The use of aluminum slag waste in the preparation of roof tiles

Abstract

Abtract Aluminum slag waste generated from the smelting process of bauxite was used to prepare roof tiles samples. Clay was substituted by slag waste in percentages reaching 40% in the basic mix and the plasticity of the obtained mud was determined. This was followed by pressing the mud in steel molds and drying. The effect of waste addition on drying shrinkage was subsequently assessed. Firing of the green bodies was carried out at three temperatures (900, 1000 and 1100 °C) and hour soaking at each temperature. Fired roof tile properties improved on increasing the percentage of alumina sludge and firing temperature possibly because of the presence of high amounts of fluxing oxides in aluminum slag. This caused a drop in porosity that increased the mechanical strength of tiles. The results showed that the substitution of clay by 40% waste and firing at 1100 °C resulted in products conforming to ASTM C-1167 for clay type roof tiles. Cold water absorption dropped to 12%, below the maximum permissible limit of 15%, the value of Saturation Coefficient was 0.83, below the 0.86 limit and the obtained breaking strength of 3370N significantly exceeded the minimum requirement of 890N.

Recycling of Iron Slag Waste in the Production of Ceramic Roof Tiles

“…is expansion in dimensions accompanying warping is greatly facilitated by the increase in liquid phase content and explains the negative values of linear firing shrinkage observed in Figure 5 as the percent slag exceeds 20%. e minimum figure obtained for cold water absorption for samples fired at 1100 °C (11.6%) is lower than that obtained by Ahmed et al [16] on incorporating 40% aluminium slag in roof tile mixes (12.8%) and that of Kallas et al [13] on adding 15% nickel slag (21%). While the values of saturation coefficient obtained in the present work for samples containing 20% GBFS fired at 1000 or 1100 °C dropped to values lower than the maximum value of 0.87 [20], the corresponding values for aluminium slag were 0.95 and 0.88, respectively [16].…”

“…e minimum figure obtained for cold water absorption for samples fired at 1100 °C (11.6%) is lower than that obtained by Ahmed et al [16] on incorporating 40% aluminium slag in roof tile mixes (12.8%) and that of Kallas et al [13] on adding 15% nickel slag (21%). While the values of saturation coefficient obtained in the present work for samples containing 20% GBFS fired at 1000 or 1100 °C dropped to values lower than the maximum value of 0.87 [20], the corresponding values for aluminium slag were 0.95 and 0.88, respectively [16]. e present values of water absorption are, however, higher than those obtained by Kim et al [19] by using 15% ferronickel slag and firing at 1125 °C (6.03%).…”

“…As observed from Figure 16, the curves of MOR follow a more or less similar pattern, producing maximum values of MOR of 11.3 MPa for samples containing 20% GBFS fired at 1000 °C and 15.4 Mpa for samples containing 15% slag fired at 1100 °C. A comparison of MOR values with those obtained by Kallas et al [13] and Ahmed et al [16] who used nickel and aluminium slags respectively in the preparation of roof tiles shows that maximum MORs of 7.2 and 10.2 Mpa were obtained using 22% nickel slag and 40% aluminium slag, respectively, firing being carried out in both cases at 1100 °C.…”

“…As shown, except for some samples fired at 900 °C, this value is largely exceeded on firing at 1000 °C and 1100 °C. Reached 5050 °N and 7000 °N, respectively, for samples containing 20% GBFS, which is much higher than that obtained by replacing aluminium slag with the same type of clay [16]. However, it appears from the results obtained at these two firing temperatures that a drop in strength takes place as the percent slag content exceeds 20%.…”

“…It is believed that the exaggerated value of compressive strength was due to the small sample size (20 × 20 × 20 mm 3 ). On the other hand, Ahmed et al [16] recently investigated the possibility of using aluminium smelting slag in the preparation of clay roof tiles. eir results revealed that it was possible to obtain tiles abiding by standards by the substitution of clay with 40% slag and firing at 1100 °C.…”