甘肃金昌红泉镁基膨润土属型分类

膨润土是一种以蒙脱石为主要成分的粘土类矿物。确定膨润土的属型,实质上是依据蒙脱石晶层间吸附阳离子的种类及其丰度。 (一) 蒙脱石吸附阳离子的主要原因 1.蒙脱石是属于一种2:1层状结构,即由二个硅氧四面体片夹一个铝氧八面体片构成的层状体。蒙脱石因四面体中Al~(3+)置换Si~(4+)和八面体中Mg~(2+)置换Al~(3+),使蒙脱石晶层间产生永久性负电荷,为了保持晶格电荷平衡,因而晶层间具有吸附阳离子和交换性阳离子的性能。     

酸化对蒙脱石成分和结构影响的研究

通过对高州蒙脱石及其酸化产物的X射线衍射、化学全分析、魔角旋转核磁共振谱（MASNMR）的研究发现,酸化导致蒙脱石成分和结构都发生一定程度的变化,特别是魔角旋转核磁共振谱研究发现,高州蒙脱石分别在八面体片和四面体片中存在六配位铝和四配位铝;其酸化产物由于八面体片内脱羟基,新出现了一类四配位铝。蒙脱石酸化后物化性能的改善至少与酸化引起的层间域中离子交换、八面体片内阳离子溶出及八面体片内脱羟基等因素有关。     

尼日利亚石—塔菲石—黑铝镁铁矿及相关系列矿物的晶体结构构筑原理

从氧原子最紧密堆积以及阳离子充填四面体和八面体空隙原理出发 ,以简单氧化物矿物最紧密堆积结构类型金绿宝石、尖晶石、铁钒矿为基础 ,深入讨论了复杂氧化物矿物最紧密堆积结构类型彭志忠石、尼日利亚石、塔菲石、黑铝镁铁 (钛 )矿等晶体结构构筑原理。以O表示全部为阳离子八面体配位的层 ;以T层表示阳离子八面体配位与阳离子四面体配位的混合层 ,其中T1表示阳离子八面体配位与一种方向阳离子四面体配位的混合层 ,T2 表示阳离子八面体配位与两种方向阳离子四面体配位的混合层。这类矿物晶体结构可用O、T1、T2 堆积方式表征 ,O层与T层交替排列。如 :彭志忠石 ( 6H)的晶体结构表示为…OT2 OT1OT1… ,塔菲石 ( 8H)的晶体结构表示为…OT2 OT1OT2 OT1… ,尼日利亚石 ( 2 4R)的晶体结构表示为…OT1OT2 OT2 OT1…× 3 ,等等 ;它们的晶体结构中既有尖晶石的…OT2 OT2 …晶体结构单位 ,又有铁钒矿的…OT1OT1…晶体结构单位。     

凹凸棒石与酸反应纳米尺度研究——反应机理和表面积变化

利用高分辨透射电子显微镜(HRTEM)和BET-比表面积分析(BET-SSA)技术调查了沉积型凹凸棒石与酸作用过程中形态和比表面积变化,并探讨了凹凸棒石与酸反应机理。对不同条件下凹凸棒石与酸反应产物纳米尺度观察表明,凹凸棒石的酸溶反应既表现出棒状晶体端部四面体和八面体一致溶解,也表现出柱面位置四面体和八面体不一致溶解。纳米尺度观察揭示出凹凸棒石与酸反应机制是质子从外表面扩散渗透,而不是质子从晶体孔道的渗透,反应速率主要受穿过酸溶产物硅酸层扩散速率控制。凹凸棒石的酸溶反应过程中,酸处理凹凸棒石的纳米孔结构现象与柱面位置四面体硅局部溶蚀有关。酸处理凹凸棒石比表面积增加归因于凹凸棒石中八面体不均匀、不连续溶解和局部四面体硅的溶蚀导致凹凸棒石孔道开放和直径扩大,从而使N2分子更多的进入凹凸棒石的孔道。部分八面体残留对四面体片起支撑作用,当凹凸棒石中八面体阳离子近于完全溶解时,四面体片失去支撑,结构塌陷,内孔孔道消失,比表面积再度下降。     

