From Marble Waste to Eco-Friendly Filament for 3D Printing to Help Renaturalization of Quarries

The excessive use of materials that are generally difficult to discard, such as stone materials, has caused growing ecological concern. Among these, marble is extracted from quarries, but when the raw material is exhausted, these places are deserted. For this reason, several measures have been adopted in recent years to requalify these areas. In addition, recent technological developments involve the creation of innovative green materials that privilege the circular economy and waste recycling. This research presents the development of innovative, sustainable filaments for the fused filament fabrication (FFF) printing technique from recycled marble waste (MW) and biocompostable and biodegradable polylactic acid (PLA) matrix. MW was added to the polymer in concentrations of 10 wt.%, 20 wt.%, and 30 wt.%, and the blends were extruded to develop innovative green filaments. The chemical/structural properties of the raw materials and the thermal and mechanical features of the new composites were investigated. Composites containing 10 and 20 wt.% of MW showed good printability. In contrast, extrusion and printing difficulties were observed with 30 wt.% of MW. Finally, this paper proposes a project to renaturalize and requalify a disused marble quarry located in Trani (Apulia, Italy) with 3D printing devices using the newly produced eco-filaments, which have better features. The main purpose of this article is to propose a concrete, economic, and sustainable application of 3D printing involving processes such as waste and by-product recycling and renaturalization of disused quarries, with both economic and environmental benefits.