KR100821608B1 - Method for producing indium-containing metal - Google Patents

Abstract

The present invention provides a starting material of an indium-containing metal which can efficiently obtain indium with high yield by using an indium-containing solution obtained by dissolving indium-containing materials obtained by recovering indium dispersed during ITO thin film production with an acid or the like as a starting material. It provides a manufacturing method. By mixing oxalic acid as a precipitant in an indium-containing solution, a precipitate of indium oxalate is formed, and the precipitate is recovered by solid-liquid separation, and the precipitate is dissolved in an acid to give an acid solution and aluminum in an acid solution A plate is put in, and sponge indium is produced by substitution reaction with aluminum, this is melted in alkali to obtain an indium-containing metal.

Indium-containing metal, ITO thin film, indium oxalate

Description

Method for producing indium-containing metal {METHOD FOR PRODUCING INDIUM-CONTAINING METAL}

The present invention relates to a method for producing an indium-containing metal containing high indium from an indium-containing solution obtained by dissolving a recovered ITO, waste ITO target, scrap containing ITO, and the like scattered during the production of an ITO thin film. .

Indium is a metal that is used in various fields such as optical materials, optoelectronic materials, compound semiconductors, and brazing materials. Recently, indium is widely used as raw material for electrode materials such as liquid crystal displays (LCDs) and plasma displays (PDPs). For this reason, it is required to reuse indium from recovered products, wastes and the like containing indium.

Since the ITO thin film made of indium-tin oxide (ITO) has both high conductivity and visible light transmittance, various transparent conductive films such as solar cells, liquid crystal display devices, touch panels, and anti-condensation heating films for window glass are used. It is used for a purpose.

As a method of manufacturing an ITO thin film, methods, such as sputtering, a vacuum vapor deposition, the sol-gel method, cluster beam vapor deposition, and a PLD, are mentioned. Among them, the sputtering method is widely used industrially because a low resistance thin film can be produced at a relatively low temperature on a large area substrate.

When manufacturing an ITO thin film by the sputtering method, it is common to irradiate plasma etc. as a target with the ITO sintered compact obtained by sintering the mixture of an indium oxide and tin oxide, and to sputter | spatter ITO, and to deposit and form an ITO thin film on a board | substrate. At this time, sputtered ITO is not deposited on the substrate, and thus ITO is scattered to the surroundings. Thus, the scattered ITO is dissolved in an acid such as hydrochloric acid to form an indium-tin-containing acid solution, and from this indium-tin-containing acid solution It is required to recover indium and tin and reuse them as ITO raw materials and the like.

As a method of recovering indium (In) from this kind of indium-containing substance, a method of combining wet purification such as an acid dissolution method, an ion exchange method, and a solvent extraction method is known in the art, and several new methods have been proposed.

For example, Patent Literature 1 below discloses an In electrolytic slime containing Sn, Pb, Cu, and Ag as an impurity other than In with hydrochloric acid, adjusts the pH to 0.5 to 2.0 with an alkaline agent, and then dissolves the insoluble residue. Subsequently, a method of recovering crude indium for electrolysis by adding a reducing agent, separating the resulting precipitate, and then adding a reducing agent is disclosed.

Patent Literature 2 below adds hydrogen peroxide and sulfuric acid to an In-containing material containing As and Mn as impurities in addition to In, dissolving a metal salt, and then adjusting the pH to 4.5-6.0 by adding an alkali agent, followed by filtration treatment. There is disclosed a method for recovering indium, in which a precipitate in which As and In coexist to obtain a precipitate, and at the same time, Mn and Zn are transferred to the liquid after neutralization, and then As is removed from the precipitate.

In the following Patent Document 3, an indium-containing mass is pulverized, and the pulverized product is leached into an acidic aqueous solution in the presence of hydrogen peroxide, and the aluminum plate is immersed in the leachate, and the sponge indium is spun on the aluminum plate by a substitution reaction. A method of recovering indium is obtained, which precipitates the precipitate, and subsequently injects the sponge indium into alkali to obtain an indium metal.

In Patent Document 4, an indium-containing hydrochloric acid solution is extracted with a solvating extraction type extract, followed by back extraction with a dilute acid, and the collected indium solution is electrolytically collected or neutralized to form a hydroxide to form carbon or hydrogen. A method for recovering indium by reducing or dissolving with sulfuric acid and electrolytically is disclosed.

The following Patent Document 5 discloses a step of dissolving ITO indium-containing scrap with hydrochloric acid to form an indium chloride solution, adding a sodium hydroxide aqueous solution to the indium chloride solution to remove tin contained in the scrap as tin hydroxide, and the tin hydroxide. Disclosed is a method for recovering indium, which comprises a step of replacing and recovering indium from zinc after removal.

Patent Document 1: Japanese Patent Application Laid-Open No. 5-156381

Patent Document 2: Japanese Patent Application Laid-Open No. 5-311267

Patent Document 3: Japanese Patent Application Laid-Open No. 9-268334

Patent Document 4: Japanese Patent Application Laid-Open No. 2002-201026

Patent Document 5: Japanese Patent Application Laid-Open No. 2002-69544

[Initiation of invention]

[Problem to Solve Invention]

The present invention provides a new indium-containing metal which can efficiently obtain indium in a high yield when an indium-containing solution obtained by dissolving indium-containing materials obtained by recovering indium scattered during ITO thin film production with an acid or the like as a starting material. It is to provide a manufacturing method.

[Means for solving the problem]

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the present inventors chose the method of mixing and precipitating an indium containing solution, precipitating and recovering indium. It is because it becomes possible to obtain an indium containing metal by less operation in such a method.

On the other hand, in such a simple method, when precipitating this indium, it is necessary to make sure that no impurities are accompanied in the precipitate as much as possible. Therefore, the present inventors have studied the precipitant which can suppress the incorporation of impurities as much as possible when precipitating indium from the indium-containing solution. As a result, it was found that oxalic acid is particularly excellent in the resolution of indium.想到).

That is, the present invention provides a method for producing an indium-containing metal from an indium-containing solution, the process of producing a precipitate of indium oxalate by mixing oxalic acid as a precipitant in an indium-containing solution, and depositing the precipitate of indium oxalate as a solid solution ( Iii) A method for producing an indium-containing metal having a step of recovering by separation.

The precipitate of indium oxalate obtained by recovering as described above may be brought into contact with ammonia or ammonia and alkali hydroxide as it is or if necessary, and then roasted to obtain an indium-containing metal.

In addition, the precipitate of indium oxalate obtained and recovered as described above is dissolved in an acid to make an acid solution, and then metal is added to the acid solution to produce sponge indium by a substitution reaction with the metal. It can also be set as an indium containing metal from a. In addition, the precipitate of indium oxalate obtained at this time is immersed in a liquid which does not dissolve indium, and in the subsequent substitution precipitation step, ions which cause passivation on the metal surface are dissolved in the liquid to remove the dissolved liquid. After carrying out the ion-washing treatment of the passivation-forming ion at least once, the washing treatment obtained by the passivation-forming ion-cleaning is dissolved in an acid to make an acid solution, and a metal is added to the acid-solution solution to replace the reaction with the metal. Sponge indium is produced | generated and it can also be set as an indium containing metal from this sponge indium.

According to the manufacturing method of such an indium-containing metal, not only an indium-containing metal such as ITO target can be efficiently produced as an indium-containing solution, or a waste washing solution containing indium as a starting material, but also impurities By suppressing the accompanying, it is possible to produce an indium-containing metal containing high indium.

Indium is a material that is attracting attention as its usage increases with the spread of LCDs and PDPs, and a surge in material costs. Therefore, the present invention can reduce the material cost and further reduce the cost of these devices through effective use of indium.

In addition, in this invention, an "indium containing metal" means the ingot containing metal mass (80 mass% or more of indium purity, Preferably it is 90 mass% or more), and means including indium oxide.

BRIEF DESCRIPTION OF THE DRAWINGS The flow explaining the process of indium recovery in Examples 1-18 and Comparative Examples 1-5.

2 is a flow for explaining a step of recovering indium in Examples 19 to 27. FIG.

Fig. 3 shows the X-ray diffraction pattern of the precipitate immediately after precipitation (a), the precipitate after contact treatment (b), and the indium oxide (c) after roasting.

[Mode for Carrying Out the Invention]

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated based on embodiment, this invention is not limited to the following embodiment.

