MECHANOCHEMICAL SYNTHESIS OF AMORPHOUS CALCIUM PHOSPHATE FROM BOVINE BONE

Abstract

The principal component of bovine bone waste was low crystalline hydroxyapatite (HAp), which was more effective to substitution of phosphorus resources. The present work was investigated about mechanochemical synthesis of amorphous calcium phosphate (ACP) from bovine bone obtained by removing protein. The raw material was used HAp obtained by heating bovine bone at 800°C. A mixture of HAp and ammonium dihydrogenphosphate in the weight ratio of 8/1 (Ca/P atomic ratio = 1.50) was ground for 24 hours. The products were characterized by means of X-ray diffraction patterns, thermal analysis (TG- DTA), transmission electron microscopic (TEM) observation, chemical analysis measurements of BET specific surface area and density. The crystalline of the mixture was decreased with increasing grinding time and amorphous phase was formed after 10 minutes. Ca/P atomic ratio of the ground mixture with particle size of 200 nm was 1.48. As results of TG-DTA, ACP obtained by liquid phase synthesis had usually exothermic peak to crystallization from ACP into β-tricalcium phosphate (β-TCP) at 670°C. Also, the ground mixture was confirmed exothermic peak at 625°C.