微量元素对闪锌矿半导体性质制约机理

闪锌矿是一种重要的宽禁带半导体材料,具有优良的光、电和催化性能,在光学器件和光催化等领域有着广泛的应用前景。天然产出的闪锌矿中存在以类质同像替代Zn的Fe、Cd和Ga等微量元素,对其电子结构产生一定的影响,继而影响天然闪锌矿的半导体性质。同时闪锌矿中微量元素的种类、含量与分布受多种因素的影响,除了与闪锌矿本身的地球化学与晶体化学的性质相关,还受到成矿的地质环境、成矿的物理化学条件和成矿溶液离子浓度的影响。所以通过对不同成因类型的闪锌矿半导体性质的研究,可以得到闪锌矿中微量元素的特征,进而反映闪锌矿的成矿条件。对于寻找生命早期闪锌矿,解释半导体矿物光催化为生命起源提供能量提供可靠的证据。已有理论研究通过第一性原理的计算,得出了闪锌矿存在半导体和绝缘体两种类型。微量元素中,只有铜杂质使闪锌矿由直接带隙变为间接带隙,说明含铜的闪锌矿不宜作为光催化剂,铁、镓、锗、铟、锡和锑元素导致费米能级向高能方向移动且使闪锌矿的半导体类型由p型变成n型,这将增加电子密度且有利于电子跃迁,而锰、钴、铜、镉、汞、银和铅元素没有改变闪锌矿的半导体类型。本研究闪锌矿样品来自不同省份不同成因类型的典型矿床,结合半导体材料电阻率及其导电类型的测量方法、紫外可见光吸收光谱的方法和地球科学微量元素测量方法,通过实验对不同成因类型矿床中代表性闪锌矿的电阻率、吸收光谱、共生矿物组合、组构特征、微量元素的测量,建立闪锌矿矿石电阻率、吸收光谱与微量元素影响的定量关系及理论模型。探讨了闪锌矿电阻率、光谱吸收特征和矿床类型及地质产状的关系。闪锌矿中Fe元素含量越高,电阻率越小,可以形成空穴型导电(p型),因Fe元素进入闪锌矿晶格中要消耗能量,所以其形成温度大于绝缘体闪锌矿形成温度,黑色闪锌矿形成温度高。     

一些热液金属矿床中闪锌矿组份的变化

闪锌矿是热液金属矿床中最常见的矿石矿物.闪锌矿中FeS含量被认为是一种很灵敏的标志,可用作地压计.闪锌矿组份的资料在许多单个矿床成因讨论的著作中均有报道,但是从区域观点阐明闪锌矿组份的著作却很少. 在日本,1963年用光谱测定了日本绿色凝灰岩区的366块闪锌矿标本.由矿床类型及矿石建造来看,显示出微量元素的区域性特征及地球化学特征.1980年对日本几十个夕卡岩型矿床中的闪锌矿作了研究,发现FeS、MnS、CdS的含量分布有一定规律.在朝鲜,1977年对选自不同地质背景16个铅锌矿床中的闪锌矿微量元素作了分析,得出微量元素之间的特殊相关关系受地质背景     

闪锌矿的标型特征、形成 条件与电子结构

本文阐述了我国几个不同成因矿床闪锌矿的化学成分、晶胞参数和物理性质,如硬度、密度、反射率、吸收边能量、磁化率等的特征;根据闪锌矿的内部电子结构和微量元素的晶体化学特征讨论了成分、结构与物理性质之间的相互关系;并探讨了这些标型特征在矿床成因和地质找矿上的意义。     

闪锌矿地质压力计的研究及进展

P.B.Barton等人(1966)在前人工作的基础上,对Fe-Zn-S体系做了详细的研究,绘制了该体系的温度-组分图,指出闪锌矿与磁黄铁矿+黄铁矿共生时,闪锌矿中铁的含量很敏感地随着温度与S_2逸度而变化,并提出在这种组合中闪锌矿作为地质温度计的可能性。S.D.Scott等人(1971)用实验证明在一定温度范围内,闪锌矿中铁含量与温度无关,而与压力关系密切,因此提出闪锌矿与磁黄铁矿+黄铁矿共生时,有可能成为有用的地质压力     