(1st embodiment)

The manufacturing method of the indium containing metal which concerns on 1st Embodiment is characterized by manufacturing an indium containing metal through the following process.

Generating a precipitate of indium oxalate by adding and mixing oxalic acid as a precipitant to an indium-containing solution (indium oxalate precipitation step),

Recovering the precipitate of indium oxalate by solid-liquid separation (; precipitate recovery step),

If necessary, the recovered precipitate is contacted with ammonia or ammonia and alkali hydroxide (; alkali contacting step),

Thereafter, roasting the recovered precipitate (; roasting step),

Through these processes, an indium-containing metal is produced.

Hereinafter, this embodiment is explained in full detail.

Raw material: Indium-containing solution

The raw material used for this embodiment is an indium containing solution containing indium.

The indium-containing solution is not particularly limited as long as it is a solution containing indium, such as a solution obtained by acid-dissolving a semiconductor containing indium, in addition to a solution in which ITO, an indium alloy scrap, an LCD, or a PDP scrap are dissolved with an acid.

In addition, nitric acid, hydrofluoric acid, hydrochloric acid, sulfuric acid, etc. can be considered as an acid which melt | dissolves this indium containing scrap etc., The object is an indium nitrate solution, an indium fluoride solution, an indium hydrochloride solution, etc. by these acids.

Impurities may be contained in the indium-containing solution. At this time, the content of the impurities may be 0.1% by weight or more of impurities in the solution, and indium containing impurities in a large amount of 1% by weight, 5% by weight, 10% by weight, or 20% by weight or more. It is also applicable to an aqueous solution.

In addition, since the indium-containing solution is derived from scrap and washing liquid as described above, it is conceivable that the impurity elements include aluminum, calcium, magnesium, copper, iron, nickel, tin, chromium and silicon alone or in plurality. Although these elements may be included. In particular, it is predicted that the scrap of the target contains a large amount of tin, and the indium-containing solution obtained from this target can also be treated.

Indium Oxalate Precipitation Process

By adding and mixing oxalic acid to the indium-containing solution, indium can be selectively precipitated as indium oxalate from the indium-containing solution containing impurities.

The form of the oxalic acid to be mixed can be applied in any form, such as a solid (including powder), an aqueous solution, or a slurry in which a solid is dispersed. When mixing solid oxalic acid, you may mix anhydride, but from a cost point of view, mixing of a dihydrate is preferable.

However, mixing in aqueous solution is more preferable in order to uniformly precipitate indium oxalate and suppress the drying of impurities. When oxalic acid is added as an aqueous solution, the concentration of oxalic acid in the aqueous solution is 10% or more lower than the saturation concentration, making it difficult to generate a solid oxalic acid precipitate even if the liquid temperature fluctuations of the oxalic acid aqueous solution occur. In addition, when the oxalic acid concentration is made too low, the amount of the oxalic acid aqueous solution for indium recovery increases, and the amount of drainage increases. In view of the above, the oxalic acid concentration of the oxalic acid aqueous solution is preferably 0.1 moL / L or more, and more preferably 0.2 moL / L or more.

As oxalic acid to be mixed, application of ammonium oxalate or ammonium oxalate is applicable because both compounds contain oxalic acid. However, according to the inventors' study, indium was used after mixing with an indium-containing solution. Application of oxalic acid is preferable because the amount of indium remaining in the containing solution is greater than that of using oxalic acid, and the recovery rate of indium decreases.

The mixing amount (in other words, the amount of oxalic acid added) of the oxalic acid mixed with the indium-containing solution is preferably 1.2 to 5 times the equivalent (also referred to as the theoretical amount) to the amount of indium contained in the indium-containing solution. This is because if the amount is less than 1.2, the residual amount of the indium in the solution increases and the recovery rate is lowered. And as a more preferable mixing amount, it is 1.4-4 times the equivalent with respect to the amount of indium contained in an indium containing solution. Also, the equivalent of oxalic acid to indium is 1.5 moL of oxalic acid per mole of indium. Accordingly, 1.2 to 5 times the equivalent of indium is 1.8 to 7.5 moL of oxalic acid per 1 moL of indium.

In this embodiment, it is preferable to perform pH control of the indium containing solution before and behind oxalic acid mixing from a viewpoint of the purity of the indium collect | recovered. It is preferable to make pH of the indium containing solution before oxalic acid mixing into 2 or less. This is because in the indium-containing solution having a pH of more than 2, part of the indium is present as a hydroxide with impurities, and the impurities in the indium oxalate obtained by mixing with oxalic acid increase. Moreover, the pH after mixing with oxalic acid can be made into the suitable range mentioned later by making pH of the indium containing solution before oxalic acid mixing into 2 or less. As for the pH of this indium containing solution, the lower one is preferable, 1.0 or less is more preferable, 0.5 or less is especially preferable.

Therefore, when pH of an indium containing solution exists out of the said range, it is preferable to perform pH adjustment to a solution. The pH adjustment is preferably performed by adding nitric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid or the like to the indium-containing solution to lower the pH. However, in order to lower pH, it is not preferable to add too much acid. When excess acid concentration is converted to monobasic acid and a large amount of acid is added in excess of 3 moL / L (monoacids such as nitric acid, hydrochloric acid, hydrofluoric acid, etc. are 3 moL / L or more, and dibasic acids such as sulfuric acid). When 1.5 moL / L or more of acid is added), the recovery rate of indium is lowered. Therefore, at the time of pH adjustment, it is preferable to add acid addition amount so that it may not exceed said value, or when exceeding this, it is preferable to adjust an acid concentration below this value by adding sodium hydroxide or potassium hydroxide.

On the other hand, about the pH of the indium containing solution after mixing oxalic acid, it is preferable to set it as 1.0 or less from a viewpoint of the impurity reduction in a deposit, and it is more preferable to reduce to 0.5 or less. Setting the pH range of the solution after oxalic acid mixing to this range can be easily achieved by setting the pH before mixing to the above range.

About the method of mixing an indium containing solution and a precipitant (oxalic acid), in addition to the method of stirring an indium containing liquid and adding a precipitant to this, the method of adding an indium containing solution, stirring a precipitant in aqueous solution or a slurry state, one Although there is a method of simultaneously introducing an indium-containing solution and a precipitant into the barrel, either may be used.

It is preferable to make mixing time of an indium containing solution and oxalic acid into 5 minutes-24 hours, and 10 minutes-12 hours are especially preferable. It is because there exists a possibility that the mixing amount of the impurity to indium oxalate may increase for less than 5 minutes, and even if it mixes more than 24 hours, there is no difference in an impurity reduction effect, and only the efficiency falls.

Moreover, although the liquid temperature at the time of mixing an indium containing solution and oxalic acid is preferable in the range of 0-90 degreeC, mixing at normal temperature without temperature control is preferable at the point of energy cost. In addition, the higher the liquid temperature at the time of mixing, the less accompanying the impurities, and also the particle size of indium oxalate and indium oxide after roasting, but the liquid temperature is not very important. Although there is little difference in impurity and also in terms of particle size, in many cases, high purity of not only the recovered indium oxide is performed, but in such a case, it is further purified after dissolution and used as an indium compound such as indium oxide or an indium metal. This is because it is assumed.

Indium oxalate precipitates by mixing the indium-containing solution and the precipitant described above.

Here, as mentioned above, although this embodiment is useful also when an impurity, such as aluminum, is contained in the indium containing solution, most of tin may accompany in a precipitate. About tin accompanying this indium oxalate, since there exists ITO as a use of indium, it can be recovered as it is and can be finally recycled as indium oxide and tin oxide.

In this case, in the present embodiment, tin may be separated to recover only indium.

In the separation method of tin in the present embodiment, before mixing the indium-containing solution and oxalic acid, the tin can be removed by adjusting the pH of the indium-containing solution with an acid or an alkali to a range of 0.5 to 4.0 and filtering it. Since tin in an indium-containing solution precipitates with a hydroxide when pH is 0.5 or more, tin can be removed by filtering this. Moreover, when pH exceeds 4.0, the amount of indium which precipitates with tin increases and it is unpreferable since the recovery rate of indium falls. In addition, it is preferable to add sodium hydroxide or potassium hydroxide as the alkali to be used when adjusting the pH for removing tin. It is because even if it is the same alkali, when ammonia is added, the amount of indium remaining in the indium-containing solution after oxalic acid is increased.

