Between scarcity and circularity of resources: technological innovation for granite scraps in Sardinia

Throughout the past two centuries, the impact of humans on Earth has resulted in the progressive consumption of natural resources, the increase in waste and pollution, and the alteration of ecosystems. This has also induced a well-knownclimate change phenomenon with significant consequences for humanity and the natural world.The growth of cities and improved living conditions will lead to increased consumption of resources, many of which are already expected to run out by the middle of the next decade, then it is important to monitor the consumption of resources with appropriate indicators to drive economic growth by encouraging decoupling. Starting from an analysis of the consumption of the four major categories of natural resources, biomass, fossil fuels, non-metallic minerals and metals ores, and relative indicators of impact, from an international scale the attention is gradually turned to consumption on the Italian level, focusing on the consumption of non-metallic minerals for use in construction.Thus, the focus was on the granite mining district of Buddusò, in Sardinia, the largest producer in Italy. Granite quarries, which have been drastically reduced in recent decades, have generated huge amounts of processing waste, causing profound changes to landscapes and ecosystems.Based on the analysis of disused quarry sites, the types of granite abandoned have been studied in detail, investigating the chemical-physical, mechanical and technological characteristics and experimenting with innovative products and alternative uses for these wastes.The results show that it is possible to use these residues as a secondary raw material for the ceramics industry, also as anenvelope for ventilated high-performance thermal insulation facades.Similarly, the study of the ecosystems of quarry sites and the evolution of sites now abandoned has shown the possibility of imagining functional redevelopment to create new places open to the public, even as opportunity to revitalise inner areas at risk of abandonment, creating opportunities for new jobs; in a vision of resource circularity that would allow economic growth decoupled from its resource consumption and impact, exploiting the material and energy embedded in them we have already spent.