Low‐Temperature Formation of Fluorapatite in Aqueous Solution

The low‐temperature formation of Fluorapatite by the reaction of particulate calcium phosphate precursors in aqueous solution was investigated: image Variations in the aqueous phase were measured and these corelated with the consumption of reations and the formation of apatitic phases. The variations in solution pH and fluoide are in accord with a mechanism by which CaF 2 precipitates relatively early in the reaction. After this, minimal fluoride is consumed until the formation of an apatitic phase reaches substantial for hydroxl and the pH increase. The extent of aptite formation exhibits a storong dependence on the concetration of the NaF solution in which reation is occuring. Analysis of reaction is saturated CaF 2 solution indicates that apatite formation precedes the uptake of fluoride from solution. For reaction in dilute suspension, a low concentration of NaF retards apatite formation whereas a higher one accelerates it. Alternatively, when reaction is carried outa low liquid‐to‐solids rario, apatite formation is accelerated in NaF solution regardless of concetration.