Process for treating molten metal during a casting operation using a filter and filter for implementing the process

Apparatus for filtering and inoculating molten metal adapted to implement a process for simultaneously filtering and inoculating a molten metal during an operation to cast said molten metal into a mold, said apparatus comprising a series of at least two refractory mineral material filtering plates in contact with each other at their periphery and defining between them at least one cavity, said filtering plates each having a series of filtering holes through which said molten metal flows and by which said molten metal is filtered, the dimensions of the filtering holes and the number of the filtering plates being selected so as to eliminate from the molten metal solid inclusions likely to affect the quality of the cast metal, said apparatus containing within said at least one cavity an inorganic inoculating material for inoculating said molten metal flowing through the cavity, said inoculating material being in the form of one of solid compressed or molded or sintered inoculating plate positioned in said at least one cavity and extending over substantially the length and the width of said at least one cavity, said inoculating plate having when viewed in the direction of metal flow, a shape such that at least one passage hole is arranged around said inoculating plate whereby said molten metal contacts and spreads over the inoculating plate before passing through said at least one passage hole and through said apparatus.