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This work discusses the effect of rich alumina bauxite on the mineralogical composition of calcium sulfoaluminate (CSA) clinker cement on their performances. After preparation of different local raw materials (rich alumina bauxite and marble), they were mixed with 15 wt% of commercial gypsum and pressed at 2 MPa. The obtained pellets were thermally treated at 1200°C to produce clinker, which is use to synthesize the CSA cements. The raw materials as well as products were characterized by many analyses, such as FT‐IR, X‐ray fluorescence, X‐ray diffraction, differential scanning calorimetry (DSC)/thermogravimetry analysis (TGA), isothermal calorimetry (ICC), scanning electron microscope, and physico‐mechanical tests. ICC analysis of the powder of clinker cement showed that the reactions are strongly affected by gypsum content. XRD results revealed that clinker and cement present a strong intensity of ye'elimite as main mineral phase. Moreover, the hydrated cement exhibited ettringite and monosulfate as the new phases formed. The compressive strength of hydrated cement reached ∼21 and 28 MPa after 1 and 28 days of curing, respectively. From the aforementioned results, this local rich alumina bauxite can be used to produce high‐strength cement for self‐leveling materials, which allow their use in engineering and building applications. [ABSTRACT FROM AUTHOR]

This research reports the investigations of threshold reactivity limit of blends of pegmatite with different calcined clays as well as the influence of calcined clay source on the geopolymerization kinetic, microstructural, and physicomechanical properties of feldspathic mineral-based inorganic polymer composites. These composites were designed from 85 to 94 wt% of the solid solution of pegmatite and calcined clay. The three-point flexural and compressive strengths, porosity, and microstructure as well as heat evolution rate of geopolymerization reactions of resulting composites were affected by the type of calcined clay. The four calcined clays provided the highest mechanical properties of the composites when added in the range of 12-15 wt%. Specifically, the values of flexural and compressive strengths ranged from 32 to 34 MPa and 101 to 105 MPa, respectively, for geopolymer composites with 15 wt% of metakolin added, while they ranged from 38 to 42 MPa and 106 to 107 MPa with 12 wt% of meta-hallosyte added. The polycondensation/polymerization process of calcined clay developed sufficient amounts of N-A-S-H and polysialate geopolymer to cover the incongruently dissolved fine particles of pegmatite. The resulting microstructure was dense and compact with the lower cumulative pore volume at about 91 mm3/g. It was concluded that designing the pegmatite/clay-based geopolymer composites with high mechanical strengths and low porosity resulted in sustainable, low energy consumption and environmental-friendly materials for civil engineering. [ABSTRACT FROM AUTHOR]

This paper examines the potential use of pegmatite and marble as additives in amalgamation with Meiganga kaolin to produce stoneware products capable to resist high temperatures as well as enhancement the mechanical characteristics. Two series of ceramic products were formulated by partly replacing kaolin with 0, 3, 5 and 7 wt% of both pegmatite and marble wastes. The specimens were sintered at 1000°C, 1050°C and 1100°C. Fired ceramic samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and the microstructure of the products was determined using an environmental scanning electron microscope and energy-dispersive X-ray spectroscopy. Also, the physico-mechanical properties were evaluated. Results divulged that, the addition of pegmatite or marble to kaolin enhances the strength of the ceramic body and act as a fluxing agent by promoting vitrification and glassy phase in clay after firing. The highest flexural strength results were observed with 7 wt% of pegmatite added at 1100 °C, with an increase - 35% compared to the control sample. High silica and alumina contents in pegmatite fill in voids, providing densification matrices. The incorporation of pegmatite allows to obtain a ceramic with better mechanical properties and energy saving as compared by the conventional ceramic. [ABSTRACT FROM AUTHOR]