Dry and firing shrinkage of ceramic tiles as a function of firing

Abstract
The effect of using the local electrostatic precipitator cement kiln dust waste (EPCKD)
collected from Tourah Portland cement factory on the production of ceramic wall and floor
tiles was studied. The EPCKD as received from the factory was used to replace gradually a
part of the total ceramic batch composition of a traditional wall and floor tile composition
(clay, feldspar, limestone, quartz). The thermal properties in terms of dry and firing shrinkage
as well as mechanical properties in terms of bending strength of the resulting wall and floor
tiles were investigated. The results showed that the EPCKD can be used with an amount of 5
up to 25 wt. % from the total batch as previously illustrated (Part I) without any dangerous
adverse effects. In the second part, the results showed that the dry shrinkage was nearly
unchanged, while the firing shrinkage increased as the firing temperature as well as the
EPCKD content increased to reach 2.8-7.9 % at 1170-1200 °C. The green bending strength
was improved and enhanced by the addition of EPCKD to reach 23.43 kg/cm2 compared with
that of the control batch (C0) 12.24 kg/cm2. The bending strength of the fired articles was
also improved and enhanced to reach 474.31 kg/cm2 compared with 249.09 kg/cm2 of the
control mix. Furthermore, an excellent ability to coloration of the tiles was detected.
Keywords: cement kiln dust, wall tiles, floor tiles, clay, feldspar, quartz, water absorption,
bulk density, apparent porosity