STATISTICAL-ANALYSIS OF APATITIC TRICALCIUM PHOSPHATE PREPARATION

Apatitic tricalcium phosphate was obtained by a continuous (3-5 kg per 24 h) process using the conventional double decomposition method between an aqueous calcium nitrate solution, Ca(NO3)2, and an aqueous ammonium phosphate solution, (NH4)2HPO4. To check the effect of certain variables on the reaction, a fractional central composite design was set up taking six variables into account: pH, (Ca/P)reagents, concentration of the calcium nitrate solution ([Ca2+]), temperature (T), duration of precipitation (R) and speed of stirring (S). The limiting factors of precipitation for apatitic tricalcium phosphate are discussed.