The benefic effect of Moroccan oil shale’s ash on blended cement (CMII)

Abstract

Recycling of Tarfaya’s oil shales (OSA) was conducted for two essential reasons: First, to follow the change of their mineralogical composition with the heat treatment and second to investigate the possibility of their use in building materials. The mineral compositions and the mineralogical transformations of the oil shale during their thermal treatment were followed respectively by X-ray fluorescence (XRF), by X-ray diffraction analysis (XRD) and Fourier transform infrared (FTIR). The XRF showed that the mineral composition of the ash burned at 850°C is similar to that of Portland clinker and the DRX showed the presence of quartz, mayenite, gehlenite, anydrite, hematite and lime as well as the existence of some characteristics phases of the clinker as C2S, C3A and C4AF. The Infrared spectrum showed the various functional groups that exist in OSA. The substitution of cement CMII by OSA increased the content of free lime and Blaine specific surface. The ash influenced beneficially the mechanical strength of the blended cement. The best results were obtained at all times of curing (2, 7, 28 and 91 Days) for the substitution of CMII by 7 and 10 % of OSA.

Characterisation of Bottom Ashes from Non-Woody Biomass Combustion for Application as Sustainable Supplementary Cementitious Material

“…The amount of mayenite increases with rising ashing temperatures, reaching more than 11 wt.% at 900 °C. The presence of mayenite in Ca-rich ashes has also been reported in some of the literature [58][59][60]. The complete results of the XRD analysis of the ashes are presented in Tables A3 and A4.…”

“…Moreover, a fair amount of mayenite (Ca 12 Al 14 O 33 ) is present in F ashes, which is formed by the interaction between CaO and Al 2 O 3 . The amount of mayenite increases with rising ashing temperatures, reaching more than 11 wt.% at 900 • C. The presence of mayenite in Ca-rich ashes has also been reported in some of the literature [58][59][60]. The complete results of the XRD analysis of the ashes are presented in Tables A3 and A4.…”

Neutralization of Acidic Industrial Wastes and Fixation of Trace Element by Oil Shale Ash: Formation of a Green Product

“…It is suggested that the first event of mass loss (at up to 300 °C) is attributed to the decomposition of the calcium phosphate compounds. The second mass loss in the range of 650–800 °C is attributed to the pyrolysis residues of organic matter and/or the decomposition of carbonate minerals . In addition, in the second process of mass loss, the mass loss decreases as the pH becomes more acidic.…”

“…The second mass loss in the range of 650–800 °C is attributed to the pyrolysis residues of organic matter and/or the decomposition of carbonate minerals. 25 In addition, in the second process of mass loss, the mass loss decreases as the pH becomes more acidic. The fact that the amount of calcite (CaCO 3 ) decreases is in agreement with the composition of the mass shown in Table 4 , which shows that the more acidic the pH, the smaller the amount of calcite (CaCO 3 ) in the mixture.…”