Method and apparatus for the introduction of an additive into a metal melt, in particular an additive which floats and/or gasifies

In order to introduce an additive into a metal melt in a vessel with an outlet sealed by a plug, the additive (36 and 37) is passed through the plug (12 and 14), which has a longitudinally extending cavity (15 and 16 respectively), during the outflow of the metal melt and is introduced into the outflow. The additive can be passed through the plug in rod form, for example, or in the form of a filling in a hollow wire (36 and 37) or in granular or powder form. The method is particularly suitable for the introduction of an additive which floats or gasifies, for example the introduction of magnesium into an iron melt during the production of spheroidal graphite iron. The method is also particularly suitable for the introduction of inoculants such as those which have hitherto been injected into a pouring stream or introduced as a ladle inoculation.