JP6201193B2 - Electrolytic apparatus for indium hydroxide powder or tin hydroxide powder, method for producing indium hydroxide powder or tin hydroxide powder, and method for producing sputtering target - Google Patents

Description

  The present invention relates to an electrolysis apparatus for indium hydroxide powder or tin hydroxide powder, a method for producing indium hydroxide powder or tin hydroxide powder, and a method for producing a sputtering target. In particular, an indium hydroxide powder or tin hydroxide powder electrolyzer capable of producing indium hydroxide powder or tin hydroxide powder having a narrow particle size distribution, and production of indium hydroxide or tin hydroxide using the electrolyzer The present invention relates to a method and a method for producing a high-density sputtering target using indium hydroxide powder and / or tin hydroxide powder.

  In recent years, the use of transparent conductive films has been increasing for applications such as solar cells and touch panels, and accordingly, the demand for materials for forming transparent conductive films in sputtering targets and the like has increased. As a material for forming these transparent conductive films, an indium oxide-based sintered material is mainly used, and indium oxide powder is used as the main raw material. The indium oxide powder used for the sputtering target is desirably as narrow as possible in order to obtain a high-density target.

  In the method for producing indium oxide powder, the precipitate of indium hydroxide formed by neutralizing an acidic aqueous solution such as an indium nitrate aqueous solution or an indium chloride aqueous solution with an alkaline aqueous solution such as ammonia water is mainly dried and calcined. Indium oxide is obtained by a so-called neutralization method.

  In Patent Document 1, in order to suppress aggregation of indium oxide powder obtained by the neutralization method, an alkaline aqueous solution is added to a high-temperature indium nitrate aqueous solution of 70 ° C. to 95 ° C. A method of obtaining has been proposed. In this method, indium oxide powder with little aggregation can be obtained by calcining acicular indium hydroxide.

  However, the indium oxide powder produced by the neutralization method tends to have a non-uniform particle size and particle size distribution, and when the sputtering target is produced, the density of the target does not increase and the density varies. There is a problem that abnormal discharge tends to occur. Moreover, in the neutralization method, after producing indium oxide powder, wastewater containing a large amount of nitrogen is generated, and thus there is a problem that wastewater treatment costs increase.

  As a method for solving such a problem, Patent Document 2 discloses a method of producing indium oxide powder by precipitating indium hydroxide by electrolytically treating metal indium, and so-called electrolytic method. Has been proposed. Patent Document 3 also proposes a method of producing tin oxide powder by causing tin hydroxide to precipitate by electrolytic treatment of tin, as in Patent Document 2, and calcining this. Compared with the neutralization method, the electrolysis method can reduce the amount of nitrogen drainage after the production of indium oxide powder and tin oxide powder to a great extent, and the obtained indium oxide powder and tin oxide powder have a uniform particle size. Can be

  However, as disclosed in Patent Document 3, indium hydroxide obtained by an electrolysis method has a problem that the pH of the electrolytic solution is very neutral and is very fine and easily aggregates. Although the indium oxide powder obtained by calcining this has a relatively uniform primary particle diameter, it becomes easy to obtain an agglomerated powder in which primary particles are strongly aggregated. The electrolytic method has a problem that the density of the target is hindered because the width of the particle size distribution is widened by aggregation of the primary particles.

  Patent Document 4 discloses a method of performing electrolysis by stirring in a suspended state a precipitate containing indium hydroxide in an electrolytic solution in order to make the pH of the electrolytic solution in a tank uniform in the electrolytic method. Proposed.

  However, in Patent Document 4, it is not always easy to control the production conditions (liquid temperature, pH, etc.) constantly with the lapse of the production time, and there is a problem that various characteristics of the obtained hydroxide powder vary. is there.

  In Patent Document 5, a nozzle is arranged in an electrolytic cell, and an electrolytic solution flowing out from an opening of the nozzle is circulated between each cathode plate and an anode plate in the electrolytic cell, and indium hydroxide or hydroxide is circulated. A method for precipitating a compound containing tin in an electrolytic solution has been proposed.

  However, in Patent Document 5, it is necessary to supply the electrolytic solution at a high speed in order to circulate the electrolytic solution. Therefore, the environment around the electrolytic device is deteriorated due to volatilization of the electrolytic solution, mist scattering, and the like. There is a problem with.

  In Patent Document 6, in order to obtain a high-density ITO target material, it is necessary to align the particle diameters of indium hydroxide and tin hydroxide within a predetermined range.

  However, in the electrolytic precipitation process of Patent Document 6, it is difficult to say that a technique for obtaining indium oxide powder having a sufficiently uniform particle diameter is provided.

JP-A-4-325415 JP-A-6-171937 JP-A-6-199523 JP-A-10-204669 JP 2013-36074 A JP-A-5-193939

  In view of the above problems, the present invention provides an electrolysis apparatus for indium hydroxide powder or tin hydroxide powder that is capable of producing indium hydroxide powder or tin hydroxide powder having excellent uniformity in particle size and narrow particle size distribution. The purpose is to provide.

  Further, the present invention provides an indium hydroxide powder or a hydroxide that can produce an indium hydroxide powder or a tin hydroxide powder having excellent particle size uniformity and a narrow particle size distribution by using the above-described electrolysis apparatus. It aims at providing the manufacturing method of tin powder.

  Furthermore, this invention provides the manufacturing method of the sputtering target which can manufacture a high-density sputtering target by using the indium hydroxide powder and / or tin hydroxide powder obtained by the above-mentioned manufacturing method. For the purpose.

An electrolysis apparatus for indium hydroxide powder or tin hydroxide powder according to the present invention is an electrolysis apparatus for producing indium hydroxide powder or tin hydroxide powder by electrolyzing indium or tin, comprising an electrolytic cell and an electrolytic solution. An adjusting tank to be adjusted, a circulating means connected to the electrolytic tank and the adjusting tank and circulating the electrolytic solution, and a drainage port for overflowing the electrolytic solution from the electrolytic tank to the adjusting tank at the upper end edge of the electrolytic tank , and circulating The electrolytic solution is circulated between the electrolytic bath and the regulating bath by means, and the electrolytic bath is provided with a supply port for supplying the electrolytic solution into the bath at the bottom of the bath, and between the anode and cathode and the bath bottom. A liquid dispersion plate is provided .

  In the electrolysis apparatus for indium hydroxide powder or tin hydroxide powder according to the present invention, the volume ratio of the adjusting tank to the electrolytic tank is preferably 0.1 or more.

  The method for producing indium hydroxide powder or tin hydroxide powder according to the present invention comprises producing indium hydroxide powder or tin hydroxide powder by electrolysis using indium or tin as an anode. Then, the electrolysis apparatus is used.

  In the method for producing indium hydroxide powder or tin hydroxide powder according to the present invention, the electrolyte flow rate per electrolytic cell is preferably 0.007 L / min / A to 0.03 L / min / A.

When the anode is indium, the method for producing indium hydroxide powder according to the present invention uses an aqueous solution of ammonium nitrate of 0.1 mol / L to 2.0 mol / L as the electrolytic solution, and the pH of the electrolytic solution is 2.5 to 2.5. 4.0, the liquid temperature 20 ° C. to 60 ° C., it is preferable and for controlling the electrode current density in the range of ^{4A / dm 2 ~20A / dm 2} .

When the anode is tin, the method for producing tin hydroxide powder according to the present invention uses an aqueous 0.1 mol / L to 2.0 mol / L ammonium nitrate aqueous solution as the electrolytic solution, and adjusts the pH of the electrolytic solution to 2.5 to 2.5. 8.0, the liquid temperature 20 ° C. to 60 ° C., it is preferable and for controlling the electrode current density in the range of ^{4A / dm 2 ~20A / dm 2} .

  The manufacturing method of the sputtering target which concerns on this invention manufactures a sputtering target using the indium hydroxide powder and / or tin hydroxide powder which were obtained by the manufacturing method of the said indium hydroxide powder or tin hydroxide powder. Features.

  In the present invention, it is possible to obtain indium hydroxide powder or tin hydroxide powder having excellent particle size uniformity and narrow particle size distribution.

  According to the method for producing a sputtering target of the present invention, a high-density sputtering target can be obtained by using the indium hydroxide powder or the tin hydroxide powder.

