Abstract: The invention relates to an apparatus for the treatment of molten metal with a reactive additive.The apparatus comprises a pouring cup having an outlet for introduction of both reactive additive and molten metal into a reaction chamber. The reaction chamber communicates via a channel, preferably of restricted cross-sectional area, with an expansion chamber provided with an outlet for the molten metal. The expansion chamber outlet has a smaller cross-sectional area than the pouring cup outlet thereby ensuring that the reaction chamber is sufficiently filled to cover any reactive additive during a pouring treatment. The apparatus permits a series of pourings to be effected without disassembly of the apparatus to introduce more reactive additive.