BOF SLAG: Basic oxygen furnace About 100 ? 200 kg of BOF slag is generated per ton of liquid steel. This material is often used in projects like road construction, but this route provides little energy efficiency gains. Steel slag can also be used in the cement clinker manufacturing process. The result is an increase in clinker production of up to 15% with no net increase in CO2 emissions. Basic oxygen furnace (BOF) slag has increased skid resistance and high level of strength (described by the impact- and crushing value) compared to natural rocks (e.g. basalt) and thus makes it an ideal aggregate for road constructions and surface layers for high skid resistance. Other fields of application are the production of fertilizers or the use of armour stones for hydraulic engineering.