The recovered precipitate (indium oxalate) is preferably washed by a washing step in order to recover indium with higher purity. At this time, an aqueous solution of water or oxalic acid is preferable, but water contains pure water and ultrapure water, and an aqueous solution of oxalic acid having a concentration of 0.5 moL / L or less is preferable.

Alkali contact process

Depending on the kind of scrap used as a raw material of an indium containing solution and the kind of acid, copper of a relatively high concentration may be contained in an indium containing solution. It is easy to mix this copper in the precipitate which consists of indium oxalate, and it is difficult to remove this copper, even if it washes with said water and oxalic acid aqueous solution.

Therefore, in the recovery step from the indium-containing solution containing copper, it is more preferable to remove the copper by contacting the precipitate with ammonia or ammonia and alkali hydroxide (hereinafter sometimes referred to as ammonia).

Copper mixed in indium oxalate, which is a precipitate, reacts with ammonia to form copper ammonia complex ion ([Cu (NH ₃ )] ₄ ] ²⁺ ), which is in a removable state. Here, this reaction may occur even with indium oxalate. Indium oxalate precipitated in the present invention has high crystallinity and it is difficult to advance the reaction with respect to copper incorporated therein. In this contact treatment, the reaction between ammonia and copper is facilitated while changing the indium oxalate to indium hydroxide by bringing ammonia, or ammonia, alkali hydroxide and indium oxalate into contact with the indium hydroxide. This contact treatment may be brought into contact with only ammonia, or may proceed with copper reaction while promoting the conversion of indium oxalate to hydroxide by contacting alkali hydroxide before and after or simultaneously with the contact of the ammonia and the precipitate (including a mixed state).

In addition, in this invention, "alkali hydroxide" means the hydroxide of an alkali metal, and ammonia is not contained. Examples of the alkali hydroxide include sodium hydroxide and potassium hydroxide, and application of sodium hydroxide is particularly preferable in terms of cost.

The total amount of the amount of ammonia to be brought into contact with the precipitate or the amount of ammonia to be brought into contact with the precipitate and the amount of alkali hydroxide is preferably at least the number of moles equivalent to 4 moL per mole of copper of the precipitate. This amount is a theoretical requirement for the copper to react.

Particularly preferably, the total number of moles is equal to or greater than the total number of moles corresponding to 4 moL per 1 moL of copper of the precipitate and the number of moles corresponding to 3 moL per 1 moL of indium of the precipitate. This is because indium oxalate is sufficiently converted to indium hydroxide, and copper easily reacts with and removes ammonia. On the other hand, the upper limit of the contact amount such as ammonia is preferably 2.5 moles or less of the total moles of the number of moles corresponding to 4 moL per 1 moL of copper of the precipitate and the number of moles corresponding to 3 moL of indium of the precipitate. Although this upper limit is not limited from the viewpoint of copper removal, when too much ammonia etc. are used, indium will elute and the recovery rate will be considered.

However, the amount of ammonia and the like used above is based on the amount of precipitate (indium oxalate). To determine the amount of ammonia or the like based on the components in the precipitate, the amount of ammonia and the like is analyzed and the amount is calculated based on the result. It is necessary to do This analysis requires some waiting time, which hinders efficient recovery. On the other hand, in a normal recovery operation, it is common to perform component analysis of the indium-containing solution before the operation.

Therefore, in this embodiment, it can be said that it is preferable to determine the usage-amount of ammonia etc. based on the component in an indium containing solution.

As the amount of ammonia or the like based on the components in the indium-containing solution, considering that most of the copper in the indium-containing solution is mixed with the precipitate, the molar equivalent of 4 moL per 1 moL of copper in the indium-containing solution is preferably at least. Do. And more preferably, the total number of moles equal to or more than the number of moles corresponding to 4 moL per 1 moL of copper in the indium-containing solution and the number of moles corresponding to 3 moL per 1 moL of indium in the indium-containing solution. The upper limit is preferably 2 times or less of the total number of moles of the number of moles corresponding to 4 moL per 1 moL of copper in the indium-containing solution and the number of moles corresponding to 3 moL per 1 moL of indium in the indium-containing solution. With this setting, the lower limit of the amount of use of ammonia or the like does not become smaller than the lower limit of the amount of use based on the sediment, and the upper limit does not become larger than the upper limit of the amount of use based on the sediment. can do.

It is preferable to perform contact treatment to a precipitate in the state of aqueous solution. And this includes mixing the precipitate and water to blow ammonia gas, adding an aqueous ammonia solution, or adding a solid alkali hydroxide, and finally the state of the aqueous solution.

The density | concentration in the case of using aqueous ammonia solution and aqueous alkali hydroxide solution is not specifically limited, What is necessary is just a solution containing said required amount. However, if the concentration is too low, the amount of drainage increases. If the concentration is too high, the amount of liquid to the amount of the precipitate is too small, so that contact is insufficient. Therefore, it is preferable that these aqueous solution concentrations are 0.5 to 15 moL / L, and 1 to 10 moL / It is more preferable to set it as L.

The number of treatments may be performed by dividing the required amount of ammonia (aqueous solution) or ammonia (aqueous solution) and alkali hydroxide (aqueous solution) a plurality of times and contacting the precipitate, but it is preferable to carry out once in view of efficiency.

Moreover, although the temperature of aqueous ammonia solution may be heated, even if it is normal temperature, since efficiency does not fall, normal temperature is preferable.

As described above, also in the case of performing contact treatment with ammonia, it is preferable to wash the precipitate with water or an oxalic acid aqueous solution before and / or after the step, particularly before. Thereby, very high purity indium can be recovered. By cleaning before the contact treatment, impurities other than those capable of generating hydroxide by the contact treatment can be removed.

As a washing method of the precipitate and a treatment method of contact with ammonia, indium oxalate in the indium-containing solution is precipitated to remove the supernatant liquid, and a washing solution or an ammonia solution is added thereto and stirred, or an indium-containing solution is filtered. And filtering the filter cake with a washing liquid or ammonia solution one or more times, or filtering the indium-containing solution by vacuum filtration, filter press, or the like, and passing the washing liquid or ammonia solution to the filtering device. The method by any of the filtration washing | cleaning methods is mentioned.

In addition, when indium oxalate is recovered immediately after addition of a precipitant, or when washing is performed by a method other than filtration washing, indium oxalate is subjected to solid-liquid separation, which can employ a conventional filtration method. .

Roasting process

The precipitate obtained by solid-liquid separation (indium oxalate or indium hydroxide) can be converted into indium oxide by roasting. This roasting preferably heats the precipitate after solid-liquid separation directly. Although drying may be carried out after solid-liquid separation and roasting thereafter, it is preferable to roast directly from the viewpoint of energy cost and efficiency. As roasting temperature, 600-1200 degreeC is preferable and 700-1100 degreeC is more preferable. The roasting time is preferably 1 to 48 hours, more preferably 2 to 24 hours. This is because the roasting conditions cannot be completely made into oxides if they are lower than the lower limit, and they are only a waste of energy even if roasted at temperatures and times exceeding the upper limit.

(2nd embodiment)

The manufacturing method of the indium containing metal which concerns on 2nd Embodiment is characterized by manufacturing an indium containing metal through the following process.

A step of producing a precipitate of indium oxalate by adding oxalic acid as a precipitant and mixing the indium-containing solution, which is an indium-containing material that is a recovered raw material, in an acid (; indium oxalate precipitation step),

Recovering the precipitate of indium oxalate by solid-liquid separation (; precipitate recovery step),

A process of performing the at least one passivation cause ion washing process of immersing the recovered precipitate in a liquid which does not dissolve indium and dissolving the ions causing passivation in the liquid and removing the dissolved liquid (; fair),

A step of dissolving the washed process obtained in the above-mentioned ion-causing ion washing process into an acid to form an acid solution (; acid dissolving step),

A step of immersing a metal plate in the acid solution to precipitate sponge indium by a substitution reaction with the metal (; substituted precipitation step),

Process of obtaining indium containing metal from sponge indium (; metallization process),

Through these processes, an indium-containing metal is produced.

In addition, "sponge indium" means the indium-containing substance of the porous state (sponge state) produced | generated by substitution reaction with a metal.

In addition, "the ion which causes a passivation on a metal plate in a substitution precipitation process" is also called "the passivation cause ion".

