CRYSTALLINE MELAMINE Russian patent published in 2004 - IPC

FIELD: production of crystalline melamine.

SUBSTANCE: the invention is dealt with production of crystalline melamine. Powder of polycrystalline melamine having following properties: specific area of surface: 0.7-5 m²/g; the share of oxygen-containing components < 0.7 mass %; color on АРНА is less than 17; melamine > 98.5 mass %; melam: <1.3 mass %, and produced by a method under high pressure, in which solid melamine is formed during transfer of the melt of melamine into a container, where the melt of melamine is cooled by an evaporating coolant. The melt of melamine having the temperature between its melting point and 450°С, is treated with 0.1-15 gram-molecule of ammonia per a mole of melamine and then is sprayed with the help of a spraying device and cooled with the help of an evaporating coolant inside the container in an atmosphere of ammonia under pressure of ammonia of 0.1-25 MPa. The melt of melamine is converted into the powder of melamine having the temperature between 200°С and its solidification point. Then the powder of melamine is cooled chill down to a temperature below 50°С. The powder is mechanically moved over at least a part of the cooing zone and is cooled directly or indirectly, and the pressure of ammonia is dropped at the temperature of below 270°С.

EFFECT: the invention allows to produce crystalline melamine.

7 cl, 2 ex, 4 dwg