Preparation method of high-porosity aluminum oxide ceramic filter

Abstract

The invention relates to a preparation method of high-porosity aluminum oxide ceramic filter. The preparation method comprises the following steps: preparing aluminum oxide compound powder and aluminum oxide ceramic slurry; freezing and forming the slurry; lyophilizing a frozen blank; and sintering a dried blank. The preparation method specifically comprises the following steps: respectively dissolving soluble aluminum salt, titanium salt, magnesium salt, yttrium salt, lanthanum salt and cerium salt in deionized water, gathering one or more ammonia solutions in the solution to form a mixed solution and settling, and carrying out vacuum filtration, washing by deionized water, drying and calcining to obtain aluminum oxide compound powder; uniformly mixing a tertiary butanol solvent, a dispersant and an adhesive to prepare a premixed solution, ball-milling the aluminum oxide compound powder and the premixed solution at constant temperature, and degassing in vacuum to prepare suspended slurry; freezing and forming the slurry at a temperature lower than the solification temperature of the solvent; lyophilizing the formed frozen blank to obtain a porous blank body; and firing the blank body at a low temperature and sintering the blank body at a high temperature to obtain the aluminum oxide ceramic filter. The whole process is free of any pore forming materials and pollution-free and is an ideal method for preparing the directional high-porosity and high-strength ceramic filter.

Description

technical field [0001] The invention relates to a method for preparing an alumina ceramic filter by a coprecipitation-freeze sublimation process, more precisely, a method for preparing a high-porosity alumina ceramic filter by combining a coprecipitation powder synthesis method with a freeze sublimation molding process. Background technique [0002] The high-temperature dust-containing gas discharged from various industrial furnaces in metallurgy, machinery, chemical industry, electric power and other industries not only has a high temperature (500-1200 ° C), but also contains a large amount of dust (5-30 μm) and corrosive reducing gas. One of the main factors causing environmental pollution. Under high temperature conditions, due to the large change in the viscous force of the dust-laden gas, the humidity drops sharply, and the agglomeration of fine particles is greatly reduced, so it is more difficult to separate the particles. The bag type dust collector cannot bear the ...

AI Technical Summary

Problems solved by technology

Porous ceramics prepared by extrusion molding have uniform pore shape and pore size distribution, but are not suitable for preparing porous ceramics with a pore size of less than 1 mm; porous ceramics prepared by adding a pore-forming agent have poor pore distribution uniformity, and are not suitable for preparing high porosity High-rate products; the foaming method adds organic or inorganic pore-forming agents, generates volatile gases through physical or chemical reactions to produce foams, and is made into porous ceramics after drying and sintering, which is not suitable for the preparation of products with through-pore structures; organic foams The impregnation method prepares porous ceramics, and its pore size mainly depends on the pore size of the organic foam, and its products cannot achieve the filtration of tiny particles; the sol-gel method obtains pores through phase change or chemical reaction, and the pore size is nanoscale. lower

Due to the limitations of the above process itself, the obtained pore size and porosity are limited to a certain range, and it is difficult to prepare porous ceramic filters with micron pore size, high porosity, and high strength.