ITO (indium tin oxide) granulation powder as well as preparation method and application thereof

Abstract

The invention relates to ITO (indium tin oxide) granulation powder as well as a preparation method and application thereof, the preparation method of the ITO granulation powder comprises the following steps: (1) ball-milling and mixing tin oxide, indium oxide, a binder, a dispersant and deionized water to obtain mixed slurry; (2) carrying out spray granulation on the mixed slurry obtained in the step (1) to obtain ITO granulation powder; the rotating speed of the spray granulation in the step (2) is 15000 to 2200rpm (revolutions per minute). By controlling the rotating speed of spray granulation and the using amount of the binder, the ITO granulation powder which is small in particle size, high in fluidity and low in powder breakage rate can be obtained, and the performance requirement of the ITO granulation powder serving as a target raw material can be met.

Description

Technical Field

[0001] The invention relates to the technical field of indium tin oxide target material preparation, and in particular to an ITO granulated powder and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of flat panel display and photovoltaic industries, the demand for transparent conductive oxides such as indium tin oxide (ITO) has increased significantly due to its excellent optical and electrical properties. The purity and particle size requirements for the raw materials of such targets have also increased.

[0003] When forming ITO, it is often difficult to fill the forming mold due to the small particle size, poor fluidity and high tap density of the powder, resulting in low density and forming degree of the green blank after forming, and increasing the difficulty of sintering. Spray granulation uses the van der Waals force between particles to connect the powders to form soft agglomerates, and finally the powder particle size increases, the fluidity is enhanced, and the integrity of the green blank can be improved.

[0004] CN 114591070A discloses a method for preparing a high-purity Mo-doped ITO target material, comprising the following steps: (1) stirring and dispersing MoO2, SnO2, water and a dispersant; (2) after stirring and dispersing, ball-milling the mixed solution to a qualified particle size; (3) emulsifying In2O3, water, a dispersant and a binder; (4) adding the emulsified solution to the mixed solution after ball milling in step (2), and continuing to ball mill to a qualified particle size; (5) spray-drying and granulating the mixed solution after ball milling in step (4); (6) preparing a target blank from the granulated powder, and then cold isostatic pressing and sintering. However, the preparation method only regulates the granulation by adjusting the inlet and outlet temperatures, and the particle size of the granulated powder is relatively large, making it difficult to obtain a target material with small crystal grains during the later sintering.

[0005] CN 116332637A discloses a method for preparing ITO rotating target materials for solar cell industry; step S1: raw material selection; step S2: indium tin oxide powder ball milling; step S3: indium oxide + tin oxide mixed powder calcination; step S4: indium oxide + tin oxide calcined powder grinding; step S5: spray granulation; step S6: molding; step S7: high temperature sintering. The invention avoids the target material from being broken due to the violent phase change during the sintering process by calcining first, but has the defects of high production energy consumption and complicated process flow.

[0006] CN 1453392A discloses a method for preparing an indium tin oxide target material, including the steps of preparing an indium tin mixed salt solution, homogeneous coprecipitation of the solution, calcination of the precipitate, oxide deoxidation, cold isostatic pressing, hot isostatic pressing, etc. The invention breaks up the obtained green body and then performs secondary isostatic pressing granulation, and the obtained powder has different shapes, poor mold filling properties, and easily causes uneven green body structure.

[0007] Therefore, in view of the shortcomings of the existing technology, it is urgent to provide an ITO granulated powder with smaller particle size, stronger fluidity and lower powder breakage rate. Summary of the invention

[0008] The purpose of the present invention is to provide an ITO granulated powder and a preparation method and application thereof. By controlling the rotation speed of spray granulation and the amount of binder, an ITO granulated powder with smaller particle size, stronger fluidity and lower powder breakage rate is obtained, which can meet the performance requirements as a target material raw material.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing ITO granulated powder, the preparation method comprising the following steps:

[0011] (1) ball milling tin oxide, indium oxide, a binder, a dispersant and deionized water to obtain a mixed slurry;

[0012] (2) spray granulating the mixed slurry obtained in step (1) to obtain ITO granulated powder;

[0013] The rotation speed of the spray granulation in step (2) is 15000-22000rpm.