闪锌矿中杂质Fe存在形式的重新认识

闪锌矿作为一种重要的金属硫化物已得到广泛的研究，但在对闪上矿中杂质Ｆｅ存在形式的认识上却存在许多问题。本文对不同含Ｆｅ量的天然闪锌矿测定并分析了Ｆｅ的Ｋ边ＥＸＡＦＳ谱，同时对低温光吸收谱及穆斯堡尔进行了研究。结果表明，Ｆｅ在闪锌矿中主要以六配位形式存在。     

扬子板块北缘马元铅锌矿床闪锌矿LA-ICP-MS微量元素特征与指示意义

马元铅锌矿床是我国近年来在扬子板块北缘探获的大型铅锌矿床,对马元铅锌矿床闪锌矿微量元素进行了高精度的LA-ICP-MS测试研究,结果表明矿床闪锌矿微量元素含量具有低Fe、Mn,高分散元素Cd、Ge、Ga,低分散元素In的特征;闪锌矿Fe、Mn含量和Ga/Ge比值特征指示了矿床成矿流体温度不高,可能为与中低温盆地流体有关的铅锌矿床;闪锌矿中分散元素In、Ge特征能有效的区分铅锌矿床的成因类型:与岩浆或火山活动有关的铅锌矿床闪锌矿具有高In或低In,低Ge的特征,而与盆地卤水有关的中低温矿床中闪锌矿则普遍富Ge贫In。依据马元铅锌矿床微量元素特征,结合矿床地质与地球化学特征,认为马元铅锌矿应属于密西西比河谷型铅锌矿床(MVT铅锌矿床)。     

嗜酸性氧化亚铁硫杆菌与硫化物矿石相互作用的实验研究

实验研究了嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.f)与硫化物矿石之间的相互作用,以观察不同矿石矿物发生微生物氧化和形成次生矿物的差异。采用ICP-OES分析了反应前后溶液成分变化,利用扫描电子显微镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)等分析手段研究了矿石表面形貌的变化和沉淀物的矿物组成。分析结果表明,A.f对同一矿石中不同矿物作用强度存在明显差异,方铅矿、闪锌矿发生强烈氧化分解,而与黄铁矿的相互作用则较弱。这种差异可能与矿物晶体结构有关,在多种矿物并存的情况下,可能发生了原电池反应,作为阴极的黄铁矿受到保护,而作为阳极的闪锌矿、方铅矿的氧化作用得到促进,总体上表现为A.f对矿石硫化矿物的选择性作用。     

“异常闪锌矿”中一种铜铁硫新出溶相矿物的研究

在内蒙古大井锡石硫化物型铜银锡矿床的闪锌矿中发现了一种铜铁硫新出溶相矿物。作者研究了其光性、化学成分、晶体结构及出溶特征,提出了它作为闪锌矿中一种新的出溶相矿物的重要证据,并对其形成机理结合加热实验及已有的硫化物体系相平衡资料以及矿床地质特点进行了分析。     

橄榄石阳离子占位次序的一种计算方法

一、引言近几年来,由于矿物物理学的迅速发展,国际上对矿物的有序—无序结构、阳离子的占位次序以及元素的迁移和富集规律等课题的研究越来越深入了.因为这些问题不仅是岩石矿物学的基础理论,而且对了解有关矿产生成的地质条件(温度、压力等热力学因素)也提供了有用的依据.目前国外用晶体化学理论、晶体场论及价键理论对不少矿物阳离子的占位度作了较满     

