TW201305389A - Method for producing indium hydroxide or compound containing indium hydroxide - Google Patents

Abstract

A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis. The purpose of this method is to suppress deterioration of the productivity and deterioration of the quality by performing electrolysis, while setting the electrical conductivity of the electrolyte solution at 10 mS/cm or more, so that indium hydroxide or a compound containing indium hydroxide is precipitated in the electrolyte solution, and then cleaning the thus-precipitated indium hydroxide or compound containing indium hydroxide until the electrical conductivity of the cleaning liquid becomes 1 mS/cm or less.

Description

Method for producing indium hydroxide or compound containing indium hydroxide

This invention relates to a method for producing indium hydroxide or a compound containing indium hydroxide which is a raw material of a powder of indium oxide or a compound containing indium oxide which is mainly used in the production of an ITO target for sputtering of an ITO film.

A film of ITO (composite oxide containing indium-tin as a main component) is widely used as a transparent electrode (film) of a display device centered on a liquid crystal display. The method of forming the ITO film is generally formed by a method generally called a physical vapor deposition method such as a vacuum deposition method or a sputtering method. In particular, in terms of workability or stability of the film, it is more often formed by magnetron sputtering.

When a film is formed by a sputtering method, a positive ion such as Ar ion is physically collided with a target placed on a cathode, and a material constituting the target is released by the collision energy, and the composition is substantially the same as the target material. The film is laminated on the opposite side of the substrate on the anode side.

The coating method by the sputtering method is characterized in that a film having a thickness of several tens of μm can be formed from a thin film of an angstrom unit at a stable film forming speed by adjusting a processing time or supplying electric power or the like.

In general, an ITO sintered body target is produced by pulverizing and mixing indium oxide and tin oxide, and molding the obtained mixed powder and sintering it. When the indium oxide and the tin oxide are pulverized and mixed, dry or wet mixing is carried out by a ball mill, a V-type mixer or a belt mixer.

Indium oxide powder which is a raw material of the ITO sintered body target can be produced by calcining indium hydroxide. Representative of the method for producing the indium hydroxide The technique is disclosed in Patent Document 1. In the method of Patent Document 1, indium hydroxide is produced by electrolysis using indium as an anode, and the indium hydroxide is calcined to obtain an indium oxide powder. Furthermore, this patent document 1 has a different name for the applicant due to the change of name, but it is the applicant's application.

As a method of producing indium oxide, a neutralization method can also be considered. However, as described in Patent Document 1, the electrolysis method is effective because of the following problems.

a) The difference in the characteristics (average particle diameter, apparent density, etc.) of the obtained indium oxide powder is large, and this is a "deterioration of quality difference" or "high quality" of an indium oxide-based display material, a phosphor, or the like. The obstacles are the cause.

b) It is not always possible to easily control the manufacturing conditions (liquid temperature, reaction speed, etc.), and in order to stabilize it, the equipment cost may increase.

c) When it is required to have a different characteristic from the previous one, it is not possible to respond flexibly to this requirement.

d) The scale of the device becomes relatively large, so if the manufacturing conditions are to be fixedly controlled, considerable labor is required, and it can be said that the increase may not be easily dealt with.

e) Because the neutralizing waste liquid (such as ammonium nitrate) is generated at any time, it must be treated, which will increase the running cost.

Next, a representative example of producing indium hydroxide by electrolysis is disclosed.

In the aqueous solution of ammonium nitrate (NH ₄ NO ₃ ), concentration: 0.2~5mol/L, pH: 4~10, temperature: 10~50°C, indium is used as anode (anode), current density is 100~1800A/ The m ^{2 is} energized to perform electrolysis. Then, the deposit at the bottom of the electrolytic cell is filtered, washed and dried to obtain indium hydroxide.

When indium oxide is produced using the indium hydroxide as a raw material, it may be calcined at a temperature of about 1,100 °C. Thereby, an indium oxide powder having an average particle diameter of 1 to 5 μm can be obtained.

In the electrolysis of the above-described indium hydroxide, an indium plate is placed in the electrolytic cell as an anode, and a normal stainless steel plate is placed on the cathode, and the electrolytic solution is allowed to flow therebetween for electrolysis. However, indium hydroxide formed on the surface of the anode is deposited on the surface of the cathode, and is in the form of branches (dendritic crystals), which causes a short circuit between the anode and the cathode, thereby causing a problem that electrolysis cannot be performed for a long time.

Further, when electrolysis is continuously performed, an element having a higher elution potential than In forms impurities and remains on the surface of the anode, resulting in a problem of surface concentration. If electrolysis is continued under such conditions, impurities are also mixed into the electrolyte, resulting in deterioration of the purity of the previously precipitated indium hydroxide. Further, on the surface of the anode, indium metal partially disappears, and the current density on the surface of the anode becomes uneven. As a result, an abnormality is also generated in which pores are locally generated on the surface of the anode, and the anode itself is detached from the bath.

Further, in the electrolysis of indium hydroxide, the following problems occur: the indium hydroxide formed on the surface of the anode is deposited, indium is deposited on the surface of the cathode, and branches are formed in the form of branches (dendrites), resulting in an anode. And the cathode is shorted.

If the prior art is investigated, the patent documents described below are disclosed.

Patent Document 2 is a method for producing an indium oxide powder, and is performed by using indium as an anode and stirring until a precipitate of indium hydroxide is suspended in an electrolytic solution. Specifically, the electrolytic cell is not stirred. The pH near the liquid surface is about 8.5, and the pH near the bottom of the tank is about 3.2. By stirring the electrolyte, the electrolyte near the liquid surface and the bottom of the tank are mixed, and the pH becomes uniform.

The degree of agitation is such that the precipitation of indium hydroxide produced by electrolysis is suspended in the electrolyte. Therefore, if the degree of agitation is weak, the effect of homogenizing the pH of the electrolytic solution is insufficient. In the usual electrolysis, it is common to carry out the electrolyte in a static flow state, and the agitation such as lifting the viscosity of the groove bottom is not performed, but the electrolysis step of the present invention is characterized in that the electrolyte is actively stirred until the precipitate is suspended. Electrolysis is carried out to the extent that it is.

The liquid temperature of the electrolyte is 40 to 80 ° C (50 to 70 ° C), and ammonium nitrate or ammonium chloride is used as the electrolyte. The concentration of the reagent in the electrolyte is 1~3mol/L, the voltage is 2~4V, the current density is 200~900A/m ² (about 700A/m ² ), the pole is 25m/m~50m/m, and the material of the cathode can be carbon. Indium plates are usually used. The calcination is usually set in the air at 700 to 1100 ° C (about 800 to 950 ° C).

Patent Document 3 describes a method for producing an indium oxide-tin oxide powder, and discloses a technique in which indium and tin are simultaneously electrolyzed as different anodes (PR type pulse energization). It is disclosed that an electrolytic solution is used for electrolysis using NH ₄ NO ₃ at a concentration of 0.2 to 5 mol/L, a pH of 4 to 9.5, a bath temperature of 0 to 50 ° C, and a current density of 100 to 1800 A/m ² . The powder thus obtained was calcined at 1,100 ° C to produce an ITO powder having an average particle diameter of 20 μm and an apparent density of 1.7 g/cm ³ . An ITO target containing a ratio of SnO ₂ of 10% by weight, a sintered body density of 6.70 g/cm ³ or 4.78 g/cm ³ was obtained.

Patent Document 4 discloses a method for producing an ITO target. A method of producing indium hydroxide by electrolysis. Specifically, it is a method of washing and dispersing indium hydroxide produced by electrolysis of indium as an anode in pure water. It is described that ammonium nitrate as the electrolytic solution is preferable in terms of cost and purity, but since the surface of the electrode is deposited as an insulator, that is, metastannic acid, electrolysis cannot be continuously performed. The content of the slurry in which the indium hydroxide dispersion solution and the metastannic acid dispersion solution are mixed is 5, using a dispersion solution in which indium hydroxide is dispersed in an indium hydroxide having a particle diameter of 10 μm or less and 10 to 80% by weight. Above and below 9.