[0014] The preparation method of ITO granulated powder provided by the present invention can obtain ITO granulated powder with smaller particle size, stronger fluidity, lower powder breakage rate and higher forming integrity rate by controlling the rotation speed of spray granulation within a reasonable range, thus solving the problems of poor powder fluidity and difficult sintering and meeting the performance requirements as a target material raw material.

[0015] The rotation speed of the spray granulation is 15000-22000 rpm, for example, it can be 15000 rpm, 16000 rpm, 18000 rpm, 20000 rpm or 22000 rpm, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0016] The "rotation speed of spray granulation" mentioned in the present invention refers to the speed at which liquid forms fine droplets through the nozzle in the atomizing equipment.

[0017] Preferably, the average particle size of the tin oxide in step (1) is 48-52 nm, for example, 48 nm, 50 nm or 52 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the average particle size of the indium oxide in step (1) is 98-102 nm, for example, 98 nm, 100 nm or 102 nm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, based on the total mass percentage being 100wt%, the tin oxide in step (1) is 1-10wt%, and the indium oxide is 90-99wt%.

[0020] The tin oxide is 1-10 wt%, for example, 1 wt%, 5 wt% or 10 wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] The indium oxide is 90-99wt%, for example, 90wt%, 95wt% or 99wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the solid content of the mixed slurry in step (1) is 28-32%, for example, it can be 28%, 29%, 30%, 31% or 32%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the mass percentage of the binder in the mixed slurry in step (1) is 2-3wt%, for example, it can be 2wt%, 2.2wt%, 2.5wt%, 2.8wt% or 3wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] In the present invention, by strictly controlling the amount of the binder within a reasonable range, the prepared ITO granulated powder can have the characteristics of small particle size, strong fluidity and low powder breakage rate. If the amount of the binder is too high, it is easy to cause the powder agglomeration particle size to be too large, the powder collection rate is low during subsequent granulation, and the granulation efficiency is reduced. If the amount of the binder is too low, the granulated powder is not easy to form a spherical shape.

[0025] Preferably, the binder in step (1) comprises PVA or PEG.

[0026] Preferably, the mass percentage of the dispersant in the mixed slurry in step (1) is 0.8-1.2wt%, for example, it can be 0.8wt%, 0.9wt%, 1wt%, 1.1wt% or 1.2wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the dispersant in step (1) comprises PAA or citric acid.

[0028] Preferably, the rotation speed of the ball milling mixing in step (1) is 200-250 rpm, for example, it can be 200 rpm, 230 rpm or 250 rpm, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] Preferably, the ball milling mixing time in step (1) is 24-48 hours, for example, 24 hours, 36 hours or 48 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the mixed slurry is placed in a stirrer before the spray granulation in step (2).

[0031] Placing the mixed slurry in a stirrer before the spray granulation can effectively improve the uniformity of the mixed slurry.

[0032] Preferably, the feed rate of the spray granulation in step (2) is 1.8-2.2 L / h, for example, 1.8 L / h, 1.9 L / h, 2 L / h, 2.1 L / h or 2.2 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] Preferably, the air inlet temperature of the spray granulation in step (2) is 155-165°C, and the air outlet temperature is 85-95°C.

[0034] The inlet air temperature of the spray granulation is 155-165° C., for example, 155° C., 158° C., 160° C., 162° C. or 165° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] The outlet air temperature of the spray granulation is 85-95°C, for example, 85°C, 88°C, 90°C, 92°C or 95°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, a peristaltic pump is used to pump the mixed slurry during the spray granulation in step (2).

[0037] In the present invention, a peristaltic pump is used to pump the mixed slurry to the centrifugal nozzle of the spray granulation tower used for spray granulation.

[0038] Preferably, the ITO granulated powder in step (2) is collected by a collector.

[0039] Preferably, the powder adhered to the spray granulation tower used for the spray granulation in step (2) is peeled off by a vibration pump and falls into the collector.

