As for the input parameters, a strong linear correlation was found between x2, x4 and x5, passing through the ternary, that is, overreaction occurs only when there is no more underreacted material. For the depicted example, we initially assume to start from the region marked by the blue circle (~ 35 vol.% δ-Al2O3, Figure ). The radar plot of the input parameters corresponding to this phase output range (bottom left in Figure )