1 is a schematic view of an electrolysis apparatus showing an embodiment of an electrolysis apparatus according to the present invention. It is the schematic which shows the state which has arrange | positioned the electrode in the electrolytic cell of the electrolysis apparatus shown in FIG.

  Hereinafter, the present invention will be described in detail with respect to specific embodiments (hereinafter referred to as “present embodiments”). Note that the present invention is not limited to the following embodiments, and can be appropriately changed without changing the gist of the present invention.

1. 1. Indium hydroxide powder or tin hydroxide powder electrolyzer 1-1. Electrolytic cell 1-2. Adjustment tank 1-3. Circulation means 2. Method for producing indium hydroxide powder or tin hydroxide powder 2-1. Electrolysis process 2-2. Electrolyte separation process 2-3. Repulp washing process 2-4. Cleaning liquid dehydration step 2-5. 2. Drying process 3. Production method of indium oxide powder or tin oxide powder Manufacturing method of sputtering target

[1. Indium hydroxide powder or tin hydroxide powder electrolyzer]
As shown in FIG. 1, an electrolysis apparatus 1 for indium hydroxide powder or tin hydroxide powder according to the present embodiment includes an electrolysis tank 10, an adjustment tank 20, and an electrolytic solution 11 in an electrolysis tank 10 and an adjustment tank 20. Circulation means 30 for circulating between them. The circulation means 30 is connected to the electrolytic cell 10 and the adjustment vessel 20, and includes a supply flow path 31 that supplies the electrolytic solution 11 from the adjustment vessel 20 to the electrolytic cell 10, and a circulation pump 32. The circulation means 30 circulates the electrolytic solution 11 between the electrolytic bath 10 and the adjustment bath 20 by the supply flow path 31 and the circulation pump 32.

(1-1. Electrolytic cell)
As shown in FIGS. 1 and 2, the electrolytic cell 10 includes an anode (anode) 12 and a cathode (cathode) 13, a liquid dispersion plate 14, a supply port 15, and a drainage port 16. The anode 12 and the cathode 13 are alternately arranged in the electrolytic cell 10. The liquid dispersion plate 14 is provided between the anode 12 and the cathode 13 and the tank bottom 17 of the electrolytic cell 10. The supply port 15 is provided in the tank bottom 17 of the electrolytic cell 10, and the drainage port 16 is provided in the tank wall 18 of the electrolytic cell 10 on the adjustment tank 20 side.

  As shown in FIG. 2, an electrolytic solution 11 is accommodated in the electrolytic cell 10, and an anode 12 and a cathode 13 are further arranged.

  The shape of the electrolytic cell 10 is not particularly limited, and may be a general rectangular parallelepiped, a cube such as a cube or the like, and is appropriately determined in consideration of the number of anodes 12 and cathodes 13 disposed in the cell. Moreover, it is preferable that the shape of the electrolytic cell 10 is rounded so that indium hydroxide powder or tin hydroxide powder can flow and local deposition does not occur.

(Anode, cathode)
The anode 12 and the cathode 13 adopt a general arrangement in which they are alternately arranged in the electrolytic cell 10 and arranged so as to be parallel to each other.

  The interelectrode distance between the anode 12 and the cathode 13 is not particularly limited, but is preferably 10 mm to 50 mm. When the interelectrode distance between the anode 12 and the cathode 13 is less than 10 mm, contact or short-circuit between the electrodes is likely to occur. On the other hand, when the distance between the electrodes exceeds 50 mm, a voltage drop due to the liquid resistance occurs and the liquid temperature rises.

  In the anode 12, indium or tin can be used as a metal. The indium used for the anode 12 is not particularly limited, but indium hydroxide powder and indium oxide powder obtained by firing the indium hydroxide powder are preferably high-purity in order to suppress contamination, and have a purity of 99.9999% ( (Common name: 6N product) is preferable. The tin used for the anode 12 is not particularly limited as in the case of the indium described above, but has a high purity so as to suppress contamination of tin hydroxide powder and tin oxide powder obtained by firing the tin hydroxide powder. Is desirable.

  The thickness of the anode 12 is preferably set such that the distance between the electrodes does not change significantly during electrolysis. Further, it is not preferable to make the anode 12 thicker than necessary due to the weight during handling.

  The cathode 13 may be made of any material that does not corrode by the electrolytic solution 11, and a conductive metal, a carbon electrode, or the like can be used. For example, insoluble titanium or platinum can be used for the cathode 13, and an insoluble electrode or stainless steel (SUS) plate in which titanium is coated with platinum may be used.

  When the anode 12 is indium, the cathode 13 may be indium which is the same material as the anode 12. When the anode 12 is tin, the cathode 13 may be tin that is the same material as the anode 12.

  The sizes of the anode 12 and the cathode 13 can be appropriately determined according to the production scale, and may be appropriately determined so as to meet the target production amount.

  For example, as shown in FIG. 2, four anodes 12 and five cathodes 13 are prepared and installed so that the distance between the electrode centers is a predetermined distance. Then, the anode 12 and the cathode 13 can be connected by a conducting wire 19 and connected to a rectifier (not shown).

(Liquid dispersion plate)
As shown in FIG. 2, the liquid dispersion plate 14 is provided between the anode 12 and the cathode 13 disposed in the electrolytic cell 10 and the cell bottom 17.

  The liquid dispersion plate 14 can be produced by pressing a thin plate made of a metal or alloy such as copper, iron, nickel, and stainless steel using a predetermined mold. The size of the liquid dispersion plate 14 can be appropriately changed so as to match the electrolytic cell 10.

  The liquid dispersion plate 14 has holes 14a that are open at predetermined equal intervals in a grid pattern, and is provided at a position facing at least the gap between the anode 12 and the cathode 13. Further, the number and size of the holes 14a in the liquid dispersion plate 14 can be changed as appropriate. Thereby, in the electrolytic cell 10, the electrolytic solution 11 supplied from the supply port 15 of the electrolytic cell 10 by the circulation means 30 spreads between the liquid dispersion plate 14 and the tank bottom 17 and passes through the hole 14 a of the liquid dispersion plate 14. Then, the gap between the anode 12 and the cathode 13 flows from the tank bottom 17 toward the liquid level in parallel with the anode 12 and the cathode 13, and a substantially uniform liquid flow without uneven flow can be secured. Examples of the liquid dispersion plate 14 include a punch plate.

  The liquid dispersion plate 14 is preferably provided in parallel to the tank bottom 17 at a predetermined height from the tank bottom 17 of the electrolytic cell 10. This is because when the electrolytic solution 11 is jetted from the supply port 15 to the entire electrolytic cell 10, the supplied electrolytic solution 11 is dispersed and the electrolytic solution 11 is uniformly jetted into the electrolytic cell 10.

(Supply port)
Although the position of the supply port 15 is not limited, it is preferably provided at the tank bottom 17 of the electrolytic cell 10, particularly at the center of the tank bottom 17. The shape of the supply port 15 can be appropriately changed depending on the shape of the tip of the supply flow path 31 to be connected, and is not particularly limited.

  The supply port 15 is for supplying the electrolytic solution 11 from the adjustment tank 20 to the electrolytic tank 10 via the supply flow path 31.

(Drainage)
The drainage port 16 is the entire upper edge of the tank wall 18 of the electrolytic cell 10. That is, when the upper end edge of the tank wall 18 becomes the drainage port 16, the electrolyte solution 11 can get over the upper end edge of the tank wall 18, and the electrolyte solution 11 can overflow from the electrolytic tank 10 to the adjustment tank 20.

  The drain port 16 may be provided by cutting out a part of the tank wall 18 at the center of the upper edge of the tank wall 18 on the adjustment tank 20 side. By setting it as such a structure, the electrolyte solution 11 can flow from the electrolytic vessel 10 to the adjustment tank 20, and can be overflowed from a notch part. The drainage port 16 provided by cutting out can stabilize the flow amount of the electrolyte solution 11 as compared with the case of overflowing from the entire upper end edge of the tank wall 18.

  The shape of the notch may be, for example, a square shape such as a U shape or a rectangular shape, and is not particularly limited.

(1-2. Adjustment tank)
As shown in FIG. 1, the adjustment tank 20 includes a stirring rod 21, a pH electrode 22, a heater 23 and a cooler 24, a chemical liquid tank 25, a chemical liquid addition metering pump 26, and a liquid feeding port 27. .

