Development of hydroxyapatite from corals obtained from contamination waters of northern java by precipitation method

Research on the development of hydroxyapatite based of coral from the North Coast of Java Island using the precipitation method has been carried out. The research was carried out by identifying the compound content in the coral of the North Coast of Java to find out its potential as a basic ingredient of hydroxyapatite. The preparation of coral powder was carried out using milling for 20 hours with a ratio of samples and ball mill is 1:20. With this treatment, the average powder size of 32.69 nm was obtained. This study was to obtain the highest percentage of hydroxyapatite by varying the concentrations of Ca(OH)₂ respectively 0.6 M, 0.85 M, and 1.1 M. Hydroxyapatite synthesized from the basic ingredients of coral, the North Coast of Java, especially in Remen Beach, Tuban, produced the highest percentage of 61.50 %.