The present invention relates to a process for preparing a granular nylon salt material, wherein an aqueous mixture, comprising at least 65 wt.% of salt components, and at most 35 wt.% of an aqueous medium, the weight percentages (wt.%) being relative to the total weight of the aqueous mixture, is flashed from a pressure vessel via a flash valve into a flash chamber, thereby evaporating the aqueous medium in an amount sufficient to result in a residual moisture content of at most 7.5 wt.%, and forming a granular nylon salt material. The invention also relates to a process for preparing a nylon polymer, comprising direct solid state polymerization of the granular salt material prepared by flash granulation.