Characterization of Morphological and Crystal Structure of Coral Reefs Samples from Depapre District, Papua

There are concern about a massive volume of unused and dead coral reefs that lie along the coastline in Depapre district, Papua Province. The application of this natural waste is strictly limited due to lack of public knowledge about the advantage of this material for any purposes. This study aims to determine the potential application of unused and dead coral reefs by characterizing their morphology and its crystal structure. One of the major advantages of this study is to find out whether this material can is suitable to use as basic material in synthesis of hydroxyapatite. There are three types of coral reefs that obtained from the area, including Acropora cervicornis, Porites mayeri, and Pocillopora damicornis. These three types of coral reefs were characterized to determine their crystal structure using X-Ray Diffraction (XRD) and their morphological shape by using a digital microscope and Scanning Electron Microscope (SEM). The characterization procedure was carried out before the calcination process and after the procedure at a temperature of 1000°C. This study have found that the samples had different size in terms of pores. Prior to the calcination process, all samples showed a single phase that consist of calcium carbonate (CaCO3) in the structure form of Aragonite crystal. After the calcination procedure, the crystal structure was shifted to Calcite and it was also decomposed to CaO. The particle size of the reef powder was much smaller in volume and it was more homogeneous after it went through the calcination process, in which it ranges from 3 μm to 5 μm.