| 摘要 |
<p>PURPOSE: To dephosphorize to refine molten iron with a good efficiency without lowering temp. of the molten iron by blowing basic flux, powdery coke and gaseous oxygen from tuyeres at different positions of a lance dipped into the molten iron. CONSTITUTION: A triple tube structural lance 1 Is dipped into the molten iron in a torpedo car, etc., and the plural tuyeres 2b are arranged at the tip part of the lance, and the gaseous oxygen is blown from an inner pipe, and gaseous nitrogen from an outer pipe as carrier gas for the powdery coke to burn the powdery coke at the tip of the tuyere. Further, the dephosphorizing flux is blown together with the gaseous oxygen and gaseous nitrogen as the carrier gas from a tuyere 2a arranged at the upper part of the lance 1. A ratio of the powdery coke to the oxygen from tuyeres 2b is regulated to coke kg/oxygen Nm<3> =1:3, and at the time of defining the depth of molten iron as Ho, the depth of the tuyere 2a as Hp and the depth of the tuyere 2b as Hco, Hco/Ho>=0.6 and Hco-Hp>=300mm are satisfied, and by these methods, an adverse effect of low temp. on the dephosphorizing reaction is eliminated, and the pre- dephosphorization and desulfurization treatments of the molten iron are efficiently executed at high temp.</p> |
