Apparatus for degassing molten metal

Apparatus for degassing molten metal and adding alloying or refining agents thereto comprises (see Fig. 1) a degassing vessel 10, e.g. having a metal shell 15 with refractory lining 16 and a nozzle 20 extending from its lower end into a movable ladle 11 below for drawing molten metal 12 for degassing into the chamber 19 of the vessel, associated with evacuating apparatus 24, and a hermetically sealed hopper 38 for supplying the agents mounted adjacent to and interconnected with the vessel, e.g. via pipe 41. The hopper is divided (see Fig. 2) into a main compartment 54 and a plurality of smaller auxiliary compartments 55 (of which three are shown), which are volumetrically interrelated according to a geometric progression which increases by a factor of two, and means are provided external to the hopper for selectively discharging the contents of the auxiliary compartments 55 into the main compartment 54 without unsealing the vessel. Such means may be control mechanisms 65 which open gates 64 in each of the compartments 55.