Production of ceramic foam filters for molten metal filtration using expanded polystyrene

Filtration of molten metals with ceramic foam filters is a proven method in order to remove the inclusions. This paper develops a new approach for the production of ceramic foam filters. In the conventional method of ceramic foam filter production, polyurethane sponges are used.In this work, ceramic foam filter was produced by using expanded polystyrene. Polystyrene is expanded in a specially designed mold by steam to form polystyrene patterns. Various ceramic slurries are then poured into the polystyrene cell and allowed to air dry. After the shaping operation, filters are subjected to sintering process under various conditions. By this new method, filter channel sizes can be controlled and traps with desired configurations can be formed. Some tests were applied to the produced filters. Thermal shock tests ensured that the filters could withstand temperatures of 1450 °C. Water absorption test showed that bauxide based material absorbed water more than the others.