硅酸盐辉石的晶体化学(下)

八面体层和四面体层间的连接在辉石中绝大多数阳离子的替换发生在八面体层内.这样的替换影响着层的大小,从而影响着与四面体链的连接.补偿错配的最显而易见的方法是O_3—O_3—O_3链的伸展和弯折.另外,也可以通过四面体的畸变或“偏离平面”的变形来调整(Cameron等,1973).后者的机理包括通过O_3原子远离和靠近含有O_3原子的平面的运动而使四面体变形.直到现在,还没有任何发表的资料讨论链拉直、四面体畸变、偏离平面的变形等在保持八面体层与四面体层间的连接上的相对重要性.涉及头两种机理的变化将在下面详细讨论,Ohashi和Finger(1974)报道了偏离平面的变形的增加与四面体链弯拆的增加密切相关.     

论尖晶石族矿物结构的转变

尖晶石族矿物结构的特征是;氧离子作立方最紧密堆积、阳离子占据八分之一的四面体空隙和二分之一的八面体孔隙。若将四面体位置叫做A位、八面体位置称作B位,其化学计量通式应为AB_2O_4。所有尖晶石族矿物都含有两种不同的阳离子,至少是两种价态的同种阳离子,其比例是2:1,根据含量较多的那种阳离子的分布,尖晶石结构又被划分为正尖晶石型和反尖晶石型,若较多的那种阳离子全部分布在八面体位置,则称之为正尖晶石型;若其平均分布     

矿物填料在橡塑制品中的应用

矿物填料在橡塑制品中的应用吴季怀（华侨大学材料物理化学研究所，福建泉州３６２０１１）关键词矿物填料橡塑制品材料科学粘土矿物填料属水合硅铝酸盐，是由硅氧四面体和铝氧八面体按一定规则叠合而成，在其表面存在羟基、不饱和键（剩余价键）、Ｌｅｗｉｓ和Ｂｒｏｎｓ...     

尼日利亚石类矿物的晶体化学研究及其意义

湖南省安化、临武、柿竹园等地区有一类含锡、镁、铁、锌、钛、锰、铝等多种元素的复杂氧化物矿物 ,它们是尼日利亚石、镁尼日利亚石 (彭志忠石 )等。本文从紧密堆积原理出发 ,深入探讨了尼日利亚石类矿物的晶体化学特征。它们的晶体结构可用O(阳离子八面体配位的层 )、T1(阳离子八面体配位与一种方向阳离子四面体配位的混合层 )、T2 (阳离子八面体配位与两种方向阳离子四面体配位的混合层 )堆积方式表征 ,O层与T层交替排列。尼日利亚石 6H的晶体结构表示为…OT2 OT1OT1… ,尼日利亚石 2 4R的晶体结构表示为…OT1OT2 OT2 OT1…× 3 ,等等 ;它们的晶体结构中既有尖晶石的…OT2 OT2 … ,又有铁钒矿的…OT1OT1…晶体结构单位。这类矿物研究在矿物学、宝石学、材料科学等方面有重要的理论和实际意义     

伟晶岩绿柱石矿物学及其通道水氢同位素研究进展

自然界绿柱石存在三个类质同象系列,即“八面体”绿柱石（ｃ／ａ＝０．９９１￣０．９９６）,“正常”绿柱石和“四面体”绿柱石。绿柱石矿物精细结构研究表明,二价离子置换八面体中Ａｌ,Ｌｉ置换四面体中Ｂｅ,而碱离子被绿柱石通道所容纳,用于补偿低价阳离子置换Ａｌ八面体和Ｂｅ四面体引起的电价不足。伟晶岩绿柱石通常含有〉１．６ｗｔ％的通道水,而包裹体中流体仅为０．１５ｗｔ％左右。室温下绿柱石通道中存在１型和Ⅱ     