  The adjustment tank 20 accommodates the electrolytic solution 11 in order to adjust the pH and temperature of the electrolytic solution 11 after electrolysis.

  The shape of the adjustment tank 20 is not particularly limited, and may be a general rectangular parallelepiped, a cube such as a cube, and the like, and is appropriately determined in consideration of various devices arranged in the tank. The shape of the adjustment tank 20 is preferably rounded so that, for example, indium hydroxide powder or tin hydroxide powder can flow and local deposition does not occur.

  As for the adjustment tank 20, it is preferable that the volume ratio of the adjustment tank 20 with respect to the electrolytic cell 10 is 0.1 or more. Furthermore, as for the adjustment tank 20, it is more preferable that the volume ratio of the adjustment tank 20 with respect to the electrolytic cell 10 is 1 or more. When the volume ratio of the adjusting tank 20 to the electrolytic tank 10 is less than 0.1, it is difficult to uniformly control the pH and the liquid temperature, so that the particle size distribution of the indium hydroxide powder or the tin hydroxide powder becomes wide.

  As shown in FIG. 1, the electrolysis apparatus 1 is one in which an electrolytic cell 10 and an adjustment tank 20 are integrated. This is only one embodiment, and the electrolytic cell 10 and the adjustment tank 20 are separate, and the electrolytic cell 10 and the adjustment tank 20 are adjusted so that the electrolytic solution 11 can overflow from the electrolytic cell 10 to the adjustment tank 20. The tank 20 can also be adjacent.

  The electrolytic solution 11 overflowed from the drainage port 16 of the electrolytic cell 10 is adjusted in pH and liquid temperature in the adjustment tank 20, and is supplied again into the electrolytic cell 10 through the supply channel 31 by the circulation pump 32. The In the adjustment tank 20, when the control and maintenance regarding the pH and the liquid temperature of the electrolytic solution 11 are not appropriately performed, the pH and the liquid temperature of the electrolytic solution 11 in the entire electrolytic tank 10 are set to the passage of the energization time by electrolysis. Change with. Thereby, the particle size distribution of the produced hydroxide indium powder or tin hydroxide powder becomes wide.

(Stir bar)
The stirring rod 21 is installed in the adjustment tank 20, and the pH and liquid temperature of the entire electrolytic solution 11 are made uniform by stirring the electrolytic solution 11.

(PH electrode)
The pH electrode 22 is installed in the adjustment tank 20 and measures the pH of the electrolytic solution 11 in the adjustment tank 20.

(Heater, cooler)
The heater 23 and the cooler 24 are installed in the adjustment tank 20, and the electrolyte solution 11 is heated or cooled to control and maintain a predetermined solution temperature.

(Chemical tank, metering pump)
The chemical liquid tank 25 and the metering pump 26 are installed adjacent to the adjustment tank 20 so that the chemical liquid can be supplied to the adjustment tank 20. The chemical tank 25 contains a pH adjuster. When adjusting the pH, the adjustment tank 20 adjusts the pressure of the metering pump 26 to adjust the amount of 1N nitric acid in the chemical solution tank 25 added to the electrolyte solution 11, thereby adjusting the pH of the electrolyte solution 11.

(Liquid feeding port)
Although the position of the liquid feeding port 27 is not limited, it is preferable that the liquid feeding port 27 is provided in the central portion of the tank bottom 28 of the adjustment tank 20. The shape of the liquid feeding port 27 can be appropriately changed depending on the shape of the tip of the supply flow path 31 and is not particularly limited.

  The liquid supply port 27 connects the adjustment tank 20 and the supply flow path 31 and allows the electrolytic solution 11 to be supplied from the adjustment tank 20 to the supply flow path 31.

(1-3. Circulation means)
The circulation means 30 includes a supply flow path 31 for supplying the electrolytic solution 11 from the adjustment tank 20 to the electrolytic tank 10, and a circulation pump 32. The circulation pump 32 is provided in the supply flow path 31. The supply flow path 31 connects the electrolytic bath 10 and the adjustment bath 20. The circulation means 30 circulates the electrolytic solution 11 between the electrolytic bath 10 and the adjustment bath 20 by the supply flow path 31 and the circulation pump 32.

  The supply flow path 31 is a pipe for supplying the electrolyte solution 11 and is a pipe made of a material that is not corroded by the electrolyte solution 11. The supply flow path 31 is connected to the supply port 15 installed at the tank bottom 17 of the electrolytic cell 10 and the liquid supply port 27 installed at the tank bottom 28 of the adjustment tank 20 at the end of the piping. The supply channel 31 is provided below the electrolysis apparatus 1, and the end on the supply port 15 side is perpendicular to the tank bottom 17. In the electrolysis apparatus 1, since the supply flow path 31 is connected perpendicularly to the tank bottom 17, the electrolytic solution 11 can be jetted from the tank bottom 17 toward the liquid surface.

  The circulation pump 32 feeds the electrolytic solution 11 whose pH and liquid temperature are adjusted in the regulating tank 20 from the feeding port 27 to the supply flow path 31, and enters the tank from the feeding port 15 on the tank bottom 17 of the electrolytic tank 10. Send it out.

  In the circulation means 30, the electrolytic solution 11 in which the pH and the liquid temperature of the electrolytic solution 11 after electrolysis are adjusted by the chemical tank 25, the metering pump 26, the heater 23, and the cooler 24 is circulated in the adjustment tank 20.

  In the circulation means 30, the electrolytic solution 11 adjusted in the adjustment tank 20 is supplied to the supply port 15 in the tank bottom 17 of the electrolytic tank 10. In the circulation means 30, the electrolytic solution 11 supplied to the tank bottom 17 is uniformly dispersed by passing through the holes 14 a of the liquid dispersion plate 14, and flows between the anode 12 and the cathode 13 from the bottom to the top. It spreads throughout the tank 10. In the circulation means 30, the supply of the electrolytic solution 11 causes the electrolytic solution 11 in the electrolytic bath 10 to overflow and flow into the adjustment tank 20 through the drain port 16.

  In the electrolytic apparatus 1 having the above configuration, the electrolytic solution 11 adjusted to have a predetermined pH and liquid temperature in the adjustment tank 20 is supplied from the tank bottom 17 of the electrolytic tank 10 through the supply flow path 31 by the circulation pump 32. Supply in. As a result, in the electrolysis apparatus 1, the electrolytic solution 11 supplied from the tank bottom 17 flows uniformly between the anode 12 and the cathode 13 from the tank bottom 17 toward the liquid surface by the liquid dispersion plate 14. In the electrolysis apparatus 1, by uniformly flowing between the anode 12 and the cathode 13, the pH and the liquid temperature of the electrolytic solution 11 can be made uniform near the liquid surface of the electrolytic cell 10 and near the cell bottom 17. In the electrolysis apparatus 1, the electrolytic solution 11 can overflow from the drain port 16 to the adjustment tank 20, and the electrolytic solution 11 near the liquid surface of the electrolytic tank 10 can be sent to the adjustment tank 20. In the electrolysis apparatus 1, the pH and the liquid temperature of the electrolytic solution 11 are adjusted again in the adjustment tank 20, and the adjusted electrolytic solution 11 is sent to the electrolytic tank 10 by the circulation means 30, so that the entire electrolytic solution in the electrolytic tank 10 is obtained. 11 pH and liquid temperature can be maintained uniformly.

  Therefore, in the electrolysis apparatus 1, hydroxide indium powder and hydroxide tin powder having a narrow particle size distribution can be obtained by maintaining the pH and liquid temperature of the electrolytic solution 11 uniformly throughout the electrolytic cell 10. In the electrolysis apparatus 1, the supply from the adjustment tank 20 to the electrolysis tank 10 may be continuous or intermittent, and a supply method is appropriately selected.

  On the other hand, when the electrolytic solution 11 is not circulated, the pH and the liquid temperature of the electrolytic solution 11 become uneven near the liquid surface of the electrolytic cell 10 and near the cell bottom 17 along with the energization time. Thereby, a difference arises in the particle size distribution of the indium hydroxide powder and the tin hydroxide powder generated near the liquid surface and near the tank bottom 17.

