Growth rate of hydroxyapatite crystals obtained by precipitation

Identification of a precipitation process consists in the formulation of a mathematical model which describes the real system characteristics. The model parameters have physical significance in terms like growth rate, nucleation rate or population density of particles. In the present work, the precipitation kinetics of hydroxyapatite (HAP) was studied at the laboratory scale using a 0.5 L batch reactor. The vessel was operated continuously at 25 °C and 50 °C at different feed concentrations. A methodology already known for other systems was applied to determine the kinetic parameters (growth rate) from the crystal size distribution (CSD) in the preparation of hydroxyapatite. Predicted particle size characteristics shown reasonable agreement with experimental data collected. The influence of feed concentration on particle size of hydroxyapatite was discussed too.