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热液中二氧化硅与成矿元素锡络合作用的实验标定 总被引：2，自引：0，他引：2
热液中二氧化硅与成矿元素锡络合作用的实验标定＊樊文苓陈紫新王声远田弋夫（中国科学院矿床地球化学开放研究实验室，贵阳５５０００２）关键词锡石溶解度二氧化硅的络合作用迁移形式前人对锡在流体中迁移形式的实验研究和热力学计算表明，锡（Ⅱ）的多种氯络合物是高温... 相似文献
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Complexation of Si in hydrothermal systems 总被引：1，自引：1，他引：0
The Au-SiO2 and Sn-SiO2 complexes have been experimentally calibrated at varying temperature,silica comcentration and pH: Au^ H2SiO4^-=AuH3SiO4 lgK=-1.65436 9611.21/T; Sn^4 4H3SiO4^-=Sn(H3SiO4)4 lgK200℃=42.73 Compared with Au-Cl,Au-HS and Sn-OH complexes,AuH3SiO4 and Sn(H3SiO4)4complexes can be recognized as the dominant transport forms in Si-bearing solurtions under pH and Eh conditions of general interest.The decrease of SiO2 concentration and oxygen fugacity would reverse the direction of dissolution-complexing reactions,resulting in the precipitation of gold and silica,as well as cassiterite and silica.This study illustrates the significance of SiO2-complexation in hydrothermal solutions for gold,tin and other metallizations. 相似文献
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我国变质岩中改造型层控金矿床金的迁移和富集 总被引：1，自引：0，他引：1
根据现有的热力学数据计算,AuCl_2~-是预富集阶段金在矿源层中迁移的主要形式,而Au(Hs)_2~-则在热液成矿阶段起主要作用,计算表明,α_(Cl)->10~0的酸性含氯溶液以及α_(ΣS)>10~(-2)的富硫热液可分别作为预富集阶段和热液成矿阶段金的主要地球化学指标。 相似文献
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快速淬火高压釜装置属于外加压、外加热、内冷淬火的高温高压地质试验装置，是从事实验矿物岩石地球化学和晶体生长等领域试验研究的重要设备。它的最大特点是在试验温度、压力下，通过内冷淬火迅速地将试验产物“冷冻”并保存到常温常压下进行测试鉴定。类似的试验装置，目前已在美国一些重要实验室应用。我们于1986年研制成功。几年来已推广应用12套，取得了良好的社会、经济效益。1高压釜装置系统和主要部件设计高压釜装置由压力系统、反应系统、加热系统和测量系统组成。压力系统包括手摇螺旋泵、阀门、管路和管件。卧式电阻炉属于加热… 相似文献
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Au在SiO2—HCl—H2O体系中200℃溶解度测定：硅化对金矿化的意义初探 总被引：8，自引：2，他引：8
实验标定了200℃时Au与SiO2间的络合反应：热力学计算表明，在具地质意义的物理化学条件下，AuH3SiO40的浓度远远高于AuCl2-,指出以硅络合对Au的活化迁移比氯重要得多。在含硫和硅的体系中，随着SiO2的增高，AuH3SiO40的作用将比Au（HS）2-更显重要。Au在SiO2水溶液中的溶解可表述为：SiO的沉淀是导致Au沉淀析出的有效机制，因此说明硅化与金矿化具有内在的联系。 相似文献
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The concept of “Slope Entropy Limit” is proposed in this paper. With the aid of computer, a Slope Entropy Limit Table can be readily established, which will be helpful to estimating the slope signs of univariant lines involved in a multisystem with a phase of unknown entropy. Under fortunate circumstances the unknown entropy is expected to be restricted within acceptable limits based on slope sign data on some critical univariant lines. Otherwise, these critical univariant reactions are considered most optimum to be tested experimentally. A critical entropy limit can be obtained only if the slope sign of such a line is confimed. The entropy limit thus obtained is subjected to a much less extent to uncertainties in PT measurements in comparison with entropy values derived from PT brackets. 相似文献
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Laihunite, a mineral of ferric and ferrous iron silicate discovered in China in recent years, occurs in high grade metamorphic BIF coexisting with magnetite, quartz,fayaiite, ferrosilite and almandine. Complete nets based on Sehreinemakers bundles and partial nets with maximum closure after the method described by H. W. Day have been constructed by taking into account the existance of this minertl in order to illustrate phase relations for the (n 3) multisystem in the system of Fe2O3-FeO-SiO2. Judging from Lindsley‘s experimental data on ferrosilits, laihunite is expected to be stable at pressures probably higher than 15 Kb. Two-pyroxene and olivine-clinopyroxene geothermometere give temperatures of formation between 600--700℃. Free energy of laihunite calcultted according to the method of Chert and estimated values of heat capacity allow oxygen fugacity to be plotted against temperature at different total pressures with respect to a number of univariant reactions in which lailunite is involved. The log fo2 -T diagram demonstrates that to a first approximation the stability flels of laihunite overlaps the upper part of the magnetite field, but its upper limit is a little beyond the hematite-magnetite equilibrium. The three major requirements for laihunite stability, i.e., an unusual high pressure, a temperature in the order of 600--700℃ and a relatively higher oxygen fugacity are mutually, exclusive in common geological environment, which may probably account for the rare occurrence of this mineral in nature. For the BIF in which laihunite occurs, the pressure caused by the weight of overlying strata is not high enough to give rise to its formation even in the extreme case of geothermal gradient.So it is suggested that additional tectonic pressure in response to plate activity might have been involved. 相似文献
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