Characterization of clays from Tharaka-Nithi County in Kenya for industrial and agricultural applications

Abstract

Clay samples from Tharaka-Nithi County in Kenya were characterized by hydrometer, X-ray fluorescence spectroscopy (XRF), atomic absorption spectroscopy (AAS), TGA, scanning electron microscopy (SEM) and powder diffraction (XRD) methods. The F-test and t-test were used to interpret the results. The major oxides present were Al 2 O 3 , SiO 2 and the minor ones were CaO, TiO 2 , MnO, Fe 2 O 3 , K 2 O, MgO and Na 2 O. The values of SiO 2 were greater than those of Al 2 O 3 , indicating that the samples were of clay minerals. The clay minerals with low cation exchange capacity (CEC) were present in the samples. The Atterberg limits showed that the inorganic clays of either low or intermediate plasticity having low contents of organic matter were present in the samples. The analysis further showed the availability of essential elements necessary for plant growth. The TGA analysis indicated that the decomposition of clay samples occurred in four steps. The scanning electron microscope photographs revealed that the samples contained a mixture of minerals of morphologies with crystallinity, high porosity and unstable under the electron beam. The major impurity in the clay is quartz, ranging from 22.6-31.9%. Albite is the most dominant component in the clay minerals contributing to 30.3 to 44.1%. The clay from the study area can be used as agro mineral additive to enhance soil fertility for crop production, a fluxing agent in ceramics and glass applications and also as functional fillers in the paint, plastic, rubber and adhesive industries after beneficiation.

Characterization and classification of clay minerals for potential applications in Rugi Ward, Kenya

“…The collection and preparation of clayey samples was carried out as described by Njoka et al (2015). The quality and resolution of the obtained results was improved by performing pretreatment of the samples in order to remove the organic matter and other unwanted materials.…”

“…PG-990 Atomic absorption spectrophotometer, Analytikjena model contra 700, IRAffinity-1 FTIR Spectrophotometer, Shimadzu, Perkin Elmer Model TGA7, Thermal gravity analyzer, Transmission Electron Microscope JOEL.JEM-1210 (120KV, MULTISCAN CAMERA), Bruker AXS D8 Advance diffractometer, Quantachrome NOVA 1200 Gas sorption analyzer. The procedures used by Njoka et al (2015) and El-Geundi et al (2014) were adopted in the present study, and the Atterberg limits were determined as described by Melo et al (2012). classify and predict the fine-grained soil behavior.…”

“…Clay is a naturally occurring material composed of layered structures of fine-grained minerals which exhibit the property of plasticity at appropriate water content but becomes permanently hard when fired (Heckroodt, 1991;Njoka et al, 2015). The clay material is formed from chemical weathering processes on the earth's surface, and contributes about 40% of the fine grained sedimentary rocks (mudrocks) which includes mud stones, clay stones and shales.…”

“…The cation exchange capacity of Illite ranges between 20-40 meq per 100 g. The colour of the minerals ranges from grey white, silvery white to greenish grey. The illites find application in structural clay industry and in agro minerals due to high potassium content (Njoka et al, 2015;Van, 2002). Mica clay ores contain a variety of impurities which includes quartz, feldspar, kaolin and pyroxene (Capedri et al, 2004).…”

Effects of Grog Additions on Some Refractory Properties of Raw (Abusoro) Kaolin Clay Deposit for Furnace Lining

“…Clay can be referred to as an earthy material composed mainly of layered systems of finegrained minerals, which exhibit the characteristic of plasticity at suitable water content but turns completely hard when fired [1]. Clay is also fashioned from the chemical weathering processes on earth's crust and, this contributes approximately two-fifth of the fine grained sedimentary rocks (mud rocks) such as mudstones, resulting into diverse sort of clay materials [2].…”