Granulated Blast Furnace Slag or GBFSis the residue of combustion in the furnace of the steel refining process. It is obtained by quenching molten iron slag from a blast furnace in water or steam, to produce a glassy, granular product that is then dried and ground into a fine powder.
GGBFS or Ground Granulated Blast Furnace Slag is formed when GBFS is further processed or ground using conventional cement clinker grinding technology.