| 摘要 |
<p>PURPOSE: To efficiently execute scrap melting without causing the wear of a furnace refractory by using a top-blowing lance having a specific size and shape of an oxygen supplying tube and executing a specific oxygen-blowing under the presence of specific quantities of slag and carbonaceous materials. CONSTITUTION: The carbonaceous materials are burnt with oxygen-containing gas from the top-blowing lance in a converter-type reaction vessel and the scrap is melted with this heat. At this time, the slag quantity is controlled to 100-400kg/t of metal and the fixed carbon content in the carbonaceous material is controlled to 100-500kg/t of slag. Further, the top-blowing lance has one thread slit-like oxygen supplying tube 2 having the cross section of concentrical circle or polygonal shape in the body 1. The opening part of this oxygen supplying tube 2 is separated with 2-10 pieces of shielding plates 3 and the length B of long sides, the length (h) of short sides and the diameter R of the lance are made to satisfy B/h=10-225 and B×h/R=0.4-4. Further, at the time of blowing oxygen, while controlling the distance G between the tip part of the lance and the slag surface to G/A=0.1-0.8 as to the diameter A of the vessel, oxygen flow rate per ton of the scrap is regulated to 200-500Nm<3> /hr.ton.</p> |
