Physico-chemical studies and mineralogical characterisation of clays for ceramic raw materials

Abstract

The use of clay for ceramic application and the quality of ceramic products has been reported in the literature. Such scientific information has helped to improve the quality of ceramic products. However, the concept is yet to improve indigenous methods of processing clay materials used by local ceramic industries. This paper characterizes clay soils from Dei-dei junction, Ushafa Hills and Nnamdi Azikiwe International Airport road in northcentral Nigeria and the locally processed clay material used by the Ushafa Pottery Center for ceramic application. It assesses clay minerals and examines their suitability for ceramic and high-temperature applications. XRD, XRF, FTIR, and TG (Thermogravimetric) results show that processed clay samples are rich in SiO2 Al2O3 and can be fired at high temperatures without shrinkage. Physical–chemical studies also reveal that raw materials have the best balance of material properties required for ceramic applications. Local processing of clay samples (water extraction method) increases SiO2, Al2O3, and K2O. TG analysis revealed that the 4.3% mass loss due to Fe2O3 and dihydroxylation of structural OH is insignificant. High % Fe2O3 in the processed sample cannot affect the firing process and quality of the ceramic products, as earlier predicted, but may affect the aesthetics of the final ceramic products. The need to develop indigenous methods of reducing Fe2O3 as an alternative to the chemical leaching of clay with acids is recommended. A model for the promotion of indigenous ceramic industries is presented as a guide for policymakers to harness the potential of deeper interaction among government, research, and organized private sector operators towards increased contribution of the solid mineral sector to national development.