Facile Conversion of Alcohols to Olefins by Tosylation and Subsequent SiO2- promoted β-elimination

A convenient and effective procedure was developed for the conversion of alcohol to olefin by tosylation and subsequent β-elimination promoted by silica gel in this study. Treatment of the alcohols with p-toluenesulfonyl chloride in pyridine at 0℃ affords tosylates which undergo β-elimination with silica gel in dichloromethane or chloroform at room temperature, yielding olefinswith high productivity.     

Synthesis and characterization of zeolite X obtained from kaolin for adsorption of Zn（Ⅱ）

This study deals with the synthesis and characterization of low-silica zeolite X, from calcined Kalabsha kaolin, for adsorption of Zn(Ⅱ) ions from aqueous solution. The synthesis processes is performed under hydrothermal treatment in alkaline solutions. The obtained zeolite samples are characterized using X-ray diffraction, grain size distribution, surface area, and SEM. The critical molar ratios of both SiO2/Al2O3 and K2O/Na2O are about 2.9 and 0.16, respectively. Those ratios are needed to give individual low silica zeolite X in a minimum reaction time. The adsorption capacity of the synthesized products is determined by adsorption of Zn(Ⅱ) ions from solution. The results suggest that the zeolite obtained could be converted to a beneficial product, which will be used in future as an ion exchanger in removing heavy metals from wastewaters.     

A shrinking particle—shrinking core model for leaching of a zinc ore containing silica

A new mathematical model was developed for leaching of zinc ores containing silicates such as hemimorphite which produce a gel during leaching with sulfuric acid. This model is based on the shrinking core model in which the particle size and the reacting core shrink simultaneously. It was shown that the actual dissolution time of the ore particles is longer than the time corresponding to the dissolution of chemical zinc oxide itself. It was suggested that because of the existence of silicates in the ore, a gelatinous layer was formed around the reacting core. Since the gel product is soft, it breaks apart when the particles collide and as a result, the particles shrink. However, a thin gelatinous layer always covers the reacting core which increases the mass transfer resistance and increases the leaching time. This model was applied to leaching of a zinc-rich tailing containing hemimorphite and the thickness of the gelatinous layer as well as the diffusion coefficient in this layer was determined.     

Silica depleted melting of pelites. Petrogenetic grid and application to the Susqueda Aureole, Spain

Metapelitic rocks in the low pressure contact metamorphic aureole around the Susqueda igneous complex, Spain show a number of features that make them an ideal testing ground for the modelling of silica‐undersaturated melting. Rocks in the aureole experienced localized depletion in silica by the segregation of quartz veins during a pre‐anatectic, regional cordierite‐andalusite grade metamorphic event. These rocks were then intruded by gabbroic to dioritic rocks of the Susqueda igneous complex that formed a migmatitic contact metamorphic aureole in the country rocks. This migmatisation event caused quartz‐saturated hornfels and restite formation in rocks that had experienced no quartz vein segregation in the previous regional metamorphic event, but silica‐undersaturated melting in those rocks that were previously depleted in silica. Silica‐undersaturated melting is investigated using a new petrogenetic P–T projection and equilibrium pseudosections calculated in the KFMASH and NCKFMASH systems, respectively. The grid considers quartz absent equilibria and a range of phases that form typically in silica‐undersaturated bulk compositions, for example corundum. It is shown that the quartz‐rich precursors in the Susqueda contact aureole produced about 10% melt during contact metamorphism. However, most of this melt was extracted leaving behind rocks with restitic bulk compositions and minor leucosome segregation. It is suggested that the melt mixed with the host igneous rocks causing an apparent magmatic zoning from diorite in the centre of the complex to tonalite at the margins. In contrast, the quartz‐poor precursors (from which the quartz veins segregated) melted in the silica‐undersaturated field producing a range of assemblages including peritectic corundum and spinel. Melting of the silica‐undersaturated rocks produced only negligible melt and no subsequent melt loss.     

福建北部近岸东台山岛火山岩形成时代、地球化学与古太平洋板块俯冲的响应

福建北部沿岸岛屿岩石组合以晚中生代火成岩为主,研究认为是古太平洋俯冲消减的产物,对反演洋盆构造演化具有重要的指示意义。本次对其中的福建北部海域东台山岛上广泛发育的酸性火山岩进行了锆石U-Pb定年以及全岩主微量地球化学分析工作。2件年代学样品分别获得了92 Ma和86 Ma的锆石U-Pb年龄,确定东台山岛火山岩形成于晚白垩世。全岩地球化学特征指示火山岩样品以酸性钙碱性岩石为主,整体富集Rb、Ba等元素,亏损Nb、Ta、Sr、Eu等元素,显示弧型岩浆岩的地球化学组成。研究认为东台山岛火山岩起源于古老下地壳变沉积岩熔融,并在浅层岩浆房内经历了不同程度的结晶分异过程。结合区域上晚中生代岩浆作用由陆向海的时空迁移特征,福建北部沿岸岛屿火山岩形成的深部动力学机制应该与古太平洋俯冲过程中的板片回转过程相关。     

东昆仑西段祁漫塔格群的重新厘定

通过区域地质调查和研究,认为前人所建立的的祁漫塔格群或滩间山群包括了不同时代的浅变质碎屑岩、中酸性火山岩及基性-超基性岩。根据在东昆仑原划奥陶系祁漫塔格群第一亚群(下部碎屑浊积岩)中采集到早志留世笔石化石组合(这是首次证实东昆仑地区存在志留系地层)及同位素测年资料(鸭子大板火山岩年龄),其时代包含了奥陶纪、志留纪和三叠纪等,根据中国地层指南及中国地层指南说明书和地层清理,对祁漫塔格群进行了解体,将其重新厘定为奥陶纪滩间山群(OT)、志留纪白干湖岩组(Sb)弧后盆地复理石沉积和鸭子泉组(Sy)岛弧火山岩、石炭纪鸭子大坂硅质岩(S i)、三叠纪鄂拉山组(T3e)、蓟县纪狼牙山岩组(Jx l)和南华—奥陶纪阿牙克库木湖蛇绿混杂岩[(N h—O)aΣ]。该成果对于祁漫塔格地区早古生代地层划分对比、构造演化提供了重要新证据。     

