| Effect of Room-temperature, Calcined Eggshell Reactants on Synthesis of Hydroxyapatite |
| Tea-Sung Kang, Cristian M. Pantilimon, Sang-Jin Lee |
| Department of Advanced Materials Science and Engineering, Mokpo National University |
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| ABSTRACT |
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Synthesis of hydroxyapatite (HA) was attempted through a room-temperature reaction of calcined eggshell with phosphoric acid. Ball-milled, calcined eggshell powder, which has a specific surface area of $31.6m^2/g$, was mixed with various concentrations of phosphoric acid at room temperature. The mixtures showed high reactivity and a vigorous exothermic reaction ; the reacted samples showed both $Ca(OH)_2$ and $CaHPO_4$ crystal phases. After heating at temperatures above $400^{circ}C$, an HA crystal phase was observed in all samples. The calcined eggshell showed a pure CaO single phase, while the $Ca(OH)_2$ phase was only observed in the wet, ball-milled calcined powder. The degree of formation of the HA crystal phase increased as the phosphoric acid concentration and the heating temperature were increased. A mixture with 50 wt% phosphoric acid concentration showed a well-developed HA crystal phase after heat treatment at $800^{circ}C$, while the formation of a more intensive amorphous phase was observed in the products of the room-temperature reaction. |
| Key words:
Biomaterials, Powder processing, Crystallization, X-ray diffraction, Hydroxyapatite |
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