硅酸盐粘土矿物的晶体结构与陶瓷减水剂的解凝机理

从泥浆微粒表面的ζ电位、粘土矿物的晶体结构以及陶瓷减水剂的解凝机理出发,说明如何根据制浆中所用粘土矿物的类型选择不同类型的减水剂,从而提高减水剂的使用性能。说明了粘土矿物种类与减水剂选择之间的关系,从而为在生产中合理、正确地选择减水剂以及开发新型减水剂提供理论依据。     

不同粘土矿物与聚羧酸减水剂相互作用机理研究

通过X射线衍射(XRD)、红外光谱(IR)、有机碳吸附(TOC)、饱和吸水率以及净浆流动性等试验方法,研究了不同粘土矿物与聚羧酸减水剂的相互作用机理.结果表明:聚羧酸减水剂的侧链可进入粘土矿物蒙脱石的层间,发生插层反应,即层间吸附,而其侧链结构不进入伊利石、高岭土、海泡石等粘土矿物的层间,仅发生表面吸附,且吸附量大小为蒙脱石>高岭土>海泡石>伊利石;饱和吸水率试验显示,粘土矿物的饱和吸水率大小为蒙脱石>高岭土>海泡石>伊利石;流动度试验表明,粘土矿物对水泥-减水剂体系净浆流动度均有不同程度的影响,且蒙脱石影响程度最大.由此可知,粘土矿物对自由水和聚羧酸减水剂的吸附是造成流动度损失的主要原因.     

粘土矿物成分对聚羧酸减水剂吸附性能的研究

劣质砂石料中的含泥对聚羧酸减水剂的性能具有强烈的抑制作用,表现为混凝土坍落度损失快,工作性能变差等.通过对粘土中蒙脱石、伊利石、高岭石等粘土矿物成分的砂浆流动度和吸附量随时间变化规律的研究,表明蒙脱石对聚羧酸减水剂的吸附能力最强.从分析矿物的晶体结构上探讨了粘土矿物成分对聚羧酸减水剂吸附的作用机理.     

聚羧酸减水剂在粘土中的插层行为及影响研究进展

聚羧酸减水剂在粘土中的吸附、插层行为会对水泥混凝土的性能产生影响.综述了聚羧酸减水剂在粘土中的吸附行为及在粘土矿物蒙脱石中的插层行为的机理、性能表征及对水泥净浆凝结时间、流动度、抗压强度;水泥胶砂流动度、抗压强度、抗折强度;混凝土和易性、坍落度、抗压强度的影响,总结了粘土与聚羧酸减水剂对水泥混凝土性能影响的评价方法,阐述了调控插层行为的措施,展望了调控聚羧酸减水剂插层行为的研究前景.     

粘土矿物作为硅橡胶补强剂应用的研究与发展

粘土矿物作为橡胶补强剂应用已有报道，但粘土矿物作为硅橡胶补强剂尚不多见。硅橡胶在航天、航空、电子工业等领域都有广泛的应用。传统的硅橡胶补强剂是气相自碳黑，因价格昂贵（3～5万元／t）使硅橡胶制品的成本大为提高，如果能通过某些物理化学加工，用粘土矿物（300～500元／t）作硅橡胶的补强剂，不仅可大大降低成本，还能提高粘土矿物的附加值，为粘土矿物的利用提供一条新途径。填料选用沈阳产A-380气相自碳黑（A1），江西产沉淀自碳黑（A2）及经过分离、提纯、分纯、超细改性后的福建南部粘土矿物（A3）和中部的粘土矿物（A4）。配方如表1：硫化温度130℃，压力14MPa，时间10min。     

聚合物-粘土矿物纳米复合材料

利用某些层状粘土矿物的吸附性、离子交换性和膨胀性,可以将一些聚合物引入到粘土矿物的层间域,形成性能优异的聚合物－粘土矿物纳米复合材料。论述了２：１型怪状粘土矿物的结构特点,聚合物－粘土矿物纳米复合材料的合成、表征及其性能。     

有效稳定粘土改善压裂效果

粘土矿物在各类储集层中普遍存在。由于粘土矿物本身的化学结构特性造成储集层的敏感性。常规压裂稳定粘土矿物的做法作用有限,压裂过程中粘土矿物仍旧对储集层有较大程度的伤害。采用复合压裂工艺,对地层粘土矿物进行专门处理,最大程度地削弱由于粘土矿物敏感性而对低渗透储集层造成的伤害,改善压裂工艺,大幅度提高低渗储集层的压裂效果。     

