Abstract: The top-submergable injection lance has an elongate conduit which extends between upper and discharge ends and defines a bore, for the supply of reactants, through the conduit and an annular, alloy steel tip at the discharge end. The conduit comprises an inner pipe defining the bore, an outer pipe, and a third pipe which divides an annular volume between the inner and an outer pipes for circulation of coolant fluid. The tip is defined by inner and outer peripheral surfaces merging at a sharp lower edge and a top surface extending between the peripheral surfaces. The top surface of the tip joins the inner and outer pipes so as to be contactable by the coolant fluid. The frusto-conical inner peripheral surface provides a continuation of the bore which increases in cross-section to an opening at the lower edge.