Crystal size distribution of hydroxyapatite precipitated in a MSMPR reactor

This paper is aimed to analyse the crystal size distribution (CSD) of hydro xyapatite (HA) Ca-5(OH)(PO4)(3) obtained in a continuous flow MSMPR reactor at 85 degreesC and pH(constant) = 9.0, at steady state. The kinetic of pre cipitation is calculated and the mechanism of particle formation is discuss ed. The method of moments in crystal volume coordinates, supposing a nuclea tion-growth-agglomeration mechanism for particle formation, has been used t o solve the population balance equation and to calculate the nucleation rat e (B-0), volume growth rate (G(v)) and the aggregation kernel (beta). The c rystal size distribution graphs of precipitates and the low values of the n ucleation rate show the inconsistency of this classical model to explain HA precipitation. However, they are in agreement with a mechanism of nucleati on-aggregation-agglomeration-growth followed by a large-scale agregation.