中康油田中康3块粘土矿物及非粘土矿物分布规律研究

利用X射线衍射物相分析方法,对中康油田中康3块不同层位进行了粘土矿物及间层比、全岩、粘土矿物总量试验分析,重点研究了粘土矿物、非粘土矿物的分布及组合类型;粘土矿物总量的分布;它们的不同层位变化规律;不同组合类型对储层的影响程度;探讨了在勘探开发中的应用。     

陆相砂岩自生粘土矿物分布因素研究

充填于砂岩孔隙中的粘土矿物主要是在成岩过程中形成的自生粘土矿物,砂岩粘土矿物分布的规律是相对的、宏观的,介质条件决定了粘土矿物在地层中的分布。本文依据砂岩粘土矿物成因的分析,反演自生粘土矿物形成时砂岩孔隙介质条件,研究总结影响我国陆相砂岩粘土矿物组成和分布的因素。     

烃源岩有机质生烃过程中的粘土矿物催化作用研究进展

本文简要回顾了国内外对于粘土矿物对有机质生烃催化作用的研究进展,系统阐述了粘土矿物催化作用机理及粘土矿物催化作用的内在决定因素和外在环境因素,着重总结了粘土矿物催化作用对有机质生烃的影响,并就这一方向的研究作了展望。     

有机粘土吸附处理水中苯酚的性能及应用

分别用溴化十六烷基三甲铵（ＣＴＭＡＢ）、氯化十六烷基吡啶（ＣＰＣ）和氯化十四烷基吡啶（ＴＰＣ）改性膨润土、沸石和硅藻土；探讨了制备有机粘土的适宜条件；研究了粘土类型、表面活性制种类及其浓度对有机粘土吸附处理水中苯酚性能的影响。结果表明，有机粘土吸附处理苯酚的性能较钉适应的的土好得多。通过Ｘ－衍射分析等手段探讨了有机粘土的结构及其吸附处理。     

Moessbauer Study of the Effect of Calcium Content on Iron Oxide Transformations in Fired Clays

Sixteen clays were studied by Moessbauer measurements in their unfired and fired forms. Thirteen of these clays were collected near ancient Greek sites and the remaining three in England and the United States. They were fired at 700°, 900°, and 1080°C to investigate the physicochemical transformations of the clay components in this temperature range. The results show distinctly different responses of the clays, according to their CaO content. Firing of the calcareous clays (>5 % CaO content) at 700°C produces small oxide particles (mainly hematite). This phase remains stable on further firing up to 1080°C, where it decreases slightly. Contrary to this behavior, the noncalcareous clays display a continuous increase of the amount and size of the oxide particles when fired up to 1080°C. This difference is attributed to stable calcium aluminosilicate phases which are formed in the calcareous clays as opposed to the continuous vitrification which occurs for the noncalcareous clays by firing up to 1080°C. The variation of the quadrupole splitting of the central doublet with firing temperature also differs for the two types of clays. The quadrupole splitting values among the clays span a range of 1.1 to 1.6 mm/s for a firing temperature of 700°C. Above this temperature, a distinct separation of the two groups occurs with the quadrupole splitting of calcareous clays lying higher.     

Soil mechanics of the potentially expansive clays in Poland

This paper is an attempt to evaluate the expansivity of the main genetic types of Polish clays which very often are considered as a bedground for engineering structures. Lithological characteristics and basic physical properties presented in this paper concern the soils of (I) Quaternary age: Boulder clays and glaciolacustrine clays, (II) Tertiary continental and marine clays: Mio-Pliocene clays of Poznan series, Miocene clays of the Carpathian Foredeep (unweathered and weathered), bentonites and bentonitic clays, oligocene clays of Szczecin area and Carboniferous bentonites (Tables 1 and 2). Based on the indirect methods described by Van der Merwe (1964) and Seed et al. (1962) nomograms were used to evaluate potentially expansive soils. Information obtained includes correlation between potential expansiveness (PE), degree of expansion (DE), swelling potential (5) and the percentage content and mineral composition of the clay fraction. Graphic illustrations are presented in Figs. 1–7, which also include nomograms for the approximate estimation of the value of swell pressure (σ_sp). The evaluation of potential expansivity of clays in Poland plays a key role in the design of engineering structures and in site selection.     

