OPERATION OF BLAST FURNACE

摘要

PROBLEM TO BE SOLVED: To provide an opening method restraining the aggravation of a ventilation in a blast furnace caused by blown powdery carbonaceous material having high ash content by effectively acting the powdery carbonaceous material blown from a tuyere as reducing agent and further, at the same time, lowering the basicity of ore with ash content in the powdery carbonaceous material. SOLUTION: The powdery carbonaceous material having >=20 wt.% ash content is blown into the furnace from the inner tube of a lance having double tube structure, in which the conditions in the following inequalities I-III are satisfied and the tip part of the lance 2 exists at the upper side than the center axis 3 of the tuyere 1 and the blowing direction is directed upward to the center axis of the tuyere, and cold blast or nitrogen is blown from the outer tube. Then, (a) in the figure is a plan view of the tip part of the lance 2 containing the center axis of the tuyere and (b) therein is the projection figure of the tip part of the lance on the perpendicular plane to the center axis of the tuyere containing the tip part of the tuyere. Inequality I, 0.5×Rt=45 deg..