Ceramics-Silikáty 64, (4) 447 - 459 (2020)

An apatite-mullite glass ceramics composition derived from clam shell (CS) and soda lime silicate (SLS) glass has been fabricated from a heat treatment process of composition, [xCaF₂⋅(45−x)SLS⋅15CS⋅20Al₂O₃⋅20P₂O₅], where x is 5, 10, 15 and 20 (wt%). The result concluded that the Ca and Si elements were found in the CS and SLS glass respectively as a major weight composition, thereby promoting the use of waste materials in the manufacture of glass ceramic samples. Besides, the CaF2 addition lowers the glass transition temperature (T_g) and crystallisation temperature (T_c) of the glass composition. The density and percentage of the linear shrinkage of the samples differs with the addition of CaF₂ and various heat treatment temperatures. For the structural properties' analysis, the formation of fluorapatite with a needle-like microstructure and mullite phase was enhanced with a higher CaF₂ content, while the growth of the anorthite phase was observed to occur at a higher heat treatment temperature. Generally, the addition of a high CaF₂ content with the help of heat treatment in apatite-mullite glass ceramics composition greatly promotes the crystallisation of the fluorapatite phase, which is crucial for denture glass ceramics.