Hereinafter, the raw material and each process in this embodiment are demonstrated in detail.

indium Inclusion

The origin of the indium-containing material as a raw material is not particularly limited. For example, after use or original use, such as recovery of ITO scattered during ITO thin film production, waste ITO target, scrap of ITO or indium alloy, scrap of LCD or PDP, recovery of semiconductor containing indium, etc. The thing which collect | recovered the indium content removed from the use is mentioned. Among them, when an indium-containing material scattered during the production of the ITO thin film is recovered, for example, an ITO sintered body obtained by sintering a mixture of indium oxide and tin oxide is irradiated with plasma or the like as a target to sputter ITO. An indium-containing material obtained by recovering ITO scattered around without being deposited on a substrate is one of the most suitable examples for the raw material of the present embodiment.

Indium-containing solution

It is preferable that the indium containing solution melt | dissolved the said indium containing thing in the acid.

Although the indium content in an indium containing solution is not specifically limited, It is preferable that indium content is 10 g / L or more, especially 15 g / L or more, especially 20 g / L or more. In addition, regarding tin, it is preferable that it is less than 10% of indium content. In addition, regarding metals other than indium and tin, considering the metal (for example, aluminum or zinc etc.) used for substitutional precipitation, it is preferable that the total amount is less than 10% of indium content. Although the manufacturing method of this embodiment does not become impossible even if it contains 10% or more of indium content, since the efficiency and indium purity in a substitution precipitation process fall, it is preferable that it is less than 10% of indium content.

Although the kind of acid which melt | dissolves an indium content is not specifically limited, What is suitable for this embodiment is an indium containing solution melt | dissolved in inorganic acids, such as hydrochloric acid, nitric acid, hydrofluoric acid, nitric hydrofluoric acid, and nitric acid is the most preferable among these.

The use of nitric acid makes it easy to dissolve the indium content. In the case of using nitric acid, the nitrate ions may form a passivation in the substitution precipitation step, which may interfere with the substitution precipitation. However, when oxalic acid is added to precipitate indium oxalate as in the present embodiment, the compatibility between nitric acid and oxalic acid is good. Since the crystal of indium oxalate (precipitate) becomes large, the separation performance at the time of solid-liquid separation becomes high, and the mother liquid amount in the precipitate after solid-liquid separation can be reduced, and the residual amount of nitrate ions can be reduced by this, and the method of solid-liquid separation is carried out. In some cases, it is possible to omit the ion cleaning process that causes the passivation.

In the case of an indium-containing material containing indium nitrate solution to be dissolved in nitric acid, the indium by an appropriate time value (靜置) in a state of solution containing nitric acid, meta annotations included in the indium-containing nitric acid solution of tartaric acid (H ₂ SnO ₃ ) can precipitate out and can reduce the burden of a post process. As stationary time at this time, it is preferable to set it as 24 hours or more, especially 168 hours or more.

Indium Oxalate Precipitation Process

Indium can be selectively precipitated as indium oxalate from the indium-containing solution by adding and mixing oxalic acid to the indium-containing solution.

The form of the oxalic acid to be added may be applied in any form, such as a solid (including powder), an aqueous solution, or a slurry in which the solid is dispersed. When mixing solid oxalic acid, you may mix anhydride, but from a cost point of view, mixing of a dihydrate is preferable.

However, in order to precipitate indium oxalate uniformly and to suppress curling of an impurity, mixing in aqueous solution is more preferable. When oxalic acid is added as an aqueous solution, the oxalic acid concentration in the aqueous solution may be 10% or more lower than the saturation concentration, so that solid oxalic acid precipitates may be less likely to occur even if the liquid temperature fluctuations occur in the oxalic acid aqueous solution. On the other hand, when the oxalic acid concentration is made too low, the amount of the oxalic acid aqueous solution for indium recovery may increase, and the amount of drainage may increase. In view of this point, the oxalic acid concentration of the oxalic acid aqueous solution is preferably at least 0.1 moL / L and more preferably at least 0.2 moL / L.

As oxalic acid to be mixed, application of ammonium oxalate or ammonium oxalate is applicable because both compounds include oxalic acid. However, when these compounds are used, the amount of indium remaining in the indium-containing solution after mixing with the indium-containing solution is used. Application of oxalic acid is preferable because the amount of oxalic acid is greater than that of using oxalic acid, and the recovery rate of indium decreases.

It is preferable that the mixed amount of oxalic acid (in other words, the amount of oxalic acid added) mixed with the indium-containing solution is 1.2 to 5 times the equivalent of indium (also referred to as the theoretical amount) in the indium-containing solution. This is because if the amount is less than 1.2, the residual amount of the indium in the solution increases and the recovery rate is lowered. A more preferable mixing amount is 1.4 to 4 times the equivalent to indium.

Also, the equivalent of oxalic acid to indium is 1.5 moL of oxalic acid per mole of indium. Accordingly, 1.2 to 5 times the equivalent of indium is 1.8 to 7.5 moL of oxalic acid per 1 moL of indium.

It is preferable to perform pH control of the indium containing solution before and after oxalic acid mixing from a viewpoint of raising the indium purity of the indium containing metal collect | recovered. The pH of the indium-containing solution before oxalic acid mixing is preferably less than 3.5, in particular 2 or less. This is because if the pH is 3.5 or more, part of the indium becomes a hydroxide and does not become indium oxalate, so the recovery rate of indium is lowered. In addition, indium recovery can be raised by setting it as pH 2 or less. From this point of view, since the pH of an indium containing solution is more preferable, 1.0 or less, especially 0.5 or less are more preferable.

When the pH of the indium-containing solution is outside the above range, it is preferable to adjust the pH of the solution. However, in order to lower pH, it is not preferable to add too much acid. When excess acid concentration is converted to monobasic acid and a large amount of acid is added in excess of 3 moL / L (monoacids such as nitric acid, hydrochloric acid, hydrofluoric acid, etc. are 3 moL / L or more, and dibasic acids such as sulfuric acid). (When an acid of 1.5 moL / L or more is added), the recovery rate of indium is lowered. Therefore, at the time of pH adjustment, it is preferable to add acid addition amount so that it may not exceed said value, or when exceeding this value, it is preferable to adjust an acid concentration below this value by adding sodium hydroxide or potassium hydroxide.

On the other hand, the pH of the indium-containing solution after mixing oxalic acid is preferably 2.0 or less, and more preferably 1.0 or less, from the viewpoint of impurity reduction in the precipitate.

About the mixing method of an indium containing solution and a precipitant (oxalic acid), in addition to the method of stirring an indium containing liquid and adding a precipitant to this, the method of adding an indium containing solution, stirring the precipitant in aqueous solution or a slurry state, and one barrel Although there is a method of simultaneously introducing an indium-containing solution and a precipitant, either may be used.

In addition, the liquid temperature of the indium containing solution at the time of mixing with oxalic acid may be 0-90 degreeC. The liquid temperature at the time of mixing tends to be less accompanied by impurities, but there is no significant effect. Therefore, mixing at room temperature without temperature control is preferable in terms of energy cost.

After adding oxalic acid to an indium containing solution, it is preferable to stir and mix for an appropriate time, and to leave it to stand suitably as needed.

At this time, the stirring time is preferably 5 minutes to 24 hours, particularly 10 minutes to 12 hours. It is because there exists a possibility that the amount of mixing of impurities into indium oxalate may increase when it is less than 5 minutes, and even if it mixes more than 24 hours, there is no difference in an impurity reduction effect, and only the efficiency falls.

Sediment recovery process

As the method for solid-liquid separation of the precipitate of indium oxalate, a well-known solid-liquid separation method may be employed, such as vacuum filtration such as suction filtration, pressure filtration such as a filter press, separation method such as decanter or centrifugation, and the like. The solid-liquid separation method can be adopted.

In addition, depending on the degree of solid-liquid separation performed in this step, it is also possible to omit the next passivation cause ion washing step. In particular, in the case of using an indium-containing nitric acid solution as a starting material, since the nitrate ions become passivation-causing ions in the substitutional precipitation process and interfere with the substitutional precipitation reaction, an ion-cleaning process causing a passivation formation is generally required. By carrying out the separation more sufficiently, for example, by employing a solid-liquid separation method with good separation performance, lengthening the filtration time, or increasing the filtration area, the amount of mother liquor contained in the indium oxalate precipitate is reduced, thereby causing ions to be formed. By reducing the amount of ions, it becomes possible to omit the ion cleaning step of the passivation formation cause. Specifically, when the passivation-caused ion washing step is omitted, the passivation-cause ions are solid-liquid separated so that the concentration of the passivation-caused ions in the solution prepared in the acid dissolution step is 10000 ppm or less, preferably 8500 ppm or less. The substitution reaction can be advanced even if the washing step is omitted.

