Fabrication and characterization of tetra-calcium phosphate from natural wastes of eggshell and cockle shell

This study focused on the utilization of natural waste materials, specifically eggshell and cockle shell, for extracting calcium carbonate (CaCO 3 ) as calcium-rich feedstocks for the synthesis of tetra-calcium phosphate (TTCP) via a solid-state reaction. The synthesized TTCP powders were compared with those produced using commercially available CaCO 3 . The CaCO 3 powders derived from eggshells and cockle shells were found to exhibit characteristic calcite structures with a high calcium content of 95–96 % and a combination of irregularly shaped amorphous and crystalline morphologies. The TTCP powders synthesized from eggshell- and cockle shell-derived CaCO 3 demonstrated a characteristic high-intensity peak, along with minor phases of hydroxyapatite (HAp) and calcium oxide (CaO). These powders were fine and white with a light-blue tint. It is speculated that the fabricated TTCP powders hold potential for medical applications, such as bone cement. • Fabrication of tetra-calcium phosphate (TTCP) from natural wastes was studied. • CaCO 3 extracted from eggshell and cockle shell could be used for TTCP synthesis. • Particle size distribution of the CaCO 3 powders influences TTCP characteristics. • With minor phase of hydroxyapatite, the synthesized TTCP could have potential for medical applications.