The study presented a powder processing method involving calcination and subsequent carbonation in the synthesis of precipitated calcium carbonate (PCC) for recycling green mussel shells, which contain a high calcium carbonate content. The purity of portlandite [Ca(OH)2] as a result of calcination and subsequent moisture absorption during storage was verified using the XRD-Rietveld method. Further quantitative XRD Rietveld analysis of the PCC product confirmed the presence of vaterite (55.20 wt.%) and calcite (44.80 wt.%) minerals after carbonation process of the calcined powder product. The SEM examination of this product revealed particle aggregates of non-uniform polyhedral and cubical grains of varying small and large sizes. The FTIR analysis also confirmed that calcination and subsequent hydration of mussel shell powder yielded pure portlandite, whereas the carbonation yielded PCC polymorphism. As a result, this powder processing method is simple to scale and reduces the cost of PCC synthesis, which is critical for practical applications. The current study demonstrated that the powder processing method for recycling green mussel shells as starting materials in biomedical applications is technically feasible.
Keywords: Green mussel shells; calcination; calcite; calcium carbonate; vaterite.