Patent Document 5 describes a method of homogenizing the concentration of the electrolytic solution in electrolytic refining and an electrolytic cell, and discloses a method in which a liquid supply bag is disposed at an end portion of the electrolytic cell, and the liquid supply bag is disposed from the liquid supply bag. When the anode plate and the cathode plate are supplied with liquid, the liquid supply bag has an opening at the upper and lower sides, and the liquid is supplied from the upper opening, the new electrolyte is supplied from the lower opening, and the hole is provided on the side of the upper side of the liquid supply bag. Liquid can also be supplied to the anode plate and the cathode plate from the holes, thereby uniformizing the concentration of the electrolyte. In this case, the anode plate and the cathode plate are supplied in a vertical direction.

Patent Document 6 discloses an electrolytic cell for electrolytic refining or electrolytic refining, and an electrolytic cell having a structure in which a plurality of liquid supply holes are provided on the inner wall of the liquid supply side and a plurality of rows on the inner wall of the liquid discharge side are provided. The liquid holes are allowed to flow straight between the anode and the cathode.

In the above-mentioned well-known literature, the conductivity in the electrolytic solution is not specified, and the problem of deterioration of current efficiency is not known at all, and the subsequent steps (cleaning of precipitated indium hydroxide or the like) affect the density at the time of sintering. And no specific method for solving this problem has been disclosed.

Moreover, the following understanding is not disclosed at all: in the electrolysis of indium hydroxide, impurities are concentrated on the surface of the anode, the anode is detached, and a hydroxide having a high impurity content other than indium hydroxide is formed in the electrolyte to cause hydrogen. The purity of indium oxide is reduced, and no specific method for solving this problem has been disclosed.

Moreover, in the above-mentioned well-known literature, the following understanding is not disclosed at all: in the electrolysis of indium hydroxide, the surface of the anode is adhered to the formed indium hydroxide, and the surface of the cathode is electrodeposited with indium and branches (twigs) The shape of the crystal extends to cause a short circuit between the anode and the cathode, and a specific method for solving the problem is not disclosed.

Patent Document 1: Japanese Patent No. 2829556

Patent Document 2: Japanese Patent Laid-Open No. Hei 10-204669

Patent Document 3: Japanese Patent No. 2736492

Patent Document 4: Japanese Laid-Open Patent Publication No. 2001-303239

Patent Document 5: Japanese Laid-Open Patent Publication No. 2007-204779

Patent Document 6: Japanese Unexamined Patent Publication No. 3-89166

The object of the present invention is to solve the problem that when indium hydroxide or a compound containing indium hydroxide is produced by electrolysis, that is, a case where the current efficiency is extremely poor, and the sintering property is deteriorated at the time of sintering, and the density does not rise. . Thereby, the decrease in productivity or the decrease in quality is suppressed.

Further, the object of the present invention is to ascertain the cause of the following problems, and to propose a specific method for solving the same, thereby suppressing a decrease in productivity or a decrease in quality, which is disposed in an electrolytic cell as an anode. Indium plate and cathode plate, allowing electrolyte to flow between them for electricity When the solution is formed, the oxide layer and impurities formed on the surface of the anode are concentrated on the oxide layer; the anode itself is detached from the middle; and indium hydroxide having a high impurity content other than indium hydroxide is formed, and the purity of the indium hydroxide is lowered.

Further, the object of the present invention is to ascertain the cause of problems caused by the production of indium hydroxide or a compound containing indium hydroxide by electrolysis, and to propose a specific countermeasure for solving such problems, thereby suppressing productivity. The problem of lowering or lowering the quality is to arrange an indium or an indium alloy plate and a cathode plate as an anode in the electrolytic cell, and to carry out electrolysis while flowing the electrolyte therebetween, and attaching to the surface of the anode. The formed indium hydroxide or the compound containing indium hydroxide is electrodeposited on the surface of the cathode with indium or an indium alloy, and extends in the form of branches (dendritic crystals), resulting in short circuit of the anode and the cathode.

The present invention provides the following methods for solving the above problems.

1) A method for producing an indium hydroxide or a compound containing indium hydroxide by electrolysis, which is a method for producing an indium hydroxide or a compound containing indium hydroxide by electrolysis, characterized in that an electrolytic solution is used Electrolysis is performed at a conductivity of 10 mS/cm or more, and indium hydroxide or a compound containing indium hydroxide is precipitated in the electrolytic solution, and the precipitated indium hydroxide or the compound containing indium hydroxide is washed until the cleaning liquid is electrically conductive. The degree is 1 mS/cm or less.

2) A method for producing an indium hydroxide or a compound containing indium hydroxide by electrolysis as in the above 1), wherein the conductivity of the cleaning liquid which is washed to precipitated indium hydroxide or a compound containing indium hydroxide is 0.1 Below mS/cm.

Further, the present invention provides the following methods for solving the above problems.

3) A method for producing indium hydroxide powder by electrolysis in which an anode plate is alternately arranged with an anode plate of indium metal as a raw material in an electrolytic cell, and the cathode plate and the anode plate are alternately arranged A method for producing an indium hydroxide powder by electrolysis, wherein an indium hydroxide particle is precipitated in the electrolytic solution, and the electrolysis is stopped at a stage where the weight of the anode plate becomes 20% to 80% of the initial weight of the anode. The used anode plate is taken out, the used anode plate is melted and a new indium metal is added and cast, thereby re-forming the anode plate, and the regenerated anode plate is used to start electrolysis to precipitate the indium hydroxide particles to the electrolysis. In the liquid.

4) A method for producing an indium hydroxide powder by electrolysis as in the above 3), wherein the electrolysis is carried out using a stainless steel plate or a titanium plate as a cathode plate.

5) The method for producing an indium hydroxide powder by electrolysis according to any one of the above 3) to 4), further comprising the step of: taking out an indium hydroxide slurry deposited in the electrolytic solution; The slurry is concentrated to separate into a solid content component concentrate and a solid content component thin liquid; and the solid matter component thin liquid is dispensed to the electrolyte solution supply nozzle.

6) The method for producing an indium hydroxide powder by electrolysis according to the above 5), comprising the steps of: filtering the solid component concentrate; and distributing the filtrate to the electrolyte supply nozzle; The step of drying the filtered solids to form an indium hydroxide powder.

Further, the present invention provides the following methods for solving the above problems.

7) An electrolytic manufacturing apparatus for indium hydroxide or a compound containing indium hydroxide, which is produced by electrolytic method to produce indium hydroxide or contain indium hydroxide The apparatus for compounding is characterized in that a cathode plate is alternately arranged with an anode plate of indium or an indium alloy as a raw material in an electrolytic cell, and between the cathode plate and the anode plate, and each of the cathode plate and the anode plate A nozzle for supplying an electrolyte to the other side edge of the cathode plate and the anode plate is disposed at a position near one of the side edges, and the electrolyte flowing out from the opening of the nozzle is placed in each of the cathode plate and the anode in the electrolytic cell. The plates are refluxed to precipitate indium hydroxide or a compound containing indium hydroxide into the electrolyte.

8) An electrolytic manufacturing apparatus of indium hydroxide or a compound containing indium hydroxide according to the above 7), wherein the cathode plate is a stainless steel plate or a titanium plate.

9) An electrolytic manufacturing apparatus of indium hydroxide or a compound containing indium hydroxide according to 7) or 8) above, wherein one or a plurality of side edges from one of the cathode plates and the anode plate are disposed to the other side The nozzle for supplying the electrolyte causes the electrolyte flowing out from the opening of the nozzle to recirculate between the cathode plates and the anode plate in the electrolytic cell, thereby causing the indium hydroxide or the compound containing indium hydroxide to be precipitated into the electrolyte. .

