The present disclosure concerns an apparatus suitable for smelting and separating metals in flexible oxido-reduction conditions. More particularly, it concerns an apparatus for smelting metallurgical charges comprising a bath furnace susceptible to contain a molten charge up to a determined level, characterized in that the furnace is equipped with: at least one non-transfer plasma torch for the generation of first hot gases; at least one oxygas burner for the generation of second hot gasses; and, submerged injectors for injecting said first and second hot gases below said determined level.