  Moreover, in this electrolysis apparatus 1, the adjustment tank 20 is not provided, but the electrolysis adjusted in the adjustment tank 20 is performed as compared with the conventional case where the electrolysis is performed by stirring the electrolytic solution 11 by installing a stirring rod in the electrolytic tank. By sending the liquid 11 to the electrolytic cell 10 by the circulation means 30, the entire electrolytic solution 11 in the electrolytic cell 10 can be maintained more uniformly.

  Furthermore, this electrolysis apparatus 1 can suppress the volatilization of the electrolyte solution 11, mist scattering, etc., and does not deteriorate the environment around the electrolysis apparatus 1, thereby improving safety problems.

[2. Method for producing indium hydroxide powder or tin hydroxide powder]
The method for producing indium hydroxide powder or tin hydroxide powder uses indium hydroxide powder or tin hydroxide powder electrolysis apparatus 1 according to the present embodiment, so that indium hydroxide powder or A tin hydroxide powder is obtained.

  The method for producing indium hydroxide powder or tin hydroxide powder includes an electrolysis process for obtaining an electrolytic solution 11 (hereinafter referred to as “electrolytic slurry”) containing indium hydroxide powder or tin hydroxide powder, and an electrolytic solution from the electrolytic slurry. 11 for solid-liquid separation, repulp washing step for adding an electrolytic solution 11 to the electrolytic slurry to perform repulp washing to obtain a washing slurry, and washing liquid dehydration step for dehydrating the washing liquid from the obtained washing slurry And a drying step of drying the indium hydroxide powder, and through each step, indium hydroxide powder or tin hydroxide powder is obtained. Hereinafter, each process will be described in detail.

(2-1. Electrolysis process)
In the electrolysis process, indium or tin is used as the anode 12, a conductive metal or a carbon electrode is used for the cathode 13 of the counter electrode, and the anode 12 and the cathode 13 are immersed in the electrolyte solution 11 to generate a potential difference between the two electrodes. Thus, the anode 12 is dissolved by generating an electric current, and the indium hydroxide powder or the tin hydroxide powder is crystallized to generate an electrolytic slurry.

  As the electrolyte solution 11, an aqueous solution of a general electrolyte salt such as a water-soluble nitrate, sulfate, or chloride salt can be used. Among these, ammonium nitrate is preferable. Ammonium nitrate does not remain as impurities by removing nitrate ions and ammonium ions as nitrogen compounds after drying and calcining after precipitation of indium hydroxide powder or tin hydroxide powder. As a result, the purity of the produced indium hydroxide powder or tin hydroxide powder can be increased and the cost can be reduced.

It is preferable that the solubility of the produced indium hydroxide powder or tin hydroxide powder is 10 ⁻⁶ mol / L to 10 ⁻³ mol / L in the electrolytic solution 11. In the electrolytic solution 11, since the growth of the primary particles is moderately promoted by setting the solubility of the indium hydroxide powder or the tin hydroxide powder within the above range, the aggregation of the primary particles is suppressed. Indium hydroxide powder or tin hydroxide powder having a narrow particle size distribution and a uniform particle size can be obtained.

When the solubility of indium hydroxide powder or tin hydroxide powder is lower than 10 ⁻⁶ mol / L, the metal ions dissolved from the anode 12 are likely to be nucleated, so that the primary particle diameter is too fine. When the primary particle diameter is too fine, it is not preferable because the subsequent separation and recovery of indium hydroxide powder or tin hydroxide powder becomes difficult.

On the other hand, when the solubility of the indium hydroxide powder or the tin hydroxide powder is higher than 10 ⁻³ mol / L, the particle growth is promoted, so that the primary particle diameter is increased. For this reason, the larger the particle is grown, the larger the difference in particle size between the growing particle and the non-growing particle. Since the difference in particle diameter affects the degree of aggregation, as a result, the width of the particle size distribution becomes wide. When the width of the particle size distribution of the indium hydroxide powder or tin hydroxide powder becomes wider, the width of the particle size distribution of the indium oxide powder or tin oxide powder obtained by calcining the indium hydroxide powder or tin hydroxide powder also becomes wider. A sputtering target obtained by sintering this is not preferable because it is difficult to obtain a high density.

  The concentration of the electrolytic solution 11 is preferably adjusted to 0.1 mol / L to 2.0 mol / L. When the concentration of the electrolytic solution 11 is less than 0.1 mol / L, a voltage increase during electrolysis increases, causing problems such as heat generation of the energizing part and high power cost. On the other hand, when the concentration of the electrolytic solution 11 exceeds 2.0 mol / L, the indium hydroxide particles or the tin hydroxide particles are coarsened by electrolysis, and the variation in the particle size increases.

  When obtaining indium hydroxide powder, it is preferable to adjust the pH of the electrolytic solution 11 to 2.5 to 4.0. When the pH of the electrolytic solution 11 is less than 2.5, indium hydroxide powder does not precipitate. On the other hand, when the pH of the electrolytic solution 11 exceeds 4.0, the precipitation of indium hydroxide powder is too fast and a precipitate is formed with the concentration of the electrolytic solution 11 being non-uniform. Therefore, the particle size distribution width cannot be controlled to be small.

  When obtaining tin hydroxide powder, it is preferable to adjust the pH of the electrolytic solution 11 to 2.5 to 8.0. When the pH of the electrolytic solution 11 is less than 2.5, precipitation of tin hydroxide powder does not occur. On the other hand, when the pH of the electrolytic solution 11 exceeds 8.0, the precipitation of the tin hydroxide powder is too fast and the precipitate is formed with the non-uniform concentration of the electrolytic solution 11, so that the particle size distribution width is wide. Therefore, the particle size distribution width cannot be controlled to be small.

  The liquid temperature of the electrolytic solution 11 is preferably adjusted to 20 ° C to 60 ° C. When the liquid temperature of the electrolyte solution 11 is less than 20 ° C., the precipitation of indium hydroxide powder or tin hydroxide powder is too slow. On the other hand, when the liquid temperature of the electrolytic solution 11 exceeds 60 ° C., indium hydroxide powder or tin hydroxide powder is deposited too quickly, so that the precipitate is formed while the concentration of the electrolytic solution 11 is not uniform. The particle size distribution width is widened.

Electrode current density during electrolysis ^is preferably adjusted to ^{4A / dm 2 ~20A / dm 2} . As a result, a wide range of electrode current densities can be obtained. When the electrode current density during electrolysis is less than 4 A / dm ² , the production efficiency of indium hydroxide powder or tin hydroxide powder is lowered. On the other hand, when the electrode current density during electrolysis exceeds 20 A / dm ² , problems such as rise of the electrolyte solution 11, passivation on the surface of the anode 12 (for example, metal indium) and difficulty in electrolysis occur.

  The electrolyte flow rate per electrolytic cell is preferably 0.007 L / min / A (battery current) to 0.03 L / min / A (battery current). When the electrolytic solution flow rate per electrolytic cell is less than 0.007 L / min / A (battery current), nuclear growth has priority over nucleation, and the particle size of indium hydroxide powder or tin hydroxide powder is large. Become. On the other hand, when the electrolytic solution flow rate per electrolytic cell exceeds 0.03 L / min / A (battery current), the environment around the electrolytic device 1 is deteriorated due to volatilization of the electrolytic solution 11, scattering of mist, and the like. Etc.

  When the electrolytic solution flow rate per electrolytic cell is 0.007 L / min / A (battery current) or more, the indium hydroxide powder or tin hydroxide powder generated in the electrolytic solution 11 does not crystallize on the tank bottom 17. Electrolysis is preferably performed in a suspended state.

  In the electrolysis process, the anode 12 and the cathode 13 as described above are used, a potential difference is generated between the two electrodes, and an electric current is generated to dissolve the anode 12, and indium hydroxide powder or tin hydroxide powder is crystallized. To produce an electrolytic slurry. In the electrolysis step, the electrolytic solution 11 is adjusted in the adjustment tank 20 and the electrolytic solution 11 is circulated during electrolysis. In the electrolysis process, the electrolytic solution 11 is circulated continuously or intermittently.

  Specifically, in the electrolysis process, the electrolytic solution 11 is supplied from the adjustment tank 20 through the supply flow path 31 by the circulation pump 32 by the amount of the electrolytic solution per predetermined electrolytic tank. In the electrolysis process, the supply of the electrolyte solution 11 causes the electrolyte solution 11 in the electrolytic cell 10 to overflow, and the electrolyte solution 11 is sent through the drain port 16.

