The reaction mechanism and rate-controlling step for the carbon reduction of fluorapatite were investigated with the shaped feeds of fluorapatite

silica（AR）and active carbon（reagent）Powders.The reaction mechanism is suggested as that 2C_a F_2 SiO_2 and Ca_3（PO_4)_2are formed in the defluorination between f1uorapatite and silica

and then the Ca_3（PO_4)_2 diffuses through the molten liquid onto the surface of carbon particle where it is reduced by carbon.The steps are The fluor is evolved in the form of SiF_4 at a higher silica-lime molar ratio.When the silica-lime molar ratio is rather lower

the fluor remains in the residue in the form of 2CaF_2·SiO_2.