Agglomeration of stoichiometric hydroxyapatite: Impact on particle size distribution and purity in the precipitation and maturation steps

Mallorie Tourbin (1) , F. Brouillet (2) , B. Galey (1) , N. Rouquet (3) , Pierre Gras (1) , N Abi Chebel (2) , D. Grossin (2) , Christine Frances (1)

1 LGC - Laboratoire de Génie Chimique
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 URODELIA

Stoichiometric hydroxyapatite (HAP) is a prominent biomaterial, notably used as coating on metal bone prostheses. High chemical purity and a specific particle size distribution are the main properties for such an application. Based on industrial practice, a reference synthesis was first performed in a lab-scale stirred reactor. Improvements were then suggested by varying the physicochemical and hydrodynamic conditions. The shear rate within the reactor, characterized by the mean Kolmogorov micro-scale, has a strong impact on the final agglomerate size distribution. By maintaining a rather high mixing rate and a high temperature, the duration of the synthesis can be reduced considerably without affecting the HAP purity provided the pH is properly regulated. This consists of imposing acidic conditions during a short period just after the initial formation of large aggregates and then setting the pH at above 7.5 to ensure the production of pure stoichiometric HAP. 2

Domaines: Matériaux; Chimie inorganique

Mallorie Tourbin, F. Brouillet, B. Galey, N. Rouquet, Pierre Gras, et al.. Agglomeration of stoichiometric hydroxyapatite: Impact on particle size distribution and purity in the precipitation and maturation steps. Powder Technology, 2020, ⟨10.1016/j.powtec.2019.10.050⟩. ⟨hal-02376251⟩