Sustainable glazes for ceramic tiles: Exploiting inertized man-made vitreous fibres waste as a resource

Traditional ceramic tiles, and especially porcelain stoneware, are still one of the top building materials in the world. In view to fulfil the current need to produce ceramic tiles in a less impactful way for the environment along with the increasing difficulty in providing natural raw materials, the attention of the ceramic sector has been focusing on optimizing resources. The solution can be found in a circular economy model, in which the virgin raw materials exploitation is minimized through the recycling of materials that otherwise would be disposed as waste in landfills. The ceramic industries are able to internally reuse most of their residues created during the production steps, in fact, most of the discarded materials are reinserted into the ceramic production cycle. The next step for the sector must be to adopt a circular economy model that use “extramuros waste” corresponding to waste derived from other production chains. We have developed a ceramic glaze by utilizing the thermal inertization product of Man-Made Vitreous Fibers (MMVF) as a secondary raw material. This waste material, characterized by being completely amorphous, serves as an ideal melting component in ceramic products. We have experimented with various formulations of ceramic glazes, incorporating between 40 % and 50 wt% of this glassy material. The most promising formulation involves 44 wt% of waste, resulting in a shiny, dark ceramic glaze. This outcome underscores the suitability of this waste material as a valuable secondary raw material for the manufacture of traditional ceramic glazes.