甲基含氢硅油对喷雾干燥磷铵灭火粉性能的影响

采用喷雾干燥法制备了球形空心超细NH4H2PO4灭火粉，并添加甲基含氢硅油乳液、氟碳表面活性剂FK-510对粉体进行原位改性，研究了表面活性剂甲基含氢硅油对NH4H2PO4灭火粉的疏水性、表面元素、表面形貌、分散性及粒度分布的影响. 结果表明，干燥过程中甲基含氢硅油及FK-510迁移聚集于颗粒表面，且FK-510位于最外层而甲基含氢硅油位于次外层，明显提高灭火粉疏水性；添加甲基含氢硅油明显改善了粉体分散性，当硅油添加量为NH4H2PO4质量的3%时，所得产品疏水性、分散性和球形度良好，活化指数提高到93.7%.

Influence of Methylhydrosiloxane on Ammonium Dihydrogen Phosphate Fire-extinguishing Powder in Spray-drying Process

Superfine spherical fire-extinguishing powder, ammonium dihydrogen phosphate, was prepared using spray-drying, and modified in situ with silicon oil emulsion and fluorocarbon surfactant FK-510. The influences of methylhydrosiloxane dosage on activation index, surface element, surface morphology, dispersion and particle size distribution of ammonium dihydrogen phosphate were studied. The results indicate that methylhydrosiloxane and FK-510 congregates on the particle surface, with FK-510 outermost and methylhydrosiloxane second outer, which improves particle hydrophobicity and bring fine dispersion. When methylhydrosiloxane dosage is 3%(ω) of ammonium dihydrogen phosphate, powder activation index reaches 93.7%, and powder gets nicer hydrophobicity, dispersion and sphericity, so it is the optimal dosage of surfactant.