10) An electrolytic production apparatus of indium hydroxide or a compound containing indium hydroxide according to any one of the above 7) to 9), which has an apparatus for taking out indium hydroxide or containing hydrogen in an electrolytic solution in an electrolytic solution A device for indium oxide compound; a device for concentrating the hydroxide to separate into a solid content component concentrate and a solid content component; and a device for distributing the solid component diluent to the electrolyte supply nozzle.

11) An electrolytic production apparatus of the indium hydroxide powder or the indium hydroxide-containing compound powder according to the above 7), comprising: a device that filters the solid content component concentrate and distributes the filtrate to the electrolyte supply nozzle; And drying the filtered solid matter to produce an indium hydroxide powder or a compound powder containing indium hydroxide.

12) A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, which is a method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, characterized in that it is in an electrolytic cell The cathode plate is alternately arranged at intervals with the anode plate of indium or indium alloy as a raw material, and is disposed adjacent to the side edge of one of the cathode plate and the anode plate between the cathode plate and the anode plate, and is disposed toward the cathode plate And a nozzle for supplying the electrolyte to the other side edge of the anode plate, and adjusting the liquid flow of the electrolyte flowing out from the opening of the nozzle to reflux between the cathode plate and the anode plate in the electrolytic cell to make hydrogen Indium oxide or a compound containing indium hydroxide is precipitated into the electrolytic solution.

13) A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis according to the above 12), wherein the electrolysis is carried out using a stainless steel plate or a titanium plate as a cathode plate.

14) A method for producing an indium hydroxide or a compound containing indium hydroxide by electrolysis according to the above 12) or 13), wherein one or a plurality of side edges from each of the cathode plate and the anode plate are disposed toward each other The other side of the nozzle for supplying the electrolyte adjusts each liquid flow of the electrolyte flowing out from the opening of the nozzle to recirculate between the cathode plate and the anode plate in the electrolytic cell to make indium hydroxide or A compound containing indium hydroxide is precipitated into the electrolytic solution.

15) The method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis according to any one of the above items 12) to 14), further comprising the step of: taking out indium hydroxide precipitated into the electrolytic solution Or a step comprising a compound of indium hydroxide; concentrating the hydroxide to separate into a solid a step of dispersing the component concentrate and the solid component; and discharging the solid component diluent to the electrolyte supply nozzle.

16) The method for producing an indium hydroxide powder or a compound powder containing indium hydroxide by electrolysis according to the above 15), comprising the steps of: filtering the solid component concentrate, and distributing the filtrate to the above a step of supplying an electrolyte to the nozzle; and drying the filtered solid to form an indium hydroxide powder or a compound powder containing indium hydroxide.

17) The method for producing indium hydroxide or a compound containing indium hydroxide according to the above 12) to 16), wherein the supply rate of the electrolyte is 0.01 to 100.0 L with respect to the current value, the electrolysis area, and the time. m ² /A. The way the electrolyte flows.

When indium hydroxide or a compound containing indium hydroxide is produced by electrolysis, indium hydroxide or a compound containing indium hydroxide can be efficiently produced, thereby having an excellent effect of improving the sinterability at the time of producing a target. .

In addition, an indium plate and a cathode plate as an anode are disposed in the electrolytic cell, and when the electrolytic solution is flowed therebetween to perform electrolysis, the electrolytic anode is regenerated in the middle of electrolysis, thereby preventing concentration of impurities. The surface of the anode and the anode are detached from the bath in the middle of electrolysis, and indium hydroxide or impurities having a high impurity content other than indium hydroxide formed by mixing in the electrolyte solution cause a difference in quality of the indium hydroxide.

Further, when indium hydroxide or a compound containing indium hydroxide is produced by electrolysis, no indium hydroxide or a compound containing indium hydroxide is adhered to the surface of the anode, and indium or an indium alloy is not electrodeposited on the surface of the cathode. The electrolyte is refluxed to efficiently produce indium hydroxide or a compound containing indium hydroxide Therefore, it has an excellent effect of improving productivity.

The scheme of the electrolysis step of producing indium hydroxide (In(OH) ₃ ) from indium (In) is shown in FIG. As shown in FIG. 1, an indium plate made of indium was produced by casting indium as a raw material, and this was placed in an electrolytic cell.

In the electrolytic cell, a plurality of cathode plates composed of a stainless steel plate or a titanium plate are alternately arranged in parallel. The electrolyte is supplied to the electrolytic cell. An aqueous solution of ammonium nitrate (NH ₄ NO ₃ ) was used as the electrolytic solution. Further, the electrolytic solution is not particularly specified, and any one of a nitric acid aqueous solution, a sulfuric acid aqueous solution, a hydrochloric acid aqueous solution, or another electrolyte may be used. However, it is preferable in terms of cost or product purity maintenance. It is an aqueous solution of ammonium nitrate.

In the following description, an example of producing indium hydroxide (In(OH) ₃ ) from indium (In) is disclosed, but the same can be applied to the case of using an indium alloy anode to produce a compound containing indium hydroxide. Representative examples of the indium alloy include an indium tin alloy or an indium zinc alloy for ITO. In addition, an alloy or the like to which other elements are added may be applied to all of the same phenomena as the case of producing indium hydroxide (In(OH) ₃ ) from indium (In) disclosed as a representative example of the present invention. situation.

Examples of the additive element include copper (Cu), silver (Ag), bismuth (Sb), strontium (Te), bismuth (Bi), and strontium (Tl), in addition to the above-mentioned tin (Sn) and zinc (Zn). Calcium (Ga), strontium (Ge), cadmium (Cd), and the like. At the time of electrolysis, most of these added elements are hydroxides in the same manner as indium, but they may be present in the form of a mixture of an elemental oxide or a monomer or alloy of an additive element or a mixture thereof. The invention of the present invention contains the inclusion of indium hydroxide Any of these compounds (including mixtures).

Indium is melted by electrolysis, and fine particles of indium hydroxide are precipitated in the electrolytic solution. The indium hydroxide deposited in the electrolytic solution is taken out, concentrated, and separated into a solid content concentrate liquid and a solid content component thin liquid. At this time, the solid component concentrate is washed, filtered, and dried to obtain an indium hydroxide powder. On the other hand, the solid matter component thin liquid is returned to the electrolytic solution, and the liquid flow is adjusted and reused. Further, the filtrate obtained by filtering the solid content concentrate is also refluxed to the electrolytic solution, and the liquid flow is adjusted and reused.

The problem here is that the current efficiency becomes extremely poor when electrolysis is performed. Further, when sintering the solid-liquid-separated indium hydroxide or a compound thereof, there is a problem that the sintered density cannot be increased or the sintered density is uneven in the target.

Therefore, after various studies, it is understood that if the conductivity in the electrolytic solution is too low, the current efficiency becomes extremely poor, and the reason why the sintered density is low is the electrolytic solution attached to the indium hydroxide.

Further, as the electrolysis progresses, the impurity elements of the indium anode plate are gradually left to concentrate on the surface of the indium anode. This situation is shown in Fig. 2.

The metal element having a higher elution potential than indium remains on the surface, and only indium is ionized and eluted. If the impurities are concentrated on the surface of the anode, the impurities, particularly metal elements having a higher elution potential than indium, are also ionized and eluted, and are mixed into the indium hydroxide slurry. Further, impurities are detached from the surface of the anode and mixed into the indium hydroxide slurry.

In the present invention, when indium hydroxide or a compound containing indium hydroxide is produced by electrolysis, electrolysis is carried out by setting the conductivity of the electrolytic solution to 10 mS/cm or more, more preferably 500 mS/cm, to make indium hydroxide or Containing hydrogen and oxygen The indium compound is precipitated into the electrolyte. Thereby, the current efficiency can be made approximately 100%.

