Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while ...Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs （SEM） show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed.展开更多
The potential equation in the positive sol of aluminium magnesium hydroxide was deduced according to the model of constant surface charge density, and the potential curves in the NaBr solution were obtained. The studi...The potential equation in the positive sol of aluminium magnesium hydroxide was deduced according to the model of constant surface charge density, and the potential curves in the NaBr solution were obtained. The studies of coagulation kinetics showed that the coagulation process of monovalent anions may be divided into a rapid and slow coagulation. The efficiencies in causing coagulation for monovalent anions followed the order Br ->I ->NO - 3>Cl -, which didnt correspond to the lyotropic series. The coagulation value of polyanion had a discrepancy with Shulze Hardy law. The higher the cation valent was, the stronger the stabilization of sol was. [WT5HZ]展开更多
针对聚磷酸铵(APP)有一定的水溶解性和阻燃效率不高等问题,提出了采用氢氧化铝(ATH)包覆改性APP的方法。X射线荧光光谱(XRF)和扫描电镜(SEM)分析结果显示,在APP颗粒表面实现了ATH的包覆改性。测试表明,ATH包覆改性后的APP溶解度明显下降...针对聚磷酸铵(APP)有一定的水溶解性和阻燃效率不高等问题,提出了采用氢氧化铝(ATH)包覆改性APP的方法。X射线荧光光谱(XRF)和扫描电镜(SEM)分析结果显示,在APP颗粒表面实现了ATH的包覆改性。测试表明,ATH包覆改性后的APP溶解度明显下降,比表面大幅增加。将改性后的APP与双季戊四醇(DPER)复配,作为膨胀阻燃剂添加到PP中,阻燃PP的燃烧性能测试结果表明:阻燃剂总添加量为25%时,包覆ATH的APP使阻燃PP 3.2 mm样条的垂直燃烧级别从V-1提高到V-0,氧指数(LOI)从26.6%增加到31.8%,热释放速率峰值(PHRR)从475 k W/m2下降至308 k W/m2,下降了约35%。对阻燃PP的燃烧残炭研究说明,APP经ATH包覆改性后,促进了阻燃PP在燃烧时形成更加完整均匀的炭层,因而改善了阻燃性能。展开更多
基金M/s NALCO, Bhubaneswar for the partial financial support to carry out this work
文摘Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs （SEM） show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed.
文摘The potential equation in the positive sol of aluminium magnesium hydroxide was deduced according to the model of constant surface charge density, and the potential curves in the NaBr solution were obtained. The studies of coagulation kinetics showed that the coagulation process of monovalent anions may be divided into a rapid and slow coagulation. The efficiencies in causing coagulation for monovalent anions followed the order Br ->I ->NO - 3>Cl -, which didnt correspond to the lyotropic series. The coagulation value of polyanion had a discrepancy with Shulze Hardy law. The higher the cation valent was, the stronger the stabilization of sol was. [WT5HZ]
文摘针对聚磷酸铵(APP)有一定的水溶解性和阻燃效率不高等问题,提出了采用氢氧化铝(ATH)包覆改性APP的方法。X射线荧光光谱(XRF)和扫描电镜(SEM)分析结果显示,在APP颗粒表面实现了ATH的包覆改性。测试表明,ATH包覆改性后的APP溶解度明显下降,比表面大幅增加。将改性后的APP与双季戊四醇(DPER)复配,作为膨胀阻燃剂添加到PP中,阻燃PP的燃烧性能测试结果表明:阻燃剂总添加量为25%时,包覆ATH的APP使阻燃PP 3.2 mm样条的垂直燃烧级别从V-1提高到V-0,氧指数(LOI)从26.6%增加到31.8%,热释放速率峰值(PHRR)从475 k W/m2下降至308 k W/m2,下降了约35%。对阻燃PP的燃烧残炭研究说明,APP经ATH包覆改性后,促进了阻燃PP在燃烧时形成更加完整均匀的炭层,因而改善了阻燃性能。
