JP2002029744A - Method for manufacturing tin oxide powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for synthesizing tin oxide powder which can be suitably used as the source material of a tin oxide sintered body used as a sputtering target and which has little aggregation of primary particles and narrow distribution of the particle size. SOLUTION: The particle size of the tin oxide powder calculated from the BET specific surface area ranges >=0.05 μm and <=1 μm, and the cumulative particle sizes D10, D50 and D90 corresponding to 10%, 50% and 90% accumulation of particles from the smaller particle size, respectively, in the cumulative distribution of particle size measured by a laser diffraction scattering method satisfy (D90-D10)/D50<=2 and D50<=1 μm. In the method for manufacturing the tin oxide powder by reacting an aqueous tin salt solution and alkali solution to produce a precipitate containing tin, then separating and drying the precipitate containing tin from the reaction liquid of the aqueous tin salt solution and alkali solution and then calcining the precipitate containing tin, the aqueous tin salt solution contains tetravalent tin ions, the reaction of the aqueous tin salt solution and alkali solution is carried out in a pH range from >=0.5 to <=4, and calcination is carried out in a temperature range from >=400 deg.C and <=1200 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tin oxide powder having a narrow particle size distribution and suitable for sintering, and a method for producing the same.

[0002]

2. Description of the Related Art Tin oxide thin films are used as a transparent conductive film together with ITO because they have high conductivity and excellent light transmittance. ITO is used as a transparent conductive film for a liquid crystal display, but is very expensive. Tin oxide is inexpensive, but the workability of the film is inferior to that of ITO, so there is no need for fine processing. TCO substrate glass for solar cells (transparent conductive oxide coated glass), heat ray reflective glass, low radiation glass, electrothermal glass It is used for The ITO thin film is manufactured by a sputtering method using a sintered body of ITO as a target. However, the tin oxide thin film targets metal tin instead of tin oxide, and oxidizes metal tin vaporized by sputtering in an oxidizing atmosphere. Tin oxide thin films are manufactured by reactive sputtering in which sputtering is performed while forming tin oxide. This is because a tin oxide sintered body having a high density usable as a target has not been obtained. A high density tin oxide sintered body suitable as a target is desired,
Conventional tin oxide powder has insufficient sinterability.

As a method for producing tin oxide powder, for example,
JP-A-3-263705 discloses that "a solution of tin chloride and antimony chloride is neutralized with an alkali to form a hydrate of tin oxide and antimony oxide, and this is fired to produce a conductive fine powder. Wherein the calcination is carried out in the presence of an ammonium salt.

[0004] In the publication, in this example, neutralization with an alkali was carried out while maintaining the pH at 7.0 or 7.3, and the formed hydrate was added to the solution in the presence of an ammonium salt for 500 hours.
A technique of firing at ５550 ° C. is disclosed. But,
The BET specific surface area of the produced powder was as large as 60 to 76 m ² / g, and was therefore an extremely fine powder, which was not always sufficient for sintering.

[0005] JP-A-7-187613 discloses a method for obtaining an oxide powder having a narrow particle size distribution by firing a metal oxide precursor in an atmosphere containing hydrogen halide or molecular halogen. Have been. In the examples of this publication, a technique of baking commercially available metastannic acid (solid obtained by the reaction of tin metal and nitric acid) in hydrogen chloride is disclosed, but aggregation remains in the primary particles of the generated powder. And it was not always enough for sintering.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tin oxide powder having a small primary particle agglomeration and a narrow particle size distribution, which can be suitably used as a raw material of a tin oxide sintered body used for a sputter target. And a method of manufacturing the same.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reacted an aqueous solution of a tin salt with an alkaline solution to form a tin-containing precipitate, After separating and drying the tin-containing precipitate from the reaction solution of the alkaline solution, the tin-containing precipitate is calcined to produce a tin oxide powder. By controlling the pH in the step of reacting the aqueous solution of the tin salt and the alkaline solution to a specific range different from the prior art, the aggregation of the primary particles is small, the particle size distribution is narrow, and the sputter target is used. The present inventors have found that tin oxide powder which can be suitably used as a raw material of a tin oxide sintered body can be produced, and have completed the present invention.