Passive  Formation Cause Ion Cleaning Process

Next, the precipitate obtained by solid-liquid separation is immersed in a liquid (also referred to as "immersion liquid") in which indium is not dissolved, and ions (ions that cause the formation of a passivation) which cause passivation on the metal plate in the subsequent substitution precipitation process are removed. By dissolving in the liquid and removing the dissolved solution one or more times, the mother liquor adhering to the surface of the precipitate or the mother liquor that has entered the aggregates of the precipitate are replaced with the immersion liquid to wash away the ions causing the passivation. By rinsing and removing the ions causing the passivation, the subsequent substitution precipitation step can be efficiently performed, and a higher purity indium-containing metal can be recovered.

Examples of the passivation ions include metals other than In, such as metal ions such as Fe, Co, Cr, and Ni, and nitrate ions (NO ₃ ⁻ ) and fluoride ions (F ⁻ ) that form salts with these metal ions. Anion can be mentioned. In the case of using an indium-containing nitric acid solution as a starting material, nitrate ions (NO ₃ ⁻ ) are the ions causing passivation, and in the case of using an indium-containing hydrofluoric acid solution, fluorine ions (F ⁻ ) and hydrogen fluoride ions (HF) are mainly used. ₂ ^-), etc. is formed in the passivation cause ion.

Although the indium does not dissolve but the immersion liquid which dissolves the ions which form the passivation, water, an aqueous solution of oxalic acid, a lower alcohol such as methanol or ethanol, or a mixture thereof may be mentioned, but most preferred is water. Water contains pure water and ultrapure water, and an oxalic acid aqueous solution having a concentration of 0.5 moL / L or less is preferable as the oxalic acid aqueous solution.

What is necessary is just to perform the process of injecting collect | recovered precipitate into a immersion liquid and separating solid-liquid at least once as a method of the ion washing process of a passivation formation cause, for example. By dividing twice or more, the amount of the immersion liquid can be reduced, and the ions causing the passivation can be removed in a short time. Furthermore, it is more preferable to add a precipitate to an immersion liquid and to stir for a suitable time.

The amount and processing time of the immersion liquid used in the ion-cleaning process of the passivation formation cause are not specifically limited.

The temperature of the immersion liquid at the time of melt | dissolution is although it does not restrict | limit especially, You may further warm from about room temperature from an efficiency viewpoint.

As a cleaning target for the passivation-causing ions, it is preferable to carry out so that the concentration of nitrate ions in the acid dissolving solution at the time of dissolving the cleaning process in the next step is 10000 ppm or less, particularly 8500 ppm or less. That is, it is preferable to adjust processing time, processing frequency, etc. to this goal. When the concentration of nitrate ions in the solution is 10000 ppm or less, in the subsequent substitution precipitation step, the passivation-causing ions can be prevented from forming a passivation on the metal plate surface, and the sponge indium can be precipitated by the substitution reaction with the metal ions of the metal plate. Can be.

From such a viewpoint, precipitation of sponge indium can be promoted more suitably if nitrate ion concentration in an acid solution in a next process is 5000 ppm or less.

As described above, the solid-liquid separation in the precipitate recovery step is more fully performed, for example, by employing a solid-liquid separation method with good separation performance, or by lengthening the filtration time to reduce the amount of mother liquor contained in the indium oxalate precipitate. By reducing the amount of ions causing formation, it is also possible to omit this step (the ion-cleaning process causing the formation of dynamic formation).

Disperse  fair

Next, what was washed in the ion-washing treatment for the passivation formation agent was dissolved in an acid to obtain an acid solution.

As the type of acid that can be used in this step, it is possible to use inorganic acids such as sulfuric acid and hydrochloric acid. It is important to use hydrochloric acid when using an indium-containing nitric acid solution as a starting material.

At this time, the concentration of hydrochloric acid is not particularly limited, but from the viewpoint of solubility, it is preferable to use 1N to 12N hydrochloric acid.

Moreover, it is preferable to adjust temperature to 30 degreeC or more by temperature control other than the heat of dissolution at the time of acid addition, and it is preferable that it is 30-60 degreeC range efficiently.

In addition, when there is a dissolution residue when dissolving the washed process in an acid, after stirring for an appropriate time, for example, about 1 hour, it is allowed to stand for an appropriate time as needed, and the solid solution is separated to remove the dissolved residue to dissolve the acid solution. This can be recovered.

substitution Precipitation  fair

Next, the acid solution obtained in the above step is placed in a reaction tank, and a metal plate, preferably an aluminum plate, is immersed and substituted with a metal (for example, aluminum) of the metal plate to precipitate sponge indium.

If the pH of the acid solution during the substitution reaction is lower than 0.5 or higher than 1.5, the substitution reactivity of the indium and the metal (for example, aluminum) decreases, so that the pH value of the acid solution is, for example, an alkali compound. It is preferable to adjust in 0.5-1.5, especially 0.5-1.0 by adding water and water. At this time, as an alkali compound to add, sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, these aqueous solutions, etc. are mentioned. In addition, when adjusting pH by adding water, what is necessary is just to make sure that the indium concentration in an acid solution does not fall too much.

Substitution reaction of indium and a metal (for example, aluminum) tends to fall rapidly as liquid temperature becomes lower than 20 degreeC, and as a result, precipitation amount of sponge indium falls. On the contrary, when temperature becomes high too much, it may become a problem from workability, a loss of thermal energy, etc. Therefore, the temperature at the time of performing this substitution reaction becomes like this. Preferably it is 20 degreeC or more, Especially preferably, it adjusts to the range of 20 degreeC-60 degreeC.

In addition to the method of immersing a metal plate, such as an aluminum plate, the substitutional precipitation of indium can also employ | adopt the method of adding metal powder, such as zinc powder (granular). However, when a metal powder such as zinc powder (granular) is added, there is a problem that zinc remains in the sponge indium, and it is preferable to conduct research for solving this problem. It is preferable to embodiment.

Metallization  fair

Next, the sponge indium obtained as mentioned above is metallized and it is set as the bulk indium metal.

Although the specific method of metallization is not specifically limited, It is preferable to cast and metallize in the alkali solution, ie, the alkali solution heated at least above melting point (156 degreeC) of indium. Sponge indium is easily oxidized, but oxidation can be prevented by performing alkali molten, and impurities in the oxide film and sponge indium that existed on the surface of the sponge indium can also be separated and removed.

Although it does not specifically limit about the alkali compound used for alkaline molten metal, It is preferable to use sodium hydroxide industrially. The indium containing metal obtained by this alkali molten metal becomes a thing with high indium quality.

In addition, embodiment mentioned above is an example of this invention, It is also possible to insert another process in the said process, or to change the order of each process, unless the effect by this invention is interrupted.

Hereinafter, the Example of this invention is described, comparing with a comparative example.

(Examples 1-18 and Comparative Examples 1-5)

The following two kinds of indium-containing solutions were prepared, and indium recovery was performed on these. These indium containing solutions are obtained by dissolving indium containing scraps with nitric acid.

TABLE 1

The indium recovery was performed about the said 2 types of indium containing solutions (A, B) in various conditions. The basic flow of this process is demonstrated using FIG.

10 L of the indium containing solution of either A or B was prepared (process (1)), and pH was adjusted by adding it suitably, referring pH of this solution (process (2)). And in some cases, it heated up at 60 degreeC (step (3)), and mixed the indium containing solution and a precipitant (step (4)). In the mixing step, a precipitant (oxalic acid in the example and ammonia water in the comparative example) was added while stirring the indium-containing solution, but in some examples, a form in which the precipitant was stirred and the indium-containing solution was added thereto was adopted.

When precipitation was complete by the addition of a precipitant, the solution was vacuum filtered (step (5)), and the precipitate was washed with pure water (step (6)). This washing step was performed by passing 100 mL of water four times. After the washing was completed, the obtained indium oxalate (in comparison, indium hydroxide in the comparative example) was roasted by heating at 1000 ° C. for 5 hours in an electric furnace (step (7)) to obtain indium oxide.

