High-resolution thermogravimetry was used to study the thermodesorption of octane from ammonium nitrate (AN) prills with different
porosities. The samples were wetted by immersion in octane. Multiple steps were obtained from the measured mass-loss curves,
which reflect the evaporation of the excess liquid, as well as the thermodesorption of octane from the pores and the surface
of the AN prills. The quantity of octane desorbed in these steps was correlated with the volume in the pores and the amount
adsorbed on the surface, and used to estimate the adsorption capacity, porosity and surface area of AN prills. The results
were also compared to observations from scanning electron microscopy.