High‐Efficiency Dephosphorization by Bottom‐Blown O2‐CaO Process for Semi‐Steelmaking

Abstract

In steelmaking, the bottom‐blown O2‐CaO process is used to achieve efficient dephosphorization. However, few studies have applied it to dephosphorization converters. Therefore, this study considers the thermodynamic and kinetic mechanisms of dephosphorization during the process. The selective oxidation transfer temperatures of C and P are calculated. Compared to the combined blowing process, the bottom‐blown O2‐CaO process reduces the optimum dephosphorization temperature from 1593 to 1573 K. Moreover, the FeO content decreases by 20.7% owing to the increased stirring energy and improved kinetic conditions; the binary basicity (R) of the slag increases, and the lime consumption decreases by 2.9 kg t−1. The higher slagging efficiency indicates that the CaO powder melts and dephosphorization is completed during the fire‐spot zone floating process. Furthermore, the optimum FeO content for dephosphorization decreases as R increases. The selective oxidation of C and P can be divided into two stages. The oxidation stage of P preferred C is extended in this process. Overall, the end‐point P content accounts for 22.52% and 46.85% of the samples prepared using the combined blowing and bottom‐blown O2‐CaO processes when the P content is 0.02–0.03%, respectively.