Abstract: For detachably holding a lance in axial alignment with the mouth or top opening of a metallurgical furnace, use is made of a chuck through which the lance can be inserted upwardly for communication with an outlet conduit extending downwardly from a vessel defining a pressure-tight air or oxygen chamber therein. A packing box supported under the outlet conduit houses means for establishing pressure-tight communication between the lance and the outlet conduit. The vessel, the packing box and the chuck are all bracketed to a carriage movable along a vertical track for causing up-and-down motion of the lance into and out of the furnace mouth. According to another embodiment of the invention, means are further provided for rotating the lance while the latter is inserted into the furnace.