Further, in the present invention, the precipitated indium hydroxide or the compound containing indium hydroxide is washed until the conductivity of the cleaning liquid becomes 1 mS/cm or less. Preferably, the cleaning degree until the conductivity of the cleaning liquid is 0.1 mS/cm or less. The hydroxide obtained thereby is dried or reduced, and this is used as a sintering raw material of an oxide, and further sintered. Thereby, the relative density of the sintered body can be increased to 99% or more.

Further, in the invention of the present invention, the above aspect is improved, and the electrolysis is stopped at a stage where the weight of the anode plate becomes 20% to 80% of the initial weight of the anode. If it is less than 20%, a large amount of impurities will concentrate on the surface of the anode, causing the problems as described above. If it exceeds 80%, the use efficiency is poor and the productivity is deteriorated. Then, the used anode plate is taken out, and the used anode plate is filled with new indium metal and cast to re-form the anode plate. The melt-casting method is not particularly limited. Without adding new indium metal, it is no problem to cast only the used anode plate.

Electrolysis is started using the reconstituted indium metal anode plate to precipitate indium hydroxide particles in the electrolyte. The reconstituted anode plate can be used in the same step, using the weight of the anode plate to be 20% to 80% of the initial weight of the anode. After use, the electrolytic anode can be regenerated by the same method. The re-manufacturing of the anode can be repeated several times.

The range of anodes that can be used is wide, ranging from 20% to 80% of the initial weight, which is primarily dependent on the difference in purity of the anode. In general, the amount of impurities in the indium raw material flowing through will vary greatly. Also, in the production stage of the anode, The amount of impurities mixed may also vary depending on the situation. When there are many impurities, when the electrolysis is performed, the amount of impurities concentrated on the surface of the anode is naturally increased, and the use efficiency is lowered. On the other hand, if the amount of impurities is small, the amount of impurities concentrated on the surface of the anode is small, so that the use efficiency is high.

Electrolysis does not uniformly consume the surface of the anode. Compared with the portion where the impurities are large, the portion where the current easily flows (the portion with less impurities) is consumed more quickly, and the anode ingot is detached from the middle. According to the above, it can be said that there is a tendency that the anode having a small impurity content is used more efficiently, and the anode having a larger impurity content is used less efficiently.

Further, there is also a case where not all of In is indium hydroxide, and In is electrodeposited in one part of the cathode, which grows to cause a short circuit. In this case, it is necessary to interrupt the electrolysis. This short circuit can be seen by the voltage change. These reasons are due to the wide range of the above 20% to 80%.

The problem here is that in the electrolysis, the generated indium hydroxide adheres to the surface of the anode plate made of indium in the electrolytic cell, and indium is deposited on the surface of the cathode plate, and there is a problem that electrolysis cannot be continued. . The indium extends in the form of branches (dendritic crystals), which also causes a problem of short circuit between the anode and the cathode.

The problem is that if the electrolytic current density is increased in order to increase the production efficiency, the adhesion of indium hydroxide or the electrodeposition of indium is more apparent. The deposition of indium on the cathode plate or the adhesion of indium hydroxide to the anode plate is not so strong, but if the amount of adhesion increases, there is a tendency that it is gradually difficult to peel off. Therefore, in the initial stage of electrolysis, the following method (test) is carried out: the electrolyte is refluxed between the anode plates and the cathode plates, and the electrolyte is refluxed. The deposition of indium on the cathode or the adhesion of indium hydroxide to the anode.

The previous electrolysis apparatus will be described using FIG. The left side shown in Fig. 3 is a plan view of the electrolytic cell, and the right side is a side view of the intermediate position between the anode plate and the cathode plate. As shown in Fig. 3, an anode plate and a cathode plate are disposed at intervals of 10 to 500 mm in an electrolytic cell, and a supply port of a nozzle for supplying an electrolytic solution is disposed in an upper portion of the electrolytic cell.

Then, the electrolyte is supplied to the electrolytic cell in the direction indicated by the arrow on the right side of FIG. The flow strength (electrolyte supply rate) supplied to the electrolyte was set to 0.5 L. m ² /A. Minute. The flow strength (electrolyte supply rate) of the electrolytic solution means a flow rate (L/min) of a current density (A/dm ² or A/m ² ) for any of the anode or the cathode. Hereinafter, the same meaning is used for the case where the flow strength (electrolyte supply rate) of the electrolytic solution is shown.

In the prior supply method of the electrolyte, the electrodeposition of indium to the cathode plate or the adhesion of indium hydroxide to the anode plate is produced. Even if the flow strength (electrolyte supply rate) of the electrolytic solution is made larger than the above, the same result is obtained.

In order to suppress the electrodeposition of indium to the cathode plate or the adhesion of indium hydroxide to the anode plate, several experiments were carried out in consideration of the direction of the liquid flow.

A schematic illustration of the electrolytic production apparatus for indium hydroxide is shown in Fig. 4 . The left side of Fig. 4 is a schematic explanatory view (top view) viewed from above, and the right side is a schematic explanatory view of the side of the intermediate position between the anode plate and the cathode plate. Except for the configuration of the nozzles, they are the same as those shown in FIG.

Then, the electrolyte was refluxed in the direction indicated by the arrow on the right side of FIG. The flow strength (electrolyte supply rate) of the electrolyte is set to 0.01 to 100.0 L. m ² /A. Minute. As shown in Fig. 4, the liquid flow was caused to rotate from the lower side to the center between the anode and the cathode.

Furthermore, if the electrolyte supply rate is lower than 0.01L. m ² /A. Even if the reflow method is used, the above problem cannot be solved. If it is higher than 100.0L. m ² /A. The circulation speed of the liquid flow is increased, the liquid flow becomes turbulent, and the indium hydroxide adhering to the surface of the anode is directly peeled off or peeled off in the form of coarse particles, or the shape of the formed hydroxide becomes extremely fine, thereby Not available. The flow strength (electrolyte supply rate) of the electrolyte is preferably 0.1 to 10.0 L. m ² /A. Minute.

According to the control result of the liquid flow of Fig. 4, if the nozzle shown in Fig. 4 is used, the electrodeposition of indium to the cathode plate or the adhesion of indium hydroxide to the anode plate disappears. In order to ascertain the cause, it was found that the electrolyte in the electrolytic cell was confirmed, and as shown in the schematic diagram of the liquid flow in Fig. 5, a sufficient flow of the electrolyte was generated in the central portion of the cathode plate and the anode plate.

As a result, the reflow method of the present invention is extremely effective, and the improvement of the adhesion of indium hydroxide to the anode plate or the electrodeposition of the indium to the cathode plate can be effectively suppressed by a simple device improvement, in the cathode plate and the anode plate. No attachment or electrodeposition was observed on all the faces.

According to the above, the electrolyte solution is supplied from the one edge to the other side between the cathode plate and the anode plate, and the reflux between the cathode plate and the anode plate in the electrolytic cell suppresses the indium-to-cathode plate. An effective method of electrodeposition or adhesion of indium hydroxide to an anode plate, the present invention is based on the results of the experiments as described above.

That is, it can be seen that the cathode plate and the anode of indium as a raw material are used in the electrolytic cell. The plates are alternately arranged at intervals of 10 to 500 mm, and the other side of the cathode plate and the anode plate are disposed between the cathode plate and the anode plate and adjacent to one side edge of each of the cathode plate and the anode plate. The nozzle for supplying the electrolyte makes it possible to reflux the electrolyte flowing out from the opening of the nozzle between the cathode plate and the anode plate in the electrolytic cell, thereby effectively depositing indium hydroxide in the electrolytic solution.

In addition, the nozzle diameter (caliber) for supplying the electrolytic solution is appropriately adjusted depending on the size of the electrolytic cell, the size of the interval between the cathode plates and the anode plates, the supply amount of the electrolytic solution, the arrangement and number of nozzles, and the like. Therefore, the nozzle diameter (caliber) is not particularly limited.

