Abstract: A treatment apparatus (10) includes a liquid reactant metal containment vessel (11) for containing a first liquid reactant metal and isolating the reactant metal from the atmosphere. A release chamber (14) is adapted to receive the first liquid reactant metal from the containment vessel (11) and a submerging arrangement (21) is adapted to dunk or submerge a container (46) of feed material into the liquid reactant metal and move the container to a release location within the release chamber (14). Relatively light materials rising from the submerged container (46), including unreacted feed material, intermediate reaction products, and perhaps final reaction products collect in a collection area (60) having an upper surface defined by an upper surface of the release chamber (14).