Coal Waste as a Promising Raw Material for the Production of Heat-Resistant Refractory β-Sialon Ceramics

The β- and 15R-sialons were obtained from coal waste (carbonaceous rocks) at the Institute of Fossil Fuels (IGI) for the first time in the world. Ceramics based on β-sialon powder made from carbonaceous rock by compression sintering possessed increased cracking resistance, as compared to that of known analogues, even when heated in a plasma flow at 2000°C. In this case, other characteristics of the ceramics, such as strength and thermal coefficient of linear expansion, are also in the acceptable ranges of characteristics for such materials. The full-scale tests of odd-shaped products at temperatures to 1420–1450°C did not cause destruction and cracking; this fact demonstrates the applicability of carbonaceous rocks of a certain composition as raw materials for the production of heat-resistant refractory nitride ceramics based on β-sialon. Technical requirements imposed on the composition of carbonaceous rocks suitable for the production of β-sialon found in the course of this study and technical characteristics of β- and 15R-sialon ceramics obtained from carbonaceous rocks are reported.