The effect of coal fly ash and borax solid waste (TW) on the properties of wall tile was investigated. The properties examined include firing strength, firing shrinkage, water absorption and microstructure. A number of wall tile compositions were prepared by the replacement of potassium feldspar with the fly ash and TW in the range of 2-10%. Further on, the wall tiles were produced by replacing potassium feldspar (in the presence of fixed quantity of 2% TW and 5% TW) with the fly ash in the range of 2-10%. The results showed that firing strength of the wall tile increased when the fly ash and TW used in the preparation of the standard tile composition. In particular, the improvement of strength was observed when the TW up to 6 wt.% was introduced as potassium feldspar replacement. Results indicate an interesting potential for the coal fly ash and TW recycling to produce useful materials. (C) 2004 Elsevier Ltd and Techna S.r.l. All rights reserved.