[0040] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0041] (1) ball milling tin oxide with an average particle size of 48-52 nm, indium oxide with an average particle size of 98-102 nm, a binder, a dispersant and deionized water at a rotation speed of 200-250 rpm for 24-48 hours to obtain a mixed slurry with a solid content of 28-32%; based on the total mass percentage of 100wt%, the tin oxide is 1-10wt%, and the indium oxide is 90-99wt%; the mass percentage of the binder in the mixed slurry is 2-3wt%, and the mass percentage of the dispersant is 0.8-1.2wt%;

[0042] (2) placing the mixed slurry obtained in step (1) in a stirrer, and then using a peristaltic pump to pump the mixed slurry for spray granulation, the rotation speed of the spray granulation is 15000-22000rpm, the feed amount is 1.8-2.2L / h, the inlet air temperature is 155-165°C, and the outlet air temperature is 85-95°C; using a collector to collect the ITO granulated powder, and the powder adhered to the spray granulation tower used for spray granulation is peeled off by a vibration pump and falls into the collector.

[0043] In a second aspect, the present invention provides an ITO granulated powder, wherein the ITO granulated powder is prepared by the preparation method described in the first aspect.

[0044] The ITO granulated powder provided by the present invention has a small average particle size and good fluidity, a complete powder morphology, and a low breakage rate, and can meet the performance requirements of being a target material raw material.

[0045] In a third aspect, the present invention provides an application of the ITO granulated powder as described in the second aspect, wherein the ITO granulated powder is used to prepare an ITO target material, and the ITO target material is used in the field of flat panel displays or solar cells.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The preparation method of ITO granulated powder provided by the present invention can obtain ITO granulated powder with smaller particle size, stronger fluidity, lower powder breakage rate and higher forming integrity rate by controlling the rotation speed of spray granulation and the dosage of binder within a reasonable range, thereby solving the problems of poor powder fluidity and difficult sintering and meeting the performance requirements as a target material raw material. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a SEM image of the ITO granulated powder provided in Example 1 of the present invention;

[0049] Figure 2 is a SEM image of the ITO granulated powder provided in Example 2 of the present invention;

[0050] Figure 3 This is a SEM image of the ITO granulated powder provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0052] Example 1

[0053] This embodiment provides an ITO granulated powder, and the preparation method of the ITO granulated powder comprises the following steps:

[0054] (1) ball milling tin oxide with an average particle size of 50 nm, indium oxide with an average particle size of 100 nm, PVA, PAA and deionized water at a rotation speed of 230 pm for 36 hours to obtain a mixed slurry with a solid content of 30%; based on the total mass percentage of 100 wt%, the tin oxide is 5 wt% and the indium oxide is 95 wt%; the mass percentage of PVA in the mixed slurry is 2.5 wt% and the mass percentage of PAA is 1 wt%;

[0055] (2) placing the mixed slurry obtained in step (1) in a stirrer, and then using a peristaltic pump to pump the mixed slurry for spray granulation, the rotation speed of the spray granulation is 15000rpm, the feed amount is 2L / h, the inlet air temperature is 160°C, and the outlet air temperature is 90°C; using a collector to collect the ITO granulated powder, the powder adhered in the spray granulation tower used for spray granulation is peeled off by a vibration pump and falls into the collector.

[0056] The SEM image of the ITO granulated powder obtained in this embodiment is as follows: Figure 1 As shown in the figure, it can be seen that the morphology of ITO granulated powder is complete and the breakage rate is low.

[0057] Example 2

[0058] This embodiment provides an ITO granulated powder, and the preparation method of the ITO granulated powder comprises the following steps:

[0059] (1) mixing tin oxide with an average particle size of 52 nm, indium oxide with an average particle size of 102 nm, PVA, PAA and deionized water by ball milling at a rotation speed of 250 rpm for 24 hours to obtain a mixed slurry with a solid content of 28%; based on the total mass percentage of 100 wt%, the tin oxide is 10 wt% and the indium oxide is 90 wt%; the mass percentage of PVA in the mixed slurry is 3 wt% and the mass percentage of PAA is 0.8 wt%;

[0060] (2) placing the mixed slurry obtained in step (1) in a stirrer, and then using a peristaltic pump to pump the mixed slurry for spray granulation, the rotation speed of the spray granulation is 15000 rpm, the feed amount is 1.8 L / h, the inlet air temperature is 155°C, and the outlet air temperature is 85°C; using a collector to collect the ITO granulated powder, the powder adhered in the spray granulation tower used for spray granulation is peeled off by a vibration pump and falls into the collector.