A wide gap can also be formed between the cathode plate and the anode plate, and in this case, the liquid flow can also be increased. That is, one or a plurality of nozzles for supplying an electrolytic solution are disposed as nozzles for supplying an electrolytic solution to the other side edge between the cathode plate and the anode plate, and each of the electrolyte flowing out from the opening of the nozzle is in the electrolytic cell. The reflux between the cathode plate and the anode plate allows precipitation of indium hydroxide into the electrolyte.

It is effective to adjust the flow of the electrolyte flowing out from the opening of the lower nozzle, the upper nozzle, or the intermediate nozzle, so that the liquid of each of them flows between the cathode plate and the anode plate from the cathode plate and the anode plate. The one side edge is reflowed (rotated) by drawing an arc to the other side edge. It is considered that in this case, the reflux of the electrolyte must flow uniformly between the cathode plates and the anode plates, and one of the streams must be bonded to the surfaces of the cathode plates and the anode plates. However, if the cathode plate and the anode plate can be reflowed to the entire surface of the cathode plate and the anode plate, it can be said that the direction of the reflow does not need to be particularly limited.

In the present invention, it is effective to use a stainless steel plate or a titanium plate as a cathode plate, but other materials may be used as long as they do not contaminate the electrolyte.

The electrolysis manufacturing apparatus may be provided with a device for taking out indium hydroxide deposited in the electrolytic solution, a device for concentrating and separating the hydroxide into a solid component solid solution and a solid component thin liquid, and The apparatus for dispensing a solid content component into the electrolyte supply nozzle further comprises: means for filtering the solid component concentrate, and distributing the filtrate to the electrolyte supply nozzle; A device for solid content; and an apparatus for producing an indium oxide powder which is further dried to form an indium oxide powder. In order to reduce the cost of the manufacturing apparatus, a solid-liquid separation apparatus, a filtration apparatus, a filtrate distribution apparatus, a water washing apparatus, a powder manufacturing apparatus, and the like may be provided along with the electrolysis apparatus of the present invention.

[Examples]

Next, an embodiment of the present invention will be described. Furthermore, this embodiment is merely an example, and the present invention is not limited to this example. That is, all the aspects or modifications other than the embodiments are included in the scope of the technical idea of the present invention.

(Example 1)

An indium plate was used for the anode, a stainless steel plate was used for the cathode, and an aqueous solution of ammonium nitrate was used as the electrolytic solution to precipitate a hydroxide by electrolysis. The electroconductivity of the electrolytic solution at this time was set to 10 mS/cm for electrolysis, and as a result, the current efficiency was 95%.

Further, the hydroxide was filtered and washed with pure water until the conductivity of the cleaning liquid became 0.1 mS/cm. Thereafter, it is dried to become indium oxide, and further sintered at 1500 ° C to obtain a relative density of 98%. Indium sintered body.

Further, this case is an example in which indium is used in the anode and indium hydroxide is precipitated by electrolysis, and an indium alloy such as indium-tin is used to make a compound containing indium hydroxide (for example, indium hydroxide and tin hydroxide). The same result can be obtained when the mixture is precipitated.

In other words, the indium hydroxide or the indium hydroxide-containing compound obtained in any case was washed, whereby the relative density was improved, and the conductivity was determined as a parameter and the controllable condition was the conductivity of the cleaning liquid.

(Example 2)

Electrolysis was carried out by replacing the conductivity of the electrolytic solution of Example 1 with 100 mS/cm. The current efficiency in this case is 99%. Thereafter, repulp washing was performed using pure water until the conductivity of the cleaning liquid became 0.01 mS/cm. Sintering was carried out under the same conditions as in Example 1, and as a result, a high-density sintered body having a sintered body having a relative density of 99.5% was obtained.

Further, this case is an example in which indium is used in the anode and indium hydroxide is precipitated by electrolysis, and a compound containing indium hydroxide (for example, a mixture of indium hydroxide and tin hydroxide) is used by using an indium alloy such as indium-tin. The same result can be obtained when the situation is precipitated.

In the same manner as in the case of the first embodiment, the indium hydroxide or the compound containing indium hydroxide was washed, whereby the relative density was improved, and the conductivity of the cleaning liquid was confirmed to be the index.

(Comparative Example 1)

Electrolysis was carried out by replacing the conductivity of the electrolytic solution of Example 1 with 8.0 mS/cm. As a result, oxygen is generated from the anode plate and hydrogen is generated from the cathode plate. Gas, so the current efficiency is about 80%, poor. Since the indium hydroxide which is the level of the sintering raw material cannot be produced, the subsequent steps are terminated.

(Comparative Example 2)

Electrolysis was carried out by replacing the conductivity of the electrolytic solution of Example 1 with 50 mS/cm. The current efficiency was 99%, which was good. Thereafter, the hydroxide was repulped and washed with pure water until the conductivity of the cleaning liquid became 2 mS/cm. Sintering was carried out under the same conditions as in Example 1. As a result, the sintered density was 95%, which was poor, and a part of the sintered body was cracked. It is considered that it is a result of insufficient washing of the precipitated indium hydroxide.

Further, this case is an example in which indium is used in the anode and indium hydroxide is precipitated by electrolysis, and a compound containing indium hydroxide (for example, a mixture of indium hydroxide and tin hydroxide) is used by using an indium alloy such as indium-tin. The same result is obtained when the situation is precipitated.

(Comparative Example 3)

Electrolysis was carried out by replacing the conductivity of the electrolytic solution of Example 1 with 1 mS/cm. As a result, the current efficiency is 50%, which is extremely poor. However, the precipitated hydroxide was repulped and washed with pure water until the conductivity of the cleaning liquid became 0.01 mS/cm.

Then, sintering was carried out under the same conditions as in Example 1, and as a result, the sintered density was 99%. Since the current efficiency at the time of electrolysis was inferior, it was not a usable condition in actual operation, but it was confirmed that the cleaning of indium hydroxide has an effect of improving the sintered density.

In addition, this case is an example in which indium is used in the anode and indium hydroxide is precipitated by electrolysis, and an indium alloy such as indium-tin is used to contain indium hydroxide. The same result is obtained when a compound such as a mixture of indium hydroxide and tin hydroxide is precipitated.

(Example 3)

In the electrolysis step of producing indium hydroxide (In(OH) ₃ ) from metal indium (In), a metal indium as a raw material is cast, and an anode plate made of metal indium is produced and placed in an electrolytic bath. In the electrolytic cell, cathode plates composed of a stainless steel plate or a titanium plate are alternately arranged. A plurality of the anode plates and the cathode plates are arranged in parallel. The electrolyte is supplied to the electrolytic cell. The electrolytic solution was started to electrolyze using an aqueous solution of ammonium nitrate (NH ₄ NO ₃ ).

Next, indium hydroxide particles were precipitated in the electrolytic solution, and electrolysis was stopped at a stage where the anode plate became 80% of the initial weight. The used anode plate is then removed to melt the used anode plate. At the time of the melting, the new indium metal was replenished and cast, and the anode plate was remade.

Using this reconstituted indium metal anode plate, electrolysis is started again, and indium hydroxide particles can be precipitated into the electrolytic solution. The reconstituted anode plate can be used in the same step to achieve a stage of 20% to 80% of the initial weight of the anode. After use, the electrolytic anode can be regenerated by the same method.

After the electrolysis, the indium hydroxide slurry deposited in the electrolytic solution is appropriately taken out, and the slurry is concentrated to separate into a solid content concentrate liquid and a solid content component thin liquid. Then, the solid content component thin liquid is dispensed to the above-described electrolyte supply nozzle. Further, the solid content concentrate is filtered, and the filtrate is distributed to the electrolytic solution supply nozzle, and the filtered solid matter is dried to obtain an indium hydroxide powder.

