Mineralizing CO2 and producing polymorphic calcium carbonates from bitumen-rock asphalt manufacturing solid residues

• Published in: Cleaner Engineering and Technology 2023-02, Vol.12, p.100602, Article 100602
• Main Authors: Pusparizkita, Y.M., Schmahl, W.W., Ambarita, M., Kholid, H.N., Sadewa, A.Y., Ismail, R., Jamari, J., Bayuseno, A.P.
• Format: Article
• Language: English
• Subjects: Ammonium salt; Carbonated minerals; CDP; Solid residues; Spherical vaterite
• ISSN: 2666-7908; 2666-7908
• DOI: 10.1016/j.clet.2023.100602

Large amounts of dry solid residues are produced during the extraction of bitumen-rock asphalt, which has the potential to be a calcium of recovery for the development of value-added carbonate minerals via CO2 mineralization. The objective of this research was to use the calcination-dissolution-precipitation (CDP) method to recover calcium sources from pulverized residue into calcium carbonates through ammonium salt leaching and pressure strengthening with CO2, with calcination at 900 °C for 5 h used to pre-treat the residue feedstock prior to leaching. The calcined residues were then leached in ammonium salts (2M-CH3COONH4, NH4Cl, or NH4NO3) at 60 °C to produce a calcium-rich solution, which was then pressure strengthened with CO2 in an extraction reactor. The pH solution set at 12 appeared to be the optimal alkalinity for precipitation of calcium carbonates from aqueous solutions, producing the highest amount (>95 wt %) of vaterite and minor calcite, as evidenced by XRD and FTIR analysis, while SEM observation confirmed the morphology of spherical vaterite product with a size less than 10 μm. Vaterite is a rare metastable phase of calcium carbonate found in nature that was formed during mineral carbonation, consuming less energy at low temperatures, and the spherical vaterite product has a wide range of applications in paper and plastic manufacturing. This method of processing is expected to provide more insight and guidance for the clean utilization of dry-solid residue and CO2 mineralization in the bitumen-rock asphalt-making industry.