ANALYSIS OF UTILIZATION OF NATURAL BULGARITE AND PETROLEUM REFINERY WASTE IN THE SYNTHESIS OF DECORATIVE GLASS-CERAMICS

Abstract

Glass-ceramic materials were prepared using natural Bulgarite, limestone, quartz sand and spent alumina-based guard-layer material originating from petroleum hydrotreating reactors. The chemical composition of the starting materials was determined by X-ray fluorescence analysis. The thermal behaviour of the glass frits was studied by differential thermal analysis, while the phase composition of the natural rock and the synthesized materials was investigated by X-ray diffraction. The frits were subjected to a two-stage heat treatment at 950 °C and 1050 °C. β-CaSiO₃ (β-wollastonite) was identified as the main crystalline phase, together with residual quartz. With increasing spent guard-layer content from 0 to 10 wt.%, the reported β-wollastonite content increased from 68 to 75 %, while the quartz content decreased from 20 to 10 %. The density of the obtained samples was 2600–2900 kg/m³. The materials exhibited brown to green-brown colours and a marble-like appearance. The results indicate the potential of combining natural Bulgarite with alumina-rich refinery waste as an alternative raw-material route for decorative glass-ceramic production.