The filtration of molten ferrous metal is accomplished by providing a porous ceramic filter preferably comprising particles of alumina and partially stabilized zirconia that are spaced by interconnected cells to form circuitous and tortuous pathways throughout the ceramic body. The filter is a disc-like structure that can have different surface configurations such as corrugations or a waffle design. The filter can be flat-surfaced with an array of cylindrical openings or counterboard openings extending completely through the filter, or with openings extending partially into the filter from the upper and lower sides of the filter. Several relatively thin filters can be arranged in tandem, if desired.