Abstract: A process or method of and apparatus for the in-ladle treatment of molten base metal iron with a nodularizing agent (e.g., a magnesium bearing alloy) so as to produce substantially uniform spheriodal graphite in the iron. The process involves placing a desired quantity of the nodularizing agent in a reaction chamber in a treatment ladle, the latter having a main chamber, a charging and filling passage leading to the reaction chamber, and one or more passages leading from the reaction chamber to the main chamber of the ladle. Molten base metal iron is then poured into the reaction chamber via the charging and filling passage thereby to effect a reaction between the nodularizing agent and the molten base metal. A hydrostatic pressure head of the molten base metal is rapidly established over the reaction chamber of sufficient depth thereby to minimize the vaporization of the nodularizing agent and to maximize the recovery of the nodularizing agent in the base metal.