That is, in the present invention, the particle size calculated from the BET specific surface area is 0.05 μm or more and 1 μm or less, and 10%, 50% and 90% from the fine particle side of the cumulative particle size distribution measured by the laser diffraction scattering method. % As D10, D50, and D90, respectively, (D90-D1
0) A tin oxide powder having a D50 of 2 or less and a D50 of 1 μm or less. Further, the present invention provides a method for producing a tin-containing precipitate by reacting an aqueous solution of a tin salt with an alkaline solution, separating and drying the tin-containing precipitate from a reaction solution of the aqueous solution of the tin salt and the alkaline solution, and then drying the tin-containing precipitate. In the method for producing tin oxide powder to be calcined, the tin salt aqueous solution contains tetravalent tin ions, and the reaction between the tin salt aqueous solution and the alkali solution is performed in a pH range of 0.5 or more and 4 or less. A method for producing the above tin oxide powder, which is performed in a temperature range of 400 ° C. to 1200 ° C. is provided. Further, the present invention provides a tin oxide sintered body using the above tin oxide powder. Further, the present invention provides a sputter target using the above tin oxide sintered body.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the method of the present invention, a tin-containing precipitate is formed by reacting an aqueous solution of a tin salt with an alkali solution, and the tin-containing precipitate is separated from a reaction solution of the aqueous solution of the tin salt and the alkali solution and dried, and then the tin-containing precipitate is formed. The precipitate is calcined. It is necessary that the tin salt aqueous solution contains tetravalent tin ions and that the reaction between the tin salt aqueous solution and the alkali solution be performed at a pH of 0.5 or more and 4 or less. is there. Tin has divalent and tetravalent valences, but when an aqueous solution of a tin salt in which tin is divalent is used,
Although the reason is not clear, it is not possible to obtain tin oxide powder suitable for sintering, and when using an aqueous solution of a tin salt in which tin is mainly tetravalent, tin oxide powder suitable for sintering is used. Can be obtained. In the prior art, the reaction between the aqueous solution of the tin salt and the alkali solution was carried out at around neutrality, that is, at around pH = 7.
When the reaction is carried out in the following pH range, tin oxide powder suitable for sintering can be obtained, although the reason is not clear.

Hereinafter, each step of the method of the present invention and the physical properties of the powder will be described in detail. 4 used in the method of the present invention
As a tin salt aqueous solution containing a valence tin ion, a solution in which metal tin is dissolved in a mixed acid of hydrochloric acid and nitric acid, or an inorganic salt of tin can be used. A tin salt containing tetravalent tin ions is prepared by dissolving metallic tin in hydrochloric acid to prepare a tin chloride aqueous solution containing divalent tin ions, and then oxidizing the divalent tin ions with nitric acid to be tetravalent. An aqueous solution can be used. Further, a tin salt aqueous solution containing divalent tin ions, such as an aqueous stannic chloride solution or an aqueous stannic sulfate solution, is reacted with nitric acid to oxidize the divalent tin ions, thereby generating tetravalent tin ions. A tin salt aqueous solution containing tetravalent tin ions can be used.

[0011] Examples of the form of metallic tin used as a raw material in the method of the present invention include ingots, shots, beads and the like.

The mixed acid used in the method of the present invention is nitric acid 1
Desirably, a mixture obtained by mixing 0.2 to 5 mol of hydrochloric acid with respect to mol is used. If the amount of hydrochloric acid to be mixed is less than 0.2 mol with respect to nitric acid, it becomes difficult to obtain a target tin oxide powder,
If the amount is more than 5 mol, divalent tin ions increase in the aqueous solution of the tin salt, which is not preferable.

The concentration of nitric acid used in the method of the present invention is
In order to set the reaction time to be industrially practicable, it is preferably at least 6 mol / l. Since the concentration of industrially available nitric acid is up to 16 mol / l,
The concentration of nitric acid in the method of the present invention is from 6 mol / l to
16 mol / l is preferred.

