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Preparation method of low-sodium microcrystalline alpha aluminum oxide

A technology of α-alumina and alumina, which is applied in the field of preparation of low-sodium microcrystalline α-alumina, which can solve problems such as incomplete acid elution of sodium, side effects of ceramic products, and harsh equipment requirements, and achieve easy sintering shrinkage, original crystal The effect of small particle size and low cost

Pending Publication Date: 2021-04-20
中铝山东有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

During the course of the invention, the applicant found that: calcining and desodiumizing under vacuum conditions are demanding on equipment, and the cost also rises accordingly; acid elution is not thorough, and the general product Na 2 O≥0.10%; direct mineralization and calcination requires the participation of a large amount of mineralizers, which react with sodium ions to form gaseous sodium-containing compounds, which form severe cyclic loads in the kiln, resulting in abnormal growth of the original grain size and remaining in the α Mineralizers in alumina will also bring side effects to the production of ceramic products

Method used

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  • Preparation method of low-sodium microcrystalline alpha aluminum oxide
  • Preparation method of low-sodium microcrystalline alpha aluminum oxide

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preparation example Construction

[0031] According to a typical embodiment of the present invention, a method for preparing low-sodium microcrystalline α-alumina is provided, the method comprising:

[0032] S1. Obtain raw materials, which include aluminum hydroxide or aluminum oxide;

[0033] S2. Mixing a sodium-removing agent and a calcining aid with the raw material to obtain a calcined mixture, the active ingredient of the sodium-removing agent includes silicon dioxide;

[0034] S3. Calcining the calcined mixture, and obtaining the low-sodium microcrystalline α-alumina after cooling;

[0035] S4. Low-sodium microcrystalline α-alumina is sieved to separate the sodium-removing agent.

[0036] When aluminum hydroxide or alumina raw materials are calcined at high temperature, along with the transformation to α-crystal phase, the crystal changes from aluminum-oxygen tetrahedral structure to octahedral structure. During the process of structural rearrangement, intergranular sodium ions gradually dissociate to th...

Embodiment 1

[0046] S1. Take industrial alumina A(Na 2 O content is 0.48%) as raw material;

[0047] S2. Add 1%-5% deep desodium agent and 0.1%-0.5% ammonium chloride (the amount added accounts for the weight % of alumina), wherein the deep desodium agent is added in granular form, and ammonium chloride is added in solid form ;

[0048] S3. Mix the deep desodium agent, calcination aid and raw materials evenly; use a box-type muffle furnace to calcine in the temperature range of 1250-1300°C, and keep it warm for 1-4h;

[0049] S4. After calcination, cool down naturally, and use a 40-mesh sieve to sieve and separate the product from the reacted deep desodiumizing agent.

Embodiment 2

[0051] S1. Take industrial alumina A(Na 2 O content is 0.48%) as raw material;

[0052] S2. Add 1%-5% deep desodium agent and 0.1%-0.5% ammonium chloride (the amount added accounts for the weight % of alumina), wherein the deep desodium agent is added in granular form, and ammonium chloride is added in solid form ;

[0053] S3. Mix the deep desodium agent, calcination aid and raw materials evenly; use a box-type muffle furnace to calcine in the temperature range of 1300-1350°C, and keep it warm for 1-4h;

[0054] S4. After calcination, cool down naturally, and use a 40-mesh sieve to sieve and separate the product from the reacted deep desodiumizing agent.

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Abstract

The invention particularly relates to a preparation method of low-sodium microcrystalline alpha aluminum oxide, and belongs to the technical field of inorganic non-metallic material synthesis. The method comprises the following steps of: obtaining raw materials including aluminum hydroxide or aluminum oxide; mixing a sodium removing agent and a calcining auxiliary agent with the raw materials, so as to obtain a calcined mixture, and the effective component of the sodium removing agent comprising silicon dioxide; and calcining the calcined mixture, and cooling to obtain the low-sodium microcrystalline alpha aluminum oxide. The prepared low-sodium microcrystalline alpha aluminum oxide has unique excellent performance, high chemical purity, small original grain size, easiness in grinding, good flowability and lower ceramic sintering temperature, and is easy to sinter and shrink to form a compact ceramic body; the whole process avoids adverse effects of foreign substances, such as pollution of a large amount of mineralizing agents to products and the environment; and the adopted sodium removing agent is low in cost and can be repeatedly used.

Description

technical field [0001] The invention belongs to the technical field of synthesis of inorganic non-metallic materials, and in particular relates to a preparation method of low-sodium microcrystalline α-alumina. Background technique [0002] Low-sodium microcrystalline α-alumina is an irreplaceable key basic raw material for special structural ceramics and functional ceramics. It is widely used in electronic power, metallurgy and chemical industry, machinery, energy, environmental protection and other industries. , Consumer electronics, national defense and military industry and other high-tech fields and new industries have also gained more and more applications. [0003] In order to realize low-sodium microcrystalline α-alumina, the current methods generally include calcination under vacuum conditions, pickling, or direct mineralization and desodium calcination. During the course of the invention, the applicant found that: calcining and desodiumizing under vacuum conditions...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/46C04B35/111
Inventor 赵善雷齐波王少武常帅
Owner 中铝山东有限公司