Abstract: Apparatus including a nozzle or refractory pipe lance for the secondary refinement of a bath of molten metal by the injection of a gas under pressure, having one or more low porosity-high density refractory plugs which contain apertures of constant diameter, at least those about the perimeter of the plugs having an arcuate shape. For the manufacture of a pipe lance, the low porosity-high density refractory plugs are attached to a central tube. The low porosity-high density of the refractory plugs provides a corrosion resistance to any change in the diameter of the gas nozzles and thereby produces a controlled high velocity radial burst gas stream. Generating the radial burst of small bubbles and maintaning the gas velocity of a high constant rate reduces erosion of the refractory material around the tope of the apparatus and extends the lifetime of the pipe lance or nozzle.