Abstract: A lance for blowing oxygen from above into a ladle of an iron foundry has a nozzle head with at least four main tuyeres of larger diameter and as many ancillary tuyeres of smaller diameter, the larger tuyeres serving to blow into the melt for decarburizing the metal while the smaller ones promote afterburning of the evolving carbon monoxide just above the melt surface. The axes of the main tuyeres are inclined to the nozzle-head axis at an angle of about 14.degree. to 17.degree. while the axes of the ancillary tuyeres have an angle of inclination exceeding that of the main tuyeres by about 30.degree. to 50.degree.. In order to slow down the air flow through the ancillary tuyeres with reference to the surface-penetrating jets of the main tuyeres, the former are provided with inner peripheral inlays or grooves of annular or helicoidal shape.

Abstract: The refractory piece permeable to gases according to the invention is designed to be incorporated in the inner refractory lining of a metallurgical container so that one of its surfaces will be in contact with the molten metal bath in said container, the opposite surface being equipped with means for introducing a gas under pressure.This piece, whose shape is generally hexahedral, consists essentially of a mass of nonporous refractory material that has a number of local discontinuities 8 extending throughout the piece along its height h between the surface in contact with the molten metal and the opposite surface. In an advantageous method of embodiment, the local discontinuities 8 are obtained by an assembly 1, in a metal casing, of nonporous refractory elements 2, in the form of plates and which are placed side by side along their large lateral surfaces, without any material gaskets or seals between them.The piece according to the invention is easy to make.

Abstract: The refractory piece permeable to gases according to the invention is designed to be incorporated in the inner refractory lining of a metallurgical container so that one of its surfaces will be in contact with the molten metal bath in said container, the opposite surface being equipped with means for introducing a gas under pressure.This piece, whose shape is generally hexahedral, consists essentially of a mass of nonporous refractory material that has a number of local discontinuities 8 extending throughout the piece along its height h between the surface in contact with the molten metal and the opposite surface. In an advantageous method of embodiment, the local discontinuities 8 are obtained by an assembly 1, in a metal casing, of nonporous refractory elements 2, in the form of plates and which are placed side by side along their large lateral surfaces, without any material gaskets or seals between them.The piece according to the invention is easy to make.