RECOVERY OF MELAMINE FROM REACTION PRODUCT OF UREA AND RECOVERY OF SOLID MELAMINE FROM MELAMINE MELT

摘要

PROBLEM TO BE SOLVED: To recover high-purity melamine from a melamine-containing urea reaction product by a noncatalytic high pressure method. ;SOLUTION: A melamine-containing urea reaction product is separated into a vapor phase and a liquid phase to cool the urea reaction product. Then the liquid phase is transported to a mixing vessel, mixed with a liquid medium, preferably ammonia and a liquid mixture is obtained at such a temperature and under such pressure as to approximately avoid the formation of a solid melamine, namely at about 1-50°C under about 10-100Mpa. Optionally the liquid mixture is pressurized, swollen and the liquid medium is evaporated to give melamine as a dried solid substance. Consequently, melamine can be recovered in an extremely high purity of 99.5-99.95wt.% from the urea reaction product.;COPYRIGHT: (C)1998,JPO