Using DSC technique, the chemical interaction in Bi2O3+MO2 mixtures resulting the Bi12MO20 phase, (M=Ti, Ge and Si) was monitored. Kinetic parameters for the primary stage of interaction were yielded by the non-isothermal method of kinetic evaluation of experimental heat flux DSC curves. The model of three-dimensional diffusion according to Jander was fitted as the best in a statistical sense.