Characterization and evaluation of selected kaolin clay deposits in Nigeria for furnace lining application

Kaolin and ball clay samples from four states in Nigeria were examined with the aim of determining their chemical composition as well as testing for their suitability as refractory materials for furnaces lining applications. Three kaolin samples were taken from Ikpeshi in Edo, Kasadi in Kebbi and Alaasan in Osun state, while the ball clay sample used as the binder was taken from Badeggi in Niger state. The kaolin samples were tested and beneficiated in other to improve on their alumina contents after which they were characterized and produced as a refractory brick by mixing each kaolin sample with the ball clay in 70:30 ratio. They were then tested comprehensively for the following refractory properties such as: firing shrinkage, apparent porosity, bulk density, cold crushing strength, thermal shock resistance, refractory under load (RUL), thermal expansion, thermal conductivity, X-ray diffraction and scanning electron microscope. The results were compared with standard refractory properties for fireclay bricks. The values obtained from the three clay samples (A, B, C) which are from Ikpeshi in Edo, Kasadi in Kebbi and Alaasan in Osun state respectively were within the recommended values for fireclay bricks, most especially sample C which has a refractoriness under load (RUL) of 1348OC which is the temperature at which the bricks will collapse under a constant load of 0.2N/mm2. This compared favourably with the RUL of other countries in the world.Keywords: Porosity, clay, brick, refractoriness, kaoli

Reviews in Automobile Brake Pads Production and Prospects of Agro Base Composites of Cashew Nut Shells and Nigerian Gum Arabic Binder.

The reviews of automobile brake pad production processes, formulations, materials, and properties revealed most works attempt mainly on replacing asbestos found to be carcinogenic with base materials with other ingredients in various formulations and particle sizes. The overview of these trends suggests the need to replace not only the asbestos but also the commonly used epoxy resins or phenolic resins or phenol formaldehyde binders that has been found to corrode outside plates of brake assembly. Therefore, this paper thrust a new research direction of replacing the asbestos and inorganic resins with agro based materials of Cashew Nut Shell and Plant Gum binder respectively to obtain a substantially green based brake pads that are non-injurious to human health and does not corrode any parts of the brake pads assembly. Taguchi design of experimental method was deployed to formulate twenty seven (27) different formulations with the help of Minitab Software approach. The particle size of the compositions was 300µm and the produced composites have favourable properties such as BHN, Compressive Strength, coefficient of friction, wear rate and very high ash content retention suggesting good thermal capacity of the brake pads. The values obtained respectively are 76.66BHN,12.187N/mm2, 0.4848, 1.16mg/m and 97.71%