Different varieties of ceramic foam filters are manufactured by the industries. The variation in the type of the foam filters is based on the type of materials used for casting and filtration. As aluminum filter is used for filtering of molten aluminum similarly SiC ceramic foam filter is used for the filtration of spheroidal Graphite. It is used for the casting of cast irons. Most of the industries which have a lot of cast iron application make use of this filter. As we all know that the ore from which iron is found comprises of a lot of impurities and the metal which is extracted from this ore is not completely pure. When the metal is molted in the industries for casting, then the impurities also melts thereby prevents to extort the complete benefit of the material.
The impurities in the molten metal make the metal completely brittle because of which when it is cast into different molds, its strength is reduced. In order to retain the strength of the metal and to extract the complete benefit, the molten cast Iron is filtered using SiC ceramic foam filter.
Since Iron is a reactive metal so, the impurities of Iron are mostly the magnesium compounds and slags of silicon. These impurities have different melting point as compared to iron, but the difference is not greater. So, when the metal is heated to a precise temperature of its melting point, the impurities remain in solid state.
When the molten metal is poured through the porous surface of SiC ceramic foam filter, the impurities reside on the surface of the filter leaving behind the molten metal to pass through the filter. Because of the large surface area of the filter, the impurities stick to the surface leaving behind the molten material. Now, the molten metal which is extracted from the filter is free of the impurities and can be poured into cavity to mold it into the required shape. Since, the molten metal is passed through the channel, so the filter can be fixed at any required position. It is completely porous and allows the molten metal to pass through.
When the molten metal with the impurities are passed through the channel, because of high turbulence, the solid impurities stick to the surface of the SiC filter. These filters are manufactured at 4 different porosities and you have to choose as per the nature of impurities in your metal. The different porosities levels are:
• Fine porous: It has a minimum of 30 porous per inch of the filter.
• Medium porous: The range of porous is around 20 per inch.
• Coarse: It has 10 porous per inch of the filter
• Extra fine: 40 porous per inch
Some of the reasons for increased use of SiC filter are:
• The degree of scrap can present in the metal can be reduced.
• Increases the quality of the metal because of which the productivity is increased.
• You don’t have to spend a lot on other filtering process as this is a much affordable process.