高岭石层面羟基的硅烷嫁接改性机理

<正>高岭石[Al2Si2O5(OH)4]是一种1∶1型的层状硅酸盐矿物,其结构单元层由一层[SiO4]四面体片和一层[AlO6]八面体片组成,因此高岭石片层具有两种不同性质的表面:硅氧烷底面和羟基底面。高岭石的羟基底面为硅烷嫁接提供了场所,通过八面体片上的羟基与有机硅烷发生缩合形成Al-O-Si共价键,嫁接后的高岭石材料较之     

云母的命名

根据容许的化学成分范围，给出了纯云母类（true micas)，脆云母类（brittle micas)和层间阳离子亏损的云母类（interlayer-cation-deficient micas)的端元矿物和矿物种，概括介绍了利用现有的各种化学分析数据计算云母晶体化学式的方法，以及描述不常见化学元素代换或多型堆积的一系列修饰词和后缀，列出了云母的同义词和变种、定名有误的物质，以及过去使用或误用的云母名称。     

藏东及邻区钾玄岩系岩石云母特征及其岩石学意义

青藏高原东部及邻区新生代钾玄岩系列岩石包括钾质碱性深成岩、火山岩、煌斑岩和偏酸性的斑岩。云母是钾玄岩系列岩石中的主要暗色矿物，分布亦较广泛。我们用单矿物化学分析方法测定本区钾玄武岩系四种岩石中云母和化学成分，其结果MF＝1．30－1．99，应为金云母－富镁黑云母，属于富碱富镁高铝贫铁类型的云母；云母的红外光谱，在450cm^-1和1000cm^-1附近都有很强的吸收谱带，显示了四种岩石中的云母具有类似的红外光谱特征；X光衍射测定，本区云母的d(060)为15．32nm-15.41nm，它们的晶胞参数变化不大，均为三八面体1M型云母。以上特征表明，本区钾玄岩系四种岩石中云母均形成于高碱度环境，它们与钙碱性系列岩石中云母形成的环境迥然不同。从四种岩石的云母具有相似的化学成分、红外光谱和晶胞参数，说明它们的寄生岩石具有钾岩的特征，其物源来自交代地幔。     

Zoning and recrystallization of phengitic micas: implications for metamorphic equilibration

White micas (phengites) in the metasediments of the Scottish Dalradian display a large range of compositions within single samples. The variations in the composition of these phengites are strongly controlled by their structural age, with early fabrics containing a paragonite-poor, celadonite-rich phengite whereas in later fabrics the micas are generally paragonite-rich and celadonite-poor. Retrograde phengite growth, identified using back scattered electron imaging, occurs as celadonite-rich rims on micas within all existing fabrics and appears to be preferentially developed along existing white mica-plagioclase grain boundaries. The presence of these chemically distinct phengite populations within single samples implies that chemical exchange between the individual micas was inefficient. It is proposed that diffusion-controlled exchange reactions in phengites have relatively high closure temperatures below which major element exchange is effectively impossible. This closed system behaviour of micas questions the ease with which phengites may equilibrate with other phases during prograde greenschist and lower amphibolite facies metamorphism. Many of the chemical variations preserved in phengites from such metamorphic rocks may reflect deformation/recrystallization controlled equilibria.     

Sector-zoned phlogopites in igneous rocks

Sector-zoned micas are described in three occurrences of igneous rocks. Basal sectors (001) and lateral sectors (010) are well defined. Analyses of probably isochronous growth points indicate that there are consistent chemical composition differences between the sectors, the (010) sector being richer in Si and poorer in Ti, Fe, Al and Ba relative to the (001) sector. Within each sector type Fe/ (Fe + Mg) increases from core to rim. These differences vary in amplitude from one occurrence to the other, but are systematic for micas with extremely different tetrahedral cations. Possible factors influencing this type of crystallization are briefly reviewed: growth rate, geometry of protosites and bulk composition of the liquid.     

