Hydroxyapatite powder was prepared by burning bone and heat treating the bone ash obtained at 600-1100 oC in an air furnace. The black ash was converted to a white powder after heat treatment. X-ray diffraction analysis and Fourier transform infra-red spectroscopy indicated that the white powder was hydroxyapatite and did not contain any organic components of the bone. Furthermore, phase transformation of the resulting hydroxyapatite to other calcium phosphate phases did not occur up to 1100 oC. X-ray fluorescence analyses revealed that calcium and phosphorous were the main elements and magnesium and sodium were present as minor impurities. The results of the energy dispersive X-ray analysis showed that the Ca/P ratio of this natural hydroxyapatite varies between 1.46 and 2.01. The resulting material was found to be thermally stable up to 1100 oC. The density of natural hydroxyapatite heat treated at 800 oC was measured to be 3.187 cm3.

Keywords: Bone ash, Natural hydroxyapatite, Heat treatment, Characterisation.