In addition, in some examples, 4 moL / L of NaOH was added until the pH was 1.8 before adjusting the pH, and then the solution was filtered to remove tin in the indium-containing solution (step (8)).

The conditions of the some indium collection | recovery performed in the Example according to the said process are as follows.

TABLE 2

* 1: The amount of precipitant used is a multiple of the theoretical amount of indium in the indium-containing solution

* 2: excessive acid concentration. Example 6: 2.5 mol / l, Example 7: 3.5 mol / l

* 3: mixing indium-containing solution with precipitant

* 4: After heating up an indium containing solution to 60 degreeC, a 60 degreeC precipitant is added.

* 5: De-tin treatment, addition of precipitant without pH adjustment after de-tin treatment

* 6: De-tin treatment, and after de-tin treatment, nitric acid is added to pH 0.1 to add a precipitant.

* 7 pH management… Determine the pH after mixing and add ammonia water until the pH is reached

Table 3 shows the component analysis values and the recovery rates of the indium oxide recovered according to the conditions of Examples 1 to 18 and Comparative Examples 1 to 5 of Table 2.

TABLE 3

* In recovery rate (%) = {indium oxide recovered (g) x indium content (% by weight)}

/ {Indium concentration (g / l) of treatment solution (A, B) x amount of treatment solution (l)}

* The theoretical value of the indium content rate in indium oxide is 82.7 weight%.

From the above results, first, when comparing the Example and the comparative example which uses ammonia as a precipitant, indium oxide collect | recovered in the comparative example had both high content of an impurity, and especially accompanying aluminum was remarkable. On the other hand, although the Example contains some aluminum, it turned out that high purity indium oxide with few impurities is generally recoverable. This can be seen even when the indium content in the recovered indium oxide is very close to the theoretical value.

In addition, when examining the difference by the recovery conditions in each Example, first, from the viewpoint of impurity mixing, incorporation of aluminum was slightly seen in Examples 3 to 5. Since aluminum content rate rises with this point and the pH increase of the indium containing solution at the time of mixing a precipitant, it turned out that it is preferable to make pH of an indium containing liquid as low as possible in this invention, and to make it 0.5 or less especially. In addition, with respect to the indium recovery, Example 8 was less than 80%. It is considered that this factor is due to the mixing amount of the precipitant. In Example 8, only one precipitant was added at the theoretical value relative to the amount of indium in the indium-containing solution. Therefore, in order to obtain a recovery rate of 80% or more, it was found that mixing of 1.2 times or more of the precipitant was preferable as in Examples 9 to 12. However, when Example 11 (5-fold addition) and Example 12 (6-fold addition) were compared, it turned out that since the recovery rate of indium hardly changes, it can be said that less than 5 times is preferable as addition amount of a precipitant.

In the indium-containing solution used in this example, solution B contained tin in a relatively high concentration. Examples 16 and 17 recovered the solution B. As can be seen from the results of both, in Example 17, in which the process of removing tin ((9)) was performed, it was confirmed that tin in the recovered indium oxide was completely removed. Therefore, when recovering a high purity indium single metal from the recovered indium oxide, it turned out that it is preferable to perform a tin removal process. However, whether or not to perform the tin oxide process is based on what purpose indium is used from the indium oxide to be recovered thereafter, and even when the tin oxide process is not performed, both indium and tin can be recovered. In addition, it was found that ITO is convenient to manufacture, and the presence or absence of tin-tin treatment is a matter of use and not a problem of superiority.

(Examples 19 to 27)

Here, the following indium containing solution (C) was prepared and indium recovery was performed about these. This indium-containing solution is a waste liquid when the liquid crystal substrate is washed with hydrofluoric acid.

TABLE 4

About this indium containing solution (C), indium collection was performed, changing conditions. The basic flow of the process of this embodiment is explained using FIG. 60 L of an indium-containing solution was prepared (indium content of 3480 g (30.3 moL), copper content of 126 g (1.98 moL): step (1)), and an indium-containing solution and a precipitant (oxalic acid) were mixed (step (2)). In the mixing of the oxalic acid solution, an aqueous solution of 0.5 mol / L of oxalic acid was added over 10 minutes in which the amount of oxalic acid was 2.5 times the theoretical amount of indium in the indium-containing solution. At this time, an aqueous solution of oxalic acid was added while stirring the indium-containing solution.

When precipitation was complete by the addition of a precipitant, the solution was vacuum filtered (step (3)), and the precipitate was washed with pure water (step (4)). This washing step was carried out by passing through 1200 mL of water four times. After the washing was completed, the obtained indium oxalate (in comparison, indium hydroxide in the comparative example) was analyzed to include 3228 g (28.1 moL) indium and 108 g (1.70 moL) copper.

Next, the recovered indium oxalate was divided into 12 parts, and 9 of the indium oxalate were subjected to contact treatment while changing the conditions (hereinafter, Examples 19 to 27 for each condition: step (5)). The contents of the contact treatment are shown in Table 5. In addition, in the present Example, it examined also about not carrying out ammonia contact treatment of a deposit for a comparison (reference example).

TABLE 5

Note: The lower limit of the amount of ammonia obtained from the amount of indium contained in the indium-containing solution (1/12 of) to be treated and the amount of indium contained in the precipitated indium oxalate (1/12) and the amount of contact treatment solution (ammonia + The upper limit and lower limit of alkali hydroxide) are as follows.

About the precipitate after the contact treatment, the solution was vacuum filtered (step (6)), and the recovered precipitate was washed with pure water (step (7)). This washing step was performed by passing 100 mL of water once. The precipitate (indium hydroxide) after washing was roasted by heating at 1000 ° C. for 5 hours in an electric furnace (step (8)) to obtain indium oxide.

The effect of indium recovery on the produced indium oxide was confirmed. In this confirmation, this evaluation was performed by comparing the recovery rate of indium calculated from the composition analysis of indium oxide and the weight of indium in the resultant indium oxide. The results are shown in Table 6.

TABLE 6

Regarding the results of Table 6, first, comparing the examples and the reference examples with respect to the presence or absence of ammonia contact treatment, the copper concentration in the recovered indium oxide became half or less by performing ammonia contact treatment, and the removal effect was Confirmed.

On the other hand, when the conditions of the contact treatment are examined, the results of treatment within a range (see the table below in Table 5) that is suitable for the range of the contact amount of ammonia (ammonia and alkali hydroxide) (the implementation surrounded by double lines in Table 6) Examples 22 to 24, Examples 26 and 27) and the results of other examples were compared, when the contact amount was small (Examples 19 to 21), the copper concentration in indium oxide was relatively high. This was considered to be because the contact amount of ammonia (or ammonia and alkali hydroxide) was insufficient, so that indium oxalate did not become indium hydroxide completely, and copper contained in partially remaining indium oxalate could not be removed. In addition, when the amount of contact was large (Example 25), the purity of the recovered indium oxide was satisfactory, but the recovery was inferior. This was considered to be because dissolution of indium oxide occurred by excessive alkali addition. As mentioned above, it was confirmed that the ammonia (or ammonia and alkali hydroxide) contact treatment is useful for removing copper in indium oxide, and more efficient indium recovery is possible by appropriately adjusting the contact amount.

Fig. 3 shows the results of X-ray diffraction analysis on the precipitate immediately after precipitation (indium oxalate) and the precipitate (indium hydroxide) subjected to ammonia contact treatment.

From Fig. 3 (a), the precipitate immediately after precipitation (indium oxalate) was indium oxalate in a state of crystallinity showing sharp peaks. Then, by contacting the indium oxalate crystal with ammonia, the precipitate exhibits a relatively broad diffraction pattern (Fig. 3 (b): shows Example 23). This change was thought to be due to the fact that the precipitate made of indium oxalate contacted with ammonia, so that the crystals were broken and replaced with indium hydroxide having weak crystallinity. In addition, it was thought that copper, which was dried in the precipitate, was removed during the destruction of the indium oxalate crystal and the substitution with indium hydroxide.

3 (c) shows a diffraction pattern of indium oxide after roasting of this indium hydroxide.

