Carbon dioxide removal could result in the use of lower-grade iron ore in a decarbonized net-negative emission steel industry

Reducing the emissions from steel production is essential in meeting climate targets while maintaining economic prosperity. Here we show that applying deep emissions mitigation to the steel industry together with the reaction of by-product slag with atmospheric carbon dioxide (CO2) could result in a carbon negative industry on the order of up to a GtCO2 yr−1 by mid-century. We used a bespoke technoeconomic assessment model that simulates a base-case scenarios in which steel is produced using a blast furnace and basic oxygen furnace. This system was augmented with a range of climate change intervention technologies including biomass based reductant, directly reduced iron, carbon capture and storage, and slag carbonation. Surprisingly, strong incentivisation ($200–500 tCO2−1) for emissions reduction and CO2 removal from the atmosphere may create conditions under which lower grade ores are commercially viable and also achieve deep emissions mitigation. The additional costs for emissions reduction could be wholly offset by value generated through carbon removal from biomass energy carbon capture and storage together with slag carbonation. •Slag carbonation could help a decarbonised steel industry turn net negative.•Incentives for atmospheric CO2 removal may promote low-grade ore use.•Cost of emissions reduction could be offset by the value of atmospheric CO2 removal.