Characterization of raw and thermally treated Nigerian kaolinite-containing clays using instrumental techniques

Abstract

Thermal behavior, surface area, oxide, mineralogical composition, and structural functional groups of raw and thermally treated five local kaolin clays [Ijero-Ekiti (IJ), Ikere-Ekiti (IK), Isan-Ekiti (IS), Abusoro (AB) and Odigbo (OD)] from two states in SouthWest Nigeria were studied in order to determine their potential uses. These properties were measured using thermogravimetric analysis coupled with differential thermal analysis (TGA/DTA), surface area and porosity analysis, X-ray fluorescence (XRF), X-Ray Diffractometry (XRD) and Fourier Transform infra-red spectroscopy (FTIR) respectively. The TGA/ DTA showed major mass losses and broad endothermic bands at temperatures 390-700 °C, which were associated with dehydroxylation of kaolinite and other clay minerals. Thermal treatment increased the surface area of the raw clays. The XRF results showed oxides of kaolinite, illite, quartz, feldspar, hematite, anatase and the phases were confirmed by XRD. The FTIR spectra displayed the characteristic absorption bands of the minerals. Combining the obtained results, Ijero-Ekiti clay was identified as feldspar (albite)-quartz containing clay, Ikere-Ekiti and Isan-Ekiti clays as kaolinite-dominated clays, Abusoro clay as kaolinite-illite-montmorillonite-containing clay and Odigbo clay as kaolinite-illite-containing clay. The TGA/DTA, XRD and FTIR indicated that crystalline kaolinite in the clays were converted into amorphous metakaolinite after thermal treatment. Based on the properties displayed, clays from IK, IS, AB and OD deposits can be thermally treated to form useful supplementary cementitious and geopolymer materials to make binders in building and construction while clay from IJ deposit can be a potential raw material for ceramic production.

Kaolin Clay-Based Geopolymer for Ionic Thermoelectric Energy Harvesting

“…The ratio of SiO 2 /Al 2 O 3 of IKW is 1:3. The silica-to-alumina ratio for high kaolinite clay is 1:1 . This confirms that IKW is a high kaolinite clay as also observed in the TGA curve (Figure a).…”

Rare earth elements (REEs) recovery and porous silica preparation from kaolinite

“…The WK-Raw showed a minimal N 2 adsorbed volume over a series of high relative pressure, and the isotherm (Fig. 4a) was typical of a type ІІ isotherm according to the IUPAC classification [67], suggesting the raw sample was a naturally occurring macroporous aggregate with low specific surface area and total pore volume (Table 4) [68,69]. Compared with WK-Raw, the WK-RL showed a similar isotherm, but with a relatively larger specific surface area and total pore volume.…”

Suitability of Blending Rice Husk Ash and Calcined Clay for the Production of Self-Compacting Concrete: A Review

“…Calcined clays and agro-waste materials could be an alternative source of SCM to sub-Saharan Africa [ 36 ]. This includes among others limestone powder [ 37 , 38 ], which is present in abundance across the region, clay minerals containing kaolinite and other mineral assemblage which can be calcined to a SCM [ 39 , 40 , 41 ]. The most widely used SCM from calcined clay in the region is metakaolin.…”