JPS6436716A - Converter blowing method - Google Patents

Abstract

PURPOSE:To reduce recovery loss of exhaust gas especially at early blowing stage by specifying operational condition in a converter at the time of executing converter blowing by using the pretreated molten iron. CONSTITUTION:Oxygen gas supplying velocity at the early blowing stage from start of blowing to start of the recovery of exhaust gas is adjusted to 0.015-0.035Nm<3>/ ton.sec. By restraining the above oxygen supplying velocity to less than the upper limit, the decarburizing reaction during the stage from the start of blowing to the start of recovery of the exhaust gas is suitably restrained, and CO gas generating quantity during this stage is remarkably reduced. However, as the early blowing stage is executed in order to raise the exhaust gas composition to effective concn. for recovery so that the exhaust gas composition does not passes through the explosion range, if the condition, in which the suitable decarburizing reaction can progress, is not set, the important part of the early blowing stage is not played. Under this viewpoint, the oxygen supplying velocity is necessary to be more than the lower limit. Therefore, this method raises CO gas concn. in the exhaust gas while suitably restraining the decarburizing reaction by setting the oxygen supplying velocity as the above-mentioned and the recovery of the exhaust gas is started at the time of reaching effective CO gas concn. to the recovery of the exhaust gas.