Characteristics of acid resisting bricks made from quarry residues and waste steel slag

The present work focuses on the recycling feasibility of kaolin fine quarry residue (KFQR) combined with granulated blast-furnace slag (GBFS) and granite-basalt fine quarry residue (GBFQR) to make a brick resistible to chemical actions, particularly sewage waters, and possesses better properties than the conventional one. The conventional brick is composed of clay, feldspar (precious material) and sand with different percentages. Chemical and mineralogical analyses were carried out using X-ray fluorescence (XRF) and X-ray diffraction (XRD) techniques, respectively. Also, scanning electron microscopy (SEM) as well as energy dispersive X-ray (EDX) analyses was used to study the microstructures of some selected fired specimens. Solid briquettes were made from five suggested batches. These batches contained 50% of KFQR as a constant percentage, while the percentage of GBFS was increased from 10 to 40% on the expense of GBFQR percentage which was decreased from 40 to 10% (by weight). Firing was performed from 1100 degrees C to 1175 degrees C at an interval of 25 degrees C with 5 degrees C/m (firing rate) and 4 h as the soaking time. In order to evaluate the possibility of making acid resisting brick (ARB), the fired specimens were characterized with respect to the Egyptian standard specification (ESS 41-1986) as well as bulk density, volume changes and firing weight loss. The study shows that the batch S2 containing 50% KFQR, 20% GBFQR and 30% GBFS fired at 1125 degrees C exhibits the most satisfying ceramic properties that meet the ESS requirements for making acid resistant brick. The study also indicates that the addition of more than 25% of GBFQR is not recommended, as it is significantly deleterious to the ceramic properties. (C) 2007 Elsevier Ltd. All rights reserved.