| 摘要 |
Multicrystalline melamine powder having the following properties: specific surface area: 0.7-5 m<2>/g; level of oxygen-containing components < 0.7 wt.%; colour APHA less than 17; melamine: > 98.5 wt.%; melam: < 1.3 wt.%. Multicrystalline melamine powder obtainable via a high-pressure process in which solid melamine is obtained by the melamine melt being transferred to a vessel where the melamine melt is cooled with an evaporating cooling medium, the melamine melt having a temperature between the melting point of melamine and 450 DEG C being treated with 0.1-15 mol of ammonia per mole of melamine and then being sprayed via spraying means and cooled with an evaporating cooling medium within a vessel in an ammonia environment at an ammonia pressure of 0.1-25 Mpa, the melamine melt being converted into melamine powder having a temperature between 200 DEG C and the solidification point of melamine, the melamine powder then being cooled to a temperature below 50 DEG C, the powder being set in motion mechanically over at least part of the cooling range and being cooled directly or indirectly, and the ammonia pressure being released at a temperature below 270 DEG C.
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