非烧结陶瓷纤维多孔过滤材料的制备与性能

采用真空抽滤成型和非烧结低温固化工艺,以硅酸铝陶瓷纤维、硅溶胶、羧甲基纤维素为主要原料,制备了陶瓷纤维多孔过滤材料。研究了原料配比和工艺参数对材料性能的影响。结果表明：最佳配方比例为陶瓷纤维2.5wt%,硅溶胶50wt%,水 47wt%,羧甲基纤维素0.5wt%,在抽滤时间为5 min,固化温度为150℃的条件下﹐可获得非烧结陶瓷纤维多孔过滤材料,其气孔率、抗折强度和压降分别为80.22%、1.83 MPa和 130 Pa。该制备方法为工业化生产高温烟气过滤材料提供了新的选择。     

短纤维增强复合过滤管的制备

以硅酸铝纤维和硅灰石为主要原料,硅溶胶为粘结剂,通过真空抽滤成型,低温干燥,制成短纤维过滤管。用SEM、XRD等测试方法对短纤维过滤管进行表征。结果表明:所制备的短纤维过滤管孔径在20～50μm;气孔率≥75%;具有良好的透气性能;抗热震性能强。     

高温陶瓷纤维膜材料的制备及影响因素分析

本文以多晶莫来石纤维、SiO2/B2O3体系结合剂为主要原料,采用真空旋转抽滤成 型工艺,制备了高温陶瓷纤维膜材料,研究了浆料性能、结合剂加入量、成型压力对陶瓷纤维 膜材料各项性能的影响。实验结果表明：浆料粘度、结合剂量及成型压力对纤维膜材料的性能 有显著影响。当浆料的粘度为 2000 mPa?s ~ 2500 mPa?s、结合剂含量为 39 wt% ~ 42 wt%、成型 压力为 ?0.04 MPa 时,可获得均匀结构的陶瓷纤维过滤材料。材料气孔率大于 88%,透气阻力 为 82 Pa,抗压强度为 1.75 MPa,可几孔径为 90 μm。     

高温气体净化用陶瓷纤维过滤材料的制备及性能

本文采用真空旋转抽滤成型工艺,以莫来石纤维为主要原料制备了高温气体净化 用陶瓷纤维过滤材料,研究了纤维浆料搅拌时间和烧结温度对纤维膜材料性能的影响,评价其 过滤及热震性能。实验结果表明：当纤维膜浆料搅拌 2 h 时,在 1000?C 下烧结可以制备出过抗 压强度为 4.75 MPa、透气阻力 95 Pa、气孔率为 85%、平均孔径为 70 ?m、显微结构均匀的纤维 膜材料,其除尘效率可达 99.99%,且具有良好的热震性能。     

高温烟气过滤用多孔陶瓷材料的研制

以氧化铝纤维和玻璃粉为主体材料,活性炭粉为造孔剂,通过半干压成型工艺制备了高温烟气过滤陶瓷.详细研究了玻璃粉含量、造孔剂含量以及烧成温度对材料过滤阻力、抗折强度、显气孔率等性能的影响,并对原料配方和烧成制度进行了优化,最优配方为:氧化铝70wt%、玻璃粉30wt%、外加造孔剂25wt%、羧甲基纤维素钠8wt%,最佳的烧成温度为1100 ℃,制得的高温烟气过滤陶瓷抗折强度8.9 MPa,过滤阻力95 Pa,显气孔率达59%.     

气固分离膜材料的制备及性能

采用无机陶瓷纤维制备气固分离膜,利用短长径比的纤维在支撑体上制备过滤膜层,对膜层的过滤阻力、滤后空气含尘量以及反吹再生性能等进行测试。经对比发现,采用长径比为8~14的硅酸铝纤维制成的过滤膜性能最佳。在1 m/min的过滤风速下该膜层的初始阻力为108 Pa,经0.6 MPa的气压循环反吹300次后的平衡阻力为145 Pa,滤后空气含尘量为195μg/m~3。对0.03~0.06 MPa的反吹压力清灰后的平衡阻力进行了测试,0.06 MPa的反吹压力下平衡阻力为146 Pa,与0.6 MPa反吹后的平衡阻力相仿,所以反吹压力≥0.06 MPa时即可达到最佳反吹效果。     

氧化锆纤维保温板的制备与表征

以氧化锆纤维、硅溶胶或锆溶胶、水为原料,制备氧化锆纤维保温板,通过对保温板的性能进行研究分析,从而确定各原料的最佳配比。结果表明：硅溶胶加入量为10％、锆溶胶加入量为15％时氧化锆纤维保温板的性能最好。     