The temperature at the time of the reaction between the metal tin and the above mixed acid to obtain a tin salt aqueous solution containing tetravalent tin ions is preferably 40 ° C. or higher. If the temperature is lower than 40 ° C., the reaction is slow and the reaction requires a long time, which is not preferable as an industrial production method.

The tin concentration in the tin salt aqueous solution is 20 to
A range of 400 g / l is preferred. Tin concentration is Sn
As less than 20 g / liter, the productivity of the obtained tin oxide powder (the production amount of tin oxide per unit volume of the aqueous solution of tin salt)
, Which is not preferable as an industrial production method. 4
Concentrations above 00 g / liter exceed saturation concentrations.

Next, in the method of the present invention, a tin salt aqueous solution and an alkali solution are reacted to form a tin-containing precipitate. The tin salt aqueous solution and the alkali solution are supplied such that the pH during the reaction between the tin salt aqueous solution and the alkali solution is maintained in the range of 0.5 to 4. If the pH during the reaction is higher than 4 or lower than 0.5, a tin oxide powder suitable for sintering having a targeted narrow particle size distribution cannot be obtained.

Examples of the alkaline solution used in the present invention include aqueous ammonia, an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution.

In order to shorten the filtration time of the obtained tin-containing precipitate, the reaction temperature of the aqueous solution of the tin salt with the alkali solution in the method of the present invention is preferably in the range of 40 ° C. or more and less than 100 ° C.

In the method of the present invention, as a method of reacting an aqueous solution of a tin salt with an alkaline solution to form a tin-containing precipitate, a method of supplying an alkaline solution to an aqueous solution of a tin salt in a reaction vessel, an alkaline solution in the reaction vessel A method of supplying an aqueous solution of a tin salt therein, a method of simultaneously supplying an aqueous solution of a tin salt and an alkaline solution to a reaction tank, and the like can be given.

As a method for producing a tin-containing precipitate by reacting an aqueous solution of a tin salt with an alkaline solution in the method of the present invention, for example, water (e.g., distilled water or ion-exchanged water) having a predetermined amount, a predetermined temperature and a predetermined pH is added to a reaction tank. ) Is added and stirred. The supply of the aqueous solution of the tin salt is started while stirring, and the supply of the aqueous solution of the tin salt lowers the pH of the liquid in the reaction vessel.
A method of supplying a required amount of an alkaline solution so that H is maintained in a range of 0.5 or more and 4 or less can be mentioned.

In the method of the present invention, the tin-containing precipitate formed by the reaction between the aqueous solution of the tin salt and the alkali solution is separated and recovered from the reaction solution of the aqueous solution of the tin salt and the alkali solution by filtration or centrifugation. I do. Examples of the apparatus used for the separation operation include a Nutsche filter, a filter press, a Kelly leaf filter, an extruder centrifuge, a screw discharge centrifugal dehydrator, a thickener, and a batch sedimentation apparatus.

In the method of the present invention, a salt (an ammonium salt such as ammonium nitrate, an alkali metal salt such as sodium nitrate) formed by a reaction between a tin salt and an alkali remains in the tin-containing precipitate after separation from the reaction solution. Because
It is desirable to wash the tin-containing precipitate. As a solution used for washing, water such as distilled water or ion-exchanged water which can dissolve salts by-produced and does not leave a residue derived from the washing solution after drying, or an alkaline aqueous solution such as ammonia water is used. Can be mentioned.

Next, in the method of the present invention, drying is required before firing. Drying can be performed using an industrially usable device such as a conical dryer or a tray type dryer. The drying temperature may be a temperature at which water adhering to the tin-containing precipitate can be removed, and is preferably in a temperature range of 20 ° C to 300 ° C, more preferably 90 ° C to 150 ° C. Further, drying can be performed in a state of being charged in a firing furnace, and the drying step and the firing step can be continuously performed.

