METHOD FOR CONVERTING CAST IRON IN CONVERTER Russian patent published in 2003 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: method involves charging scrap; feeding solid carbon-containing fuel; providing preliminary heating of scrap; pouring cast iron; blasting while changing position of tuyere and oxygen flow rate; providing distributed introduction of lime and manganese-containing materials in the process of blowing; discharging melt and deoxidizing it in ladle. Cast iron used comprises silicon and manganese not in the excess of 0.35 wt%. Scrap is heated while anthracite and coal gas are supplied at the ratio of 1:(0.2-0.5) and oxygen flow rate of 0.3-0.5 cu.m/kg of fuel. Anthracite is supplied in an amount of 70-85% of total weight during the first minute of heating process and the remaining part during main part of oxygen blasting process. Manganese-containing materials are introduced in an amount of 0.6-1.5% by weight of cast iron, with 45-60% of total weight of manganese-containing materials being introduced during first minute of oxygen blasting process and the remaining part during 50-80% of blasting time. Method allows lime consumption to be reduced by 10.5 kg/t, residual content of manganese in metal to be increased by 0.12% upon termination of blasting process, and steel yield to be increased by 1.0%. Method is used for melting steel from cast iron with decreased content of silicon and manganese. EFFECT: increased efficiency and improved steel yield.