Experiments on silicate liquid phase sintering of YSZ ceramics with addition of 0.5 mol % of rare earth ions have been done in order to study the effect of these ions on the kinetics of grain growth and the expulsion of glass through the grain boundaries. Kinetics follow a third power law in the following order YPr > YPrEr > YY > YEr. The expelled glass does not spread over the ceramic grains and its mass is inversely related to grain size. Glass phase separation inside the grain boundaries is found to be a necessary condition for glass expulsion.