ABSTRACT
I. Introduction 475 II. Hydroxyapatite: Formation, Morphology, and Structure 476
III. Hydroxyapatite Dissolution 479 A. Ionic crystal dissolution 479 B. Dissolution reaction of HAP 480 C. Dissolution-rate experiments 481 D. Kinetics behavior 483 E. Models of dissolution 484 F. Dissolution of carbonated apatites and fluorapatites 494 G. Conclusion 495
IV. Inhibition o f Dissolution by Adsorbed Compounds 496 A. Adsorption and inhibition o f dissolution 496 B. Inhibition by surfactants 497 C. Inhibition by adsorbed ions 497 D. Inhibition by low molecular weight organic compounds 502 E. Inhibition by proteins 502 F. Inhibition by synthetic macromolecules 505 G. Conclusion 506 References 508
I. INTRODUCTION
Apatites form an important series of minerals that occur as minor constituents of many igneous rocks. They are also present in most metamorphic rocks, especially crystalline limestones. Less well crystallized deposits referred to generally as rock phosphate or phosphorite occur also in large sediments of several marine shelves, some of which were formed by the reaction between phosphate solutions from guano and calcareous rock or precipitated from sea water. The rock phosphates provide most of the world’s phosphorus supply for industrial applications including water treatment, fertilizers, detergents, insecticides, and other chemical industries.
