Conditions for oxidative burning out of template, di-n-propylamine, from MeAPO-31 materials have been studied by means of thermal analysis. The materials were doped with very low amounts of Cu, Cd, Co, Mn, Mg, and Zn, ranging from 0.04 to 0.63 wt.%. These low contents of heteroatoms have significantly determined the observed effects. The same holds for the stability of the microporous ATO (aluminophosphate thirty-one) type structure. Grinding of the crystallites leads to more efficient exchange of atmosphere and the gaseous products and thus results in a tendency to lower calcination temperature. This observation may be useful when considering a lower thermal stability of higher doped microporous MeAPO-31 materials. (C) 2003 Elsevier B.V. All rights reserved.