(Examples 28-30)

In this embodiment, when the ITO sintered body obtained by sintering a mixture of indium oxide and tin oxide is irradiated with plasma or the like as a target, when the ITO is sputtered, the ITO-containing substance adhering to the antifouling plate is converted into nitric acid. An indium-containing nitric acid solution (pH 0.12) obtained by dissolving was used as a raw material. This indium-containing nitric acid solution was analyzed by ion chromatography, and it was found that In 30g / L, Sn 0.06g / L, Al 10g / L, Mg 0.23g / L, Zn 0.03g / L, Fe 0.04g / L, Cr 10ppm It included less than.

500 mL of said indium containing nitric acid solution (liquid temperature 27 degreeC) was prepared, 500 mL of oxalic acid aqueous solution (liquid temperature 26 degreeC, oxalic acid concentration 80g / L) was added, and it stirred for 30 minutes, and then left still for 1 hour and 30 minutes. Subsequently, suction filtration was carried out with Nutsche using filter papers of various sizes shown in Table 7 (manufactured by Toyoro Co., Ltd.), and the precipitate (indium oxalate) and the filtrate (NO ₃ ⁻ concentration, pH). , In concentrations are shown in Table 7). In addition, when the cake had a crack in the middle of filtration, the surface was evened once and filtration was continued. In either case, the filtration was completed 15 minutes after the indium-containing nitric acid solution was added to the lot.

The obtained precipitate was put into 450 mL of water, 50 mL of 12N hydrochloric acid was added, the pH was adjusted to 0.5, and acid dissolved to obtain an acid solution of 500 mL (NO ₃ ⁻ concentration, pH, and In concentration are shown in Table 7).

Then, the mixture was stirred for 1 hour while controlling the temperature so that the acid solution did not exceed 60 ° C, filtered through a liquid, and the residue (undissolved solid) was removed to recover the acid solution, and the acid solution (pH 0.7). ), An aluminum plate having a width of 100 mm, a length of 300 mm, and a thickness of 6 mm was immersed, and the temperature was controlled so that the liquid temperature was 50 ° C, while stirring was continued for 1 hour under stirring. After recovering the sponge indium precipitated by the substitution reaction and removing water and the like, alkaline-molded solution (300 ° C) was performed using sodium hydroxide to remove the indium-containing metal into the mold.

The amount of sponge indium collected (g), the amount of indium-containing metal (g), the In grade of the indium-containing metal, and the In recovery rate (In recovery rate (%)) = (In in indium-containing metal recoverable from the acid solution Amount / amount of In in the acid solution) x 100), hereinafter referred to as "In recovery rate" are shown in Table 7.

The In quality of the indium-containing metal was analyzed by ICP emission spectroscopy, and the nitrate ion concentration was measured by the ion chromatograph method (the same applies hereinafter).

(Examples 31 to 32)

500 mL of an indium-containing nitric acid solution similar to Example 28 was prepared, 500 mL of an oxalic acid aqueous solution (solution temperature 26 ° C., oxalic acid concentration 80 g / L) was added thereto, and the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes for 1 hour. Subsequently, suction filtration was carried out by a nutche using filter papers of various sizes (Table 4, manufactured by Toyoro Co., Ltd.), and the precipitate (indium oxalate) and the filtrate (NO ₃ ⁻ concentration, pH, In concentration) were used. Is shown in Table 7). In addition, when the cake had a crack in the middle of filtration, the surface was evened once and filtration was continued. In either case, the filtration was terminated when 15 minutes had elapsed after the indium-containing nitric acid solution was added to the lot.

The obtained precipitate was poured into 200 mL of water (20 ° C.), stirred for 10 minutes, the stirring was stopped, left standing for 0.5 hours, and washed once to remove the water phase by decantation. in example 32 is repeated twice, a liquid cleaning as a cleaning process (NO ₃ ^- concentration, refers to the pH, concentration of in in Table 7) was obtained.

The washed solution was added to 450 mL of water, 50 mL of 12N hydrochloric acid was added thereto, adjusted to pH 0.5, and acid dissolved to obtain 500 mL of an acid solution (NO ₃ ⁻ , pH, and In concentrations are shown in Table 7).

Then, the mixture was stirred for 1 hour while controlling the temperature so that the acid solution did not exceed 60 ° C, filtered through a liquid, and the residue (undissolved solid) was removed to recover the acid solution, and the acid solution (pH 0.7). ), An aluminum plate having a width of 100 mm, a length of 300 mm, and a thickness of 6 mm was immersed, and the temperature was controlled so that the liquid temperature was 50 ° C, while stirring was continued for 1 hour. After recovering the sponge indium precipitated by the substitution reaction and removing water and the like, alkaline-molded solution (300 ° C) was performed using sodium hydroxide to remove the indium-containing metal into the mold.

Table 7 shows the sampling amount (g) of the sponge indium, the sampling amount (g) of the indium-containing metal, the In quality of the indium-containing metal, and the In recovery rate.

(Comparative Example 6)

500 mL of the same indium-containing nitric acid solution as in Example 28 was prepared, 100 mL of water at room temperature (20 ° C) was added thereto, and 25% ammonia water was added thereto to adjust the pH to 4.5. Indium was deposited to obtain a slurry. Subsequently, suction filtration was carried out using a filter paper (4A manufactured by Toyoro City Co., Ltd.) of the size shown in Table 7, and the neutralized precipitate and the filtrate (NO ₃ ⁻ concentration, pH, and In concentration were shown in Table 7 below. It is obtained. At this time, when cracking occurred in the cake, filtration was continued while the surface was evened, and filtration was terminated after 1 hour after adding an indium-containing nitric acid solution.

260 g of this neutralized precipitate was added to 360 mL of water, concentrated sulfuric acid was added to adjust pH to 0.5, and acid dissolved to obtain 500 mL of an acid solution (NO ₃ ^- concentration, pH, and In concentration are shown in Table 7).

Next, the mixture was stirred for 1 hour while controlling the temperature so that the acid solution did not exceed 60 ° C, and the residue (undissolved solid) was removed by filtration with a liquid, and the acid solution was recovered.

Subsequently, after adjusting with this acid solution (pH 0.7), the aluminum plate of width 100mm, length 300mm, and thickness 6mm is immersed, and temperature control is carried out so that liquid temperature may be 50 degreeC, and stirring is continued for 24 hours. However, precipitation of sponge indium was not seen.

(Comparative Example 7)

500 mL of the same indium-containing nitric acid solution as in Example 28 was prepared, 100 mL of water at room temperature (20 ° C.) was added thereto, and 25% ammonia water was added thereto to adjust the pH to 4.5, followed by stirring for 0.5 hour. Suction filtration was carried out using a filter paper (4A manufactured by Toyoro City Co., Ltd.) of the indicated size to obtain a neutral precipitate and a filtrate (NO ₃ ⁻ concentration, pH, and In concentration are shown in Table 7). At this time, when cracking occurred in the cake, filtration was continued while the surface was evened, and filtration was terminated after 1 hour after adding an indium-containing nitric acid solution.

260 g of this neutralized precipitate was added to 400 mL of water (20 DEG C), stirred for 10 minutes, the stirring was stopped, left standing for 0.5 hours, washed twice to remove the aqueous phase by decantation, and washed. A solution (NO ₃ ⁻ concentration, pH, and In concentrations are shown in Table 7).

Next, this washed process was poured into 360 mL of water, concentrated sulfuric acid was added to adjust pH to 0.5, and acid dissolved to obtain 500 mL of an acid solution (NO ₃ ^- concentration, pH, and In concentration are shown in Table 7). .

Then, it stirred for 1 hour, controlling temperature so that an acid solution might not exceed 60 degreeC, it filtered by the liquid, the residue (undissolved solid) was removed, and the acid solution was collect | recovered.

After adjusting to this acid solution (pH 0.7), the aluminum plate of width 100mm, length 300mm, and thickness 6mm was immersed, and the temperature was controlled so that liquid temperature might be 50 degreeC, and stirring was continued for 8 hours. After recovering the sponge indium precipitated by the substitution reaction and removing water and the like, alkaline-molded solution (300 占 폚) was performed using sodium hydroxide, and the indium metal was removed from the mold.

Table 7 shows the sampling amount (g) of the sponge indium, the sampling amount (g) of the indium-containing metal, the In quality of the indium-containing metal, and the In recovery rate.