Volatile contents of phlogopite micas from South African kimberlite

Phlogopite micas from nodules in South African kimberlites were analyzed for major elements with the electron microprobe and for volatile contents by high temperature mass spectrometry. The micas are from primary- (deformed) and secondary- (undeformed) textured grains in perodotite xenoliths, glimmerites, MARID (mica-amphibole-rutile-ilmenite-diopside) suite nodules and a mica megacryst. The major element and volatile contents of micas exhibiting these modes of occurrence overlap to a greater extent than indicated in previous studies. Concentrations of volatile species occupying structurally defined crystallographic sites (H₂O, F, Cl) are greater for many of the micas than predicted on the basis of the mica formula, particularly for the glimmerite and MARID suite samples. A correlation exists between micas with tetrahedral and octahedral cation deficiencies and those with excess H₂O, F and Cl. Substitution of H⁺ for tetrahedral and possibly octahedral cations may be responsible for the excess H₂O in these micas. Except for one sample, the major element and volatile data for the peridotite, glimmerite and MARID suite micas indicate that they crystallized at oxygen fugacities below the quartz-fayalite-magnetite buffer. F and K₂O are in the correct proportion in the micas to provide the source for these elements in alkali basalts, but not in mid-ocean ridge basalts. Kaersutite amphibole is a more likely source of potassium and fluorine in mid-ocean ridge basalts.     

On micas from magmatic and metamorphic rocks

Micas from magmatic and metamorphic rocks differ from one another in chemical composition and in trace element content. The chemical composition of micas is discussed in relation to their occurrence, paragenesis and sequence of crystallization. On the basis of previous studies of the relationship between the physical properties and the chemical composition of 34 chemically analysed micas, reliable physical methods have been established which permit identification of different mica varieties in the same rock. Structural formulae and trace element content of micas from basic and granitic rocks, as well as from skarns, schists, ortho- and paragneisses are discussed. The relationship between the components of the tetrahedral and octahedral layers and of the interlayer are illustrated as ratios. Poorly differentiated, hybrid and metasomatic rocks often contain more than one variety of mica. Some prophyritic basalts and lamprophyres contain an early phlogopite which is paragenetically related to pyroxene phenocrysts and late biotite which occurs in the groundmass and in the fractures as a result of the crystallization of residual magma. The biotitemuscovite assemblage was observed in granodiorites, quartz-monzonites, schists and gneisses. In the albite-K-feldspar granites, muscovite predominates and the biotite is usually altered. The chemical composition of micas from metamorphic rocks depends on the grade of metamorphism and on the nature of associated minerals. The biotite from paragneisses contains considerable quantities of octahedral alumina. Pre-metamorphic micas show variable deficiencies of the (OH, F) group. The micas are useful minerals in determining the degree of differentiation and subsequent alteration of igneous rocks. The present study was carried out on the basis of 34 recent complete chemical analyses andca 100 X-ray fluorescence analyses. Dedicated to Professor Dr.Carl W. Correns on the occasion of his 70th birthday.     

Chemical Features of White Micas from the Piemonte Calc-schists, Western Alps and Implications for K–Ar Ages of Metamorphism

