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1.
有关银星石的矿物学工作,不少学者作过研究,但对其化学式、晶胞参数等有不同看法,对于空间群的判定亦未作详细叙述。本文通过银星石晶体结构的测定认为该矿物属斜方晶系,空间群系 C 2v9-P (c2)1n而非 D 2h16-P cmn,共化学式为 Al 3(OH) 3(PO 4) 2·6H 2O,每个晶胞中含有四个分子。同时文中也对银星石的物理性质作了较满意的解释。 相似文献
2.
1975年我们在鉴定陕西汉中超基性岩岩体矿物时,发现了绿纤石矿物,对其进行了X射线粉晶分析及光性特征鉴定,现作一报导。绿纤石Ca 4(Mg,Fe,Mn)(Al,Fe,Ti),(OH) 2[(Si 3OH)(SiO 4) 5],2H 2O产自超基性岩体的辉长岩蚀变带中,主要分布在走向200°、倾向53°及走向30°、倾向82°的两组节理面上,多成放射状集合体产出。单体无色,集合体呈很浅的灰绿色。玻璃光泽。具柱面条纹。性脆,硬度小,比重3.19。 相似文献
3.
在对宽甸砖庙硼矿床的研究中发现了电气石与遂安石共生的现象,电气石为钙镁电气石,由电子探针分析结果计算的晶体化学式为:(Ca 0.59Na 0.355K 0.06)(Mg 2.557Fe 0.1512+Ti 0.013Cr 0.002Ni 0.006)(Al 5.416Fe 0.5642-(BO 3) 3Si 6.16 O 16(OH) 4,同围岩中的电气石相比:(1)淡绿色,多色性弱;(2)折射率为Ne=1.646,Ns=1.624;(3)成分上富Mg(MgO 11.47%)和Ca(CaO3.14%);相对贫Na(Na 2O 1.09%),Fe(FeO4.63%)和Al(Al 2O 326.69%)(4)结构上d 101=3.393A,a 0=15.957±0.002,c 0=7.227±0.001;(5)红外光谱晶格Si-O 4四面体振动I 1001>I 1036。这些标型特征具有硼矿床的找矿指示意义。 相似文献
4.
采用CaO为助剂,在水热条件下分解钾长石,进而合成雪硅钙石。影响反应的主要因素为:n(CaO)/n(SiO 2+AlO 1.5)、晶化温度和晶化时间等。在n(CaO)/n(SiO 2+AlO 1.5)为0.75~1.00、晶化温度为230~250 ℃、晶化时间为5~8 h的条件下,可以合成结晶良好的雪硅钙石晶体。反应机理分析表明:在钾长石-氧化钙的水热体系中,钾长石的分解并不是简单的离子交换作用或铝硅酸盐解聚作用,而是在碱金属离子与水作用的基础上,反应物中H +与矿物表面的碱金属离子K +、Na +、Ca 2+作用,首先形成表面富硅贫铝的前驱聚合体(SiO 2·nH 2O);然后这些前驱聚合体分解,与溶液中的Ca 2+作用,生成C-S-H凝胶和水钙铝榴石;随着反应时间的延长,C-S-H凝胶和水钙铝榴石进一步转变为雪硅钙石。 相似文献
5.
前言作者等于1956-1957年在柴达木北緣某鉛鋅矿床氧化带中找到若干含鋅很高的硫酸盐矿物。其中二种,經过1962-63年的室內工作肯定为鋅赤铁矾(Zincobotryogen)和鋅叶綠矾(Zincocopiapite)。前者是赤铁矾族的新变种,后者是叶綠矾族的新变种。它們在成分上接近于这两族矿物的鋅的极端組分,即鋅赤铁矾的理論分子式为ZnFe 3+(SO 4) 2(OH)·7H 2O,鋅叶綠矾的理論分子式为ZnFe 43+(SO 4) 6(OH) 2·2OH 2O。工作中曾利用了叶韵琴同志采集的部分标本。 相似文献
6.
对翁泉沟硼矿采集的4个矿石样品进行测试,分析得出其主要成分由硼镁石Mg 2[B 2O 4(OH)](OH)和硼镁铁矿(Mg,Fe) 2Fe(BO 3)O 2组成.本物相分析方法通过对样品进行湿法磁选、酸溶方法测定硼镁铁矿中的硼元素.磁选后残渣经酸溶测定硼镁石中硼元素,结果显示其组分与实际地质成矿组分相吻合.实验证明本测试方法对硼矿石物相及硼矿物在自然界中的赋存状态测定分析快速、准确,为当前的硼矿石研究提供了新的思路,能够满足测试要求. 相似文献
7.