铅锌矿床地质样品的Ge同位素预处理方法研究

目前Ge同位素研究主要局限于地球有机质(煤等)、火成岩及陨石样品,作为Ge重要储库之一的铅锌矿床,其Ge同位素的研究涉及较少。铅锌矿床样品中Ge的化学分离及提纯是Ge同位素研究的基础。本文详细考察了陨石样品中Ge同位素预处理方法(分离和提纯)对铅锌矿石样品的适用性。阴离子条件实验说明,目前普遍采用的离子交换树脂单柱法虽然对铅锌矿样品中Fe、Se等元素的剔除效果理想,但无法有效剔除其中的Zn,当Zn/Ge比值大于3时,样品必须经过阳离子交换树脂柱作进一步处理剔除Zn。通过对闪锌矿标准样品、锌矿石标准样品的条件实验以及实际闪锌矿样品对条件结果的验证显示,当闪锌矿的称样量为0.15 g左右时,仅需将前人对玄武岩等样品Ge同位素处理方法中阴离子树脂洗脱酸(1.4 mol/L硝酸)的用量6 mL调整为10 mL,而阳离子树脂洗脱方法保持不变,此方法即满足闪锌矿样品Ge同位素的化学分离和提纯要求。样品经过本文推荐的阴阳离子交换树脂双柱法处理后,主要干扰元素(Fe、Zn、Se、Ni)及基质元素的剔除率接近100%,Ge的回收率优于99%。而前人对玄武岩等样品的Ge同位素处理方法中,主要干扰元素(Fe、Zn、Se、Ni)及基质元素的剔除效果亦较好,但Ge的回收率仅为97.3%,比本文推荐方法的Ge回收率要差。利用MC-ICP-MS对Ge化学分离和提纯后的富乐铅锌矿床闪锌矿样品的检验结果显示,测试过程中未见同质异位素以及可能的多原子离子影响,样品中Ge同位素符合质量分馏定律,经过调整后的阴阳离子交换树脂双柱法满足闪锌矿样品的Ge同位素测试要求。     

Iron content variations in sphalerite and their effects on reflectance and internal reflections under reflected light

Reflectance (R%) and internal reflections (IR) in the iron variant, sphalerite, are investigated by using the scanning electron microprobe and reflected light microscope. Iron contents in sphalerite positively affect reflectance and can be considered as a control factor of internal reflections color. Internal reflections of sphalerite grains that contain less than 10% Fe appear to be whitish yellow color but are with reddish brown color when Fe rises to 10% to 17%. This work is an effort for developing ore microscopy and ore petrography technique by using the optical properties as a geochemical tool for fast preliminary estimating iron content in sphalerite by using reflected light microscope.     

Characterisation of sphalerite and pyrite flotation samples by XPS and ToF-SIMS

The surface analytical techniques of X-ray Photoelectron Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectroscopy (ToF-SIMS) have provided information on the type and concentration of species on the surface of sphalerite and pyrite particles in flotation concentrate and tail samples, but also on their distribution on each particle and across particles of different sizes. From this surface analytical study, a more accurate interpretation of the flotation results of sphalerite and pyrite minerals in a mixed mineral system could be made as a function of the concentrations of copper sulphate activator and xanthate collector, and particle size. In particular, it was found that sphalerite particles reporting to the concentrate are larger in size and contain less iron hydroxide on their surface than particles reporting to the tail. As for the pyrite particles, their lower recovery than the sphalerite particles is the result of a larger proportion of iron hydroxide on their surface inhibiting copper and collector adsorption.     

Changes in iron content in sphalerites in relation to structural conditions and localization of ores in Kholst deposit

A consistent, relatively rapid decrease in FeS molecular content of sphalerites at decreasing depth is recognizable in upper parts of this structurally controlled Pb-Zn ore deposit, as an expression of tectonic calm and continuity of the productive stages of the mineralization. Elsewhere, in the depths, abrupt changes in quantity of isomorphous iron in sphalerites, within a relatively short depth-span, signify intensive movements during deposition of the ore. Wherever the structures are bent and healed by early quartz sufficiently to retard circulation of the solutions and to promote their cooling, variations in the FeS content of sphalerite at different depths may be related to thermal “knickpoints” of the ascending solutions. Nonetheless, FeS molecular content of sphalerites is no clue to the temperature of their crystallization. There is no relationship between the depth at which sphalerite was formed and the isomorphous Cd or Mn in crystal structures of the mineral. — V.P. Sokoloff.     

