石油羧酸盐的磁化降吸附研究

探讨了磁化前后，石油羧酸盐表面活性剂在高岭土表面静吸附规律的变化。实验发现，经磁化处理的石油羧酸盐表面活性剂，在高岭土表面的吸附速度变快，液固比变小，吸附等温线仍有最大值，但已大为下降，从而推断其吸附模式发生改变。     

偏高岭土微波法合成13X分子筛的生长过程

以鄂尔多斯煤系高岭土经730℃煅烧后得到的偏高岭土为主要原料,采用微波加热法合成了13X分子筛。通过XRD、FTIR、SEM和水静态饱和吸附测定等方法对连续晶化期间不同时间下的固相产物进行了分析,研究了微波条件下偏高岭土合成13X分子筛的生长过程。表征结果显示,在晶化时间为55 min时开始出现13X分子筛晶体,在晶化时间为75 min时13X分子筛晶体生长完全,在晶化时间为150 min时13X分子筛开始向P型分子筛转变。13X分子筛晶体的生长过程包括:偏高岭土溶解并释放出硅、铝物种;硅、铝物种与添加的硅源三者形成硅铝酸钠凝胶;凝胶中出现四、六元环和β笼的基本结构单元;基本结构单元通过有序连接形成13X分子筛晶体。     

Behavior of Paramagnetic Iron during the Thermal Transformations of Kaolinite

Kaolinites with various degrees of structural order and iron content were heated and subsequently analyzed via electron paramagnetic resonance. Iron was present in two different states in the heated materials, either as dilute structural Fe³⁺ ions or in concentrated Fe³⁺ phases. During metakaolinization, the environment of dilute Fe³⁺ ions changed, following modifications of the Al³⁺ coordination, and the Fe³⁺ concentration increased. With the breakdown of metakaolinite, the diffusion of Fe³⁺ ions induced their exsolution in superparamagnetic iron-rich domains (Fe³⁺ clusters in γ-Al₂O₃ and/or Fe³⁺ oxide nanophases), which produced a decrease in the dilute Fe³⁺ concentration. The subsequent breakdown of γ-Al₂O₃ and the formation of mullite made the dilute Fe³⁺ concentration increase again, because of the incorporation of Fe³⁺ ions in the mullite structure.     

Overview on Polystyrene/Nanoclay Composite: Physical Properties and Application

This article reviews the research and progress on polystyrene and nanoclay-based nanocomposite. Polystyrene is one of the most extensively used commercial polymers in the world. This review is designed to be an expansive source for polystyrene–clay nanocomposite research, including synthesis, characterization, structure/property relationship, manufacturing techniques, and applications considering thermal, mechanical, barrier, electrical conductivity, non-flammability, and biodegradability. The frequently used clays with polystyrene are montmorillonite, bentonite, hectorite, and kaolinite. The polystyrene–clay nanocomposite has several interesting commercial significances in packaging, automotive, fuel cell, construction, and electrical materials. Finally, future challenges toward the technical applications of these advance materials have been discussed.     

Hydrothermal synthesis (200 °C) of Co–kaolinite and Al–Co–serpentine

In the systems CoO–Al₂O₃–SiO₂–H₂O and CoO–Al₂O₃–SiO₂–HCl–H₂O, at initial pH between 5.5 and 8.1 and temperature of 200 °C, kaolinite is unstable and the following phases form through a dissolution-precipitation process: a) kaolinite and Co-bearing kaolinite; b) Al–Co–serpentine; and c) poorly crystalline phases. Identification of the several phases was carried out from a combination of X-ray diffraction and transmission/analytical electron microscopy.Co–kaolinite shows variable morphologies: a) Platy lath-shaped particles with very low Co content; b) Spherical particles, with relatively constant Co contents (in the order of 0.10 apfu); c) Kaolinite stacks with very variable Co contents (up to 0.25 apfu). Analytical data indicate that the presence of Co(OH)₂ in the system favors the dissolution process as well as serpentine formation but it leads to the parallel formation of abundant poorly crystalline phases. The Co-content in kaolinite increased as a function of the Co(OH)₂/CoCl₂ ratio in the initial systems, and it is reflected by a parallel increase of the b-cell parameter of kaolinite. The average composition of the coexisting Al–Co–serpentine is: (Al_1.20Fe_0.11Co_1.27)(Si_1.64Al_0.36)O₅(OH,Cl)₂, with Cl contents in the order of 0.14 apfu.The assemblage Co–kaolinite + Al–Co–serpentine, which appears to be stable at 200 °C, has not been described in natural environments, probably because it requires unusual Al- and Co-rich chemical systems.     

高岭石矿物表面化学的量子化学研究

用量子化学的理论和计算方法，研究高岭石表面的化学状态、表面化学活性位置及其成键特征、结果表明，高岭石分子簇的最高占据轨道基本上是由上、下表面的一些氧原子组成的，且具有较高的能态，说明这些位置具有较高的化学活性，易于与获得电子能力较强的物质形成化学键。而其最低空轨道则主要由硅、铝和少量的侧面O原子组成．相对而言，能级较低，易于与提供电子的体系作用，其化学反应活性较大。因此，当高岭石与带负电荷的离子或离子基团作用时，可能在侧面的位置形成表面化合物。Al和Si都是组成LUMO分子轨道的主要成分，但Al原子的化学活性要大于Si原子，因此，当高岭石表面与提供电子的体系发生化学作用时，最可能的位置应该是八面体的Al原子。     

天然高岭土原位还原制备SiCw/Al2O3复相陶瓷粉末

采用天然高岭土为主要原料,以碳黑作为碳源,原位还原制备SiCw/Al2O3复相陶瓷粉末.研究原位还原合成的热力学过程,并对SiC晶须形成机理进行探讨.结果表明:保护气氛下通过原位碳化,在1550℃下保温1.5h合成出SiCw/Al2O3复相陶瓷粉末.产物中SiC呈晶须状,其直径≤200nm,长度≥5μm.反应机理:高岭土中的SiO2与碳黑反应先形成SiO气相,SiO与碳黑通过气固反应形成SiC微晶颗粒;由SiO与CO气相反应沉积到前述SiC微晶颗粒上,沿(111)晶面择优生长逐渐形成晶须状产物;莫莱石还原反应同时进行;最后形成以SiCw包覆Al2O3的结构并均匀分布.     

The Effect of Kaolinite Structure Changes on Its Transformation Temperature of Phases

The relationship between kaolinite structure and the temperature of thermal transformation of phase was discussed in this paper through grinding and henting treatment. The results show that the structure of kaolinite is destroyed rapidly with mechanical grinding time, and the kaolinite structure collapses completely after 1 h grinding. The temperature of thermal transfomlation of phase of decreases with the destruction of kaolinite structure. This result has a great significance for the utilization of kaolinitic rocks in China coal measures.     

重力坝深层抗滑稳定的非线性边界元分析

针对实际工程中的复杂地基问题,本文以间接边界元法——不连续位移法和不连续应力法为基础,按增量变刚度法建立了软弱夹层问题的非线性边界元法,其中软弱夹层用非线性节理单元模拟,然后用这个方法分析了重力坝深层抗滑稳定问题并给出了算例。算例表明该方法应用方便灵活、工作量小、能节省机时减少计算费用,而且能获得令人满意的安全度指标和位移应力的变化规律,是分析这类问题的一种较合理的计算方法。