The calcination in the method of the present invention is carried out at a temperature in the range of 400 ° C. to 1200 ° C.
A temperature range of 00 ° C or less is desirable. The firing temperature is 400 ° C
If it is less than 1, the crystallization temperature is not sufficient, or the decomposition of salts such as ammonium nitrate adhered to the dried tin-containing precipitate is insufficient. If the firing temperature exceeds 1200 ° C., the primary particles may grow crystals and a part of the particles may aggregate, so that tin oxide powder having good dispersibility of the primary particles may not be obtained.
The appropriate firing time depends on the concentration of the atmosphere gas and the firing temperature, but is preferably 1 minute to 24 hours, more preferably 10 minutes to 10 hours.

As the atmosphere gas for firing in the method of the present invention, air, oxygen, nitrogen, a hydrogen halide gas such as hydrogen chloride, hydrogen bromide, hydrogen iodide, or a halogen gas such as chlorine, bromine, iodine, etc. Is preferably used, but firing in an atmosphere containing a hydrogen halide gas or a halogen gas is more preferable, and firing in an atmosphere gas containing a hydrogen chloride gas is particularly preferable. By firing in an atmosphere gas containing hydrogen chloride gas, tin oxide powder with the least aggregation of primary particles can be obtained.

In the method of the present invention, when firing in an atmosphere containing a hydrogen halide gas or a halogen gas, particularly a hydrogen chloride gas, the gas is preferably 0.5% by volume with respect to the total volume of the atmosphere gas. The firing is performed in an atmosphere gas containing 1% by volume, more preferably 2% by volume or more, more preferably. The upper limit of the concentration of the hydrogen halide gas is not particularly limited, but is preferably 50% by volume or less, more preferably 20% by volume or less, and still more preferably 10% by volume or less from the viewpoint of industrial productivity. Examples of the diluting gas for the gas include an inert gas such as argon, nitrogen, oxygen, air, and a mixed gas thereof.

In the method of the present invention, when firing is performed in a hydrogen halide gas or an atmosphere containing a halogen gas,
As a method for supplying the atmospheric gas, for example, a cylinder or the like in which a gas is mixed at a predetermined concentration can be used. The pressure of the atmosphere gas in the firing can be selected in a range used industrially.

In the method of the present invention, examples of the firing apparatus include firing furnaces such as a gas furnace, an electric furnace, and a tunnel furnace.

In the method of the present invention, when calcination is performed in an atmosphere containing a hydrogen halide gas or a halogen gas,
The firing furnace is preferably made of a material that is not corroded by hydrogen halide gas or halogen gas, and is preferably airtight. When calcination is performed in an atmosphere containing a hydrogen halide gas or a halogen gas in the method of the present invention, a container (a crucible or a boat) for storing a high-temperature portion of the firing furnace or a tin-containing precipitate is made of alumina, quartz, acid-resistant brick or graphite. It is preferable that it is manufactured.

The tin oxide powder after firing by the method of the present invention can be pulverized if necessary. Examples of the method of pulverizing tin oxide powder include, for example, a method commonly used in industry, such as a vibration mill, a ball mill, a jet mill, and an attrition mill.The tin oxide powder of the present invention is an agglomeration of primary particles. Therefore, for example, a light grinding method using a ball mill, a jet mill, or the like can be used. In ball mill pulverization, any of dry pulverization, wet pulverization or a combination thereof can be used.

Examples of the pulverizing container used for pulverizing the tin oxide powder according to the method of the present invention include those made of alumina, resin, and the like. Examples of the pulverizing balls include those made of alumina, zirconia, and resin. Things can be mentioned. In order to suppress contamination from the crushing container and the balls during the ball mill crushing, it is preferable to use a resin container as the crushing container and a zirconia ball with high wear resistance as the crushing ball.

