Active Belite Cement Clinker Produced with Mineral Waste

This paper presents a laboratory study on active belite cement linker using mineral waste as one of the major raw meal components. The main chemical component of mineral waste employed in this study is silica (SiO2), around 70%. The raw meals were soaked in Muffle Furnace at 1350oC for 10 minutes and 20minutes respectively, then, cooled down to room temperature using air blower. Boron Oxide was used to stabilize high temperature phases of C2S. QXRD analysis indicates that active belite cement clinker has major mineral components consisting of Dicalcium Silicate (C2S), Ferrite (C2 (A0.48F1.52) O5) and trace amount of Tricalcium Silicate (C3S). Among them, Dicalcium silicate is over 85 percent, Ferrite around 10 percent and Tricalcium silicate less than 10 percent. Also, significant amount of high temperature polymorphic C2S was stabilized under room temperature. Among polymorphic belite phases, αH-C2S accounts for around 66% of cement clinker, and αL-C2S for about 22% of cement clinker. Scanning Eαlectronic Microscope (SEM) analysis also shows coαnsiderable round grains of C2S. TGA-DSC spectrum indicated there is no significant phase change while cement clinker was cooling down. Also, the mechanical tests on active belite cement show that active belite cement clinker has a slow strength development at early ages, but rapid strength gain over 70Mpa at 28 days. Thus, this active belite cement clinker demonstrates very promising prospect in sustainable cement industry development.