铝板带连铸连轧铸嘴板材制备及可加工性能的研究

以硅酸铝陶瓷纤维、高岭土、三聚磷酸铝等为主要原料,分别以硅溶胶和硅溶胶-环氧树脂为结合体系,经制浆、浇注成型后,在不同温度(分别为25、30、35、40、45、50和60℃)下保温不同时间(分别为40、60、90和120 min)进行固化,再经120℃干燥和800℃热处理,制成连铸连轧铸嘴材料试样,然后检测试样的硅溶胶...     

硅酸铝纤维制备高温气体除尘材料的性能

采用真空抽滤并加热处理的方法制备硅酸铝纤维高温气体除尘材料,并通过扫描电子显微镜(SEM)、金相显微镜和压汞仪分别对材料的显微结构、纤维分散性、孔径大小和分布进行了分析.结果表明,在800℃并保温1h加热处理后,材料的抗折强度达到3.14MPa,过滤阻力为79.75Pa/m/min,孔直径在10～80μm的孔占总体积的70.23％,气孔率达到72.99％.硅酸铝纤维多孔陶瓷材料具有较高的抗折强度,孔隙率和较低的过滤阻力,可用于高温条件下粉尘颗粒的过滤.     

海泡石纤维密封材料抽滤成型时间影响因素的研究

探讨膨胀石墨、粘合剂丁腈胶乳、防水剂甲基硅醇钠和絮凝剂对海泡石纤维密封材料抽滤成型时间的影响。结果表明 ,无粘合剂和防水剂时 ,膨胀石墨用量为 2 0份 ,海泡石纤维密封材料的抽滤成型时间最短 ;加入粘合剂和防水剂后 ,膨胀石墨用量变化对密封材料的抽滤成型时间无明显影响 ;丁腈胶乳用量达到 15份后 ,密封材料的抽滤成型时间趋于稳定 ;甲基硅醇钠用量增大 ,密封材料的抽滤成型时间缩短 ;絮凝剂为聚合氯化铝的密封材料抽滤成型时间较短。     

AS型泡沫陶瓷过滤器的研制

详细说明了用网状弹性聚氨基甲酸乙脂切片浸渍陶瓷料浆研制AS型泡沫陶瓷过滤器的工艺。采用非磷酸盐添加剂粘合,由碳化硅、氧化铝、硅胶及少量硅酸铝纤维制成的AS型泡沫陶瓷过滤器抗压强度可达1．65MPa而厚度仅为15mm,并且不会造成环境污染,完全可以满足过滤铁熔液的要求。     

硅源对无定形硅铝物化性能的影响

以硅溶胶和九水硅酸钠为硅源,九水硝酸铝为铝源,采用分步沉淀法制备一系列不同硅铝比的无定形硅铝,通过XRD、BET和NH₃-TPD等考察硅源对无定形硅铝物化性能的影响。结果表明,以九水硅酸钠为硅源制备的无定形硅铝比表面积和酸性均明显优于以硅溶胶为硅源制备的无定形硅铝;以九水硅酸钠为硅源,在SiO2质量分数为55%时,该无定形硅铝呈现出最大酸量和高的比表面积,作为性能优异的催化材料将具有良好的应用价值。     

硅酸铝纤维和玻璃纤维复合二氧化硅气凝胶材料的制备与性能

分别以硅酸铝纤维和玻璃纤维为骨架材料,采用溶胶-凝胶、常压干燥制得纤维复合二氧化硅气凝胶材料,并对材料进行了结构和性能的测试分析。结果表明,二氧化硅气凝胶附着于纤维表面,提高了材料力学强度。硅酸铝纤维复合二氧化硅气凝胶材料的隔音性能优于玻璃纤维复合二氧化硅气凝胶材料。两种纤维复合二氧化硅气凝胶材料耐高温、燃烧性能均达到A级。硅酸铝纤维复合二氧化硅气凝胶材料和玻璃纤维复合二氧化硅气凝胶材料的产烟毒性分别为AQ₁级和AQ₂级,导热系数分别为0.034 W/（m·K）和0.033 W/（m·K）。     

