Patent ID: 6274731
Filing Date: 2001-08-14
Classification: C07D

Abstract:
A method for preparing melamine from urea via a high-pressure process by which solid melamine is obtained comprising steps:(a) forming a melamine melt, the melamine melt having a temperature between 450.degree. C. and the melting point of melamine;(b) spraying the melamine melt into a vessel, the vessel having an ammonia environment at an elevated ammonia pressure, to form droplets of melamine melt;(c) cooling and solidifying the droplets of melamine melt with an evaporating cooling medium, the evaporating cooling medium being introduced into the vessel separately from the melamine melt to form melamine powder having an intermediate temperature of 270.degree. C. or less;(d) releasing the ammonia pressure and cooling, either directly or indirectly, the melamine powder to a final temperature, the difference between the intermediate temperature and the final temperature defining a cooling range; and(e) mechanically agitating the melamine powder during at least a portion of the cooling range.