Effect of replacing weathered feldspar for potash feldspar in the production of stoneware tiles containing fish bone ash

In the present study, the use of naturally occurring weathered feldspar for partial or total substitution of conventional potash feldspar in the batches containing fish bone ash was evaluated. Weathered feldspar, Hafafit feldfpasr and El-Tieh kaolin from Sinai, Egypt; together with fish bone ash were characterized and employed to obtain stoneware tiles. Technological properties such as bulk density, apparent porosity, bending strength and thermal expansion behavior were measured. Phase composition and microstructure of the fired tiles were accomplished in order to determine the relationship between them. The results show that the produced tiles fulfill the requirement of ISO 10545-4 and 13006.