在苏联,从盐湖中,开采自行沉积岩,从岩池中开采食盐(NaCl),其中还有硫酸鈉-芒硝(Na 2SO 4·10H 2O),无水芒硝(Na 2SO 4),天然碳酸鈉(Na 2CO 3·6H 2O),石膏,水石盐(NaCl·2H 2O),泻利盐(MgSO 4·7H 2O),白鈉鎂矾(Na 2SO 4·MgSO 4·4H 2O)。在克里木的薩基湖曾經专門开辟了盐池,把原生滷水引过来蒸晒,使其浓縮为光滷石(KCI·Mg(Cl 2·6H 2O),并且作了試驗想从中采取鉀盐;后来发現这样作在經济上很不合算,因为苏联已有了世界上最富的鉀盐矿床,自盐湖的原生滷水中还开采溴酸盐并試图提取硼和鋰。 相似文献
8.
为探究不同煤阶煤吸附CH 4和H 2O吸附机理,采用量子化学方法中的密度泛函理论(DFT),在B3LYP/6-31G基组上计算了不同煤阶煤的大分子稳定构型及煤分别吸附CH 4、H 2O及CH 4与H 2O共存条件下的吸附能和电荷转移情况。研究结果表明:煤吸附CH 4为物理吸附,随着煤阶升高,煤吸附CH 4能力增强;吸附H 2O时以氢键形式作用,其中煤中含氧官能团为氢键供体,H 2O中-OH为氢键受体,随着煤阶升高,吸附H 2O能力减弱;当H 2O与CH 4共存时,H 2O抢占CH 4吸附位,导致煤优先吸附H 2O,使吸附态CH 4减少,游离态CH 4增多。从分子水平完善了煤吸附甲烷和H 2O的吸附机理,为注热蒸汽开发煤层气奠定了吸附理论基础。 相似文献
9.
Recent work on the Panzhihua intrusion has produced two separate models for the crystallisation of the intrusion:(1) low-Ti,high CaO and low H 2O(0.5 wt.%) parent magma(equivalent to Emeishan low-Ti basalt) at FMQ;and(2) high-Ti,low CaO and higher H 2O(>1.5 wt.%) parent magma(equivalent to Emeishan high-Ti basalt) at FMQ + 1.5.Modelling of these parent magma compositions produces significantly different results. We present here detailed f(O 2) and H 2O modelling for average compositions of both Emeishan high-Ti and low-Ti ferrobasalts in order to constrain the effects on crystallisation sequences for Emeishan ultra-mafic -mafic layered intrusions.Modelling is consistent with numerous experimental studies on ferro-basaltic magmas from other localities(e.g.Skaergaard intrusion).Modelling is compared with the geology of the Panzhihua intrusion in order to constrain the crystallisation of the gabbroic rocks and the Fe-Ti oxides ore layers.We suggest that the gabbroic rocks at the Panzhihua intrusion can be best explained by crystallisation from a parent magma similar to that of the high-Ti Emeishan basalt at moderate H 2O contents(0.5-1 wt.%) but at the lower end of TiO 2 content for typical high-Ti basalts(2.5 wt.%TiO 2). Distinct silicate disequilibrium textures in the Fe-Ti oxide ore layers suggest that an influx of H 2O may be responsible for changing the crystallisation path.An increase in H 2O during crystallisation of gabbroic rocks will result in the depression of silicate liquidus temperatures and resultant disequilibrium with the liquid.Continued cooling of the magma with high H 2O then results in precipitation of Mt-Uv alone. The H 2O content of parent magmas for mafic layered intrusions associated with the ELIP is an important variable.H 2O alters the crystallisation sequence of the basaltic magmas so that at high H 2O and f(O 2) Mt -Uv crystallises earlier than plagioclase and clinopyroxene.Furthermore,the addition of H 2O to an anhydrous magma can explain silicate disequilibrium texture observed in the Fe-Ti oxide ore layers. 相似文献
10.
选取广西北部湾地区表层土壤中As元素为研究对象,采集了7 327个土壤样品,400个岩石样品,分析As、K 2O、Na 2O、CaO、MgO、SiO 2、Al 2O 3、TFe 2O 3、Mn、Ti、pH和有机碳(SOC)等指标,探讨了土壤成土母岩、成土作用、土壤组成、pH和有机质等对表层土壤As元素的影响。结果表明:As元素平均质量分数为7.96×10 -6,为中国土壤背景值0.80倍;风化作用对于As元素的次生富集起到极为重要的作用,明显强于成土母岩As元素背景的影响。Pearson相关分析和主成分分析表明:在土壤组成和土壤性质等因素中,含Al矿物(Al 2O 3)、含Fe矿物(TFe 2O 3)、含Si矿物(SiO 2)和SOC,对土壤As的富集起到主导作用;pH 和含 Ca矿物(CaO)的作用较弱;而含K矿物(K 2O)、含Na矿物(Na 2O)和含Mg矿物(MgO)对As的次生富集作用可以忽略不计。 相似文献
11.
