Patent ID: 6793710
Filing Date: 2004-09-21
Classification: C21C

Abstract:
A method for blowing oxygen into molten iron in a converter, in an oxygen refining process wherein oxygen is blown into the converter using a top-blown lance having a Laval nozzle installed at the tip of the top-blown lance, and wherein the Laval nozzle has a back pressure of the nozzle Po(kPa) satisfying the following formula with respect to a oxygen-flow-rate FhS(Nm3/hr) per hole of the Laval nozzle determined from the oxygen-flow-rate FS(Nm3/hr) in a high carbon region in a peak of decarburization and a throat diameter Dt (mm),Po=FhS/(0.00465Â·Dt2) the Laval nozzle has an exit diameter De satisfying the following formula with respect to the back pressure of the nozzle Po(kPa), an ambient pressure Pe(kPa), and said throat diameter Dt (mm): De2&lE;0.23Ã—Dt2/{(Pe/Po)5/7Ã—[1âˆ’(Pe/Po)2/7]}.