Reactions between PbO, ZrO2 and TiO2.

Reactions between the above oxides were studied by the classical kinetic analysis, experiments on tablets with marked and unmarked contact surfaces and by the method of limited contact between the reacting compounds. It is shown that the reaction rate depends mainly on the diffusion of PbO through the reaction product already formed. In the early stages, on the other hand, the reaction is governed by another mechanism. Experiments with isolated reactants showed that PbO is transported into the reaction zone via a gaseous phase. The activation energy of the reaction was determined and a detailed reaction mechanism is proposed.