[0061] The SEM image of the ITO granulated powder obtained in this embodiment is as follows: Figure 2 As shown in the figure, it can be seen that the morphology of ITO granulated powder is complete and the breakage rate is low.

[0062] Example 3

[0063] This embodiment provides an ITO granulated powder, and the preparation method of the ITO granulated powder comprises the following steps:

[0064] (1) ball milling tin oxide with an average particle size of 48 nm, indium oxide with an average particle size of 98 nm, PEG, citric acid and deionized water at a rotation speed of 200 rpm for 48 hours to obtain a mixed slurry with a solid content of 32%; based on the total mass percentage of 100 wt%, the tin oxide is 1 wt% and the indium oxide is 99 wt%; the mass percentage of PEG in the mixed slurry is 2 wt%, and the mass percentage of citric acid is 1.2 wt%;

[0065] (2) placing the mixed slurry obtained in step (1) in a stirrer, and then using a peristaltic pump to pump the mixed slurry for spray granulation, the rotation speed of the spray granulation is 22000rpm, the feed amount is 2.2L / h, the inlet air temperature is 165°C, and the outlet air temperature is 95°C; using a collector to collect the ITO granulated powder, the powder adhered in the spray granulation tower used for spray granulation is peeled off by a vibration pump and falls into the collector.

[0066] The SEM image of the ITO granulated powder obtained in this embodiment is as follows: Figure 3 As shown in the figure, it can be seen that the morphology of ITO granulated powder is complete and the breakage rate is low.

[0067] Example 4

[0068] This embodiment provides an ITO granulated powder. The difference between the preparation method of the ITO granulated powder and that of Embodiment 1 is that, except for adjusting the mass percentage of PVA in the mixed slurry in step (1) to 1.5wt%, the rest is the same as that of Embodiment 1.

[0069] Example 5

[0070] This embodiment provides an ITO granulated powder. The difference between the preparation method of the ITO granulated powder and that of Embodiment 1 is that, except for adjusting the mass percentage of PVA in the mixed slurry in step (1) to 3.5wt%, the rest is the same as that of Embodiment 1.

[0071] Example 6

[0072] This embodiment provides an ITO granulated powder. The difference between the preparation method of the ITO granulated powder and that of Embodiment 1 is that, except for adjusting the inlet air temperature of the spray granulation in step (2) to 150°C and the outlet air temperature to 80°C, the rest is the same as that of Embodiment 1.

[0073] Example 7

[0074] This embodiment provides an ITO granulated powder. The difference between the preparation method of the ITO granulated powder and that of Embodiment 1 is that, except for adjusting the inlet air temperature of the spray granulation in step (2) to 170°C and the outlet air temperature to 100°C, the rest is the same as that of Embodiment 1.

[0075] Comparative Example 1

[0076] This comparative example provides an ITO granulated powder. The difference between the preparation method of the ITO granulated powder and that of Example 1 is that, except for adjusting the rotation speed of the spray granulation in step (2) to 14000 rpm, the rest is the same as that of Example 1.

[0077] Comparative Example 2

[0078] This comparative example provides an ITO granulated powder. The difference between the preparation method of the ITO granulated powder and that of Example 1 is that, except for adjusting the rotation speed of the spray granulation in step (2) to 23000 rpm, the rest is the same as that of Example 1.

