Hydration of Germanium Oxide Carnotite

The quaternary invariant point was reached in the CaO–GeO₂–P₂O₅–H₂O system by the hydration of germanium oxide carnotite. Complete reaction was achieved although the kinetics were very slow. Three products were identified by X-ray diffraction: calcium germanate hydrate, hydroxyapatite, and calcium hydroxide. Energy dispersive X-ray analyses established the compositions of the three phases present in the heterogeneous microstructure. Calcium germanate hydrate exhibited a fibrous habit and was present as large individual fibers as well as small thin fibers. The small fibers were intermixed with hydroxyapatite. The latter was observed to form feltlike assemblages. Stacked calcium hydroxide plates were unequivocally observed.