硅溶胶硅酸钾混合物微量热法研究

在25.0℃及搅拌条件下,采用等温热导微量热法研究了硅溶胶与硅酸钾的混合过程。结果表明,硅溶胶与硅酸钾混合,立刻发生了SiO2溶解和复杂的化学反应,并产生了完全不同于硅溶胶和硅酸钾的SiO2胶体粒子和化学成分以及热效应,热效应受硅溶胶所占的相对重量百分比的影响。其反应的特征是硅溶胶和硅酸钾的反应级数从低到高时刻都在快速不断交替变化;随着硅溶胶所占比例的提高,热谱曲线峰高、硅溶胶与硅酸钾的混合化学反应完全的曲线总面积(总焓变QT)和热力学焓变(ΔH)数值都表现出不断增大的趋势。     

Preparation of high-strength lightweight alumina with plant-derived pore using corn stalk as pore-forming agent

To improve the mechanical and thermal insulation properties of lightweight alumina, which was prepared by using pore-forming agent from biological sources, the silica sol-infiltrated corn stalk was utilized. Spring back and hygroscopicity of corn stalk powder as well as cold compressive strength, thermal conductivity, microstructure, and pore size distribution of lightweight alumina were characterized. The results indicate that impregnation of silica sol leads to different degrees of decrease in spring back height due to achieving better mesh by silica gel between the corn stalk powders, and then improves the formability, although at the same time the large number of hydrophilic groups results in an increase in hygroscopicity. Furthermore, sol impregnated pore-forming agent optimizes the microstructure of the lightweight alumina pores. Lightweight alumina with a cold compressive strength up to 48.64 MPa was produced, and with the silica sol concentration of 3 wt%, lower thermal conductivity values at all test temperatures were obtained. Hence, the use of corn stalk impregnated with the appropriate concentration of silica sol as pore-forming agent could enhance the mechanical and thermal insulation properties of lightweight alumina for the spheroidization of pore shape, randomization of pore distribution as well as miniaturization of pore size.     

Nano mullite bonded refractory castable composition for high temperature applications

Development of high pure alumina castable is studied by using synthesized mullite sol as the sole binder. Mullite sol is prepared by wet chemical route and is characterized by its solid content, particle size, thermal analysis, phase development with temperature, microstructure, etc. This sol is used at two different percentages in high alumina castable compositions with two different particle size distribution patterns. Conventional castable processing is done on the compositions and the characterizations are done after heat treatment at three different temperatures. Finally, the best composition is also compared with the commercially available silica sol containing high alumina castable with similar particle size distribution. Considerably improved hot strength, high corrosion resistance and flexural strength (hot modulus of rupture) are obtained for the mullite sol containing composition but with relatively lower thermal shock resistance.     

Enhancement of bonding network for silica sol bonded SiC castables by reactive micropowder

Silica sol bonded castables have obvious advantages over low cement or hydratable alumina bonded castables in drying performance and sintering properties for SiC castables. However, they are not widely used due to their weak strength at low temperature. The efficiency of bonding network for silica sol bonded SiC castable in the presence of different reactive micropowder such as SiO₂ micropowder and α-Al₂O₃ micropowder was evaluated through oscillatory tests, sintered properties and microstructural analysis. Results show that the polymerization reaction between SiO₂ micropowders enhanced the siloxane network and reinforced the bonding strength, furthermore, the addition of α-Al₂O₃ micropowder contributed to accelerating the formation of the siloxane network and hardening of the silica sol at lower temperatures and shorter time. Silica sol performed well as a binder agent for SiC castables with an addition content of 3 wt% SiO₂ micropowder and 2 wt% α-Al₂O₃ micropowder, which showed high strength and good workability at room temperature. And Silica sol bonded SiC castable with the above micropowder contents possessed the best mechanical behavior after heat treatment due to combined binding of SiC whiskers and mullite.     

Dispersion properties of alumina powders in silica sol

The dispersion of alumina powders in silica sol has been investigated by zeta potential, sedimentation, and rheological measurements. Zeta potential of alumina in silica sol changes significantly in comparison with that of alumina in deionized water. This is caused by the absorption of silica colloidal particles with negative charge on the surface of alumina particles. Sol-dispersed alumina slurry shows a minimum in sedimentation volume and viscosity around pH 10. The viscosity depends strongly on the silica sol concentration and reaches a minimum in 10–15 wt.% silica sols. It is proposed that the dispersion and stabilization of alumina particles in silica sol are attributed to the electrostatic and steric effects of the colloidal particles absorption. Effects of pH, solids content and silica sol concentration on the rheological behavior of sol-dispersed alumina slurries are discussed in detail.