The ceramic foam filters manufacturing raw material is made of an open-cell hydrophilic flexible foam material having a plurality of interconnected voids, which are surrounded by a net of the flexible foam material. Typical materials that can be used include polymer foams, such as polyurethane foams, and cellulose foams. Generally, any combustible organic plastic foam that has elasticity and the ability to restore its original shape can be used. The foam must be burned or volatilized below the firing temperature of the ceramic material used. Likewise, a foam material with 5 to 100 pores per inch should be used to provide the necessary filtering surface. Of course, the size of the foam material can vary according to the desired size of the end filter material.
Generally, the aqueous ceramic slurry used naturally depends on the desired ceramic material of the selected metal to be filtered. A structure and/or mechanical strength that must have sufficient properties in the final product to resist specific molten metal chemical attack and resist specific high temperature conditions. In addition, the slurry should have high fluidity and consist of an aqueous suspension of ceramics intended for use in filters. Typical ceramic materials that can be used include aluminum oxide, chromium oxide, zirconium oxide, magnesium oxide, titanium dioxide, silicon dioxide and mixtures thereof. The preferred ceramic material includes 40 to 95% Al 2 O 3; preferably, the content of Al 2 O 3 is 50%. 1 to 25% Cr 2 O 3; 0.1 to 12% bentonite; 0.1 to 12% kaolin; and 2.5% to 25% air setting agent. According to the present invention, the ceramic fiber additive is added to the ceramic slurry and dispersed therein by a high-intensity mixer. It has been found that adding more than 5% by weight of ceramic fibers to the slurry can cause agglomeration of the fibers, so that good dispersibility cannot be obtained. In addition, it has been found that at least 1% must be added to significantly increase the strength. Ideally, the addition amount preferably exceeds 1.5%.
Ceramic Foam Filters Manufacturing Process
An aqueous ceramic slurry with ceramic fiber additives is prepared, and the foam is impregnated with the foam material to coat the fiber web with it and substantially fill the voids with it. Then, compress the impregnated material by squeezing through a preset roll, so that about 80% of the slurry is preferably discharged, and the balance is evenly distributed throughout the foam material, preferably, so that some holes are uniformly distributed Blocked to increase the twists and turns. The coated foam material is then dried and heated to first burn out the flexible organic foam, and then sinter the ceramic coating, thereby providing a molten ceramic foam with a plurality of interconnected voids, which is bonded in the flexible foam construction Or surrounded by molten ceramic mesh. Ceramic fibers protrude from the walls of the molten ceramic, thereby providing a fuzzy surface on the pores of the ceramic foam filter, which tends to increase the molten metal filtration efficiency.