Intrinsic kinetics of the oxidation of Na2TiF6 and Na3TiF6

The intrinsic kinetics, unaffected by diffusional and mass transfer effects, of the air oxidation of Na2TiF6 and Na3TiF6 were determined by using a nonisothermal technique. The oxidation of these sodium fluorotitanates proceeds through two-step reactions involving the formation of oxyfluorotitanate, i.e. Na3TiOF5, as the intermediate. The oxidation rate shows a first-order dependence on the amount of the unreacted solids for each of the two-step reactions for both fluorotitanates. The activation energy for the further oxidation of Na3TiOF5 to a mixture of NaF + TiO2 was determined to be 52.4 kJ/mol and 55.3 kJ/raol for Na2TiF6 and Na3TiF6 as reactants, respectively.