Patent ID: 7041822

Claim:
A process for preparing pure melamine in a high-pressure process by pyrolysis of urea, wherein the melamine melt formed is fed into a stripping vessel having at least a first and a second separate gas inlet in which the melamine melt is, in countercurrent, in a first stage brought into contact with hot fresh gaseous NH 3 from the second stage, with the temperature of the melt remaining the same or becoming higher, whereby the gaseous NH 3 is injected at the first gas inlet into the first stage, in a second stage brought into contact with cold gaseous NH 3 in such a way that it is cooled to a temperature which is 1–30° C. above the pressure-dependent melting point of melamine, whereby the gaseous NH 3 is injected at the second gas inlet into the second stage, whereupon the melamine melt is worked up in any desired way.