Sustainable application of calcium carbide residue as a filler for 3D printing materials.

Industrial activity results in ton-scale production of calcium carbide and generation of a significant amount of calcium carbide residue (CCR), which is often disposed of in the environment as waste. CCR is an active chemical, and rain washes away alkali from sludge, changing the pH of soils and water and damaging the environment. In this work, we explored new opportunities for the utilization of CCR in view of the coming industrial uptake of digital design and additive technologies. Amazingly, CCR can be successfully used as a filler for the modification of 3D printed materials towards the introduction of hybrid organic/inorganic frameworks. A series of commercially available plastics (PLA, ABS, Nylon, PETG, SBS) were successfully used as matrices for CCR-based composite production with high CCR contents up to 28%. Tensile analyses showed increases in tensile strength and Young's modulus of 9% and 60%, respectively. Moreover, in comparison with the pure plastics, the CCR-based materials better maintained the digitally designed shape (lower shrinkage). Importantly, CCR-filled materials are 3D printable, making them very promising components in the building sector. Considering the amount of already available CCR stored in the environment, this material is available in large quantities in the near future for hybrid materials, and anticipated opportunities exist in the additive manufacturing sector. The involvement of CCR in practical composite materials is equally important for environmental protection and reuse of already available multiple-ton wastes.