Usage of Fly Ash as Binder in Micropelletization Process as a Partial Replacement of Bentonite - Mining, Metallurgy & Exploration (2021)

Fly ash is a by-product generated from combustion of coal in thermal power plant. Disposal of fly ash is a major environmental concern for the power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, substantial quantity remains unutilized. Silica and alumina are the major constituents in fly ash along with lime. Aluminosilicates and unhydrated lime present in fly ash, in presence of water, undergo a pozzolanic reaction and form cementitious bond which holds the particles together. Bentonite is commonly used as binder in micropelletization of process waste to attain the mechanical strength required for handling and transportation. The bonding of particles by bentonite is a physical mechanism, while fly ash bonding is a chemical mechanism. The present paper deals with the partial replacement of bentonite with fly ash in micropelletization without affecting the quality of micropellets.