The reaction of SO2 with synthetic apatites was studied by TG, XRD and IR a
nalyses at 400-1000 degrees C. Due to an interaction of apatite with SO2, d
estruction of apatite and formation of CaSO4 and diphosphate up to 750 degr
ees C takes place. The further calcination leads to the formation of beta-C
a-3(PO4)(2) and a part of the SO2 bound is lost again. The amount of SO2 bo
und with apatite at calcination depends on the substitutions (F- <--> OH-,
PO43- <--> CO32-, Ca2+ <--> Mg2+) in its structure.