Coaxial material-stirring lance and method of use

A coaxial material-stirring lance (40) for use in a hot metal desulfurization process performed in a mill having a motorized lance drive with a lance weight support capacity, a ladle holding a predetermined quantity of hot metal, and a gas manifold supplying a gas supply, where the coaxial material-stirring lance is supported by the motorized lance drive in the predetermined quantity of hot metal in the ladle, the coaxial material-stirring lance comprising:

• a gas chamber (48) having a first end and a terminal end, and a length between the first end and the terminal end defining a chamber wall, the chamber wall further defining an interior space having an interior wall side facing the interior space and an opposed outer wall side;
• a refractory coat (46) encasing an exterior of the coaxial material-stirring lance;
• a gas connection pipe (44) at the first end coupled to the gas manifold and to the gas supply;
• at least one material chamber (43) defined by a material chamber wall having at a first end a material connection pipe (42) and at a second end terminating in at least one material discharge port (60);
• a port disposed as a gas permeable structure having a body formed with an inlet at one end and an opposed outlet, the inlet positioned against the opposed outer wall side and secured to a through-hole formed into the chamber wall, and the outlet positioned relative to the refractory coat so as to allow fluid communication between the interior space of the gas chamber and an exterior area beyond the refractory coat through the port;
• and
• a weight of the coaxial material-stirring lance (40);
• wherein the weight of the coaxial material-stirring lance is a same weight as the lance weight capable of support by the motorized lance drive;
• wherein the refractory coat encases both the outer wall side and an exterior of the body of the port;
• wherein the outlet has an outlet diameter measurement between about 0.5 cm to about 13 cm;
• wherein the port is further comprised of a bottom port (51) and at least one of an upper port (50) and a lower port (52) in vertical spaced-apart relationship with the bottom port;
• wherein the bottom port and the at least one of the upper port and the lower port is at least one of a pipe, a porous plug, a directional plug, and a nozzle;
• and
• wherein the material chamber (43) is positioned inside the gas chamber (48) so as to create a pair of coaxial chambers.