Mineralogical Characterization of the Trapani–Paceco Saltworks: Insights into the Valorization of a Byproduct “Mamma Caura” from Waste to Resource

Saltworks are anthropogenic environments providing important ecosystem services ranging from biodiversity support to ecotourism. The traditional management of small Mediterranean coastal saltworks is slowly declining. Consequently, there is a need to deepen the study of these active evaporitic basins and valorize the byproducts of the production cycle. In accordance with circular economy principles, these byproducts are traditionally reused as essential ingredients for the purification of edible salt. The study area is a small Mediterranean saltwork, “Chiusicella,” located within the Trapani–Paceco Saltworks Nature Reserve (Sicily, Italy). Sediments from various ponds and a waste material used by salt workers, locally known as “mamma caura”, were analyzed using X-ray diffraction (XRD) and Scanning Electron Microscopy coupled with Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). Additionally, brines from high-salinity ponds were used to analyze the precipitation sequence following total evaporation. Results demonstrate a clear relationship between the stability fields of mineral phases typical of evaporitic environments and the pond typologies. Furthermore, the interaction and synergy between bacterial activity in the water and the precipitating mineral phases appear more evident, thus outlining a clearer profile of the role of byproduct reuse within the saltwork’s annual production cycle.