CERAMIC POTENTIAL OF SOME TRINIDAD CLAYS .2. FIRED CHARACTERISTICS

The fired characteristics of clays from five different locations in Tr inidad (Longdenville, Valencia, Caparo, Cocoloco, and La Brea) have be en investigated in the temperature range 900-1100 degrees C with a vie w to assessing their ceramic and refractory potential. The characteris tics explored included vitrification behaviour str ength and toughness , shrinkage, microstructure, bulk density, apparent porosity, and wate r absorption. Of high plasticity, the La Brea and Cocoloco clays exhib ited flexural strength and fracture toughness (K-1c) values greater th an 15 MN m(-2) and 0.5 MN m(-3/2), respectively, by 1050 degrees C. At this temperature, apparent porosity and water absorption were 18% and 11%, respectively, in the Cocoloco, and 6% and 4%, respectively, in t he La Brea samples. Significant vitrification commenced in the Valenci a clay only above 1000 degrees C, while the degree of sintering and vi trification of the Caparo and Longdenville clays, was pool over the en tire firing temperature range.