(Example 4)

In the same manner as in Example 1, the indium hydroxide particles were deposited in the electrolytic solution, and the electrolysis was stopped at the stage where the anode plate became 20% of the initial weight. Re-production was carried out in the same manner as in the first embodiment, and electrolysis was started. The reconstituted anode plate is used up to 50% of the initial weight of the anode. After use, the electrolytic anode was regenerated by the same method.

After the electrolysis, the indium hydroxide slurry deposited in the electrolytic solution is appropriately taken out, and the slurry is concentrated to separate into a solid content concentrate liquid and a solid content component thin liquid. Then, the solid content component thin liquid is dispensed to the above-described electrolyte supply nozzle. Further, the solid content concentrate is filtered, and the filtrate is distributed to the electrolytic solution supply nozzle, and the filtered solid matter is dried to obtain an indium hydroxide powder.

(Example 5)

In the same manner as in Example 1, the indium hydroxide particles were deposited in the electrolytic solution, and the electrolysis was stopped at the stage where the anode plate became 60% of the initial weight. Then, the used anode plate is taken out and melted, and new indium metal is added during melting.

Electrolysis was started using the reworked anode plate. The reconstituted anode plate was used up to 30% of the initial weight of the anode. After use, the electrolytic anode was regenerated by the same method.

After the electrolysis, the indium hydroxide slurry deposited in the electrolytic solution is appropriately taken out, and the slurry is concentrated to separate into a solid content concentrate liquid and a solid content component thin liquid. Then, the solid content component thin liquid is dispensed to the above-described electrolyte supply nozzle. Further, the solid content concentrate is filtered, and the filtrate is distributed to the electrolyte supply nozzle, and the filter is filtered. The solid matter is dried to prepare an indium hydroxide powder.

(Comparative Example 4)

In the electrolysis step of producing indium hydroxide (In(OH) ₃ ) from metal indium (In), a metal indium as a raw material is cast, and an anode plate made of metal indium is produced and placed in an electrolytic bath. In the electrolytic cell, cathode plates composed of a stainless steel plate or a titanium plate are alternately arranged. A plurality of the anode plates and the cathode plates are arranged in parallel. The electrolyte is supplied to the electrolytic cell. An aqueous solution of ammonium nitrate (NH ₄ NO ₃ ) was used as the electrolytic solution.

In order to increase the production efficiency of electrolysis, it is intended to continue to be about 15% of the initial weight of the anode. In the middle of the electrolysis, a large amount of indium coarse particles are generated in the indium anode plate and the stainless steel cathode plate, and the anode plate and the cathode plate are short-circuited due to the coarse particulate impurities. Perform electrolysis.

In the anode plate made of indium metal, since the impurities are concentrated, the voltage rises and the impurities are eluted. As a result, impurities are mixed into the indium hydroxide to cause a problem that the purity in the electrolytic solution is deteriorated.

(Comparative Example 5)

Since the impurity concentration of the anode is high, the electrolysis is stopped at a time point of about 85% of the initial weight of the anode. The obtained hydroxide has no problem in terms of purity and the like, but a large amount of impurities are concentrated on the surface of the anode, and if electrolysis is continued, a difference in quality of indium hydroxide is caused.

(Comparative Example 6)

In order to increase the production efficiency of electrolysis, it is desired to proceed to about 5% of the initial weight of the anode. In the middle of the electrolysis, on the part of the anode plate A hole is formed, the anode falls off in the bath, the device is damaged, and electrolysis cannot be continued.

Moreover, the difference in the quality of the completed hydroxide is large and cannot be used.

(Example 6)

Indium hydroxide was precipitated by electrolysis using the apparatus shown in Fig. 4 described above. Specifically, in the electrolytic cell, 11 sets of stainless steel cathode plates of 1000 mm × 700 mm × 5 mmt and 10 sets of 1000 mm × 700 mm × 50 mmt anode plates made of indium as raw materials are alternately arranged in 10 groups, and the cathode plates are alternately arranged. 50 mm between the anode plate and the anode plate and the anode plate at a position near the lower end of the side (1000 mm from the liquid surface), and the electrolyte is supplied to the other side of the cathode plate and the anode plate. Nozzle.

Then, the electrolyte is refluxed in the direction indicated by the arrow on the right side of FIG. 4, and the electrolyte flowing out from the opening of the nozzle is recirculated between the cathode plates and the anode plate in the electrolytic cell to make indium hydroxide. Precipitated into the electrolyte. The flow strength of the electrolyte (electrolyte supply rate) was set to 0.1 L. m ² /A (ampere). Minute. As shown in Fig. 4, the liquid flow is performed to rotate from the bottom to the top.

It can be seen that, according to the direction of the reflow shown in FIG. 4, a missing portion of the electrolyte flow is not generated between the cathode plate and the anode plate, but an overall uniform reflux (spin reflow) is produced. As a result, adhesion of indium hydroxide to the anode plate or electrodeposition of indium to the cathode plate can be suppressed. No such adhesion or electrodeposition was observed on all sides of the cathode and anode plates.

In addition, this case is an example in which indium is used in the anode and indium hydroxide is precipitated by electrolysis, and an indium alloy such as indium-tin is used to contain indium hydroxide. The same phenomenon can also be obtained when the compound is precipitated. The same applies to the following examples.

(Example 7)

The flow strength (electrolyte supply rate) of the electrolytic solution was set to 10 L in the same manner as in Example 1. m ² /A. Minute. In this case, in the same manner as in the first embodiment, the electrodeposition of indium to the cathode plate or the adhesion of indium hydroxide to the anode plate can be suppressed. This electrodeposition or adhesion was not observed on all sides of the cathode and anode plates.

(Example 8)

The flow strength (electrolyte supply rate) of the electrolytic solution was set to 0.01 L in the same manner as in Example 1. m ² /A. Minute. In this case, although indium is partially formed by electrodeposition of the cathode plate or adhesion of indium hydroxide to the anode plate, it is not unusable.

(Example 9)

The flow strength (electrolyte supply rate) of the electrolytic solution was set to 50 L in the same manner as in Example 1. m ² /A. Minute. In this case, the coarse particles of indium hydroxide are slightly peeled off from the anode, but can be used.

(Embodiment 10)

The flow strength (electrolyte supply rate) of the electrolytic solution was set to 100 L in the same manner as in Example 1. m ² /A. Minute. In this case, at the anode, a part of the coarse particles of indium hydroxide are partially peeled off, and a small amount of fine hydroxide (the average particle diameter after calcination at 1100 ° C is 0.5 μm or less) is generated. However, this is not a big problem in itself and can be used.

(Example 11)

Indium hydroxide was precipitated by electrolysis using a device as shown in FIG. Specifically, the same anode and cathode as in Example 1 were used, and the position near the lower end of one side edge between the cathode plate and the anode plate and between the cathode plates and the anode plate (1000 mm from the liquid surface) was used. And a lower nozzle and an upper nozzle for supplying electrolyte to the other side edges of the cathode plate and the anode plate at a position of 155 mm from the liquid surface.

Then, the two electrolytes are reflowed in the direction indicated by the arrow in the right side of FIG. 6, and the electrolyte flowing out from the openings of the lower nozzle and the upper nozzle is placed in each of the cathode and anode plates in the electrolytic cell. The aluminum hydroxide was refluxed to precipitate indium hydroxide into the electrolyte. The flow strength of the electrolyte (electrolyte supply rate) was set to 10 L. m ² /A. Minute. As shown in Fig. 6, the liquid flow is caused by the two types of rotation from the center to the center and from the center to the center.

