Preparation of hydroxyapatite by neutralization at low temperature - influence of purity of the raw material

A method to prepare hydroxyapatite-Ca-10(PO4)(6)(OH)(2)-at low temperature is studied. This simple and non-polluting method consists in neutralizing a suspension of lime (Ca(OH)(2)) with a solution of orthophosphoric acid. The chemical and physical properties of the initial lime particles have a great influence on the quality of the hydroxyapatite produced. Several kinds of lime were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, size analysis, specific surface area and chemical analysis and tested in this work. Among the impurities contained in the lime, magnesium ion shows a strong influence on the formation of hydroxyapatite. The stoichiometry of the hydroxyapatite precipitate and its purity once calcinated depend on the quality of the raw materials. (C) 1999 Elsevier Science S.A. All rights reserved.