The tin oxide powder of the present invention has a particle size calculated from the BET specific surface area (hereinafter referred to as “BET specific surface area diameter”).
Is not less than 0.05 μm and not more than 1 μm, and the particle diameters of 10%, 50% and 90% from the fine particle side of the cumulative particle size distribution by the laser diffraction scattering method are D10 and D5, respectively.
0 and D90, (D90−D10) / D50 is 2 or less, preferably 1.5 or less, and D50 is 1 μm
It has the following particle size distribution: The tin oxide powder of the present invention can be suitably used for sintering because it has an appropriate particle size for sintering and has a uniform particle size with little aggregation of primary particles.
When the BET specific surface area diameter is smaller than 0.05 μm, the primary particles aggregate and the sinterability decreases. BET specific surface area diameter is 1μm
If it is larger, the sinterability decreases. (D90-D10) /
When D50 is larger than 2, the sinterability is reduced because the particle diameter is not uniform. If D50 is too large, the particle size is too large, and the sinterability decreases. D50 / (BET specific surface area diameter) is 1 to
10 is preferred. If it is larger than 10 or smaller than 1, there may be a large number of agglomerated particles, strong agglomeration and reduced sinterability.

The method for sintering the tin oxide powder of the present invention includes:
For example, a known method disclosed in Japanese Patent Application Laid-Open No. H11-116325 can be used. The sintered body produced using the tin oxide powder of the present invention is suitable as a sputter target for producing a transparent conductive film. Can be used for

[0034]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

In the present invention, the cumulative particle size distribution and BE
The measurement of the T specific surface area was performed as follows. 1. Particle size distribution The particle size distribution was measured using a SALD-2000A model manufactured by Shimadzu Corporation, which is a particle size distribution measuring apparatus based on a laser diffraction scattering method. 2. BET specific surface area The BET specific surface area was measured using a flowsorb II2300 model manufactured by Shimadzu Corporation, a BET specific surface area measuring device. The BET specific surface area diameter was calculated by the following equation. BET specific surface area diameter (μm) = 6 / (S * ρ) S is the BET specific surface area (m ² / g) and ρ is the theoretical density of tin oxide, which is 7.00 g / cm ³ .

Example 1 600 ml of hydrochloric acid having a concentration of 35% by mass and a concentration of 60
A mixed acid (A) (molar ratio of hydrochloric acid / nitric acid = 2.6) was obtained by mixing 200 ml of mass% nitric acid. Metal tin 113.66
g and the mixed acid (A) were mixed to obtain a tin chloride (tetravalent) aqueous solution. Next, 1 liter of pure water was placed in a separable flask having a capacity of 2 liters and kept at 60 ° C. While stirring 1 liter of the pure water at 60 ° C. at a stirring rotation speed of 290 rpm, 627.34 g of an aqueous solution of tin chloride (tetravalent) and aqueous ammonia having a concentration of 28% by mass are maintained at a pH of 2.0 during the reaction. For 122 minutes to produce a tin-containing precipitate. After the formation of the tin-containing precipitate, the mixture was stirred at 60 ° C. for 30 minutes, and left still at room temperature overnight to mature the precipitate. The tin-containing precipitate was adjusted to pH = 8 and stirred at room temperature for 30 minutes. Next, suction filtration was performed, washing was performed, and the precipitate was collected. The precipitate was dried at 130 ° C.

Next, the dried precipitate was charged into an alumina boat and fired in a tubular furnace. Firing temperature is 11
30 minutes at 00 ° C, heating rate is 10 ° C up to 900 ° C
/ Minute from 900 ° C, 5 ° C / minute. As atmosphere gas, only air is allowed to flow from room temperature to 1000 ° C.
From 00 ° C to 1100 ° C, 2.5% by volume hydrogen chloride gas-97.5% by volume air was flown. After the firing, the air was cooled by flowing only air, and the powder taken out of the furnace was washed with water and dried to obtain a tin oxide powder. The obtained tin oxide powder was wet-pulverized.

When the particle size distribution of the tin oxide powder obtained by wet pulverization was measured, D50 was 0.65 μm and (D90
-D10) / D50 was 1.05. The BET specific surface area was 4.42 m ² / g. The calculated BET specific surface area diameter is 0.19 μm, and the value obtained by dividing D50 by the BET specific surface area diameter is 3.42.

