Effect of Adding Ornamental Rock Carbonate Mineral Residue on the Properties of Poly(lactic acid) and Parts Processed by Material Extrusion

The utilization of waste, defined as commercially worthless or discarded material, is becoming an increasingly important topic in the context of environmental material overload. Thus, the development of new products should integrate waste, adding commercial value to materials that would have otherwise been discarded. In this context, Material Extrusion (ME), the most widely used technique in Additive Manufacturing (AM), has introduced a new manufacturing model, opening opportunities for developing innovative products. On the other hand, during the beneficiation process of ornamental rocks, tons of mineral waste are generated. This study aims to develop a polylactic acid (PLA) filament using Beige Bahia marble waste as a raw material source via the ME technique. Compositional mapping through Energy Dispersive Spectroscopy (EDS) indicated that, as the mass fraction increased, particle clustering within the PLA matrix decreased. Mass compositions ranging from 0–30% mineral waste to PLA were evaluated. Gel Permeation Chromatography (GPC) showed that the PLA molar mass in the PLA00 and PLA30 compositions was 109,103 and 120,103 g.mol⁻¹, respectively, indicating that the mineral waste helped preserve the polymer’s molar mass during material processing. An increase was observed in the elastic modulus. The total roughness profile demonstrated higher values for pure PLA, while the partial roughness profile showed higher noise due to the greater presence of particles on the surface. The final product exhibited characteristics like the original rock and could serve as an alternative when such features are desired.