Patent ID: 6923843

Claim:
A method of processing molten metal in a vessel by the injection of oxygen to a process through a water cooled supersonic horizontally disposed oxygen injection lance into said vessel, and for maintaining constant an optimum total gas flowrate through said lance while concurrently maintaining an oxygen gas flow at an optimal oxygen gas flowrate through said lance into said vessel, said lance comprised of a body and a tip comprising a jet, and said method comprising the steps of: (a) first injecting oxygen through said injection lance at said optimum total gas flowrate to said vessel, said optimum total gas flowrate being the optimal total gas flow rate for the particular design of said lance tip, (b) continuously measuring at least one process variable related to said optimal oxygen gas flowrate to said vessel, (c) reducing said oxygen gas flow as required to maintain said optimal oxygen gas flow rate through said lance during said process, (d) supplying and mixing an amount of a second gas at a second gas flow rate with said oxygen gas flow into a mixed gas stream to said horizontally disposed oxygen injection lance, wherein the sum of said optimal oxygen gas flow rate and said second gas flow rate is equal to said optimum total gas flowrate, and (e) delivering said mixed gas stream through said body, said tip, and said jet of said horizontally disposed oxygen injection lance into said vessel.