Generally the converter end [Mn] of low manganese steel is required to control ≤0.05%

according to the issues of high flux consumption and inconstancy of removing manganese from liquid by traditional double slag process

based on thermodynamics and kinetics analysis and. data in production situ

the effect of slag basicity (R 1.68-2.00)

temperature (1340-1460℃ ) and FeO content in slag-(FeO) (15.5%-18.7%) on ability of slag to remove manganese in liquid by remaining and double slag process is studied. With the measures including adding partial limestone in splashing and remaining slag period

at blowing beginning adding a small amount dolomite replace partial light burning dolomite and adding a small amount o£ fluorite

and in blowing initial period using higher level lance position to strengthen top slag stirring and speed up early period oxidation of manganese

the end [ Mn] decreases from ≤0.06% to ≤0.045% ； as compared with traditional double slag process

with optimized process the lime consumption of lime decreases by 6.5 kg/t

that of fluoride decreases by 1.48 kg/t and that of iron scale decreases by 6.42 kg/t

the steelmaking flux cost reduces obviously.