  In the electrolysis process, the electrolytic solution 11 sent from the electrolytic cell 10 is controlled and maintained at a predetermined temperature by the heater 23 and the cooler 24. Here, in the electrolysis step, 1N nitric acid is added from the chemical solution tank 25 to the adjustment tank 20 by the metering pump 26, and the electrolyte solution 11 is controlled and maintained at a predetermined pH while measuring the pH with the pH electrode 22. Further, in the electrolysis step, the stirring rod 21 is used to eliminate the difference in pH and liquid temperature of the electrolyte solution 11 in the adjustment tank 20 and make it uniform. In the electrolysis process, the electrolytic solution 11 sent from the electrolytic cell 10 in the adjustment tank 20 is adjusted to a predetermined liquid temperature and pH.

  In the electrolysis step, the electrolytic solution 11 in the adjustment tank 20 controlled to a predetermined pH and liquid temperature is supplied to the tank bottom 17 of the electrolytic tank 10 through the supply flow path 31 by the circulation pump 32. In the electrolysis process, the electrolytic solution 11 is jetted from the supply port 15 installed in the tank bottom 17 of the electrolytic cell 10. In the electrolysis process, the jetted electrolyte solution 11 is dispersed by passing through the holes 14 a of the liquid dispersion plate 14, flows uniformly between the anode 12 and the cathode 13, and the electrolyte solution 11 in the entire electrolytic cell 10. PH and liquid temperature become uniform.

  Thereby, in the electrolysis process, the electrolytic solution 11 controlled to a predetermined pH or liquid temperature is supplied to the electrolytic cell 10, and the electrolytic solution 11 circulates, whereby the pH of the electrolytic solution 11 between the electrodes in the electrolytic cell 10. In addition, the liquid temperature becomes uniform, and the electrolytic solution 11 in the electrolytic cell 10 can be electrolyzed in a uniform state.

  As described above, in the electrolysis step, an electrolytic slurry made of the electrolytic solution 11 containing indium hydroxide powder or tin hydroxide powder having a uniform particle size and a narrow particle size distribution is obtained.

(2-2. Electrolyte separation process)
In the electrolytic solution separation step, the electrolytic solution 11 obtained by the electrolysis step is subjected to solid-liquid separation from the electrolytic solution 11 and indium hydroxide powder or tin hydroxide powder.

In the electrolytic solution separation step, the electrolytic solution 11 is separated using a cross-flow rotary filter that does not cause clogging even if it is a fine powder and has high recovery efficiency of indium hydroxide powder or tin hydroxide powder. . The filter cloth used in the rotary filter is preferably as low as possible in order to increase the recovery rate of indium hydroxide powder or tin hydroxide powder. More preferably, the air permeability is 0.3 cm ³ / sec / cm ² or less.

(2-3. Repulp washing process)
In the repulp washing process, since the electrolyte solution 11 is contained in the indium hydroxide powder or tin hydroxide powder after the solid-liquid separation in the electrolyte solution separation process, the washing solution is added to the indium hydroxide powder or tin hydroxide powder to perform hydroxylation. Repulp the indium powder or tin hydroxide powder.

  In the repulp washing step, pure water is used because it is desirable that the washing liquid used for the repulp washing has less impurities. In particular, the pure water is desirably A2 grade or higher as defined in JIS K0557. On the other hand, when it is A1 grade or less, impurities such as silica are mixed, which causes a problem when a sputtering target using the produced indium hydroxide powder or tin hydroxide powder is produced.

  In the repulp washing process, it is preferable to wash using 5 L to 20 L of pure water with respect to 1 kg of indium hydroxide powder or tin hydroxide powder. When the amount of pure water to be used is less than 5 L, a large amount of ammonium nitrate as an electrolyte component remains in the indium hydroxide powder or tin hydroxide powder. Due to this residue, when indium hydroxide powder or tin hydroxide powder is dried, there is a risk of fire occurring when indium hydroxide powder or tin hydroxide powder is calcined to obtain indium oxide powder or tin oxide powder. Get higher. On the other hand, when the amount of pure water used exceeds 20 L, the amount of waste water treated after washing increases, resulting in an increase in cost.

  In the repulp washing step, a washing liquid can be added to the indium hydroxide powder or tin hydroxide powder and stirred as necessary. Moreover, the electrolytic solution 11 in an indium hydroxide powder or a tin hydroxide powder can be removed by carrying out a repulp washing | cleaning once or more, and an indium hydroxide powder or a tin hydroxide powder can be wash | cleaned.

  From the above, in the repulp washing step, washing slurry is obtained by repulping the indium hydroxide powder or tin hydroxide powder.

(2-4. Cleaning liquid dehydration step)
In the cleaning liquid dehydration process, the cleaning liquid is dehydrated from the cleaning slurry obtained in the repulp cleaning process. Here, for the dehydration, it is preferable to use a cross flow type rotary filter which is difficult to clog even with a fine powder and has a high recovery rate.

  In the cleaning liquid dehydrating step, indium hydroxide powder or tin hydroxide powder is obtained by cleaning and dehydrating the cleaning slurry.

  In the cleaning liquid dehydration step, when the electrolytic solution 11 and the cleaning liquid are reused, the cleaning liquid obtained in the cleaning liquid dehydration process is heated and distilled under reduced pressure for a predetermined time to obtain a concentrated liquid.

  In the washing liquid dehydration process, the obtained concentrated liquid is mixed with the electrolytic solution 11 separated in the electrolytic solution separation process, and adjusted by adding pure water so as to be the same as the electrolytic solution 11 used in the electrolysis process. Can do. Thereafter, the adjusted electrolytic solution 11 is again put into the adjusting tank 20 and supplied to the electrolytic tank 10 through the supply flow path 31 by the circulation pump 32 to perform new electrolysis.

  In the electrolysis process, the electrolytic solution 11 obtained as described above can be reused. Thereby, the electrolyte solution 11 is not discarded as a waste solution.

(2-5. Drying step)
In the drying step, the indium hydroxide powder or tin hydroxide powder obtained after the cleaning liquid dehydration step is dried.

  Although it does not specifically limit as a drying method in a drying process, It carries out with drying machines, such as a spray dryer, an air convection type drying furnace, and an infrared drying furnace.

  Although it will not specifically limit in a drying process if the water | moisture content of an indium hydroxide powder or a tin hydroxide powder can be removed about drying conditions, Preferably a drying temperature is set to 80 to 150 degreeC. When the drying temperature is less than 80 ° C., drying of water-containing indium hydroxide powder or tin hydroxide powder becomes insufficient. On the other hand, when the drying temperature exceeds 150 ° C., too much moisture is blown off, so that indium oxide powder or tin oxide powder is produced from tin hydroxide powder.

  In the drying step, the drying time is preferably set to about 10 to 24 hours, although it varies depending on the drying temperature.

  In the drying step, indium hydroxide powder or tin hydroxide powder is obtained by drying the indium hydroxide powder or tin hydroxide powder after the cleaning liquid dehydration step.

  From the above, in the method for producing indium hydroxide powder or tin hydroxide powder, the electrolytic solution 11 adjusted in the adjustment tank 20 is obtained by using the above-described electrolysis apparatus 1 of indium hydroxide powder or tin hydroxide powder. And the electrolyte solution 11 is circulated to obtain indium hydroxide powder or tin hydroxide powder having a uniform particle size and a narrow particle size distribution.

  Moreover, in the manufacturing method of indium hydroxide powder or tin hydroxide powder, since the wastewater treatment is not performed by reusing the electrolyte solution 11 and the cleaning solution as in the past, the loss of the electrolyte solution 11 and the cleaning solution can be suppressed and the environment can be reduced. Can be suppressed. Therefore, this manufacturing method has a high industrial value.

[3. Method for producing indium oxide powder or tin oxide powder]
In the method for producing indium oxide powder or tin oxide powder, the obtained indium hydroxide powder or tin hydroxide powder is calcined under predetermined conditions to obtain indium oxide powder or tin oxide powder.

  In the method for producing indium oxide powder or tin oxide powder, the calcining conditions are appropriately determined, but the calcining temperature is preferably set to 600 ° C to 800 ° C.

When the calcining temperature is less than 600 ° C., the obtained indium oxide powder or tin oxide powder becomes a powder having cohesiveness because the BET value exceeds 15 m ² / g and the primary particles are too small. . With such indium oxide powder or tin oxide powder, a high-density sintered material, for example, indium tin oxide (ITO) sintered material cannot be obtained.

