  The moisture absorption in granulated materials used in foundry technologies
is analyzed. The absorption process has a diffusive behavior mainly. A simple
experimental technique, in which the wet weight increment was recorded as the
experimental parameter and an analytic method with computing procedure to find
the parameters characterizing the process was used. The determination of these
parameters by traditional methods is a very difficult task so, very refined and
expensive trials are needed. The fitting of the model permits to determine the
diffusion coefficient and the moisture concentration in the separation surface
between the sample and the environment. The concentration profiles are
established for different times. Finally, the possibility of occurrence of
superimposed diffusive processes in some materials is analyzed and the
diffusion coefficient and the amount of moisture incorporated by each process
are calculated.
