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.