THE DEFLOCCULATION OF CLAY SLIPS AND RELATED PROPERTIES1

In an earlier paper² the authors have given the particle analysis and other tests of a number of English china clays, one English ball clay and several domestic kaolins. In this paper are presented the following additional data for the same clays: the carbon content as a measure of organic matter; the change in state of dispersion with pH for 20% slips as determined by settling tests; the change in viscosity with pH as determined with 40% slips; the alkali absorption for 20% and 40% slips. The more plastic clays are characterized by high organic content, high alkali absorption, and dispersion at low pH. Casting slips made up with the different china clays and two ball clays in varying proportions show that ball clay causes fluidity and that the plastic china clays produce more viscous slips than the less plastic.     

TESTING AND IMPROVING THE DRYING BEHAVIOR OF CLAYS*

A simple test has been developed to measure the drying behavior of clays by noting the relative rate of flow of water through the clays as compared with the rate of evaporation from the surface. The addition of 0.2% of various chemicals to clays improved their drying properties. No one chemical was best for all of the clays, but the most effective chemicals varied in their reaction on different clays. Iron chloride exerted beneficial effect on most of the clays. A wetting agent, such as sodium chloride, hydrochloric acid, or soda ash, also improved the drying properties of certain clays.     

REHYDRATION STUDY OF CLAYS*

The rehydration characteristics of a group of twenty clays were studied by dehydrating at 300°C. and then rehydrating by exposure to a water-saturated atmosphere at 30°C. for periods extending from approximately 28 to 80 days. A sharp differentiation was obtained between the montmorillonite and the kaolinite-illite types of clays. A simple, rapid rehydration-dehydration test and the results on ninety-five clay samples are presented as an aid in the evaluation of clays. The test can be completed within five hours and permits a limited but useful classification of clays.     

THERMAL AND MOISTURE EXPANSION OF BALL CLAYS AND BODIES FIRED TO DIFFERENT TEMPERATURES*

Thermal and moisture expansion determinations were made on ten ball clays of the Kentucky, Tennessee, and English types alone and on typical semivitreous and vitreous bodies in which each of these ball clays was incorporated. The clays and bodies were fired at cones 6, 9, and 11. The data indicate that the ball clays fall into five distinct groups. Although none of the clays showed a direct relation between its expansion and that of the bodies in which it was incorporated, a majority possessed characteristics sufficiently similar to permit their classification into groups in which the behavior of the clays alone is indicative of their influence on the bodies. When several ball clays were jointly incorporated into bodies, they showed additive thermal and moisture expansion values.     

The operation of clay grinding machines in refractories plants

Conclusions The use of shredders is not justified for all cases. The processing of frozen clays and stone-like clays (flinty clays) requires the design of a new type of machine working on the principle of splitting and fracturing.Plate and tray feeders can be used for controlling raw-material feed in kiln installations.     

Polymer nanocomposites from modified clays: Recent advances and challenges

Since the end of the last century, the discovery of polymer nanocomposites and their ever-expanding use in various applications has been the result of continuous developments in polymer science and nanotechnology. In that regard, progress in developments on the use of modified natural and synthetic clays for designing polymer nanocomposites is presented herein. The modified clays used in composite preparation include natural clays such as montmorrilonite, hectorite, sepiolite, laponite, saponite, rectorite, bentonite, vermiculite, biedellite, kaolinite, and chlorite, as well as synthetic clays including various layered double hydroxides, synthetic montmorrilonite, hectorite, etc. The preparation, structure and properties of polymer nanocomposites using the modified clays are discussed. Even at a low loading, these composites are endowed with remarkably enhanced mechanical, thermal, dynamic mechanical, adhesion and barrier properties, flame retardancy, etc. The properties of the nanocomposites depend significantly on the chemistry of polymer matrices, nature of clays, their modification and the preparation methods. The uniform dispersion of clays in polymer matrices is a general prerequisite for achieving improved mechanical and physical characteristics. Various theories and models used to design polymer/clay nanocomposites have also been highlighted. A synopsis of the applications of these advanced, high-performance polymer nanocomposites is presented, pointing out gaps to motivate potential research in this field.