Various stages have been observed during the stoichiometric hydroxyapatite.
(Ca/P= 1.667) precipitation, particularly during the first 2 hours necessa
ry for the reactor to reach a steady state. The results show that an amorph
ous Ca2+ deficient phosphate is formed in the early minutes of precipitatio
n, then transforms into an apatitic phase which leads to a stoichiometric h
ydroxyapatite.