Partial Replacement of Bentonite by Fly-Ash as a Binder in Pellet Making

Bentonite is the most common binder in iron ore pelletization. In the present work, laboratory experiment as well as basket trials were carried out with partial replacement of bentonite by fly-ash as a binder. Fly-ash is a coal combustion residue produced from power plants. Laboratory tests were carried out with different proportion of fly-ash replacement in the pellet. Pellets prepared in the laboratory with up to 20% replacement of bentonite by fly-ash show favorable green ball properties such as green compressive strength, drop number and dry compressive strength. Based on laboratory tests, basket trials were carried out using 10% fly-ash replacement. Pellets prepared for basket trial show no major variation in green ball properties. However, drop-in cold compressive strength (CCS) of pellet was observed in fly-ash-based pellet as compared to base case (100% Bentonite). Microstructure characterization of the fired pellets indicated the presence of large pores in the case of the pellets containing fly-ash, which are believed to reduce their compressive strength.