中国东部花岗岩类141个Mg-Fe云母的化学成分将近90%的变化属于八面体层内的类质同象置换,置换矢量Mg 1Fe +2和Fe -3+2(R Ⅵ+3) -2□ Ⅵ组成了天然黑云母平面,大约80%的变化应当解释为基本置换8Mg 1Fe +2+Fe -3+2(R Ⅵ+3) 2□ Ⅵ.这些是Mg-Fe云母在广泛的自然条件下表现出来的最主要的晶体化学关系。文中还提出了置换矢量的长度、分量和以及电价和三个参数,用以识别矿物化学成分变化的类质同象置换特征。 相似文献
12.
铁酸钙是高碱度烧结矿中的主要黏结相矿物,它的含量、结晶形态、化学成分及晶体结构等矿物学特性对烧结矿质量起着关键性作用,而烧结原料中各组分的含量直接影响着铁酸钙的生成。以Fe 3O 4、SiO 2、CaO、MgO、Al 2O 3的化学纯试剂为原料,在实验室进行微型烧结实验,运用XRD、偏光显微镜、电子探针等手段,定量分析研究了原料组分中MgO、Al 2O 3对烧结矿中铁酸钙的生成及其矿物学特性的影响。原料中MgO含量的增加对铁酸钙的生成有一定抑制作用,尤其在MgO含量为2.0%~3.0%时,烧结矿中铁酸钙含量明显减少,其晶体形态也从以板柱状和针状为主逐渐过渡为它形不规则状;原料中Al 2O 3的增加,对烧结矿中铁酸钙的形成具有促进作用,即随着Al 2O 3的增加铁酸钙含量呈明显增加趋势,且铁酸钙的形态也由以柱状和针状为主向板柱状变化。电子探针成分分析及矿物化学式计算结果表明,铁酸钙是由Fe 2O 3、CaO、SiO 2、Al 2O 3及MgO组成的复杂结晶体,其化学通式为Ca 2.60Mg 0.44Si 1.07Al 0.96Fe 8.92O 20。原料中MgO、Al 2O 3含量的变化,对铁酸钙的化学成分中Fe 2O 3/CaO摩尔分数比影响不大,均接近3∶2。上述研究结果对于深刻理解烧结工艺条件下铁酸钙晶相的晶体化学特征及其对烧结矿质量的影响具有重要指导意义。 相似文献
13.
Experimental research on K-rich phases and observations from diamond inclusions, UHP metamorphic rocks, and xenoliths provide insights about the hosts for potassium at mantle conditions. K-rich clinopyroxene (Kcpx–KM 3+Si 2O 6) can be an important component in clinopyroxenes at P>4 GPa, dependent upon coexisting K-bearing phases (solid or liquid) but not, apparently, upon temperature. Maximum Kcpx content can reach 25 mol%, with 17 mol% the highest reported in nature. Partitioning (K)D(cpx/liquid) above 7 GPa=0.1–0.2 require ultrapotassic liquids to form highly potassic cpx or critical solid reactions, e.g., between Kspar and Di. Phlogopite can be stable to about 8 GPa at 1250 °C where either amphibole or liquid forms. When fluorine is present, it generally increases in Phl upon increasing P (and probably T) to about 6 GPa, but reactions forming amphibole and/or KMgF 3 limit F content between 6 and 8 GPa. The perovskite KMgF 3 is stable up to 10 GPa and 1400 °C as subsolidus breakdown products of phlogopite upon increasing P. (M4)K-substituted potassic richterite (ideally K(KCa)Mg 5Si 8O 22(OH,F) 2) is produced in K-rich peridotites above 6 GPa and in Di+Phl from 6 to 13 GPa. K content of amphibole is positively correlated with P; Al and F content decrease with P. In the system 1Kspar+1H 2O K-cymrite (hydrous hexasanidine–KAlSi 3O 8· nH 2O–Kcym) is stable from 2.5 GPa at 400 to 1200 °C and 9 GPa; Kcym can be a supersolidus phase. Formation of Kcym is sensitive to water content, not forming within experiments with H 2O 2O>Kspar. Phase X, a potassium di-magnesium acid disilicate ((K1−x−n)2(Mg1−nMn3+)2Si2O7H2x), forms in mafic compositions at T=1150–1400 °C and P=9–17 GPa and is a potential host for K and H2O at mantle conditions with a low-T geotherm or in subducting slabs. The composition of phase-X is not fixed but actually represents a solid solution in the stoichiometries □2Mg2Si2O7H2–(K□)Mg2Si2O7H–K2Mg2Si2O7 (□=vacancy), apparently stable only near the central composition. K-hollandite, KAlSi3O8, is possibly the most important K-rich phase at very high pressure, as it appears to be stable to conditions near the core–mantle boundary, 95 GPa and 2300 °C. Other K-rich phases are considered. 相似文献
14.
