Carbonizing solid waste generated from the extraction of Indonesian carbonate asphalt to produce precipitated calcium carbonate filler for use in polymer composites

Calcium carbonate micro- and nanoparticles are chemically inert materials that serve as fillers in various industries, including plastics, paper, paint, sealants, and adhesives. On the other hand, the abundant solid wastes generated during the extraction of Indonesian carbonate asphalt serve as a sustainable powder feedstock for the production of high-grade precipitated calcium carbonate (PCC) with spherical vaterite particles, which can reinforce polymer matrix composites. The current study involves calcination and subsequent acid leaching using HNO₃ with NH₄OH to recover Ca sources from the solid residues of natural rock asphalt extraction, facilitating a CO₂-mineralization process and leading to the formation of precipitated calcium carbonate (PCC) as spherical vaterite particles, as validated by XRD and SEM analysis. PVC (polyvinyl chloride) resin, dioctyl phthalate, lubricants, and PCC were combined at phr ( parts per hundred resin ) ratios of 140, 180, 220, 260, and 300, resulting in increased density and tensile strength in the PCC/PVC composite. This study develops prospective micro-PCC fillers with spherical vaterite for reinforcing PVC composites.