A likely increasingly important pathway for future low-carbon ironmaking and steelmaking is the
combination of gas-based direct reduction with electric furnace steelmaking (DRI-EAF route), or with
electric smelting (DRI-ESF route). In the DRI-EAF route, the gangue that is present in the iron ore is
fluxed and removed as slag in the melting (steelmaking) step. This is in contrast with integrated
steelmaking, in which the gangue is removed as part of blast furnace ironmaking. For DRI-EAF
steelmaking, the amount and composition of slag depend on the iron ore composition, flux additions
and iron yield. Slag volume and composition affect phosphorus removal, foaming behaviour and the
process energy requirements. In this work, heat data from a year of DRI-EAF production was
analysed to test whether the expected relationship between slag volume and electricity consumption
for EAF steelmaking was observed. The data include slag analyses (one sample per shift), and heatlevel
information on all inputs, final steel temperature and dissolved oxygen concentration, electricity
consumption, tapped steel mass and tap-to-tap time. In analysing the data, the slag volume was
estimated from the assayed slag CaO concentration and CaO inputs to the EAF. The expected effect
of slag volume on steelmaking energy consumption was calculated with a mass and energy balance,
considering the heat of mixing of the slag. The calculated energy requirement of slag formation is in
line with previous estimates reported in the literature.