Example 2 30.0 kg of metallic tin was dissolved in 39.7 kg of 35 mass% hydrochloric acid to obtain an aqueous tin chloride (divalent) solution (A). Subsequently, 352.5 g of tin chloride (divalent) aqueous solution (A) and a concentration of 35% by mass were used.
Was mixed with 209.5 g of hydrochloric acid to obtain a tin chloride (divalent) aqueous solution (B). Then, tin chloride (divalent) aqueous solution (B) was added to 8
It was kept at 0 ° C. A concentration of 6 in this solution maintained at 80 ° C.
188.5 g of 0 mass% nitric acid was added dropwise over 68 minutes to obtain a tin chloride (tetravalent) aqueous solution (C). Next, 1 liter of pure water was placed in a 2 liter separable flask,
Held. While stirring 1 liter of the pure water at 60 ° C. at a stirring rotation speed of 298 rpm, 733.3 g of a tin chloride (tetravalent) aqueous solution (C) and a 28% by mass ammonia water solution were added.
The reaction was carried out by simultaneously supplying over 122 minutes to maintain the pH during the reaction at 2.0, thereby producing a tin-containing precipitate. After the formation of the tin-containing precipitate, the mixture was stirred at 60 ° C. for 30 minutes, and left still at room temperature overnight to mature the precipitate. The tin-containing precipitate was adjusted to pH 8 and stirred at room temperature for 30 minutes. Next, suction filtration was performed, washing was performed, and the precipitate was collected. This precipitate is
Dried at 30 ° C.

Next, the dried precipitate was filled in an alumina boat and fired in a tubular furnace. Firing temperature is 11
30 minutes at 00 ° C, heating rate is 10 ° C up to 900 ° C
/ Minute from 900 ° C, 5 ° C / minute. As atmosphere gas, only air is allowed to flow from room temperature to 1000 ° C.
From 00 ° C to 1100 ° C, 2.5% by volume hydrogen chloride gas-97.5% by volume air was flown. After the firing, the air was cooled by flowing only air, and the powder taken out of the furnace was washed with water and dried to obtain a tin oxide powder. The BET specific surface area of the obtained tin oxide powder was 3.12 m ² / g. The obtained tin oxide powder was wet-pulverized.

When the particle size distribution of the tin oxide powder obtained by the wet pulverization was measured, D50 was 0.49 μm and (D9
0-D10) / D50 was 0.72. The BET specific surface area was 13.09 m ² / g. The calculated BET specific surface area diameter is 0.07 μm, and the value obtained by dividing D50 by the BET specific surface area diameter is 7.00.

Comparative Example 1 Metal tin was reacted with nitric acid having a concentration of 60% by mass to obtain metastannic acid (solid). Then perform suction filtration, wash,
Metastannic acid was recovered. After drying this metastannic acid at 130 ° C., it was charged into a quartz glass boat and fired in a tubular furnace. The firing temperature is 1100 ° C for 60 minutes,
The heating rate was 5 ° C./min. As the atmosphere gas, only air is allowed to flow from room temperature to 1000 ° C., and from 1000 ° C. to 1100 ° C., 20% by volume of hydrogen chloride gas−80% by volume.
The air was shed. After the firing, the air was cooled by flowing only air, and the powder taken out of the furnace was washed with water and dried to obtain a tin oxide powder.
The obtained tin oxide powder was wet-pulverized. When the particle size distribution of the crushed tin oxide powder was measured, D50 was 1.32 μm.
m, (D90−D10) / D50 is 2.35, and B
The ET specific surface area was 9.26 m ² / g. The BET specific surface area diameter is 0.09 μm, and the value obtained by dividing D50 by the BET specific surface area diameter is 14.67.

