Preparation method of porous mullite block

A technology for porous mullite and block, which is applied in the field of preparation of porous mullite blocks, can solve problems such as difficult control, complicated processes such as co-hydrolysis sol-gel transition and phase separation, and achieves low equipment cost and low process technology. simple effect

Inactive Publication Date: 2013-08-14
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the theoretical basis for the preparation of porous bulks from single-component systems has been established, there is little research on two-phase or three-phase systems such as SiO 2 -Al 2 o 3 , CaO-Al 2 o 3 , MgO-Al 2 o 3 -SiO 2 , and research on complex oxide porous materials such as mullite, mayenite, and cordierite
Because compared with the one-component system, the processes of co-hydrolysis, formation of homogeneous complex sol, sol-gel transition and phase separation are more complicated and difficult to control in the binary or ternary system.

Method used

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  • Preparation method of porous mullite block

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Effect test

Embodiment 1

[0020] Embodiment 1, a kind of preparation method of porous mullite block body, with 2g aluminum chloride hexahydrate (AlCl 3 ·6H 2 O) as aluminum source, 0.2805 mL of orthomethyl silicate (TMOS) as silicon source, 1.8 mL of propylene oxide (PO) as gel accelerator, 0.025 g of polyethylene oxide (PEO, average molecular weight 1×10 6 ) is a phase separation inducer; the following steps are carried out in sequence:

[0021] 1), first 2g aluminum chloride hexahydrate (AlCl 3 ·6H 2 O) and 0.025g of polyethylene oxide (PEO) were dissolved in a solvent consisting of 2.1mL of ethanol and 2mL of deionized water, and then 0.2805mL of orthomethyl silicate (TMOS) was added dropwise under stirring; 1 minute dropwise After finishing, continue stirring reaction 60min; Reaction temperature is room temperature;

[0022] 2) At room temperature, quickly add 1.8mL propylene oxide (PO) to the product obtained in step 1) (a transparent and clear solution), and stir evenly for 1 minute to obtai...

Embodiment 2

[0027] Embodiment 2, a kind of preparation method of porous mullite block,

[0028] Change the heat treatment temperature in Step 5) of Example 1 from 800°C to 1100°C, and the rest are the same as in Example 1.

[0029] The prepared porous mullite block crystallizes well and completely, and has a co-continuous macroscopic through-pore structure and a complete framework (see figure 1 ), while the framework consists of disc-like or needle-like nanocrystalline particles. Its pore size distribution is concentrated, and its bulk density is about 1.34 g cm -3 , the calculated relative density is 42%. The N of the porous mullite block 2 The adsorption-desorption curve is H3 type, indicating that the block has slit-like mesopores due to its skeleton structure, and the mesopores almost disappear. The average pore size of the macropores is 1.2 μm, and the specific surface area is 54 m 2 / g.

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Abstract

The invention discloses a preparation method of a porous mullite block. The preparation method of the porous mullite block comprises the following steps of: (1) dissolving aluminum chloride hexahydrate and polyoxyethylene in a solvent, dropwise adding tetramethyl orthosilicate, and then stirring continuously and reacting for 50-70minutes; (2) under the room temperature, adding epoxypropane in the mixture obtained in the step (1) and stirring uniformly to obtain a homogeneous solution; (3) sealing the homogeneous solution in a container and then gelling at 35-45 DEG C for 8-12minutes to obtain wet gel; (4) aging the wet gel at 35-45 DEG C for 68-76 hours; and (5) drying the aged gel prepared in the step (4) at 70-80 DEG C for 2-3 days, and then carrying out heat treatment at 800-1400 DEG C for 4-6 hours to obtain the porous mullite block. The porous mullite block prepared by the method has the characteristics that the block has a hierarchical porous structure, the size and amount of apertures are controllable, the frameworks are continuous, the specific surface area is large, and the like.

Description

technical field [0001] The invention relates to a method for preparing a porous mullite block, in particular to a method for preparing a porous mullite block with a sol-gel phase separation method. Background technique [0002] Mullite (usually composed of 3Al 2 o 3 2SiO2 2 ) is the SiO 2 -Al 2 o 3 The only stable crystal in a two-phase system and one of the most common industrial ceramics. Because mullite has excellent high temperature strength, creep resistance, low thermal expansion coefficient, good dielectric properties, high transmittance in the mid-infrared region, good chemical stability and thermal stability, and can be maintained at elevated temperatures It has excellent mechanical properties and stability in oxidizing atmosphere, and it has important application prospects in electronics, optics and high temperature structures. [0003] Porous mullite with controllable porous structure has become a new development in the application of mullite in catalyst su...

Claims

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Application Information

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IPC IPC(8): C04B30/00C01B33/26
Inventor 郭兴忠吕林一秀杨辉李文彦
Owner ZHEJIANG UNIV
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