Crystal Research and Technology
Cryst. Res. Technol. 36 (2001) 15 - Abstract -

J. Gómez-Morales, J. Torrent-Burgués*, T. Boix , J. Fraile, R. Rodríguez-Clemente

Institut de Ciència de Materials de Barcelona (CSIC)
*Departament d´Enginyeria Química, UPC

Precipitation of Stoichiometric Hydroxyapatite by a Continuous Method

In this paper we present the precipitation of hydroxyapatite (HA), Ca5(OH)(PO4)3, from highly concentrated CaCl2 and K2HPO4 solutions, carried out by a continuous method in a MSMPR reactor. The procedure consists of adding the reagents in a ratio Ca to P equal to 1.67, maintaining a temperature of 85 ºC, inert N2 atmosphere inside the reactor, and monitoring and adjusting automatically the pH by means of a pH-stat system (pH = 9.0 ∓ 0.1). Under these conditions HA with a Ca to P ratio equal or close to the stoichiometric composition (Ca/P=1.667), with a high yield (up to 99%) and a high production rate (up to 1.17 g/l.min) is obtained at steady state. The CSD, morphology, crystallinity of the precipitates and impurities present fit the requirement for its biomedical applications.

Keywords: stoichiometric hydroxyapatite, continuous precipitation, crystallite size, crystallinity, aggregation


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