| 摘要 |
A method for the preparation of highly condensed ammonium pyrophosphate of chain structure comprises heating the mixture, which contains urea and ammonium orthophosphate at a ratio thereof of (1-1.2):1 respectively at the temperature of 270-300 DEGREE C in the presence of ammonium polyphosphate, and subsequent grounding product, at that mixture of ammonium orthophosphate and urea is supplied to the layer of ammonium polyphosphate. Besides, for the purpose of increasing condensation degree of ammonium polyphosphate, increasing thermal stability thereof, reduction of total consumption of initial feedstock per unit of finished product the part of urea is substituted by melamine, and the process is carried out at a molar ratio of ammonium orthophosphate: urea: melamine =1:(0.5-0.9):(0.2-0.1).
|