On the other hand, when the calcining temperature exceeds 800 ° C., in the obtained indium oxide powder or tin oxide powder, the BET value is less than 10 m ² / g, so the primary particle diameter becomes large, and voids are generated between the particles. As a result, the sinterability decreases. With such indium oxide powder or tin oxide powder, a high-density sintered material cannot be obtained. Therefore, in order to obtain a high-density sintered material, the calcining temperature is preferably set to 600 ° C to 800 ° C.

  Moreover, in the manufacturing method of an indium oxide powder or a tin oxide powder, although calcining conditions are suitably determined according to calcining temperature, Preferably calcining time is set to 1 hour-10 hours.

Indium oxide powder or tin oxide powder is BET value of specific surface area is controlled within a range of ^{10m 2} / ^g~15m 2 / g, cumulative particle size of 10% the diameter of the particle size distribution (D10) is 0.2μm or more, The cumulative particle size 90% diameter (D90) is 2.7 μm or less. Such indium oxide powder or tin oxide powder has a specific surface area controlled, good dispersibility, and little aggregation, so that a high-density sintered material can be generated.

  In the method for producing indium oxide powder or tin oxide powder, the indium hydroxide powder or tin hydroxide powder can be crushed or pulverized as necessary in order to obtain a more desired particle size. Further, in the method for producing indium oxide powder or tin oxide powder, when ammonium nitrate is used as the electrolytic solution 11 during electrolysis of indium hydroxide powder or tin hydroxide powder, decomposition of ammonium nitrate occurs, so indium oxide powder or oxidation Mixing into the tin powder can be prevented.

  As described above, the indium oxide powder or tin oxide powder inherits the characteristic that the particle size distribution of the indium hydroxide powder or tin hydroxide powder obtained by the electrolysis apparatus 1 of indium hydroxide powder or tin hydroxide powder is narrow. Yes.

  As mentioned above, the manufacturing method of indium oxide powder or tin oxide powder can obtain indium oxide powder or tin oxide powder with narrow particle size distribution by using the indium hydroxide powder or tin hydroxide powder with narrow particle size distribution described above.

[4. Manufacturing method of sputtering target]
The sputtering target is produced by oxidizing the indium hydroxide powder and / or tin hydroxide powder having a narrow particle size distribution obtained by the above-described method for producing indium hydroxide powder or tin hydroxide powder, and obtaining the indium oxide obtained. A sputtering target is obtained by using powder and / or tin oxide powder.

  By drying indium hydroxide powder or tin hydroxide powder having a narrow particle size distribution obtained by the method for producing indium hydroxide powder or tin hydroxide powder, indium oxide powder or tin oxide powder having a narrow particle size distribution is obtained. Next, the target of the obtained indium oxide powder and tin oxide powder is mixed at a predetermined ratio to produce granulated powder. Next, a molded body is produced by using the produced granulated powder, for example, by a cold press method. Next, the molded body is sintered at, for example, 1300 ° C. to 1600 ° C. under atmospheric pressure. Next, processing such as polishing the flat surface and side surfaces of the sintered body is performed as necessary. And an indium tin oxide sputtering target (ITO sputtering target) is obtained by bonding a sintered compact to Cu backing plate. Moreover, an indium oxide sputtering target or a tin oxide sputtering target is obtained by sputtering using the obtained indium oxide powder or tin oxide powder.

  In the sputtering target manufacturing method, since the particle size distribution of the indium oxide powder and the tin oxide powder as raw materials is narrow, the specific surface area is controlled, and these indium oxide powder and tin oxide powder have good dispersibility. Therefore, a high-density sputtering target can be obtained. Thereby, in the manufacturing method of a sputtering target, a crack, a chip | tip, etc. do not arise during the process of a target, but it can also control that abnormal discharge generate | occur | produces in the case of sputtering.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited by these.

<Example 1>
(1) Electrolysis Step In Example 1, in the electrolysis step, indium hydroxide powder was generated using the electrolysis apparatus 1 shown in FIG. The electrolysis apparatus 1 shown in FIG. 1 includes a 200 L electrolytic cell 10 having a length of 100 cm, a width of 40 cm, and a depth of 50 cm, and a 40 L adjustment tank 20 having a length of 20 cm, a width of 40 cm, and a depth of 50 cm. Are provided adjacent to each other. In the electrolysis apparatus 1, the supply flow path 31 is provided in the electrolytic cell 10 and the adjustment tank 20, and the supply flow channel 31 is provided with a circulation pump 32.

  In the electrolytic cell 10, a liquid dispersion plate 14 was provided in order to disperse the liquid flow of the electrolytic solution 11 at a height of 2 cm from the cell bottom 17 in parallel with the cell bottom 17. That is, the liquid dispersion plate 14 has a total of 25 holes 3a having a diameter of 3 mm, each having 5 rows and 5 rows per 10 cm square. As a result, in the electrolytic cell 10, the electrolytic solution 11 supplied from the circulation means 30 through the supply port 15 by the circulation pump 32 passes through the liquid dispersion plate 14, and each liquid flow has a substantially uniform liquid flow rate with no drift. Secured.

  Further, as shown in FIG. 2, a plurality of anodes 12 and cathodes 13 are arranged in the electrolytic cell 10. As the cathode 13, five titanium metal plates having a width of 26 cm, a height of 40 cm, and a thickness of 4 mm were prepared. In addition, as anode 12, four sheets of 99.9999% pure metal indium formed into a plate shape having a width of 26 cm, a height of 40 cm, and a thickness of 8 mm were prepared. In the electrolysis apparatus 1, these five cathodes 13 and four anodes 12 are placed vertically on a liquid dispersion plate 14 in the electrolytic cell 10 so that both electrodes are parallel to each other, as shown in FIG. Alternatingly arranged. In the electrolyzer 1, the distance between the anode 12 and the cathode 13 was adjusted to 2.0 cm. The four anodes 12 were electrically connected to the five cathodes 13 and the conductive wires 19.

  The adjustment tank 20 includes a stirring rod 21 for stirring the electrolytic solution 11, a pH electrode 22 for measuring pH, a heater 23 and a cooler 24 for controlling and maintaining the liquid temperature of the electrolytic solution 11, and controlling the pH of the electrolytic solution 11. The chemical solution tank 25 to be maintained and the metering pump 26 for adding the chemical solution were installed in or adjacent to the tank.

  In the electrolysis apparatus 1, as shown in Table 1, 200 L of 1.0 mol / L ammonium nitrate aqueous solution was put in the electrolytic cell 10, and 40 L of 1.0 mol / L ammonium nitrate aqueous solution was put in the adjustment vessel 20. In the adjustment tank 20, 1N nitric acid was added to the ammonium nitrate aqueous solution of the electrolytic solution 11, and the hydrogen ion concentration index pH was adjusted to 4.0. The pH was measured using a pH electrode 22 attached to the adjustment tank 20. In the adjustment tank 20, while maintaining this state, the temperature of the electrolyte solution 11 was maintained at 25 ° C. using the heater 23 and the cooler 24. In the adjustment tank 20, the electrolyte solution 11 was adjusted by stirring the electrolyte solution 11 in the tank with the stirring rod 21.

  In the electrolysis apparatus 1, during the electrolysis, the electrolytic solution 11 in the adjustment tank 20 was supplied to the electrolytic tank 10 through the supply port 15 via the supply channel 31 by the circulation pump 32 at a speed of 20 L / min. In addition, in the electrolyte solution 11, it was 0.015 L / min / A (battery current) when converted into the electrolyte solution flow rate per electrolytic vessel. The electrolytic solution 11 in the electrolytic bath 10 was sent to the regulating bath 20 by overflow from the drainage port 16 disposed at the center of the upper end of the bath wall 18 on the regulating bath 20 side of the electrolytic bath 10.

In the electrolysis apparatus 1, the electrode current density was adjusted to 15 A / dm ² and electrolysis was continued for 6 hours. By this electrolysis, an electrolytic slurry containing indium hydroxide powder was obtained in the electrolysis process.

