PROCESS FOR OBTAINING CRYSTALLINE MELAMINE FROM MELAMINE MELT

摘要

The invention relates to a process for obtaining crystalline melamine from a melamine melt, comprising: a) a cooling step, in which the melamine melt is given a pressure between 0.1 MPa and 20 MPa and a temperature below the melting point of melamine at the prevailing pressure, upon which solid melamine is formed; b) a pressure adjustment step, in which the pressure of the solid melamine is adjusted to a value between 0.1 and 5 MPa; c) a dissolving step, in which the solid melamine is contacted with an aqueous phase that has a pH between 6 and 13 and in which less than 5 wt.% ammonia is present, upon which a solution is formed; d) a crystallization step, in which the solution is cooled by at least 20 DEG C, upon which crystalline melamine is formed; e) a separation step, in which crystalline melamine is separated from the solution.