Recycling Etna volcanic ash for the production of ceramic materials

The presence of active volcanoes often influences human life both in terms of health impact and socio-economic consequences. Explosive eruptions can release into the atmosphere huge quantities of ashes which then fall to the ground, causing many inconveniences to communities living and working in close proximity to the volcano. A further problem is represented by the high costs that the involved administrations (Civil Protection or Municipalities) of the interested areas must face whenever this material, considered as waste, needs to be collected and disposed of in landfill.

To overcome this problem, it would be suitable to find ‘‘end of waste” alternatives for volcanic ash as raw material in the productive sectors, e.g., in building materials (tiles, bricks, mortars, concretes, etc.). A paradigm shift leading to consider ashes no longer as a waste but a resource.

This contribution deals with an experimental study aimed at assessing the possible re-use of volcanic ash as temper in the manufacture of ceramic tiles. Volcanic ashes recently erupted by Mount Etna volcano in Sicily (Southern Italy), one of the most active basaltic volcanoes in the world, have been here chosen as case study for such a purpose. Ceramic test-tiles were manufactured by mixing volcanic ash with a calcareous clayey raw material, by using specific proportions of clay/temper. In order to assess the quality of the products, the tiles underwent several physical–mechanical tests including: a) water absorption; b) bending resistance; c) impact resistance; d) resistance to deep abrasion; e) thermal shock resistance; f) frost resistance; and g) accelerated aging test by salt crystallization (Belfiore et al. 2020). The obtained results have been then compared with those of a reference product manufactured by using another volcanic material known as azolo (i.e., finely ground basalt) for a long time on the market. Our data demonstrate how basaltic ash recovering through this methodological approach is highly promising in the sector of building materials.

Reference

Belfiore C.M., Amato C., Pezzino A., Viccaro M., 2020. An end of waste alternative for volcanic ash: A resource in the manufacture of ceramic tiles. Construction and Building Materials, 263, 120118, doi: 10.1016/j.conbuildmat.2020.120118