(2) Electrolyte separation process Next, in Example 1, the obtained indium hydroxide slurry was subjected to solid-liquid separation in the electrolyte separation process. In this step, a rotary filter (RFU-02B manufactured by Kotobuki Industries Co., Ltd.) and a filter cloth (KE-022, air permeability 0.1 cm ³ / sec / cm ² ) are used for solid-liquid separation of the indium hydroxide slurry. I went there. In the electrolytic solution separation step, the indium hydroxide slurry and the separated electrolytic solution 11 were obtained as a result of solid-liquid separation of the indium hydroxide slurry.

(3) Repulp washing process Next, in Example 1, the obtained indium hydroxide cake was washed in the repulp washing process in the washing liquid dehydration process. In the repulp washing step, pure water was added to the indium hydroxide cake, and the mixture was stirred in a stainless bucket container and redispersed. Subsequently, this was subjected to solid-liquid separation operation in the same manner as in the electrolytic solution separation step, and an indium hydroxide cake and a cleaning solution were obtained again.

(4) Cleaning liquid dehydration process In Example 1, in the cleaning liquid dehydration process, using a vacuum distillation apparatus (Eco Prima) manufactured by Nippon Steel Sumitomo Environment Co., Ltd., the heater pot for concentration heating (capacity 1 m ³ ) is used for the repulp cleaning process. 100 L of the cleaning liquid obtained in the above was charged, and vacuum distillation was performed for 4 hours with an electric heater 100 kW / hr.

  In Example 1, this concentrated solution was mixed with the electrolytic solution 11 separated in the electrolytic solution separation step, and adjusted by adding pure water so as to be the same as the electrolytic solution 11 used in the electrolysis step. Thereafter, in the washing liquid dehydration step, the adjusted electrolytic solution 11 was again put into the adjusting tank 20 and supplied to the electrolytic tank 10 via the supply flow path 31 by the circulation pump 32 to perform new electrolysis. In the steps so far, the electrolyte solution 11 has not been discarded as a waste solution.

  In Example 1, the washing liquid dehydration process was repeated three times, and the obtained electrolytic slurry containing indium hydroxide powder was sampled, and the particle size distribution was measured by a laser diffraction / scattering method (device name: SALD-2200, company name: Shimadzu Corporation). Measured by a manufacturing company).

(5) Drying step In Example 1, in the drying step, the electrolytic slurry containing the indium hydroxide powder obtained in the washing and dehydrating step was spray-dried with a spray dryer to obtain indium hydroxide powder. As shown in Table 1, the obtained indium hydroxide powder had a very narrow particle size distribution with a minimum diameter of 0.3 μm and a maximum diameter of 1.2 μm.

(6) Manufacturing process of indium oxide powder In Example 1, the indium hydroxide powder obtained in the drying process was baked at 700 ° C in the air to obtain indium oxide powder.

<Example 2>
In Example 2, as shown in Table 1, indium hydroxide powder was obtained in the same manner as in Example 1 except that the amount of liquid in the adjustment tank 20 was 200 L. As shown in Table 1, the obtained indium hydroxide powder had a very narrow particle size distribution with a minimum diameter of 0.3 μm and a maximum diameter of 1.2 μm.

  In Example 2, in the same manner as in Example 1, indium hydroxide powder was baked at 700 ° C. in the air to obtain indium oxide powder.

<Example 3>
In Example 3, as shown in Table 1, indium hydroxide powder was obtained in the same manner as in Example 1 except that the electrolytic solution flow rate per electrolytic cell was set to 0.027 L / min / A. As shown in Table 1, the obtained indium hydroxide powder had a very narrow particle size distribution with a minimum diameter of 0.3 μm and a maximum diameter of 1.1 μm.

  In Example 3, as in Example 1, indium hydroxide powder was baked at 700 ° C. in the atmosphere to obtain indium oxide powder.

<Example 4>
In Example 4, tin hydroxide powder was obtained in the same manner as in Example 1 except that metal anode having a purity of 99.99% was used for the anode 12 and the pH of the electrolyte solution 11 was adjusted to 7.0. It was. As shown in Table 2, the obtained tin hydroxide powder had a very narrow particle size distribution because it had a minimum diameter of 0.3 μm and a maximum diameter of 3.4 μm.

  In Example 4, the obtained tin hydroxide powder was baked at 700 ° C. in the air in the same manner as in Example 1 to obtain tin oxide powder.

<Example 5>
In Example 5, a tin hydroxide powder was obtained in the same manner as in Example 3 except that the amount of liquid in the adjustment tank 20 was 200 L as shown in Table 2. As shown in Table 2, the obtained tin hydroxide powder had a very narrow particle size distribution because it had a minimum diameter of 0.3 μm and a maximum diameter of 3.4 μm.

  In Example 5, the obtained tin hydroxide powder was baked at 700 ° C. in the air in the same manner as in Example 1 to obtain tin oxide powder.

<Example 6>
In Example 6, 990 g of indium oxide powder obtained in Example 1 and 10 g of tin oxide powder obtained in Example 4 were formed by a mixed cold press method. Next, in Example 6, the obtained molded body was sintered for 30 hours at 1400 ° C. in an atmospheric pressure to obtain an indium oxide-tin oxide based sintered body. As shown in Table 3, the relative density of the obtained sintered body was 99.7% when measured by the Archimedes method.

<Example 7>
In Example 7, 990 g of indium oxide powder obtained in Example 2 and 10 g of tin oxide powder obtained in Example 5 were formed by a mixed cold press method. Next, in Example 7, the obtained molded body was sintered for 30 hours at 1400 ° C. in atmospheric pressure to obtain an indium oxide-tin oxide based sintered body. As shown in Table 3, the relative density of the obtained sintered body was 99.7% when measured by the Archimedes method.

<Comparative Example 1>
In the comparative example 1, it electrolyzed only with the electrolytic tank, without using an adjustment tank. At that time, a stirring bar, a pH electrode, a heater, and a cooler were installed in the electrolytic cell, and the liquid dispersion plate in the electrolytic cell was removed. In Comparative Example 1, as shown in Table 1, indium hydroxide powder was obtained in the same manner as in Example 1 except that stirring was performed at the number of rotations of the stirring rod in the electrolytic cell (60 rpm). As shown in Table 1, the obtained indium hydroxide powder had a wide particle size distribution because it had a minimum diameter of 0.2 μm and a maximum diameter of 12.0 μm.

  In Comparative Example 1, drying was performed in the same manner as in Example 1, and the obtained indium hydroxide powder was baked at 700 ° C. in the atmosphere to obtain indium oxide powder.

<Comparative example 2>
In the comparative example 2, it electrolyzed only with the electrolytic cell, without using an adjustment tank. At that time, a stirring bar, a pH electrode, a heater, and a cooler were installed in the electrolytic cell. The liquid dispersion plate in the electrolytic cell was removed. In Comparative Example 2, as shown in Table 1, indium hydroxide powder was obtained in the same manner as in Example 1 except that stirring was performed at the rotation speed (300 rpm) of the stirring rod in the electrolytic cell. As shown in Table 1, the obtained indium hydroxide powder had a wide particle size distribution because it had a minimum diameter of 0.2 μm and a maximum diameter of 4.0 μm.

  In Comparative Example 2, the obtained indium hydroxide powder was fired at 700 ° C. in the air in the same manner as in Example 1 to obtain indium oxide powder.

<Comparative Example 3>
In Comparative Example 3, as shown in Table 1, indium hydroxide powder was obtained in the same manner as in Example 1 except that the flow rate of the electrolytic solution per electrolytic cell was 0.005 L / min / A. As shown in Table 1, the obtained indium hydroxide powder had a wide particle size distribution since it had a minimum diameter of 0.2 μm and a maximum diameter of 8.0 μm.

  In Comparative Example 3, the obtained indium hydroxide powder was fired at 700 ° C. in the air in the same manner as in Example 1 to obtain indium oxide powder.

<Comparative Example 4>
In Comparative Example 4, an indium hydroxide powder was tried in the same manner as in Example 1 except that the electrolytic solution flow rate per electrolytic cell was 0.050 L / min / A as shown in Table 1. However, in Comparative Example 4, the electrolysis solution was volatilized and the mist was scattered so that the electrolysis was stopped. Therefore, in Comparative Example 4, indium hydroxide powder could not be obtained.