秦岭泥盆系硅岩岩石类型对比研究

硅岩可以通过化学沉积（真溶液或胶体沉淀）和内碎屑堆积而成。由于热水有较强的化学活动性，因而在水岩界面附近也会形成交代成因的硅岩。在许多情况下，硅岩既具有沉积岩的岩石学特征，又具有交代岩的岩石学特征，其成岩环境十分特殊。因此，虽然有许多地球化学方法可以区分不同类型的硅岩，但岩石学特征是最基本的和最直接的标志。     

FTIR Spectrum of Phenocryst Olivine as an Indicator of Silica Saturation in Magmas

Fourier Transform infrared (FTIR) absorption spectra of hydroxylwere measured on olivine phenocrysts from hydrous basaltic meltsthat originated in island-arc tectonic settings. The basalticmelts encompass a wide range of silica activities from orthopyroxene-saturatedhypersthene-normative to nepheline-normative compositions. Theintensities and wavenumber placement of hydroxyl absorptionbands correlate with the degree of silica saturation of theparent melt from which the olivine crystallized. Olivines fromsilica-undersaturated nepheline-normative melts absorb IR radiationin the wavenumber range 3430–3590 cm^–1 (Group 1).In contrast, olivines from orthopyroxene-saturated boniniticmelts exhibit hydroxyl absorption bands in the wavenumber range3285–3380 cm^–1 (Group 2). Olivines crystallizedat intermediate silica activities exhibit a combination of thetwo groups of hydroxyl IR bands, where the proportion of Group2 bands increases with increasing silica saturation of the parentmelt. The positions of hydroxyl absorption peaks observed herefor natural samples are consistent with previous measurementson experimentally annealed olivines. Thus protonation experimentscan be employed to make spectroscopically dry olivine structuresvisible by IR, yielding information on the silica saturationof the parental magmas. Hydroxyl concentrations in the studiedolivines were estimated to be 1–2 ppm, corresponding toan olivine–melt partition coefficient of (1·0 ±0·3) x 10^–4. KEY WORDS: nominally anhydrous minerals; olivine; water; mantle; silica activity; melt inclusions     

新疆三塘湖盆地马朗凹陷中二叠统芦草沟组泥页岩层系SiO2赋存状态与成因

为了弄清新疆三塘湖盆地马朗凹陷芦草沟组泥页岩层系中SiO_2对储集层物性、脆性等特性的影响,通过全岩和黏土矿物X衍射、岩石力学性质、阴极发光、扫描电镜及电子能谱等实验手段对其中SiO_2的赋存状态进行了研究,初步探讨了SiO_2不同形态赋存的机理,并在此基础上探究了石英含量对储层的影响。研究表明:凝灰岩、泥页岩和粉砂质泥岩中二氧化硅多以非晶态形式存在。二氧化硅在凝灰岩中多呈不规则球粒状,而在泥页岩和粉砂质页岩中无固定形态。凝灰质泥岩、凝灰质白云岩和白云岩中二氧化硅呈现一定的晶体形态。在凝灰质泥岩中,二氧化硅以自生石英形态聚集呈条带状,在凝灰质白云岩中则以自生石英形态发育于孤立的孔、洞之中,而白云岩中二氧化硅只能生长成Opal-A/Opal-CT阶段。凝灰质成分及其脱玻化作用为自生石英的生长提供了二氧化硅和生长空间,是控制SiO_2赋存状态的根本因素。此外,储集层孔隙度、渗透率和抗压强度都与石英含量呈一定正相关性,泊松比则与其呈负相关性。     

Precise and Accurate Doping of Nanoporous Silica Gel for the Synthesis of Trace Element Microanalytical Reference Materials

This study presents an experimental procedure to fabricate high‐purity silica glass containing a selected element at a specified mass fraction. The procedure was used to prepare glasses doped with trace‐level mass fractions of Ti with the goal of improving analytical confidence when measuring trace elements in quartz. Systematic tests were performed to determine the ideal conditions and procedures for doping nanoporous silica gel with the highest efficiency of dopant recovery. Silica gel was cleaned in concentrated HCl, immersed in a non‐polar doping medium at a controlled pH and doped with precise quantities of ICP‐MS standard solution. Using liquids composed of longer chain molecules as the doping medium diminishes recovery, suggesting that large molecules could obstruct nanopores to inhibit capillary uptake of the dopant. A control experiment using crystalline quartz reinforced the effectiveness of nanoporous silica gel for doping with trace‐level precision. Layered aggregates of silica gel doped with different Ti mass fractions were hot‐pressed to create multi‐layered reference materials that were analysed with multiple techniques at a variety of spatial scales. Analyses at the intra‐grain scale (cathodoluminescence scanning electron microscopy, electron probe microanalysis), at the single grain scale (SIMS), at the sample layer scale (EPMA, laser ablation‐ICP‐MS) and at the bulk scale (ICP‐OES) demonstrated acceptable homogeneity at sample volumes characteristic of most microanalysis techniques and show that nanoporous silica gel holds promise as a highly retentive doping substrate for preparing reference materials for laser‐, electron‐ and ion‐beam microanalysis.