Cordierite samples from pegmatites and metamorphic rocks have been analysed for major [electron microprobe analysis (EMPA)] and trace elements [inductively coupled plasma mass spectrometry (ICP-MS), secondary ion mass spectrometry analyses (SIMS)] as well as for H 2O and CO 2 (coulometric titration), and the results evaluated in conjunction with published data in order to determine which exchange mechanisms are significant. Apart from the homovalent substitutions FeMg −1 and MnMg −1 on the octahedral site, some minor KNa −1 on the Ch0 channel site, and Fe 3+Al −1 on the T 11 tetrahedral site, the three most important substitution mechanisms are those for the incorporation of Li on the octahedral sites (NaLi□ −1Mg −1), and of Be and other divalent cations on the tetrahedral T 11 site (NaBe□ −1Al −1 and Na(Mg,Fe 2+)□ −1Al −1). The dominant role of the last vector is clearly demonstrated. We propose a new generalized formula for cordierite: Ch(Na,K) 0–1 VI(Mg,Fe 2+,Mn,Li) 2 IVSi 5 IVAl 3 IV(Al, Be, Mg, Fe 2+, Fe 3+)O 18 * xCh(H 2O, CO 2…). Our results show that the population of (Mg, Fe 2+) on the T 11-site is limited to about 0.08 a.p.f.u. Other exchange mechanisms that were encountered in experiments operate only under P– T conditions or in bulk compositions that are rarely realized in nature. Routine analyses by electron microprobe in which Li and Be are not determined can be plotted as (Mg+Fe+Mn) versus (Si+Al) to assess whether significant amounts of Li and Be could be present. These amounts can be calculated as Li (a.p.f.u.)=Al+Na–4 and Be (a.p.f.u.)=10–2Al–M 2+–Na. 相似文献
15.
对内蒙古大沟井钒矿床的矿石样品进行了系统的常量和微量元素、X射线粉晶衍射以及显微能谱分析,探讨矿石中钒的赋存形式、形成环境以及保存条件等.研究结果表明,矿石样品中P2 O5含量变化范围为0.81%~6.14%,显示其磷含量普遍较高,反映地层中较为富集磷;样品烧失量的范围为7.75%~41.24%,比较大,反映云母及泥质... 相似文献
16.
Reaction rims of titanite on ilmenite are described in samples from four terranes of amphibolite-facies metapelites and amphibolites namely the Tamil Nadu area, southern India; the Val Strona area of the Ivrea-Verbano Zone, northern Italy, the Bamble Sector, southern Norway, and the northwestern Austroalpine Ötztal Complex. The titanite rims, and hence the stability of titanite (CaTiSiO 4O) and Al–OH titanite, i.e. vuaganatite (hypothetical end-member CaAlSiO 4OH), are discussed in the light of fH 2O- and fO 2-buffered equilibria involving clinopyroxene, amphibole, biotite, ilmenite, magnetite, and quartz in the systems CaO–FeO/Fe 2O 3–TiO 2–SiO 2–H 2O–O 2 (CFTSH) and CaO–FeO/Fe 2O 3–Al 2O 3–SiO 2–H 2O–O 2 (CFASH) present in each of the examples. Textural evidence suggests that titanite reaction rims on ilmenite in rocks from Tamil Nadu, Val Strona, and the Bamble Sector originated most likely due to hydration reactions such as clinopyroxene + ilmenite + quartz + H 2O = amphibole + titanite and oxidation reactions such as amphibole + ilmenite + O 2 = titanite + magnetite + quartz + H 2O during amphibolite-facies metamorphism, or, as in the case of the Ötztal Complex, during a subsequent greenschist-facies overprint. Overstepping of these reactions requires fH 2O and fO 2 to be high for titanite formation, which is also in accordance with equilibria involving Al–OH titanite. This study shows that, in addition to P, T, bulk–rock composition and composition of the coexisting fluid, fO 2 and fH 2O also play an important role in the formation of Al-bearing titanite during amphibolite- and greenschist-facies metamorphism. 相似文献
17.
