水化硅酸钙粉体补强橡胶的性能

动态水热法合成的超细水化硅酸钙粉体,进行表面改性后在炭黑检验配方中完全取代炭黑以用作橡胶的补强填料。对所得复合橡胶进行性能测试,发现掺量为40%,且以160℃、3 min为硫化条件时,其硫化胶的拉伸强度、抗撕裂强度与同配方下N220炭黑橡胶基本一致,且扯断延伸率明显增大。结论是低温低压动态水热合成工艺下制备的水化硅酸钙无定型超细粉体,经过改性剂B改性后与天然橡胶所得的复合橡胶强度性能较好,在实验室条件下与中超强N220炭黑补强效果相当。

钠钙硅渣常压脱碱同步制备硅酸钙粉体

以低温低钙烧结法处理赤泥产生的钠钙硅渣为原料,通过常压反应制备了硅酸钙粉体。利用XRD、XRF、PSD、SEM-EDS等检测手段,系统研究了不同反应条件对钠钙硅渣脱碱性能、物相转变和制备硅酸钙粉体的影响规律及其反应机理。结果表明:钠钙硅渣脱碱的最佳工艺条件为反应温度97℃、反应时间4 h、液固比10、苛碱质量浓度60 g/L,此时钠钙硅渣的脱碱率为94.67%,硅酸钙粉体的含水率和堆积密度分别为55.1%和0.31 g/cm^(3)。具有锡箔片状结构的C-S-H(I)型水化硅酸钙凝胶为硅酸钙粉体的主要物相。钠钙硅渣脱碱反应由内扩散控制,反应表观活化能为11.22 kJ/mol。

Effect of P addition on mineral transition of CaO-Al_2O_3-SiO_2 system during high-temperature sintering

The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sintering were systematically studied by XRF, XRD, SEM-EDS and DSC-TG technologies. The clinkers sintered at 1350 °C mainly contain 12CaO·7Al2O3, CaO·Al2O3,β-2CaO·SiO2 and γ-2CaO·SiO2. The content of β-2CaO·SiO2 increases while the content of γ-2CaO·SiO2 decreases as the P addition increases. The self-pulverization property of clinkers deteriorates with increasing P addition. P distributes evenly in the clinkers, and inhibits the transformation of β-2CaO·SiO2 to γ-2CaO·SiO2. The cell volumes of 12CaO·7Al2O3 and CaO·Al2O3 decrease and increase respectively as the P addition increases, and P decreases their formation temperatures. The Al2O3 leaching rate of calcium aluminate clinkers decreases obviously with increasing P addition, which decreases form 95.01% to 83.84% as the P addition increases from 0 to 0.85%.