It can be seen that, according to the direction of the reflow shown in Fig. 6, the missing portion of the electrolyte flow is not generated at a specific position of the cathode plate and the anode plate, but an overall uniform reflux (spin reflow) is produced. The main difference from the first embodiment is that an upper nozzle is provided at a position 155 mm from the liquid surface. As a result, the electrodeposition of indium to the cathode plate or the adhesion of indium hydroxide to the anode plate can be suppressed. This electrodeposition or adhesion was not observed on all sides of the cathode and anode plates.

Further, as shown in the schematic diagram of the liquid flow in Fig. 8, in the same manner as in the second embodiment, the nozzles arranged in two stages were used, and the nozzles of the upper stage were placed at a position 322 mm from the liquid surface, and the same experiment as in the second embodiment was carried out. As a result, the same results as in Example 2 were obtained.

(Embodiment 12)

Indium hydroxide was precipitated by electrolysis using a device as shown in FIG. Specifically, the same anode and cathode as in Example 1 were used, and the position between the cathode plate and the anode plate and the lower end of one side of each of the cathode plate and the anode plate (position 1000 mm from the liquid surface), The lower nozzle, the intermediate nozzle, and the upper nozzle that supply the electrolyte to the other side edges of the cathode plate and the anode plate are disposed at a position 322 mm from the liquid surface and a position near the upper end (a position 155 mm from the liquid surface).

Then, the three electrolytes are reflowed in the direction indicated by the arrow on the right side of FIG. 9, and the electrolyte flowing out from the openings of the lower nozzle, the intermediate nozzle, and the upper nozzle is placed in each of the cathode and anode plates in the electrolytic cell. The aluminum hydroxide was refluxed to precipitate indium hydroxide into the electrolyte. The flow strength of the electrolyte (electrolyte supply rate) was set to 10 L. m ² /A. Minute. The flow is caused to flow in three ways: from top to bottom from the upper nozzle, from the upper nozzle to the upper and lower branches, and from the lower nozzle from bottom to top.

It can be seen that, according to the direction of the reflow shown in Fig. 9, the missing portion of the electrolyte flow does not occur in the central portion of the cathode plate and the anode plate, but an overall uniform reflux (spin reflow) occurs. The main difference from the second embodiment is that the opening of the intermediate nozzle is disposed at a position 322 mm from the liquid surface. In this case, the electrodeposition of the indium plate or the indium hydroxide on the anode plate can also be suppressed. Attached. This electrodeposition or adhesion was not observed on all sides of the cathode and anode plates.

(Comparative Example 7)

Using an apparatus as shown in Fig. 3, an electrolytic solution was introduced from the liquid surface on one side of the electrolytic cell, and indium hydroxide was precipitated by electrolysis. Specifically, the same anode and cathode as in Example 1 were used. The electrolyte supply speed of the electrolyte is set to 0.5L. m ² /A. Minute. As a result, indium hydroxide is largely attached to the anode plate, and indium is also deposited on the cathode plate, and electrolysis becomes difficult.

(Comparative Example 8)

Using the device shown in Figure 3, the electrolyte supply rate was set to 10L. m ² /A. Electrolysis is carried out. As a result, indium hydroxide adheres to the anode plate, and electrodeposition of indium to the cathode plate is produced. The adhesion or electrodeposition is mainly generated in the substantially central portion and the lower portion of the cathode plate and the anode plate. Even if the flow strength (electrolyte supply rate) of the electrolytic solution is made larger than the above value, the same result is obtained.

(Comparative Example 9)

Using an electrolysis apparatus, an electrolytic solution was introduced from one portion of the bottom of one side of the electrolytic cell in accordance with Fig. 3, and indium hydroxide was precipitated by electrolysis. In this case, a nozzle is not disposed between each of the cathode plate and the anode plate, and the electrolytic solution is reflowed between the plates, and the electrolyte is supplied from a portion (one portion) of the bottom of the electrolytic cell only in the same manner as in Fig. 3 . . Set the electrolyte supply speed to 0.5L. m ² /A. Minute.

As a result, indium hydroxide adheres to the anode plate, and electrodeposition of indium to the cathode plate is produced. The adhesion or electrodeposition is mainly generated at a substantially central portion of the cathode plate and the anode plate. Even if the flow strength (electrolyte supply rate) of the electrolytic solution is made larger than the above value, the same result is obtained.

(Comparative Example 10)

Under the same conditions as in Example 1, the electrolyte supply rate was set to 0.009 L. m ² /A. Minute. As a result, indium hydroxide adheres to the anode plate in a large amount, and indium is electrodeposited on the cathode plate, causing the anode and the cathode to be short-circuited, and it is difficult to continue electrolysis. The adhesion or electrodeposition is mainly generated at a substantially central portion of the cathode plate and the anode plate.

(Comparative Example 11)

Under the same conditions as in Example 1, the electrolyte supply rate was set to 110 L. m ² /A. Minute. As a result, no adhesion of indium hydroxide to the anode plate or electrodeposition of indium to the cathode plate was produced, but the coarse particles of indium were largely peeled off from the anode, and a large amount of fine hydroxide was produced (after calcination at 1100 ° C) The average particle diameter is 0.5 μm or less) and cannot be used.

[Industrial availability]

The present invention relates to a method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, wherein electrolysis is performed by setting the conductivity of the electrolytic solution to 10 mS/cm or more to cause indium hydroxide or a compound containing indium hydroxide The precipitated indium hydroxide or the compound containing indium hydroxide is washed until the conductivity of the cleaning liquid is 1 mS/cm or less, thereby suppressing deterioration in productivity or deterioration in quality. The effect is therefore useful for the production of an ITO target for sputtering such as an ITO film.

Further, in the present invention, the cathode plate and the anode plate of the indium metal as a raw material are alternately arranged in an electrolytic cell, and an electrolytic solution is supplied between the cathode plate and the anode plate to produce indium hydroxide by electrolysis. In the method of powder, the indium hydroxide particles are precipitated into the electrolytic solution, and the electrolysis is stopped at a stage where the anode plate immersed in the electrolytic solution becomes 20% to 80% of the initial weight, and the used anode plate is taken out to make the use. After the anode plate is melted and replenished with indium metal and cast, the anode plate is re-made, and the re-made yang is used. Electrolysis is started in the electrode plate to precipitate indium hydroxide particles in the electrolytic solution. As a result, adhesion due to the production method of the indium hydroxide powder due to electrolysis can be suppressed, and indium metal can be prevented from being formed on the surface of the cathode, thereby suppressing Reduced productivity. This method is useful for the production of an ITO target for sputtering of an ITO film.

Further, the present invention relates to a method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, which is a method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, characterized in that: The cathode plate is alternately arranged with the anode plate of the indium or indium alloy as a raw material in an electrolytic cell, and is disposed between the cathode plate and the anode plate and adjacent to one side edge of each of the cathode plate and the anode plate. Providing a nozzle for supplying an electrolyte to the other side edge of the cathode plate and the anode plate, and adjusting the flow of the electrolyte flowing out from the opening of the nozzle to make the cathode plate and the anode plate in the electrolytic cell The mixture is refluxed to precipitate indium hydroxide or a compound containing indium hydroxide into the electrolytic solution. When indium hydroxide or a compound containing indium hydroxide is produced by an electrolytic method, it is possible to prevent indium hydroxide or a compound containing indium hydroxide from adhering to the surface of the anode, and to prevent formation of indium or an indium alloy on the surface of the cathode. This has an excellent effect of suppressing a decrease in productivity, and therefore is useful for the production of an ITO target for sputtering of an ITO film.

Fig. 1 is a view showing the flow of an electrolysis step of producing indium hydroxide from indium.

Fig. 2 is a view showing a state in which impurities are concentrated on the surface of an indium anode plate in the case where the current density is increased in order to increase the production efficiency of electrolysis.

3 is an arrangement in which an anode plate and a cathode plate are spaced apart from each other in an electrolytic cell, and a supply port of a nozzle for supplying an electrolytic solution is disposed in an upper portion of the electrolytic cell to supply an electrolyte solution to the electrolytic cell. A schematic illustration of the electrolysis unit.

