用煤系高岭土制备轻质隔热材料的研究

以煤系高岭土、紫木节粘土为主要原料,以木屑和聚苯乙烯球为造孔剂,制备了体积密度为0.74 g/cm3、抗压强度为2.84 MPa,导热系数0.15 W/m.K的莫来石质轻质隔热耐高温材料。优化的工艺条件为:配料中煤系高岭土用量达到了90 wt%,添加木屑和聚苯乙烯球总加入量为12 wt%作为复合造孔剂,最终烧成温度为1300℃。通过XRD、SEM等分析的得到:轻质隔热材料的物相组成为莫来石、刚玉和少量方石英。材料内部的孔结构特征为1~2 mm的相对孤立的较大孔和微米级的小孔。     

高岭土水热合成4A沸石实验研究

水热法合成4A沸石的实验是在不同的碱度、不同的液固比、不同的晶化温度和不同的晶化时间条件下进行的,并进行了实验结果和各种合成因素的分析及研究.实验结果分析表明在加碱煅烧及合成沸石的过程中,使用NaOH的效果比使用Na2CO3和KOH,加入适量的晶种能缩短晶化反应时间并能提高合成沸石的质量.在碱度为2.5～4.0M、液固比6∶1～8∶1、晶化温度90～103℃以及晶化时间为3～5h的实验条件下,采用苏州高岭土合成了4A沸石.文中还采用X射线衍射仪和扫描电镜对合成的沸石样品进行了表征.     

Interfacial interaction in kaolin-filled polyethylene composites

Kaolin-filled polyethylene composites were prepared under different mixing conditions. Viscoelastic properties of specimens were measured by torsion pendulum tests. Fracture behaviour was studied by tensile tests, and fracture surfaces by scanning electron microscopy and ESCA. Fracture properties turned out to be strongly influenced by processing conditions and to correlate with the amount of undissolvable polyethylene bound to the filler surface. This bound layer has an appreciably lower heat of fusion than the unfilled polyethylene.Dedicated Prof. Dr. R. Bonart on the occasion on his 60th birthday.     

一种高岭土基多孔硅材料的制备及其对Ca2+和Mg2+的吸附

成功合成了一种高岭土基新型多孔硅材料（ASM）并以FTIR,XRD,FE-SEM和N₂吸附-脱附进行了系统的表征。ASM的制备过程涉及两步：SiO₃^2-提取和ASM的制备。SiO₃^2-提取的最优条件为煅烧温度为960℃,NaOH浓度为20%,反应温度为90℃,反应时间为90 min,在此条件下SiO₃^2-提取率为60.45%（w/w）。以此提取液为原材料,调整提取液中SiO₃^2-的浓度为12 g·L^-1,反应温度为90℃,反应时间为60 min,然后再搅拌2 h可制得ASM。以此ASM对Ca²⁺和Mg²⁺进行吸附研究,脱除率分别可达94.99%和62.32%。     

Impact of Various Parameters Over the Adsorption of Polyvinylpyrrolidone onto Kaolin

The adsorption of water-soluble polymer, polyvinylpyrrolidone having molecular mass 9.1 ± 1.43 × 10³Kg mole^?1 on kaolin has been investigated. The effect of different parameters like pH, molecular mass of polymer and pre-heat treatment on the adsorption of PVP has been deliberated. The 20.7% decrease in adsorption in pH ranging from 2–10 have been found, which was an indication of the fact that with the increase in pH the kaolin surfaces sites charge amount and ultimately sign changes. Maximum adsorption was observed at pH 5.6 that was also molecular mass dependent. By increasing the pretreatment temperature, the amount of polymer adsorbed was also increased. However, above the specific temperature adsorption of PVP was decreased and attributed to decrease in specific surface area of kaolin.     

