公开(公告)号：US20220259686A1

公开(公告)日：2022-08-18

申请号：US17626083

申请日：2020-07-02

Applicant: JFE STEEL CORPORATION

Inventor： Yumi MURAKAMI ,  Nobuhiko ODA ,  Hidemitsu NEGISHI ,  Ryo KAWABATA ,  Naoki KIKUCHI ,  Yusuke FUJII

IPC: C21C1/02

Abstract: A dephosphorization method using a top and bottom blown converter. This method uses a converter charged with molten iron and slag, to blow an oxygen-containing gas from a top-blowing lance, supply the gas from an inlet of a blowing hole, and supply a control gas from an opening toward an axial center. This method has: a slag top-surface position measurement step, with the top surface of the molten iron measured in advance, measuring an arbitrary position in a top surface of the slag; a slag top-surface difference calculation of slag thickness difference between the measured top-surface positions of the molten iron and the slag; and a jetting condition adjustment step of, using the obtained slag thickness, adjusting a jetting condition of the gas jetted from the top-blowing lance into an appropriate range. The top-blown jetting condition is adjusted by comparing the slag thickness and the depth of a surface depression.