A Novel Clinkerization Process for Fly-Ash Utilization

Abstract

Keeping in view the chemistry of Indian fly ashes, a novel process route has been developed in the author's laboratory to address the disposal of fly ash in India. This process involves activation of fly ash with alkali under non-hydrothermal conditions. The activated fly ash is reacted with hydrated lime in predetermined proportions to produce the Calcium silicate/aluminate hydrates gels (hydrogels), which is de-watered, dried and sintered at 1150-1350 degrees Centigrade to produce the cement clinker. The sintering temperature depends on the type of cement intended to be produced. The above hydrogel process makes it possible to use about 30% fly ash in the manufacture of cement clinkers. The present paper highlights the activation technique and the process of hydrogel clinkering route. The chemico-mineralogical, microstructural characteristics of the clinkers produced through this process is also illustrated.