A Fluorescence Polarization Study of Polyaromatic Hydrocarbons Adsorbed on Colloidal Kaolin

Abstract

The adsorption of a number of polyaromatic hydrocarbons onto aqueous colloidal kaolin was studied. The fluorescence polarization and hence the fluorescence anistropy of the hydrocarbons was measured as a function of their concentrations in aqueous solutions containing the colloid. The fluorescence anisotropy was found to be highest for dilute solutions of polyaromatic hydrocarbons, with often sharp decreases at higher concentrations. More concentrated solutions gave an isotropies similar to those of plain aqueous solutions of the fluorophores. The concentration versus fluorescence anisotropy curves and BET surface area data were used to calculate surface coverage of the colloid by the adsorbed hydrocarbons. Coverage in the range of 1% to 14% of the colloid surface was found at surface saturation for the compounds studied. This suggested that colloidal clays have the potential of transporting polyaromatic hydrocarbons through environmental waters.     

Elucidation of Gram-Positive Bacterial Iron(III) Reduction for Kaolinite Clay Refinement

Recently, microbial-based iron reduction has been considered as a viable alternative to typical chemical-based treatments. The iron reduction is an important process in kaolin refining, where iron-bearing impurities in kaolin clay affects the whiteness, refractory properties, and its commercial value. In recent years, Gram-negative bacteria has been in the center stage of iron reduction research, whereas little is known about the potential use of Gram-positive bacteria to refine kaolin clay. In this study, we investigated the ferric reducing capabilities of five microbes by manipulating the microbial growth conditions. Out of the five, we discovered that Bacillus cereus and Staphylococcus aureus outperformed the other microbes under nitrogen-rich media. Through the biochemical changes and the microbial behavior, we mapped the hypothetical pathway leading to the iron reduction cellular properties, and found that the iron reduction properties of these Gram-positive bacteria rely heavily on the media composition. The media composition results in increased basification of the media that is a prerequisite for the cellular reduction of ferric ions. Further, these changes impact the formation of biofilm, suggesting that the cellular interaction for the iron(III)oxide reduction is not solely reliant on the formation of biofilms. This article reveals the potential development of Gram-positive microbes in facilitating the microbial-based removal of metal contaminants from clays or ores. Further studies to elucidate the corresponding pathways would be crucial for the further development of the field.     

悬浮物测定的质量控制方法

为完善现行国标法GB 11901–1989《水质悬浮物的测定重量法》中质量控制与质量保证相关内容,促进悬浮物标准品的研发,利用高岭土研制的标准溶液建立了悬浮物测定的质量控制方法。根据水样的属性,取样体积范围在50 m L~200 m L区间,采用水系0.45μm滤膜和三联抽滤装置对水样进行预处理操作,以重量法测定水样悬浮物的含量。确定方法的空白测定值稳定于上下警告线内波动,检出限为5 mg/L,样品6次测定结果的相对标准偏差小于10%,标准样品10次测定相对误差在±10%内,满足分析质量控制要求。     

高岭土对准东高碱煤煤灰熔融特性影响的量子化学与实验研究

采用量子化学理论计算与实验表征相结合的方法,研究了高岭土对准东高碱煤煤灰熔融特性及其熔融过程中矿物质演变规律的影响,并从矿物质微观结构特性角度阐述了高岭土对改变准东煤煤灰熔融特性的影响机制。结果表明,准东高碱煤煤灰熔融温度随高岭土的添加呈现先快速升高后逐渐变缓的趋势,当高岭土添加比例大于10%时,其提高煤灰熔融温度的趋势变缓;准东高碱煤添加高岭土后,其在1 000-1200℃下的低熔融矿物钙长石、硬石膏等量明显减少,1 200-1 300℃下有一定量的莫来石生成,是其煤灰熔点升高的主要原因;高岭石分子结构中的O(26)、O(22)、Si(6)、Si(8)的反应活性较高,能够与灰中的Fe~(2+)等金属离子成键,促使高岭石的铝氧键断裂。煤中的碱金属或碱土金属(Na或Ca)氧化物中的的O2-,作为亲核试剂,与高岭石的Si(6)和Si(8)发生亲核反应,使桥氧键S-O-Si断裂。     

水溶性疏水缔合聚合物在高岭土/水界面的吸附

表面活性剂;水溶性疏水缔合聚合物在高岭土/水界面的吸附