A New Perspective on Fluorapatite Dissolution in Hydrochloric Acid: Thermodynamic Calculations and Experimental Study

Apatite (Ap) dissolution in diluted acids is well described the literature, but technological processes which use more concentrated acids, reaction fast, and it complicated to follow process kinetics. The relationship between pH change apatite rate depending on HCl concentration was studied by thermodynamic calculations experiments with synthetic fluorapatite (FAp). On basis of experimental measurements, kinetics analyzed. solution composition (P, Ca, F) determined wet chemical methods solid part characterized XRD FTIR. It shown that amount needed for FAp depends acid concentration. cannot be deduced from solubility data P, Ca or F as secondary reactions CaF2 CaHPO4 formation take place simultaneously. found Ap can followed change.