Optimum Blast Furnace Slag Composition for Hot Metal Production, Slag Granulation and Cement Use
Blast furnace slag, an essential part of the blast furnace process, is increasingly sold as a valuable by-product to cement producers. When selecting a slag composition, competing requirements must be considered to meet blast furnace and cement producer needs. To better understand the optimum slag composition, certain property data was reviewed including liquidus temperature, viscosity, basicity, sulfur and alkali removal capacity, as well as the impact of titania additions. Wet granulation, slag pelletizing and dry slag atomization technologies were compared to better understand the flexibility that each process has to treat a range of blast furnace compositions and produce by-product slag suitable for sale. Slag cement specifications are described and slag produced from European and North American blast furnaces are compared to the slag cement standards. Considering these various requirements, blast furnace operators can select a slag composition that maximizes profit and value in use to the steel plant operation.