1971 Volume 4 Issue 3 Pages 251-256
A heating process to produce lightweight aggregate from a mixture of fly ash and pulp waste liquor was studied from the standpoint of reaction kinetics, involving the structure of pellet matrix, reaction kinetics, and the peculiar properties of lightweight aggregate.
The results indicate that the reaction taking part in the bloating is the reduction of Fe2O3 to release oxygen. The relationship between reaction progress and feasibility of the bloating suggest that the preferable heating method is to calcine the pellet in such a way as to form as much grey zone as possible. The gray zone is the matrix where some portion of Fe2O3 is reduced, and the extent of reduction can be estimated from the proposed reaction model.