Anomalously large chemical ranges in muscovite-paragonite and muscovite-celadonite systems are observed in white micas from the Piemonte calcschists in the Chisone valley area, internal western Alps. The petrographical and chemical observations on white mica strongly suggest that most mica crystals with high Na/K ratios in the chlorite zone are of detrital origin, and were derived from the pre-Alpine high-temperature metamorphic sequence such the Caledonian and/or Variscan. Submicroscopic muscovite (Ms) - paragonite (Pg) composite aggregates occur in the chlorite zone and their EPMA analyses give an apparent chemical composition range from Ms_0.6Pg_0.4 to Ms_0.2Pg_0.8. In the rutile zone, the paragonite content of the white micas is less than 20%, suggesting that the white micas have been homogenized during the Alpine metamorphism even if detrital white micas existed.Metamorphic mica is also very heterogeneous. The total range in Si content becomes wider with increasing of metamorphic grade: 3.22–3.39 pfu for the chlorite zone, 3.07–3.45 pfu for the chloritoid zone and 3.06–3.59 pfu for the rutile zone. This clearly indicates that the micas have experienced significant retrogressive chemical reactions during cooling and exhumations of the host schists.The detrital white mica in the chlorite zone has not reset well in its K-Ar system during the Alpine subduction-related metamorphism. The wide range of the white mica K-Ar ages from 115 to 41 Ma must be due to a mixture of various amounts of detrital white mica in the separates. This feature is also observed in the chloritoid zone though the age variation is not so large as that in the chlorite zone. In contrast, the mica in the rutile zone, which was higher than 450°C, has been reset completely during Alpine HP metamorphism.     

The biotite isograd, Central Pyrenees: a deformation-controlled reaction

The biotite isograd reaction in Cambro–Ordovician pelites from the Garonne dome in the Central Pyrenees involves the production of biotite at the expense of chlorite, and the gradual reduction in the celadonite (Si) content of individual white micas. The mineral assemblages in the biotite-bearing rocks in the Melles area retain abundant evidence of chemical disequilibrium, due to the sluggish nature of major element diffusion within the white micas. The progress of the isograd reaction is strongly controlled by the progressive development of regional Variscan fabrics, and chemical exchange in the white micas in these metamorphic conditions is only possible during active deformation. Chemical resetting of the white micas takes place via the development of compositional zoning in the deforming micas; this probably occurs as a consequence of the introduction of defects and dislocations, causing more efficient diffusion within parts of individual grains. In the absence of deformation, this biotite isograd reaction would take place at significantly higher temperature and be controlled by the relatively high closure temperature of major element diffusion in white micas. Thus, assigning thermal significance to such continuous isograd reactions is impossible without independent constraints: kinetic factors such as deformation may be the dominant influence in many cases, not the thermodynamic controls.     

Chemical and deformational controls on recrystallization of mica

Chemical and microstructural data from one experimentally and two naturally deformed and recrystallized micas are discussed in terms of established metallurgical mechanisms for strain-induced nucleation and growth during recrystallization. It is suggested that none of these nucleation mechanisms is applicable, and that nucleation is driven by energy from both chemical and permanent strain sources. Subsequent growth of the nuclei is influenced by the deformation or by coincidence lattice relationships.     

Compositions of micas in peraluminous granitoids of the eastern Arabian shield

Compositions and pleochroism of micas in fourteen peraluminous alkali-feldspar granites in the eastern part of the Late Proterozoic Arabian Shield are unlike those of micas (principally biotite) in most calc-alkaline granitoid rocks. Compositions of these micas are distinguished by elevated abundances of Li₂O, F, and numerous cations and by low MgO abundances. These micas, constituents of highly evolved rare-metal enriched granitoids, represent an iron-lithium substitution series that ranges from lithium-poor siderophyllite to lithium-rich ferroan lepidolite. The eastern Arabian Shield also hosts six epizonal granitoids that contain colorless micas. Compositions of these micas, mostly muscovite, and their host granitoids are distinct from those of the iron-lithium micas and their host granitoids. Compositions of the analyzed micas have a number of petrogenetic implications. The twenty granitoids containing these micas form three compositional groups that reflect genesis in particular tectonic regimes; mica compositions define the same three groups. The presence of magmatic muscovite in six of these shallowly crystallized granitoids conflicts with experimental data indicating muscovite stability at pressures greater than 3 kbar. Muscovite in the Arabian granitoids probably results from its non-ideal composition; the presence of muscovite cannot be used as a pressure indicator. Finally, mineral/matrix partition coefficients are significantly greater than 1.0 for a number of cations, the rare-earth elements in particular, in many of the analyzed iron-lithium micas. Involvement of these types of micas in partial melting or fractionation processes can have a major influence on silicate liquid compositions.