This paper examines the idea of using shredded scrap steel as a blast
furnace burden material. Charging scrap, or metallics, with the burden
offers several possible benefits including increased productivity and
decreased fuel rate. In this paper, scrap charging is investigated nu
merically using a previously presented mathematical model. Furnace ope
rations at both fixed hot metal temperature and fixed top gas temperat
ure are investigated with scrap charged either near the axis, radially
uniformly or near the wall. When the average temperature of metal ent
ering the hearth is kept constant, the production and fuel rate are pr
edicted to increase and decrease respectively as scrap feed rate incre
ases. These changes are due to scrap being already fully reduced, thus
not requiring heat or carbon for reduction. However, the top gas temp
erature decreases, particularly when scrap was charged only over the i
nner half radius of the furnace. Under conditions of constant top gas
temperature the productivity and fuel rate still increase and decrease
respectively with increasing scrap:ore ratio. Of the three scrap char
ging patterns tested, the optimum pattern is to charge scrap over the
outer half radius of the furnace, which results in the least change in
the furnace internal state compared to operations without scrap while
showing significant increases in production and decreases in fuel rat
e. Finally, scrap diameter is found to have only a small effect on the
furnace state.