| 摘要 |
PROBLEM TO BE SOLVED: To reduce dust generation amount by suppressing generation of spitting and slopping, when molten pig iron is decarburized and smelted by blowing oxygen gas from a top-blowing lance onto the surface of molten pig iron bath in the converter.SOLUTION: When molten pig iron 11 is decarburized and smelted using the top-blowing lance 1 where a plurality of Laval nozzles 7 are disposed at the tip end thereof, oxygen gas is blown from the top-blowing lance by adjusting supply amount of oxygen gas and lance height so that the volume of recess of cavity becomes 1.0-2.0 m, using the top-blowing lance designed based on blowing conditions scheduled so that the volume of recess of cavity defined by formula (1): V=n×L×A becomes 1.0-2.0 m, provided that V is the volume of recess of cavity; n is a number of nozzle holes; L is depth of cavity; and A is the area of cavity. |
