Method for crystallising a melamine melt

• Main Author: TJIOE TJAY TJIEN M
• Format: Patent
• Language: English
• Published: 22.04.2008
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; CHEMISTRY; CRYSTAL GROWTH; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; THEIR RELEVANT APPARATUS; TRANSPORTING; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

Method for crystallizing a melamine melt to form melamine particles with a D90 of at most 2 mm by cooling a melamine melt to below the crystallization temperature of the melamine, comprising the formation of a suspension of melamine particles in the cooling medium by spraying the melamine melt with at most 10 wt % of CO2 relative to the sprayed quantity of melamine melt in a space in which a layer of a liquid cooling medium is present that has a temperature below the crystallization temperature of the melamine and under cooling conditions at which at least 50 wt % of the sprayed melamine melt directly turns into suspended melamine particles. Method for the production of melamine from urea in a preferably continuous, high-pressure process, with application of the present method for the crystallization.