4. Conclusions
The volcanic ash, once deposited, results in a major problem in urban and agricultural areas. It becomes a solid waste with important consequences in all activities, including human health and animal livestock. A rapid collection of the ashes would allow obtaining an ash with better quality and purity. And the rapid restart of the previous economic activities. The possible application will undoubtedly encourage the recollection.
The present study presents additional information about the possible utilization of volcanic ashes as raw materials for ceramic materials, particularly, as the fluxing agent in a triaxial (clay quartz flux) formula. A representative sample of volcanic ash was characterized and a triaxial (clay–quartz–flux) formulation was performed and compared with the model (feldspar) one. The chemical thermal processes and the sinterability were determined. The actual temperature of this processes were also established.
The sintering and thermal evolution of the mechanical properties of the ceramic produced were also studied and compared with a model triaxial (clay–quartz–feldspar) formula. It was shown that with thermal cycles similar to those used for manufacturing traditional ceramics the obtained ceramics presented appropriate textural and mechanical properties comparable with materials produced with the traditional raw materials: feldspar.
Particularly a decrease in the maturation temperature range was observed. No important difference in the mullitization behavior was observed. Properties of the obtained materials present similar correlations with the processing variables but with a slight decrease in the mechanical properties explained by the porosity presence (2–4%) and cristobalite, the first one can be improved by the optimization of the processing variables (particle size, firing cycle, other secondary fluxes addition.
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