Investigation on "Slag-Remaining+Double-Slag" BOF Steelmaking Technology

The Slag-Remaining+Double-Slag BOF steelmaking technology has been developed and applied on a large scale in Qianan Steelworks and Shouqin Steelworks of Shougang Corporation Ltd.As the result,the lime consumption and the slag generated in BOF steelmaking have been remarkably decreased.In this paper,three important measures taken in application of the new steelmaking technology are introduced: ① To solve the two most serious problems,i.e.difficult to make fast and especially enough amount of deslagging and decrease the amount of the metallic Fe droplets in the slag,low basicity(w(CaO)/w(SiO2)∶1.3~1.5) and low MgO(≤7.5%) slag is used in the dephosphorization stage.②Hard blow pattern(low oxygen lance position and high O2 flow rate) is adopted to take use of the top blown O2 jet to strengthen the agitation of the bath in the dephosphorization stage,through which good dephosphorization has been obtained.③By speeding up the operations and particularly by optimize the control and matching of the steelmaking,secondary refining and continuous casting,the output of the steel has not been reduced though the BOF tap to tap time has been increased by about 4min after using the new technology.