Process for preparing nylon salt and its polymerization

[0021]The effect of the process according to the invention, comprising flashing of an aqueous salt mixture at elevated temperature, is that a solid salt in the form of a granular material is obtained in an effective and efficient manner. With the process the granular nylon salt material is obtained in a much faster and simpler manner than crystallization or spray drying. Less water is needed, also because a slurry can be used, and no controlled droplet size atomization is required. The aqueous mixture can be flashed by a flash valve having a relatively large opening, without the need of spray nozzles with a small opening, which significantly reduces the risk of blocking of the opening and also allows the use of slurries, which have a salt content well above the solubility level. Because of the high temperature and the relatively low water content, the water is evaporated adiabatically, or at least essentially so, without the need for applying a large countercurrent of heated inert gas.