<Comparative Example 5>
In the comparative example 5, it electrolyzed only with the electrolytic tank, without using an adjustment tank. At that time, a pH electrode, a heater, a cooler, and a stirring rod were installed in the electrolytic cell, and the liquid dispersion plate in the electrolytic cell was removed. In Comparative Example 5, as shown in Table 2, tin hydroxide powder was obtained in the same manner as in Example 3 except that stirring was performed at the number of rotations of the stirring rod in the electrolytic cell (60 rpm). As shown in Table 2, the obtained tin hydroxide powder had a wide particle size distribution because it had a minimum diameter of 0.2 μm and a maximum diameter of 34.2 μm.

  In Comparative Example 5, as in Example 1, tin hydroxide powder was fired at 700 ° C. in the atmosphere to obtain tin oxide powder.

<Comparative Example 6>
In the comparative example 6, it electrolyzed only with the electrolytic cell, without using an adjustment tank. At that time, a pH electrode, a heater, a cooler, and a stirring rod were installed in the electrolytic cell, and the liquid dispersion plate in the electrolytic cell was removed. In Comparative Example 6, as shown in Table 2, tin hydroxide powder was obtained in the same manner as in Example 3 except that stirring was performed at the number of revolutions of the stirring rod in the electrolytic cell (300 rpm). As shown in Table 2, the obtained tin hydroxide powder had a minimum particle diameter of 0.2 μm and a maximum diameter of 11.4 μm, and thus had a wide particle size distribution.

  In Comparative Example 6, as in Example 1, tin hydroxide powder was fired at 700 ° C. in the atmosphere to obtain tin oxide powder.

<Comparative Example 7>
In Comparative Example 7, as shown in Table 2, tin hydroxide powder was obtained in the same manner as in Example 3 except that the flow rate was 0.005 L / min / A depending on the electrolyte flow rate per electrolytic cell. As shown in Table 1, the obtained tin hydroxide powder had a wide particle size distribution because it had a minimum diameter of 0.2 μm and a maximum diameter of 22.8 μm.

  In Comparative Example 7, the obtained tin hydroxide powder was fired at 700 ° C. in the air in the same manner as in Example 1 to obtain tin oxide powder.

<Comparative Example 8>
In Comparative Example 8, as shown in Table 2, the production of tin hydroxide powder was attempted in the same manner as in Example 3 except that the electrolytic solution flow rate per electrolytic cell was 0.050 L / min / A. However, in Comparative Example 8, the volatilization of the electrolyte and the scattering of mist were severe, and the electrolysis was stopped. Therefore, in Comparative Example 8, tin hydroxide powder was not obtained.

<Comparative Example 9>
In Comparative Example 9, 990 g of the indium oxide powder obtained in Comparative Example 1 and 10 g of the tin oxide powder obtained in Comparative Example 5 were formed by a mixed cold press method. Next, in Comparative Example 9, the obtained molded body was sintered at 1400 ° C. in atmospheric pressure for 30 hours, and an indium oxide-tin oxide based sintered body was obtained. The relative density of the obtained sintered body was 88.6% as measured by Archimedes method as shown in Table 3.

<Comparative Example 10>
In Comparative Example 10, 990 g of the indium oxide powder obtained in Comparative Example 3 and 10 g of the tin oxide powder obtained in Comparative Example 7 were formed by a mixed cold press method. Next, in Comparative Example 10, the obtained molded body was sintered for 30 hours at 1400 ° C. in atmospheric pressure, and an indium oxide-tin oxide based sintered body was obtained. As shown in Table 3, the relative density of the obtained sintered body was 87.1% as measured by Archimedes method.

  From the results of Example 1 to Example 5, by using the electrolytic device 1 of indium hydroxide powder or tin hydroxide powder, indium hydroxide powder or hydroxide having a narrow particle size distribution as shown in Tables 1 and 2 Tin powder was obtained.

  As the results of Example 6 and Example 7 show, the indium hydroxide powder and tin hydroxide powder with extremely narrow particle size distribution obtained in Example 1, Example 2, Example 4, and Example 5 were used. As a result, a high-density sputtering target as shown in Table 3 was obtained.

  From the above results, it was found that an indium oxide-tin oxide sintered body having a high relative density can be obtained by using indium hydroxide powder and tin hydroxide powder having an extremely narrow particle size distribution.

  As Comparative Example 1, Comparative Example 2, Comparative Example 5, and Comparative Example 6 show, the electrolytic solution 11 was not circulated between the electrolytic cell 10 and the adjustment cell 20, and as shown in Tables 1 and 2. Indium hydroxide powder or tin hydroxide powder having a narrow particle size distribution was not obtained.

  As Comparative Example 3, Comparative Example 4, Comparative Example 5, and Comparative Example 6 show, the electrolyte flow rate per electrolytic cell was out of the range of 0.007 L / min / A to 0.03 L / min / A. Indium hydroxide powder or tin hydroxide powder having a narrow particle size distribution as shown in Tables 1 and 2 was not obtained.

  As Comparative Example 9 and Comparative Example 10 show, by using the indium hydroxide powder and tin hydroxide powder having a wide particle size distribution obtained in Comparative Example 1, Comparative Example 3, Comparative Example 5, and Comparative Example 7, A high-density sputtering target as shown in Table 3 was not obtained.

  From the above results, it was found that an indium oxide-tin oxide sintered body having a high relative density could not be obtained even when indium hydroxide powder and tin hydroxide powder having a wide particle size distribution were used.

  DESCRIPTION OF SYMBOLS 1 Electrolyzer, 10 Electrolyzer, 11 Electrolyte, 12 Anode (anode), 13 Cathode (cathode), 14 Liquid dispersion plate, 14a Hole, 15 Supply port, 16 Drain port, 17 Tank bottom, 18 Tank wall, 19 Conductor, 20 adjustment tank, 21 stirring rod, 22 pH electrode, 23 heater, 24 cooler, 25 chemical tank, 26 metering pump, 27 liquid feed port, 28 tank bottom, 30 circulation means, 31 supply flow path, 32 circulation pump

Claims (7)

An electrolysis device for producing indium hydroxide powder or tin hydroxide powder by electrolyzing indium or tin,
An electrolytic tank, an adjustment tank for adjusting the electrolytic solution, a circulation means connected to the electrolytic tank and the adjustment tank for circulating the electrolytic solution, and an upper end edge of the electrolytic tank from the electrolytic tank to the adjusting tank. A drain port for overflowing the electrolyte ,
By the circulating means, the electrolytic solution is circulated between the electrolytic cell and the adjusting tank ,
The electrolytic cell is provided with a supply port for supplying the electrolytic solution into the cell at the cell bottom, and a liquid dispersion plate is provided between the anode and the cathode and the cell bottom. Or an electrolysis device of tin hydroxide powder.   2. The electrolytic apparatus for indium hydroxide powder or tin hydroxide powder according to claim 1, wherein a volume ratio of the adjusting tank to the electrolytic tank is 0.1 or more. A method for producing indium hydroxide powder or tin hydroxide powder by producing indium hydroxide powder or tin hydroxide powder by electrolysis using indium or tin as an anode,
A method for producing indium hydroxide powder or tin hydroxide powder, wherein the electrolytic apparatus according to claim 1 or 2 is used. The method for producing indium hydroxide powder or tin hydroxide powder according to claim 3 , wherein the electrolytic solution flow rate per electrolytic cell is 0.007 L / min / A to 0.03 L / min / A. When the anode is indium, a 0.1 mol / L to 2.0 mol / L ammonium nitrate aqueous solution is used as the electrolytic solution, the pH of the electrolytic solution is 2.5 to 4.0, and the liquid temperature is 20 ° C. to 60 ° C., and method of manufacturing the indium hydroxide powder according to claim 3 or claim 4, characterized in that controlling the electrodes current density in the range of ^{4A / dm 2 ~20A / dm 2} . When the anode is tin, a 0.1 mol / L to 2.0 mol / L ammonium nitrate aqueous solution is used as the electrolytic solution, the pH of the electrolytic solution is 2.5 to 8.0, and the liquid temperature is 20 ° C. to 60 ° C., and method for producing a tin hydroxide powder according to claim 3 or claim 4, characterized in that controlling the electrodes current density in the range of ^{4A / dm 2 ~20A / dm 2} . With claims 3 to indium hydroxide powder obtained by the method for producing been indium hydroxide powder or tin hydroxide powder according to any one of claims 6 and / or tin hydroxide powder, a sputtering target A manufacturing method of a sputtering target, characterized by manufacturing.

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