Process for desulphurization of hot metal

摘要

A pig iron is desulphurised by mixing it with the slag remaining after tapping off a steel alloy from a furnace. The slag composition is, in %: 45-70 CaO; 2-17 SiO2; 4-8 MgO; 14-22 Al2O3; 0.5-6 FeO plus molten metal residue from the steel treatment phase. The pig iron is added at 1250-1400 degrees C and after an initial stirring an immersion lance is used to introduce the powder desulphurising agent together with a carrier gas which ensures further stirring.