TABLE 7

In addition, the analysis results of the indium-containing nitric acid solution were the same as those of Example 28. Although the variation in the In content in the acid solution was observed due to the In concentration difference, the handling error, and the like of the indium-containing nitric acid solution, as shown in Table 7, the In recovery rate Regarding to, it has been found that when the nitric acid content in the acid solution is less than 10000 ppm, In can be efficiently recovered.

Trial 1: Acid solution  Nitrate Ion Concentration and Aluminum Substitution Precipitation  relation

The influence of the concentration of nitrate ions in the acid solution on the aluminum substitution precipitation reaction was examined.

A predetermined amount of 14N nitric acid was added to 500 mL of the acid solution obtained in Example 28, the concentration of NO ₃ ⁻ in the acid solution was adjusted as shown in Table 8, and substitutional precipitation using an aluminum plate was performed as in Example 28. Sponge In was obtained, and also alkaline-sprayed in the same manner as in Example 28 to obtain an indium-containing metal.

At this time, the substitution precipitation reaction using the aluminum plate was evaluated based on the following criteria.

  ◎: Substitution precipitation was completed within 1 hour.

  (Circle): Substitution precipitation completed within 1 to 1.5 hours.

  (Triangle | delta): Although substitution was performed, substitution was not complete | finished at 2 hours.

  ×: not substituted

TABLE 8

From Table 8, in the case where an indium-containing nitric acid solution is used as a starting material, in order to perform the aluminum substitution precipitation reaction, the concentration of nitrate ions (the ion concentration causing the dynamic formation) in the acid solution needs to be less than 22000 ppm, preferably less than 15000 ppm In particular, it was found that it is preferably 10000 ppm or less.

Claims (37)

As a method for producing an indium-containing metal from an indium-containing solution containing indium, Dissolving the indium-containing substance in nitric acid to form an indium-containing nitric acid solution, and standing in the state of the indium-containing nitric acid solution to precipitate and remove tin contained in the indium-containing nitric acid solution; and oxalic acid as a precipitant in the indium-containing solution. A process for producing an indium oxalate precipitate by mixing the same, and a process for recovering the precipitate of indium oxalate by solid-liquid separation. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete As a method for producing an indium-containing metal from an indium-containing solution containing indium, Adjusting the pH of the indium-containing solution to 2 or less and generating a precipitate of indium oxalate by mixing oxalic acid with the indium-containing solution as a precipitating agent, Recovering the precipitate of indium oxalate by solid-liquid separation; When the indium-containing solution contains copper, removing the copper from the precipitate by contacting the recovered precipitate of indium oxalate with ammonia or with ammonia and alkali hydroxide, The manufacturing method of the indium containing metal which has a process of roasting collect | recovered indium oxalate. As a method for producing an indium-containing metal from an indium-containing nitric acid solution obtained by dissolving an indium-containing substance in nitric acid, A step of producing a precipitate of indium oxalate by mixing oxalic acid as a precipitant in an indium-containing nitric acid solution, Recovering the precipitate of indium oxalate by solid-liquid separation; Dissolving the recovered precipitate of indium oxalate in hydrochloric acid to form an acid solution; Adding aluminum to the acid solution and producing sponge indium by a substitution reaction with the aluminum; The manufacturing method of the indium containing metal which has a process of obtaining an indium containing metal from this sponge indium. As a method for producing an indium-containing metal from an indium-containing nitric acid solution obtained by dissolving an indium-containing substance in nitric acid, A step of producing a precipitate of indium oxalate by mixing oxalic acid as a precipitant in an indium-containing nitric acid solution, Recovering the precipitate of indium oxalate by solid-liquid separation; The recovered precipitate of indium oxalate is immersed in a liquid which does not dissolve indium, and the passivation cause ion which dissolves in the liquid the ion which causes a passivation on the metal surface in the subsequent substitution precipitation process, and removes this solution. A process of carrying out the cleaning treatment one or more times, A process of dissolving the washing treatment obtained by the above-mentioned ion-causing ion washing treatment in hydrochloric acid to form an acid solution, Adding aluminum to the acid solution and producing sponge indium by a substitution reaction with the aluminum; The manufacturing method of the indium containing metal which has a process of obtaining an indium containing metal from this sponge indium. delete delete As a method for producing an indium-containing metal from an indium-containing solution containing indium, A pH of the indium-containing solution is set to 0.5 to 4.0, the indium-containing solution is filtered to remove tin, and thereafter, oxalic acid is mixed with the indium-containing solution as a precipitant to produce a precipitate of indium oxalate, and the precipitate of indium oxalate. The manufacturing method of the indium containing metal which has a process of collect | recovering by solid-liquid separation. As a method for producing an indium-containing metal from an indium-containing solution containing indium, When the indium-containing solution contains copper, a step of removing copper from the precipitate by contacting the recovered precipitate of indium oxalate with ammonia or ammonia and alkali hydroxide, and oxalic acid as a precipitant in an indium-containing solution The manufacturing method of the indium containing metal which has the process of producing the precipitate of indium oxalate by this, and the process of collect | recovering the said precipitate of indium oxalate by solid-liquid separation. The method of claim 23, wherein A contact amount of ammonia or a total contact amount of ammonia and alkali hydroxide is equal to or greater than the number of moles corresponding to 4 moL per 1 moL of copper contained in the indium-containing solution. The method of claim 23, wherein A method for producing an indium-containing metal, wherein the precipitate before or after contact with ammonia or ammonia and alkali hydroxide is washed with water or an oxalic acid aqueous solution. The method according to any one of claims 1 and 22 to 25, The mixing amount of oxalic acid when mixing oxalic acid with an indium containing solution is 1.2 to 5 times the equivalent with respect to the amount of indium contained in an indium containing solution, The manufacturing method of the indium containing metal characterized by the above-mentioned. The method according to any one of claims 1 and 22 to 25, The pH of an indium containing solution is adjusted to 2 or less before mixing oxalic acid with an indium containing solution, The manufacturing method of the indium containing metal characterized by the above-mentioned. The method according to any one of claims 1 and 22 to 25, The pH of an indium containing solution is adjusted to 0.5 or less before mixing oxalic acid with an indium containing solution, The manufacturing method of the indium containing metal characterized by the above-mentioned. The method according to any one of claims 1 and 22 to 25, PH of the indium containing solution after mixing with oxalic acid is 1.0 or less, The manufacturing method of the indium containing metal characterized by the above-mentioned. The method according to any one of claims 1 and 22 to 25, The manufacturing method of the indium containing metal containing the process of roasting collect | recovered indium oxalate. The method of claim 30, The roasting temperature is 600-1200 degreeC, The manufacturing method of the indium containing metal characterized by the above-mentioned. The method according to any one of claims 1 and 22 to 25, A process of dissolving the recovered indium oxalate precipitate in an acid to form an acid solution, adding aluminum to the acid solution, and producing sponge indium by a substitution reaction with the aluminum; and an indium-containing metal from the sponge indium The manufacturing method of the indium containing metal which has a process of obtaining. 33. The method of claim 32, After the step of recovering the precipitate of indium oxalate by solid-liquid separation, the recovered ions of indium oxalate are immersed in a liquid in which indium is not dissolved, and the ions causing the passivation on the metal surface in the subsequent substitution precipitation process are the liquid. It has a process of dissolving in water and performing the passivation cause ion washing process which removes this melt | dissolution liquid once or more, Instead of the step of dissolving the recovered precipitate of indium oxalate in acid to form an acid solution, The manufacturing method of the indium containing metal which has the process of melt | dissolving what was wash | cleaned by the ion-washing process of the said passivation formation cause, and making it into an acid solution. 33. The method of claim 32, An indium-containing solution containing indium, wherein an indium-containing nitric acid solution obtained by dissolving an indium-containing substance in nitric acid is used, and hydrochloric acid is used to prepare an acid solution. 33. The method of claim 32, In the process of obtaining an indium containing metal from sponge indium, an indium containing metal is obtained by alkali-molding sponge indium, The manufacturing method of the indium containing metal characterized by the above-mentioned. The method of claim 33, wherein An indium-containing solution containing indium, wherein an indium-containing nitric acid solution obtained by dissolving an indium-containing substance in nitric acid is used, and hydrochloric acid is used to prepare an acid solution. The method of claim 33, wherein In the step of obtaining an indium-containing metal from sponge indium, alkaline infusion of sponge indium is obtained to obtain an indium-containing metal.

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