“…However, very complex, sophisticated, biological unsafe, toxic byproducts and the high cost are the main difficulties associated with HAP synthesized from inorganic chemical methods. HAP can be obtained from natural resources such as bovine [6,15,16], chicken bone [17], pork [18,19] and fish bone [20,21] by many extraction techniques such as vibro-milling method [22], alkaline hydrolysis, Subcritical water process, Hydrothermal, Thermal decomposition [23,24] to eliminate organic components so as to avoid infections, immunological defensive reactions and disease transmission [1,23]. Usually, the synthesis of HAP by most conventional chemical methods produced HAP without a trace of valuable elements.…”