Statistical analysis of calcium phosphates preparation

Calcium phosphate was obtained by a semicontinuous wet process using the co nventional double decomposition method between an aqueous calcium nitate so lution, Ca(NO3)(2), and an aqueous ammonium phosphate solution, (NH4)(2)HPO 4. To check the effet of certain variables, on the reaction, a fractional c entral composite design was set up taking five variables into account: PH, (Ca/P)(reagents), concentration of the calcium nitrate solution ([Ca2+]), t emperature (T) and duration of precipitation (D). The limiting factors of p recipitation for apatitic tricalcium phosphate are discussed.