The filtering capacity (the efficiency of removing inclusions) of the aluminum cast house ceramic foam filter mainly depends on the roughness (number of meshes) of the mesh formed in the aggregate mesh member. Therefore, in order to remove small inclusion particles of about 10 to 25 μm, the refractory aggregate mesh member preferably has fine meshes, specifically 2 per inch, and more preferably 6 or more openings per inch. However, in the case of many inclusions, too fine sieve holes may cause the actual problem of filter clogging in a relatively short operating time, thereby shortening the service life of the filter. Therefore, in order to prevent the shortening of the filter life, the fineness of the screen is preferably 10 holes per inch or less.
As the refractory material of the aggregate mesh member, any refractory material capable of forming a mesh member can be used. The conventional refractory material may be appropriately selected from alumina, magnesia, silica, mullite, silicon carbide, and mixtures thereof. Then, the clay or slurry of these ceramics is molded and baked into a porous body of a suitable shape having the desired mesh size, such as a honeycomb shape and a tube shape, to form a net-shaped member. The proper shape of the mesh member allows the obtained filter to have the strength required to resist thermal shock and abrasion caused by molten Al.
Aluminum raw materials are smelted in a furnace. The obtained molten aluminum is transported to the holding furnace through the molten aluminum launder, where it is refined as needed. Then, the molten aluminum is degassed by a degassing device. The degassed molten aluminum passes through the molten aluminum launder and passes through the aluminum cast house filter before flowing to the mold. The holding furnace and degassing device do not have to be used, if they are used, they can be arranged at any stage as needed.
The aluminum cast house ceramic foam filter can be set in the filter box like a dam to block the molten aluminum. It is also possible to set a group of filters as multi-stage filters.