The present work represents a comparative study on the impurities removal
from pig iron melt by addition of partially reduced highly fluxed direct
reduced iron (DRI) to make steel in a 2 kg capacity electric arc furnace
(EAF). Three types of fluxed DRI (30, 50, 80% Reduction (%R) with similar
basicity-8) were used to maintain different level of oxidizing potential on
the bath for studying the kinetic behaviour of impurities removal from melt.
Results showed that the rate of removal of impurities (i.e. C, Si, Mn, P, S
etc.) was increased initially up to 5 minutes of reaction time then
decreased afterwards. Phosphorus (~64%), sulfur (~16%) and carbon (~94%)
were removed simultaneously up to 25 minutes of reaction time using 30%R
fluxed DRI. Similarly, phosphorus (~33%), sulfur (~50%) and carbon (~62%)
were removed simultaneously using 50%R fluxed DRI while highly reduced
(80%R) flux DRI removed sulfur (~58%), carbon (~56%) with a small fraction
of phosphorus (~18%) from pig iron. It was observed in all the cases that
silicon (>99%) and manganese (>80%) were removed. From the present study, it
can be concluded that ~30%R DRI is favorable for effective phosphorus
removal whereas ~80%R is favorable for sulfur removal. The significant
removal of impurities could be achieved by charging ~50%R fluxed DRI in the
pig iron melt.