Abstract: A preparation method for a water-insoluble crystal form ammonium polyphosphate includes conveying crystal H-type phosphorus pentoxide and diammonium phosphate at a molar ratio of 1:1-1.5 into a malaxator with twin screws, and injecting ammonia gas for 3-40 minutes into the malaxator at 20-25 m3/h while preheating the material at a temperature between 100° C. and 300° C. Therafter one injects ammonia gas again at 8-15 m3/h for 4-8 hours. The resulting material is transferred to another sealed container and stirred while coupling agent is added. Stirring continues until the material drops below 60° C., the material then being transferred into organic solvent for washing for 30-50 minutes. Thereafter the material is first filter pressed, then subjected to low temperature drying, and then sieved to obtain the final product.

Abstract: A preparation method for a water-insoluble crystal form ammonium polyphosphate includes conveying crystal H-type phosphorus pentoxide and diammonium phosphate at a molar ratio of 1:1-1.5 into a malaxator with twin screws, and injecting ammonia gas for 3-40 minutes into the malaxator at 20-25 m3/h while preheating the material at a temperature between 100° C. and 300° C. Therafter one injects ammonia gas again at 8-15 m3/h for 4-8 hours. The resulting material is transferred to another sealed container and stirred while coupling agent is added. Stirring continues until the material drops below 60° C., the material then being transferred into organic solvent for washing for 30-50 minutes. Thereafter the material is first filter pressed, then subjected to low temperature drying, and then sieved to obtain the final product.

Abstract: The present invention relates to a process for the synthesis of melamine cyanurate in lamellar crystalline shape with high purity and flowability. The procedures include that 1) melamine and cyanuric acid react to form mixture solution, 2) the mixture solution is filter-pressed to prepare filter cake, 3) filter cake and silicon oil are mixed to obtain semi-finished product, 4) dried the semi-finished product until the water content is less than 1.0%, 5) heat the temperature and control certain vacuum degree for curing and crystallizing, 6) the product is obtained. The processing steps of present invention are easy to operate, the processing parameters are easy to control, the production time of melamine cyanurate is short, the quantity of pure water is low, and utilization of equipments is high. Removing the incompletely reacted raw materials and impurities by filter-pressing, greatly increases the purity of semi-products.