New Glass Ceramic Materials Obtained from Cathode Ray Tubes Glass Wastes and Fly Ash

This paper presents an alternative way to recycle cathode ray tube glass waste, together with fly ash and kaolin, into new glass ceramic materials. The samples were obtained using three firing temperatures: 700, 800, and 900 °C. The effect of the fly ash/CRT waste ratio upon the materials’ firing shrinkage, apparent density, apparent and total porosity, chemical stability, and compression strength was investigated. The firing shrinkage used as a dimensional stability parameter, a firing shrinkage range between 2.19–8.18%, was positively influenced by the waste mix amount. The apparent density of the obtained materials is positively affected by the heat treatment temperature, rising from 2.09 to 2.93 (g·cm−3), while the apparent porosity decreases with the increase of the firing temperature from 6.08 to 2.24 %. All the studied glass ceramics show very good chemical stability and complete immobilization of the Pb2+ and Ba2+ ions in the glass ceramic matrix. The compression strength of the sintered materials ranges between 1.42–11.83 (N·mm−2), being positively influenced by the kaolin amount and negatively influenced by porosity. The obtained results confirm the viability of the proposed alternative to use CRT waste and fly ash together with kaolin to obtain glass ceramic materials that can be used for outdoor paving applications.