4 is an arrangement in which an anode plate and a cathode plate are spaced apart from each other in an electrolytic cell, and a supply port of a nozzle for supplying an electrolyte is disposed on a lower side of the electrolytic cell and is a cathode plate and an anode. A schematic illustration of an electrolysis device for recirculating electrolyte in an electrolytic cell with one side edge between the plates.

Fig. 5 is a view schematically showing a flow of liquid when the apparatus of Fig. 4 is used.

6 is an arrangement in which an anode plate and a cathode plate are spaced apart from each other in an electrolytic cell, and a supply port of a two-stage nozzle for supplying an electrolytic solution is disposed on a lower side and an upper side of the electrolytic cell and is each A schematic view of an electrolysis apparatus for returning an electrolyte solution to an electrolytic cell by a side edge between the cathode plate and the anode plate.

Fig. 7 is a view schematically showing a flow of liquid when the apparatus of Fig. 6 is used.

Fig. 8 is a view schematically showing a flow of a liquid in the case of using a device for changing the position of the upper nozzle of Fig. 7.

9 is an arrangement in which an anode plate and a cathode plate are arranged at intervals in an electrolytic cell, and a supply port of a three-stage nozzle for supplying an electrolytic solution is disposed in a lower side, a middle position, and an upper side of the electrolytic cell; A schematic view of an electrolysis apparatus for refluxing an electrolytic solution in an electrolytic cell for one side edge between each of the cathode plate and the anode plate.

Fig. 10 is a view schematically showing a flow of liquid when the apparatus of Fig. 9 is used.

Claims (17)

A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, which is a method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, characterized in that the conductivity of the electrolyte is Electrolysis is performed at 10 mS/cm or more, and indium hydroxide or a compound containing indium hydroxide is precipitated in the electrolytic solution, and the precipitated indium hydroxide or the compound containing indium hydroxide is washed until the conductivity of the cleaning liquid becomes 1 mS/cm or less. A method for producing an indium hydroxide or a compound containing indium hydroxide by electrolysis according to the first aspect of the patent application, wherein the conductivity of the cleaning solution which is washed to precipitated indium hydroxide or a compound containing indium hydroxide is 0.1 mS/cm or less. A method for producing an indium hydroxide powder by electrolysis, which is a method for producing an indium hydroxide powder by electrolysis, characterized in that an indium hydroxide particle is precipitated from an anode into an electrolytic solution at a weight of an anode plate The electrolysis is stopped at a stage of 20% to 80% of the initial weight of the anode, and the used anode plate is taken out, the used anode plate is melted and indium metal is replenished and cast, thereby re-forming the anode plate, and the re-made anode is used. The plate begins to electrolyze, and the indium hydroxide particles are precipitated into the electrolyte. A method for producing an indium hydroxide powder by electrolysis according to the third aspect of the patent application, wherein the electrolysis is carried out using a stainless steel plate or a titanium plate as a cathode plate. A method for producing an indium hydroxide powder by electrolysis according to claim 3 or 4, further comprising the steps of: taking out the precipitate a step of concentrating the indium hydroxide slurry in the electrolyte; concentrating the slurry to separate into a solid content component concentrate and a solid content component thin liquid; and dispensing the solid matter component thin liquid to the electrolyte supply nozzle step. a method for producing an indium hydroxide powder by electrolysis according to the fifth aspect of the patent application, comprising the steps of: filtering the solid component concentrate, and distributing the filtrate to the electrolyte supply nozzle; And the step of drying the filtered solid matter to form an indium hydroxide powder. An apparatus for electrolytically producing indium hydroxide or a compound containing indium hydroxide, which is an apparatus for producing indium hydroxide or a compound containing indium hydroxide by an electrolytic method, characterized in that a cathode plate is used in an electrolytic bath The anode plates of the indium or indium alloy of the raw materials are alternately arranged at intervals, and between the cathode plate and the anode plate and adjacent to one side edge of each of the cathode plate and the anode plate, a cathode plate and an anode plate are disposed. The other side edge is supplied with a nozzle for the electrolyte, and the electrolyte flowing out from the opening of the nozzle is recirculated between the cathode plates and the anode plate in the electrolytic cell to precipitate indium hydroxide or a compound containing indium hydroxide to the electrolysis. In the liquid. An electrolytic manufacturing apparatus of indium hydroxide or a compound containing indium hydroxide according to item 7 of the patent application, wherein the cathode plate is a stainless steel plate or a titanium plate. An electrolytic manufacturing apparatus of indium hydroxide or a compound containing indium hydroxide according to claim 7 or 8, wherein one or a plurality of side edges from each of the cathode plates and the anode plates are disposed to the other side The nozzle for supplying the electrolyte causes the electrolyte flowing out from the opening of the nozzle to flow back between the cathode plates and the anode plate in the electrolytic cell to make indium hydroxide or contain indium hydroxide The compound is precipitated into the electrolyte. An electrolytic manufacturing apparatus for indium hydroxide or an indium hydroxide-containing compound according to any one of claims 7 to 9, which has an apparatus for taking out indium hydroxide or indium hydroxide deposited in an electrolytic solution. A device for concentrating the hydroxide, separating the solid content component concentrate and the solid content component thin liquid; and dispersing the solid content component thin liquid to the electrolyte supply nozzle. An apparatus for electrolytically producing indium hydroxide powder according to claim 10, comprising: filtering the solid component concentrate, distributing the filtrate to the electrolyte supply nozzle; and performing the filtered solid matter A device for drying, producing an indium hydroxide powder or a compound powder containing indium hydroxide. A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, which is a method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis, characterized in that a cathode is provided in an electrolytic cell The plate is alternately arranged at intervals from the anode plate of the indium or indium alloy as a raw material, and is disposed adjacent to the lower end of the side edge of one of the cathode plate and the anode plate, and is disposed toward the cathode plate and the anode. The other side of the plate is supplied with a nozzle for the electrolyte, and the liquid flow of the electrolyte flowing out from the opening of the nozzle is adjusted to be refluxed between the cathode plate and the anode plate in the electrolytic cell to make indium hydroxide Or a compound containing indium hydroxide is precipitated into the electrolyte. A method for producing an indium hydroxide or a compound containing indium hydroxide by electrolysis, as in claim 12, wherein stainless steel is used. The steel plate or the titanium plate is electrolyzed as a cathode plate. A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis according to claim 12 or 13, wherein one or a plurality of side edges from each of the cathode plates and the anode plate are disposed The other side of the nozzle for supplying the electrolyte adjusts each liquid flow of the electrolyte flowing out from the opening of the nozzle to recirculate between the cathode plate and the anode plate in the electrolytic cell to make indium hydroxide or A compound containing indium hydroxide is precipitated into the electrolytic solution. A method for producing indium hydroxide or a compound containing indium hydroxide by electrolysis according to any one of claims 12 to 14, further comprising the step of: taking out indium hydroxide deposited in the electrolytic solution Or a step of containing a compound of indium hydroxide; a step of concentrating the hydroxide to separate a solid component concentrate and a solid component thinner; and dispensing the solid component diluent to the electrolyte supply nozzle. A method for producing an indium hydroxide powder or a compound powder containing indium hydroxide by electrolysis according to the fifteenth aspect of the patent application, comprising the steps of: filtering the solid component concentrate, and distributing the filtrate to The step of supplying the electrolyte to the nozzle; and the step of drying the filtered solid to form an indium hydroxide powder or a compound powder containing indium hydroxide. The method for producing indium hydroxide or a compound containing indium hydroxide according to any one of claims 12 to 16, wherein the supply rate of the electrolyte is 0.01 to 100.0 L for the current value, the electrolysis area, and the time. m ² /A. The way the electrolyte flows.