It is difficult to ensure complete homogeneity in a sample processed via grinding. Better results may be obtained by pressing samples into ceramic pellets, ensuring all reactants are in intimate contact. In many cases, a binder will be used to ensure the pellet maintains mechanical integrity before firing.
Pellet Press Pellets are never fully dense; the density of the as-pressed pellet is known as green density, and is usually low (~50%). After firing at high temperature, pellets typically densify as the ceramic material sinters and grains grow. Pellets densities can reach ~90% of the theoretical crystal density.
Calcination of pellets containing hydrated salts will obtain much lower density.