CERTAIN PROPERTIES OF CALCIUM HYDROXYAPATITE FROM SKIPJACK TUNA BONE (Katsuwonus pelamis)

Abstract

This paper is concerned with certain properties of calcium hydroxyapatite from skipjack tuna bone (Katsuwonus pelamis) which are by-products of fish export industry. Hydroxyapatite Ca10(PO4)6(OH)2 and β-tricalcium phosphate Ca3(PO4)2, the high-value compounds, have been successfully extracted from skipjack tuna bones. The bones were heated at different temperatures of 600oC, 900oC, 1200oC. While at 600oC hydroxyapatites were obtained with Ca/P ratio of 1.658, comparable to the value of 1.67 found in human bone; the hydroxyapatite crystals of average size of 0.25 µm were formed with the same size distribution. In case of heated bone samples at 900°C and 1200°C, the calcium formed were biphasic calcium phosphate composed of hydroxyapatite and β-tricalcium phosphate; the Ca/P ratio was between 1.660–1.665; the calcium crystals of more than 1 µm were highly porous and connected to each other in priority orientation of tube direction.