为了探讨伊利石对煤化作用和沉积环境的指示作用,以华北地区京西煤田侏罗纪煤层夹矸为研究对象,采用X射线衍射方法(XRD)和X射线荧光方法(XRF)分别测定煤层夹矸的矿物组成和化学组成,研究夹矸中伊利石矿物学特征及成因。结果表明,京西煤田侏罗纪煤层夹矸主要由伊利石、绿泥石和石英组成,其中,伊利石质量分数平均为62.92%。将XRD数据和XRF数据进行对比分析,计算得到伊利石平均化学式为(K 0.37(NH 4) 0.03)Al 2(Si 3.60Al 0.40O 10)(OH) 2。京西煤田煤层夹矸中伊利石主要由高岭石转化而来,伊利石的NH 4+占层间阳离子的比例具有随沉积古盐度升高而逐渐升高的趋势,n(Si)/n(Al)Ⅳ具有随煤化程度升高而逐渐降低的趋势,这表明京西煤田侏罗纪煤层夹矸中的伊利石矿物学特征对沉积环境和煤化作用具有一定的指示作用。 相似文献
18.
丹池盆地硅岩(D 31)属于典型的热水成因沉积物。它的显著地球化学特征之一是Sb.As和Ag富集,而REE贫乏,并且从近热水喷口→远离热水喷口,即沿着类碧玉岩→纹理状硅岩→块状泥质硅岩→硅页岩方向,元素、元素组合及稀土元素特征出现规律性的变化。 相似文献
19.
The quantitative determination of the main compounds Al (OH) 3 (gibbsite) as Al 2O 3 and hydrated Fe-oxides as Fe 2O 3 in natural and beneficiated ferruginous bauxites (low-grade bauxites) by X-ray diffraction (XRD) is presented employing the external standard method. The calibration parameters for the analysis by XRD were ascertained by using ten synthetic mixtures of the pure oxides Al 2O 3 and Fe 2O 3 which were calcined at 1200°C. The concentration ranges for Fe 2O 3 were 10–70 wt.% and those for alumina 30–90 wt.%. The standard deviation for the calibrations of the two oxides was 3.33 wt.%. The results obtained by XRD for both oxides were compared with those attained by X-ray fluorescence. The precision of the determinations by XRD was ascertained by analysing a natural sample consecutively 5 times. The accuracy was verified by the analysis of two international standard reference materials with low silica contents. 相似文献
20.
Minerals corresponding in chemical composition to probable götzenite solid solutions, götzenite ss, ideally (Ca, Na) 3 (Ti, Zr) (Si 2O 7) (F, O, OH) 2, khibinskite (K 4Zr 2Si 4O 14) and apophyllite (KCa 4Si 8O 20(OH, F)) were first reported in an aphyric, glass-bearing kalsilitite from Cupaello (Umbria), Italy, by Cundari and Ferguson (1991). To the authors knowledge, this occurrence of khibinskite is only the second recorded. Götzenite ss was also found in a leucite-, melilite-rich pegmatoid in an olivine-melilitite from San Venanzo, S. Venanzo, in the same region. The S. Venanzo phase, with significant Zr (0.18 atoms per formula unit) is transitional to rosenbuschite, which is the Zr-rich end-member of the isostructural series götzenite-rosenbuschite, while that from Cupaello, virtually Zr free, is close to the ideal götzenite end-member. The S. Venanzo phase crystallized as the preferred Zr phase from the relatively low-Zr (Zr=335 ppm) S. Venanzo lava. This probably inhibited khibinskite crystallization in the S. Venanzo lava, whereas khibinskite is the preferred Zr phase in the Cupaello lava (Zr=760 ppm), coexisting with low-Zr götzenitess. The structural formula of the Cupaello khibinskite, based on 10 cations, yielded: K3.89[Zr1.99Mg0.01Fe0.042+Ti0.02]2.06Si4.05O14.1 which is very close to the composition first reported by Khomiakov et al. (1974). Apophyllite, also occurring in the Cupaello assemblages and in cavities in the lava, yielded a composition close to the ideal formula and supports the important role of alkali-rich fluids in the crystallization history of this lava. The rare records of these minerals reflect, at least in part, the difficulty in identifying them. Their role as potential acceptors of both large ion lithophile and high field strength elements in peralkaline rock compositions is important in understanding the geochemistry of lamproitic rocks and in detecting possible genetic links with related rocks. 相似文献
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