The formation of mullite from rock wastes containing alumina and silica

摘要

This work describes the recovery of slate powders in order to evaluate the kinetics of the transformation of the aluminum silicates into mullite, with the addition of γ-Al{sub}2O{sub}3 as a mullite precursor. The powders were uniaxially pressed as rectangular specimens and sintered in air using a muffle type furnace. The sintered samples were subsequently characterised by X-ray diffraction, optical and scanning microscopy and mechanical testing. Bending strengths of 60 MPa were obtained which compare favorably with the 30 MPa of current ceramic tiles, based on clay.