and In in the precipitate and the filtrate, and aluminum and zinc as impurities were quantified, and the precipitation rate was determined for each. The results are shown in Table 3 of FIG.

[0031]

As described in detail above, the present invention provides Ga,
A first step of adjusting the pH of the solution containing In to pH 2 to 4 using a mineral acid or an alkali agent in the presence of iron (III) ions, sulfate ions, and monovalent cations; While stirring the obtained solution vigorously, the liquid temperature was increased to 70 to 150.
C. and reacted for 2 to 24 hours to produce jarosite, co-precipitating Ga and In together with the jarosite particles, and solid-liquid separation of the reaction product obtained in the second step And a third step of recovering jarosite containing Ga and In. A method for separating and concentrating Ga and In in a solution, comprising the steps of recovering jarosite containing Ga and In. Can be recovered.

[Brief description of the drawings]

FIG. 1 shows Ga, in a solution according to an embodiment of the present invention.
It is a flowchart which shows schematic structure of the separation and concentration method of In.

FIG. 2 is a diagram collectively showing a settling rate and the like of Examples.

Claims (5)

[Claims] 1. A solution containing Ga and In containing iron (II)
I) a first step of adjusting the pH to 2 to 4 using a mineral acid or an alkali agent in the presence of ions, sulfate ions, and monovalent cations, and stirring the solution obtained in the first step. 70 ~ 1
The mixture was heated to 50 ° C. and reacted for 2 to 24 hours to generate jarosite.
a second step of co-precipitating n, and solid-liquid separation of the reaction product obtained in the second step to obtain Ga,
And a third step of recovering jarosite containing In. 2. The method for separating and concentrating Ga and In in a solution according to claim 1, wherein in the second step, jarosite particles separately produced are added so as to have a pulp concentration of 50 to 150 g / L. A method for separating and concentrating Ga and In in a solution. 3. The solution according to claim 1, wherein Ga,
In the method of separating and concentrating In, in the second step, the G recovered earlier in the third step
At least a part of the jarosite containing a and In is added so that the content of Ga and In in the jarosite containing Ga and In obtained in the third step becomes 1 to 5%. A method for separating and concentrating Ga and In in a solution, comprising repeating the treatment. 4. The method for separating and concentrating Ga and In in a solution according to claim 1, wherein the concentration of iron (III) ion in the solution containing Ga and In is 0.2 to 5 g / g. L, a sulfate ion concentration of 0.2 g /
A method for separating and concentrating Ga and In in a solution, wherein the concentration of a monovalent cation is adjusted to 0.01 to 0.1 mol / L. 5. The method for separating and concentrating Ga and In in a solution according to claim 1, wherein the monovalent cation is at least one of Na ⁺ , K ⁺ , and NH ₄ ^+. Ga, In in a solution characterized by being
Separation and concentration method.