Recovery and valuation of ultrafine marble dust contained in waste slurries deriving from carbonatic natural stones processing plants

The research, conducted in Italy and in Spain, aims at recovery and enhancement of marble powder, deriving from marble processing plants, in the building sector. The building industry is very capable of incorporating and reusing different types of waste materials deriving from different industries. The goal of the investigation is to identify potential uses for the sawing sludge as an alternative to its disposal in dumps, a practise no compatible with the concept of sustainable development. By utilizing the stone processing waste retrieved through recovery-recycling operations this material is no longer considered as waste but as primary or secondary raw materials for use in other production processes, thereby pursuing the dual objective of minimizing waste generation and disposal and producing added value. The investigation focused on the marble district area in Orosei (North-East Sardinia). Firstly, chemical physical and mineralogical determinations were carried out in order to characterize the material; secondly, test specimens were prepared to be submitted at the experimental phase, including mechanical studies. The data emerging from the chemical and mechanical analysis demonstrate the feasibility of these uses (concrete production; brick making; plaster industry; autoclaved aerated concrete manufacturing). Economic evaluation is also considered.