Abstract
Hydroxyapatite (HAp) powder has been synthesized using phytin contained in rice bran as a P-source, and the processes of formation and calcination of calcium phytate were observed by SEM and TEM.
Phytin was extracted from 10g of oilless rice bran by 0.01N HCl solution at 60°C. The mixture of CaCO3 (0.7g) and Ca(OH)2 (0.3g) was then added to 200ml of the extract to obtain calcium phytate.The product was washed, dried and finally calcined at 1000°C for 3hr. to obtain HAp powder. The Ca/P atomic ratio of HAp powder obtained was 1.67.
The observations by SEM and TEM showed that the calcium phytate consisted of spherical particles, which contained a small nucleus of calcium carbonate. The reaction between the nuclei and calcium phytate started from about 500°C, and then, the nuclei decreased gradually in size with increasing heat temperature and disappeared at 900°C. On the other hand, HAp powders obtained by calcining at 1000°C for 3hr. were spherical particles of about 0.2μm in the diameter.
