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Preparation method of large primary crystal alpha-alumina

A technology of alumina and primary crystal, which is applied in the field of preparation of large primary crystal α-alumina, which can solve the problems of unstable performance of α-alumina, downtime and maintenance of kiln equipment, and high maintenance cost, so as to reduce corrosion damage and maintenance The effect of cost and convenient operation

Active Publication Date: 2021-08-06
雅安百图高新材料股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003]However, during the preparation process of alumina powder, the fluorine-containing additives corrode the kiln equipment greatly, causing the kiln equipment to be shut down for maintenance many times. higher cost
On the other hand, due to the difference in the quality of alumina powder raw materials, the performance of the prepared α-alumina is unstable

Method used

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  • Preparation method of large primary crystal alpha-alumina
  • Preparation method of large primary crystal alpha-alumina
  • Preparation method of large primary crystal alpha-alumina

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] A method for preparing large primary crystal α-alumina, comprising the following steps,

[0029] Step 1: Boric acid and calcium carbonate reagent were mixed at a ratio of 10:1 for 20 minutes to obtain M1. Among them, the purity of boric acid and calcium carbonate is greater than 99%.

[0030] Step 2: Add 1%wt of M1 to the γ-alumina raw material and mix with a mixer for 120min to obtain M2. Among them, the moisture content of γ-alumina is less than 3%wt, and the median particle size is 50-100 μm.

[0031] Step 3: Put M2 into a high-temperature furnace for calcination at 1500° C. for 5 hours to obtain M3. Among them, before M2 is put into the high-temperature furnace, the temperature in the furnace will be gradually raised to 1000°C, and the heating time is 1.5-2h. During the heating process, nitrogen and air are alternately injected into the furnace, and the time for a single injection of nitrogen or air is 0.5h. , flow 1~10m 3 / min.

[0032] Step 4: Put M3 into the...

Embodiment 2

[0034] A method for preparing large primary crystal α-alumina, comprising the following steps,

[0035] Step 1: Boric acid and calcium carbonate reagent were mixed at a ratio of 10:2 for 20 minutes to obtain M1. Among them, the purity of boric acid and calcium carbonate is greater than 99%.

[0036] Step 2: Add 2%wt of M1 to the γ-alumina raw material and mix with a mixer for 120min to obtain M2. Among them, the moisture content of γ-alumina is less than 3%wt, and the median particle size is 50-100 μm.

[0037] Step 3: Put M2 into a high-temperature furnace for calcination at 1500° C. for 5 hours to obtain M3. Among them, before M2 is put into the high-temperature furnace, the temperature in the furnace will be gradually raised to 1000°C, and the heating time is 1.5-2h. During the heating process, nitrogen and air are alternately injected into the furnace, and the time for a single injection of nitrogen or air is 0.5h. , flow 1~10m 3 / min.

[0038] Step 4: Put M3 into the...

Embodiment 3

[0041] A method for preparing large primary crystal α-alumina, comprising the following steps,

[0042] Step 1: boric acid and calcium carbonate reagent were mixed at a ratio of 10:2 for 20 minutes to obtain M1, wherein the purity of boric acid and calcium carbonate was greater than 99%.

[0043] Step 2: Add 2%wt of M1 to the γ-alumina raw material and mix with a mixer for 120min to obtain M2. Among them, the moisture content of γ-alumina is less than 3%wt, and the median particle size is 50-100 μm.

[0044] Step 3: Put M2 into a high-temperature furnace for calcination at 1300° C. for 5 hours to obtain M3.

[0045] Step 4: Put M3 into the jet mill to grind, and the classifier cooperates with the classification to select the powder to obtain the product large primary crystal α-alumina, with a median particle size D50 of 4.0 μm. Wherein, the jet mill grinding pressure is 0.50MPa.

[0046] The γ-alumina raw material before calcination and the large primary crystal α-alumina a...

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Abstract

The invention discloses a preparation method of large primary crystal alpha-aluminum oxide, and aims to solve the problem that in the prior art, a fluorine-containing additive seriously corrodes kiln equipment for aluminum oxide powder production. The method comprises the following steps: 1, mixing boric acid and a calcium carbonate reagent in a weight ratio of 10: (0.1-2) for 5-40 minutes to obtain M1; 2, adding the M1 into gamma-aluminum oxide, mixing for 5-120 min, and obtaining M2, wherein the use amount of M1 accounts for 0.2-3% of the weight of gamma-aluminum oxide; 3, calcining the M2 at the temperature of 1300-1500 DEG C for 2-8 hours to obtain M3; and 4, grinding the M3 for 1-3 hours to obtain the large primary crystal alpha-aluminum oxide. According to the preparation method of the large primary crystal alpha-aluminum oxide provided by the invention, no fluorine-containing additive is adopted in the raw materials, so that the corrosion damage to high-temperature kiln equipment is reduced, and the maintenance cost is reduced.

Description

technical field [0001] The invention relates to the technical field of alumina powder preparation, in particular to a method for preparing large primary crystal α-alumina. Background technique [0002] In the field of electronic devices, a large amount of alumina with a median particle size D50 of 2-5 μm is used as a thermally conductive filler, or spherical alumina is prepared from alumina raw materials with a median particle size D50 of 2-5 μm, and the market demand is large. In the prior art, a large amount of fluorine-containing additives are often added during the preparation of alumina powder to promote grain development. [0003] However, during the preparation process of alumina powder, the fluorine-containing additives have great corrosion on the kiln equipment, causing the kiln equipment to need to be shut down for maintenance many times, and the maintenance cost is high. On the other hand, the properties of the prepared α-alumina are unstable due to the differenc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
CPCC01F7/021C01P2004/61C01P2002/72
Inventor 黄君郭洪王石平
Owner 雅安百图高新材料股份有限公司
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