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在对低品位硅藻土进行低温一次焙烧、酸浸提纯工艺的基础上,研究了低温二次焙烧对硅藻土孔径分布和组分的影响.通过扫描电镜(SEM)、X射线衍射(XRD)、比表面积及孔径分析等手段对硅藻土提纯前后进行表征.结果表明:依次经过一次焙烧、酸浸和二次焙烧处理后,硅藻土内SiO2含量明显增加,由原来的73.67%增加到88.03%;比表面积显著增大,由原来的16.4882 m2/g增加到32.0527 m2/g;硅藻土中微孔和介孔数量显著增多,孔结构得到明显改善,硅藻土中自生矿物杂质得到有效去除,硅藻土的纯度得到显著提高. 相似文献
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《硅酸盐学报》2021,49(7):1385-1394
采用酸浸、碱浸及碱浸-水热联合工艺对红辉沸石进行孔结构调控,并对处理前后样品的孔结构特性、成份组成、微观形貌及调湿性能进行了系统分析。结果表明:酸浸有利于增加红辉沸石中微孔及2~10 nm的小尺寸介孔数量,而碱浸有利于增加红辉沸石中2~50nm的介孔数量;碱浸-水热联合工艺可实现以较低碱浓度对红辉沸石孔结构调控;微孔的增加有利于提升红辉沸石的吸湿性能,而10~50 nm中大尺寸介孔及大孔的增加有利于提升红辉沸石的放湿性能;在相对湿度33%~75%的环境下,碱浸样品的吸放湿均衡性优于酸浸样品,经3.0 mol/L盐酸酸浸、5.0 mol/L氢氧化钠碱浸、0.6 mol/L氢氧化钠水热碱浸后样品的12 h调湿量分别可达4.44%、5.41%、3.72%,相比未处理红辉沸石分别增加4.62倍、5.84倍、3.71倍。 相似文献
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由工业固废制备轻质节能建筑材料的同时,实现其功能性,是拓宽其应用途径的重要方面.本文中使用CaCl2溶液对硅藻土的调湿性能进行改性,并将改性硅藻土应用到EPS-磷石膏体系中.实验结果表明:当使用质量浓度为30%的CaCl2改性时,改性硅藻土48 h吸湿率可达到192.2%,48 h放湿率为32.81%;当改性硅藻土掺量为20%时,EPS-磷石膏硬化体的吸放湿性能相对最优,但会对硬化体的强度产生一定影响;CaCl2的使用,使硅藻土的平均孔径增大,且CaCl2的化学吸附被认为有效提高了硅藻土的调湿能力. 相似文献
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活化温度对海泡石纤维自调湿性能的影响 总被引:5,自引:0,他引:5
用物理和化学方法对天然海泡石材料进行纤维剥离和活化处理,研究了海泡石纤维活化温度对其吸湿和放湿的影响。通过海泡石纤维质量损失、吸放湿实验,结合对海泡石纤维特殊晶体结构、比表面积和孔隙度的表征分析,综合评价海泡石纤维自调湿性能。结果表明:当活化温度在200~250℃之间,加热6h时,其孔隙度和比表面积最大,自调湿性能最为理想。从晶型结构分析,当温度超过250℃时,海泡石纤维孔径继续增大,比表面积减小,吸附性减弱;当温度超过300℃时,结晶水分解,使晶体发生改变,纤维孔出现塌陷、堵塞,吸附性急剧降低。 相似文献
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The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion. 相似文献
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Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement 总被引:1,自引:0,他引:1
In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably. 相似文献
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组合凹模的应力分析是一个非常复杂的问题,对其进行精确分析是解决模具寿命的关键。本文采用有限元分析软件Ansys对转子的组合凹模进行了分析,为转子组合凹模的优化设计提供了依据。 相似文献
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