SYNTHESIS OF POROUS HYDROXYAPATITE CERAMICS FROM LIMESTONE VIA HYDROTHERMAL PROCESS

Abstract

Porous hydroxyapatite (HA) ceramics was prepared by hydrothermal method from

limestone in two ways: synthesized directly from limestone (calcite CaCO₃) and synthesized from CaO, which was product of limestone thermal decomposition. Conditions of hydrothermal reaction are 200^oC, 15 atm in 24 hours. The samples were characterized by XRD, SEM, DTA/TGA and FTIR. The results confirmed that ceramics of single phase HA was formed by the indirect synthesized from limestone obtained CaO. Water played an important role as the reactant and as solvent in the formation of HA by hydrothermal process. After the calcination at 1000^oC in 1 hour, porous ceramics was structured by three-dimentional interconnected pores of 100 to 300 nm. XRD and FTIR characterizations of obtained HA are similar to HA references materials of NIST.