Use of vitrified urban incinerator waste as raw material for production ofsintered glass-ceramics

The crystallization behavior of vitrified industrial waste (fly ash from do miciliary solid waste incineration) was examined by differential thermal an alysis, X-ray diffractometry and scanning electron microscopy, It was demon strated that powder processing route was required to transform the vitrifie d industrial waste into glass-ceramics products. Time-Temperature-Transform ation (TTT) diagrams were drawn for the two main crystalline phases, diopsi de and wollastonite. The wollastonite existed in both monoclinic and tricli nic forms and an iron-rich phase was also observed at the boundaries betwee n glass particles. The morphology of the crystalline phases and the develop ment of microstructure were observed as a function of heat treatment time a nd temperature. The optimum heat treatment was 900 degreesC for 40-50 minut es. (C) 2001 Elsevier Science Ltd. All rights reserved.