[0079] The ITO granulated powders provided in Examples 1-7 and Comparative Examples 1 and 2 were tested for particle size using a laser particle size analyzer. The fluidity of the ITO granulated powders was visually observed and the results were classified as "excellent", "good", "average" and "poor". The results are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] It can be seen from Table 1 that the ITO granulated powder provided by the present invention has a small particle size and good fluidity, and can meet the performance requirements of being used as a target material raw material;

[0084] By comparing Example 1 with Examples 4 and 5, it can be seen that if the amount of binder is too low or too high, the granulation powder forming rate is low; by comparing Example 1 with Examples 6 and 7, it can be seen that if the inlet and outlet air temperatures of the spray granulation are too low, the granulation powder forming rate will be low, and if the temperature is too high, the slurry will dry instantly, resulting in serious particle agglomeration;

[0085] By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that if the rotation speed of the spray granulation is too low, the obtained powder particle size is relatively high, and if the rotation speed is too high, the obtained powder particle size is relatively small. However, if the rotation speed exceeds the limited range, the fluidity of the powder will decrease.

[0086] In summary, the preparation method of ITO granulated powder provided by the present invention can obtain ITO granulated powder with smaller particle size, stronger fluidity, low powder breakage rate and high forming integrity rate by controlling the rotation speed of spray granulation and the amount of binder used within a reasonable range, which solves the problems of poor powder fluidity and difficult sintering, and can meet the performance requirements as a target material raw material.

[0087] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing ITO granulated powder, characterized in that: The preparation method comprises the following steps: (1) ball milling tin oxide, indium oxide, a binder, a dispersant and deionized water to obtain a mixed slurry; (2) spray granulating the mixed slurry obtained in step (1) to obtain ITO granulated powder; The rotation speed of the spray granulation in step (2) is 15000-22000rpm.

2. The preparation method according to claim 1, characterized in that: The average particle size of the tin oxide in step (1) is 48-52 nm; Preferably, the average particle size of the indium oxide in step (1) is 98-102 nm; Preferably, based on the total mass percentage being 100wt%, the tin oxide in step (1) is 1-10wt%, and the indium oxide is 90-99wt%.

3. The preparation method according to claim 1 or 2, characterized in that: The solid content of the mixed slurry in step (1) is 28-32%; Preferably, the mass percentage of the binder in the mixed slurry in step (1) is 2-3wt%; Preferably, the binder in step (1) comprises PVA or PEG.

4. The preparation method according to any one of claims 1 to 3, characterized in that The mass percentage of the dispersant in the mixed slurry of step (1) is 0.8-1.2wt%; Preferably, the dispersant in step (1) comprises PAA or citric acid.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The rotation speed of the ball milling mixing in step (1) is 200-250 rpm; Preferably, the ball milling mixing time in step (1) is 24-48 hours.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the mixed slurry is placed in a stirrer before the spray granulation; Preferably, the feed rate of the spray granulation in step (2) is 1.8-2.2 L / h; Preferably, the air inlet temperature of the spray granulation in step (2) is 155-165°C, and the air outlet temperature is 85-95°C.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (2), a peristaltic pump is used to pump the mixed slurry during the spray granulation; Preferably, the ITO granulated powder in step (2) is collected by a collector; Preferably, the powder adhered to the spray granulation tower used for the spray granulation in step (2) is peeled off by a vibration pump and falls into the collector.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) ball milling tin oxide with an average particle size of 48-52 nm, indium oxide with an average particle size of 98-102 nm, a binder, a dispersant and deionized water at a rotation speed of 200-250 rpm for 24-48 hours to obtain a mixed slurry with a solid content of 28-32%; based on the total mass percentage of 100wt%, the tin oxide is 1-10wt%, and the indium oxide is 90-99wt%; the mass percentage of the binder in the mixed slurry is 2-3wt%, and the mass percentage of the dispersant is 0.8-1.2wt%; (2) placing the mixed slurry obtained in step (1) in a stirrer, and then using a peristaltic pump to pump the mixed slurry for spray granulation, the rotation speed of the spray granulation is 15000-22000rpm, the feed amount is 1.8-2.2L / h, the inlet air temperature is 155-165°C, and the outlet air temperature is 85-95°C; using a collector to collect the ITO granulated powder, and the powder adhered to the spray granulation tower used for spray granulation is peeled off by a vibration pump and falls into the collector.

9. An ITO granulated powder, characterized in that: The ITO granulated powder is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of the ITO granulated powder as claimed in claim 9, characterized in that: The ITO granulated powder is used to prepare an ITO target material, and the ITO target material is used in the field of flat panel display or solar cell.

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