Influence of volcanic ash as flux on ceramic properties of low plasticity clay and high plasticity clay of Trinidad

Abstract

AbstractCurrently there is interest in exploring the commercial viability of using ash from the erupting Soufriere Hills volcano on the island of Montserrat in the eastern Caribbean as a flux component in ceramics. Consequently, the fired characteristics (at 1100°C) of model test pieces fabricated from blends of the ash, covering the range 0–30%, with a low plasticity clay and a high plasticity clay (both kaolinitic) of Trinidad have been investigated. The results show that while 5–10% of the ash has little effect on the fired physical and mechanical properties of the low plasticity clay, 15% and above more than doubles the strength and significantly lowers the porosity. At the same time the linear shrinkage is increased by only a few per cent. On the other hand, addition of the ash to the high plasticity clay appears detrimental. In particular, compared with the properties of the clay without ash, increasing amounts of ash progressively and significantly decrease both the green and fired strength and sli...