Using selective HCl and H2SO4 acids to extract calcium from extracted asphalt waste residues in preparation for subsequent indirect mineral carbonation

Abstract

A substantial amount of dry solid waste residues in Indonesia produced during the extraction of asphalt-rock bitumen offers the potential for calcium recovery for reducing CO₂ emissions toward value-added carbonate minerals via indirect mineral carbonation. This study used the residue by crushing and calcining at 900 °C for 5 hours, leached with 2 M HCl and 1 M H2SO4 at 60 °C to form a calcium-rich solution, and mixed with NH4HCO3 at a pH of 11.2–12 to precipitate calcium carbonate (PCC) at varying 30–70 °C. The PCC product has substantial calcite and small vaterite with spherical morphology, potentially various applications in paper and plastic-making industries.

Keywords

• Indirect mineral carbonation
• Solid waste residues
• PCC product
• Calcite and vaterite