Blast Furnace Slag is formed when iron ore or iron pellets, coke and a flux (either limestone or dolomite) are melted together in a blast furnace. Blast furnace slag is most widely used in production of materials for construction of facilities and automobile roads.

During smelting, the amount of blast-furnace slag is equal to 0,5–0,6 t per 1 ton of cast iron. Blast furnace slag is processed to obtain cement slag for producing cement and lime-slag bonding fillers of concrete, lime-slag pumice, used as concrete filler, blast furnace mineral wool slag, crushed stone and sand. Using these materials in construction allows saving primary mineral resources (sand, limestone, clay, gravel), straight cement and fuel. Using granulated slag as concrete filler results in significant saving production factors.