Comparative Example 2 30.0 kg of metallic tin was dissolved in 39.7 kg of 35% by mass hydrochloric acid to obtain an aqueous solution of tin chloride (divalent). Next, 400 ml of pure water was placed in a 1 liter separable flask and maintained at 60 ° C. While stirring 400 ml of the pure water at 60 ° C. at a stirring rotation speed of 250 rpm, 150.0 g of an aqueous solution of tin chloride (divalent) and 28% by mass of aqueous ammonia were added to form 65% so that the pH during the reaction was maintained at 6.0. The reaction was fed simultaneously over a period of minutes to produce a tin-containing precipitate. After the formation of the tin-containing precipitate, the mixture was stirred at 60 ° C. for 30 minutes, and left still at room temperature overnight to mature the precipitate. The tin-containing precipitate was adjusted to pH = 8 and stirred at room temperature for 30 minutes. Next, suction filtration was performed, washing was performed, and the precipitate was collected. The precipitate was dried at 130 ° C.

Next, the dried precipitate was charged into an alumina boat and fired in a tubular furnace. Firing temperature is 11
30 minutes at 00 ° C, heating rate is 10 ° C up to 900 ° C
/ Minute from 900 ° C, 5 ° C / minute. As atmosphere gas, only air is allowed to flow from room temperature to 1000 ° C.
From 00 ° C to 1100 ° C, 10% by volume of hydrogen chloride gas-90% by volume of air was flowed. After the firing, the air was cooled by flowing only air, and the powder taken out of the furnace was washed with water and dried to obtain a tin oxide powder. When the particle size distribution of the obtained tin oxide powder was measured, D50 was 1.77 μm, and (D90-D10) /
D50 was 2.36.

[0045]

The tin oxide powder of the present invention is a powder which is suitable for sintering and has a small primary particle agglomeration and a narrow particle size distribution. The tin oxide powder can be produced by the production method of the present invention. The present invention is industrially useful.

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Kunio Saegusa 6 Kitahara, Tsukuba, Ibaraki F-term in Sumitomo Chemical Co., Ltd. 4K029 BA47 DC05 DC09

Claims (9)

[Claims] A particle diameter calculated from a BET specific surface area is 0.0
5 μm or more and 1 μm or less, and the particle diameters of 10%, 50% and 90% from the fine particle side of the cumulative particle size distribution measured by the laser diffraction scattering method are D10, D50,
Tin oxide powder wherein D90 is (D90-D10) / D50 is 2 or less and D50 is 1 μm or less. 2. The tin oxide powder according to claim 1, wherein a value obtained by dividing D50 by a particle diameter calculated from a BET specific surface area is 1 to 10. 3. An aqueous solution of a tin salt and an alkaline solution are reacted to form a tin-containing precipitate. The tin-containing precipitate is separated from a reaction solution of the aqueous solution of the tin salt and the alkali solution and dried. In the method for producing a tin oxide powder to be calcined, the tin salt aqueous solution is a tin salt aqueous solution containing tetravalent tin ions, and the reaction between the tin salt aqueous solution and the alkali solution is performed at a pH of 0.5 or more and 4 or less. And the firing is performed at 400 ° C. or more and 1200 ° C.
The method for producing tin oxide powder according to claim 1, wherein the method is performed in the following temperature range. 4. The method for producing tin oxide powder according to claim 3, wherein the firing is performed in an atmosphere gas containing 0.5% by volume or more of a hydrogen halide gas or a halogen gas. 5. A tin salt aqueous solution containing tetravalent tin ions, and a mixed acid obtained by mixing 0.2 mol to 5 mol of hydrochloric acid with respect to 1 mol of nitric acid to react with metal tin. 4. The method for producing tin oxide powder according to claim 3, which is an aqueous solution of a tin salt containing monovalent tin ions. 6. A tin salt aqueous solution containing tetravalent tin ions obtained by reacting a tin salt aqueous solution containing divalent tin ions with nitric acid. A method for producing the tin oxide powder described above. 7. The method for producing tin oxide powder according to claim 6, wherein the tin salt aqueous solution containing divalent tin ions is a tin salt aqueous solution containing divalent tin ions obtained by reacting metal tin with hydrochloric acid. . 8. A tin oxide sintered body using the tin oxide powder according to claim 1. 9. A sputter target using the tin oxide sintered body according to claim 8.