Development of High Strength Fly Ash Glass-ceramics by Concrete Sludge Addition

Abstract

A large amount of fly ash is exhausted from the thermal powder plant and it is a poisonous substance including the heavy metals and dioxin. The glass solidification is an effective method as one of the waste solidification technologies. Further, producing new materials by mixing together more than two kinds of raw materials is a more useful method. However, a number of trials are required in this method. We selected glass-ceramics with the crystal structure of an Anorthite (CaO·Al 2 O 3 ・ 2SiO 2 ), fly ash as inorganic wastes and concrete sludge for construction materials. It is necessary to clarify the optimum production method. Batches were prepared by mixing these raw materials with various weight ratios. Glass samples were produced by melting the batches at 1450 ℃ and quenching. They were reheated in the region of 950-1100 ℃ to make into glass-ceramic. The properties of obtained glass-ceramics were examined by XRD analysis, SEM observation, and some material tests for the strength, hardness, toughness, and so on. The XRD analysis and SEM observation showed that the crystallized phase of the produced glass-ceramics were identified as an Anorthite. The material tests showed that the Vickers hardness was very high, while the chemical resistance was relatively low.