Synthesis And Characterization Of Hydroxyapatite Derived From Limestone

Limestone has a high calcium carbonate (CaCO3) content, making it an ideal source of calcium for the synthesis of hydroxyapatite. This study aims to synthesize hydroxyapatite from limestone and analyze the results by examining the phase and crystallinity. CaO was obtained through the calcination of limestone at a temperature of 1000°C for 10 hours. Hydroxyapatite synthesis was conducted by combining CaO as the calcium precursor and Diamonium hidrogen fosfat (NH4)2HPO4 as the phosphate precursor using the precipitation method. Subsequently, the resulting samples were sintered in a furnace at a temperature of 900°C for 5 hours. After the synthesis process, the products were characterized using XRD and SEM. The synthesis results indicate that the obtained hydroxyapatite has a crystalline phase. The crystal system formed is hexagonal, with a space group of P63/m. During the synthesis of hydroxyapatite, another compound, β-tricalcium phosphate (Ca3(PO4)2), was also formed. The resulting hydroxyapatite exhibited agglomeration properties, with individual particles tending to be spherical in shape. The size of the hydroxyapatite formed is relatively small, with particle sizes ranging from 140 to 300 nm.