Field Characteristics and other Properties of a Fireclay
Fireclay from Enugu coalfield in Nigeria was studied for its in-situ characteristics and properties relevant to its use as refractory raw material and other applications. The clay has silica content which is higher, and alumina content which is lower than the usual ranges for fireclays. The low contents of iron oxide and alkali are characteristic of high quality fireclay. The desirable low dimensional change quality is due to the low plasticity of the fireclay which manifests too, in low air-drying and firing shrinkages. At elevated temperature up to 900oC the colour changes from pale grey to white. Other qualities which make the fireclay attractive refractive raw material are the abundance and comparative cheapness. The low in-place moisture content in relation to the liquid and the plastic limits, and the shape of the void ratio-log pressure consolidation curve, all suggest apparent preconsolidation of the in-situ fireclay.