An attempt has been made to reveal the mechanisms responsible for changes in molecular mobility after addition of aluminum nitrate to ethylammonium nitrate using molecular dynamics modeling. The main goal was not only to quantitatively estimate the kinetic characteristics of the components of the mixture at different ratios, but also to correlate the local structure rearrangement at increased salt concentrations with the rotational reorientation of ions. The model systems, radial distribution functions, self-diffusion coefficients, and reorientation times of the intramolecular vectors of the nitrate anion were calculated. At increased concentrations of aluminum nitrate in the system, the reorientation of the nitrate anion and the translational motions of the system components slowed down. It was demonstrated, using the radial distribution functions, that the aluminum ion does not penetrate into the nearest environment of the ethylammonium cation. The appearance of triply charged aluminum ions, however, has a noticeable effect on the ordering of nitrate anions, including those that are part of the environment of the ethylammonium cation. This just leads to a slowdown in the rotational reorientation of the nitrate anion.