Production of ground granulated blast-furnace slag cement: Energy and carbon reduction efficiency of cement-grinding system

This study used clinker, ground granulated blast-furnace slag (GGBS), and gypsum in a cement-grinding system to produce GGBS cement (GCE). Gypsum was used as the alkaline activator to modify the surface area of GCE and increase its compressive strength. The results revealed that the use of the gypsum activator and the modification of the surface area of GCE effectively increased the formerly inadequate compressive strength of GCE (GGBS > 60%) in the early stage. In addition, energy consumption data were obtained during the production of GCE and Portland cement (PCE) by the cement-grinding system. The calculations concerning the production proportions indicated that when GCE was produced in place of PCE, the overall demand for clinker fell by 65%. By comparison, the total energy consumption per ton of production decreased from 1539 to 602 kWh, and CO2 emissions decreased from 0.78 to 0.31 tons. Furthermore, energy efficiency and carbon-reduction efficiency both reached 60.9%. In summary, the production of GCE through the proposed cement-grinding system appears to be feasible and able to considerably increase the energy efficiency and carbon reduction efficiency of cement production.