The effect of sintering temperature on cavitation erosion in glass-ceramics based on coal fly ash

Abstract

The incombustible portion of coal that remains after burning is known as bottom or fly ash, and it has a detrimental influence on the environment. One of the possible alternatives for reducing the amount of ash deposited in landfills might be the production of useful glass-ceramic from vitrified fly ash. Glass-ceramic was synthesized using fly ash from the thermal power plant "Nikola Tesla" and fluxing additives. Sinter-crystallization of the parent glass resulted in glass ceramics. The glass was created by melting a combination of coal fly ash (CFA), Na2CO3, and CaCO3 at T= 1500 °C and quenching the melt in the air. Glass powders were sintered at temperatures 850 and 900 °C. The resulting glass-ceramics were characterized microstructurally, physically, and mechanically. The cavitation erosion of samples was evaluated. The cavitation rate was 0.015 mg/min for the sample sintered at 850 °C, and 0.0053 mg/min for the sample sintered at 900 °C. The leaching of heavy metals in glass-ceramic samples was determined using the Toxicity Characteristic Leaching Procedure. A low concentration of heavy metals in the leaching solution showed that heavy metals were successfully incorporated in the glass matrix and that obtained glass-ceramics are ecologically safe for usage. Both samples exhibit good resistance to cavitation erosion, suggesting their potential as possible replacements for structural ceramics commonly employed components of hydraulic machinery.