Iron and zinc partitioning between coexisting stannite and sphalerite: a possible indicator of temperature and sulfur fugacity

Stannite and sphalerite coexisting with iron sulfides (pyrite and/or pyrrhotite) from Japanese ore deposits associated with tin mineralization were analyzed. Based on the iron and zinc partitioning between stannite and sphalerite, the formation temperature and sulfur fugacity for this mineral assemblage were estimated. A good correlation between stannite-sphalerite temperatures and filling temperatures of fluid inclusions and sulfur isotope temperatures was obtained. This good correlation suggests that the stannite-sphalerite pair is a useful indicator of temperature and sulfur fugacity. It is deduced that the formation temperatures are not different for skarn-type, polymetallic vein-type and Sn-W vein-type deposits, whereas the sulfur fugacities are different; sulfur fugacities increase from the skarn-type through the Sn-W vein-type to the polymetallic vein-type deposits.     

热液脉型铅-锌-银矿床富铁闪锌矿中硫化物包裹体成因探讨

通过对热液脉型的铅－锌－银矿床（３个）和银矿床（１个）和闪锌矿中硫化物包囊体的特征研究表明,石英－硫化物阶段富铁闪锌矿（主矿物）的硫化物包裹体十分发育：沿生长带产出的乳滴状黄铜矿与主矿物为共同沉淀成因;沿穿切主矿物的黄铜矿或石英细脉两侧,和受粗粒黄铜矿溶蚀的富铁闪锌矿近接触部位发育的乳滴状黄铜矿为渗透－交代产物;沿解理（裂隙）或粒间、粒内产出的各种形态磁黄铁矿是充填－交代的结果;沿解理分布的脉状毒     

闪锌矿的吸收光谱和颜色的本质

本文采用电子吸收光谱和分子轨道（MO）－能带理论模型，系统地研究了不同颜色的闪锌矿呈色的机理和本质。闪锌矿由于其形成条件不同，所含杂质元素各异而颜色变化。黑色闪锌矿含Fe高，其颜色是由于以配位体硫为特征的非键轨道2e到Fe^2 的晶体场型轨道的电子转移在500nm产生吸收所致。只有闪锌矿含Fe低（＜1％）时，它才可具有其他颜色，黄色与受主能级Cu^ 到导带或价带到施主能级Ga^3 的电子跃迁在410nm产生吸收有关；绿色是Co^2 的晶体场跃迁^4A2→^4T2(P)在700nm附近产生的吸收峰所致；红色可能与受主能级Hg^ 到施主能级Ga^3 的电子跃迁在470nm产生宽吸收带有关。当闪锌矿的吸收光谱有其中两个吸收带叠加时，它具有过渡的颜色，如黄绿色或绿黄色、桔黄色或桔红色，主要色调取决于两个吸收带的相对强度。     

Copper ion activation of synthetic sphalerites with various iron contents

The adsorption of copper ions on synthetic sphalerites of various iron contents was measured using a radiotracer technique. The correlation of Cu²⁺ ions adsorption with the pH of solution, the iron content of the solid and the degree of surface oxidation of synthetic sphalerite were determined. The experiments proved that oxidation of the surface of the sphalerite samples caused a decrease in Cu²⁺ ions sorption with the exception of samples of iron containing sphalerite. Acidity of the solution affected the adsorption of Cu²⁺ ions by deoxidized sphalerite surfaces, whereas the adsorption on oxidized surfaces did not depend on the pH.     

Cathodoluminescence Characteristics and Mineral Chemistry of Tennessee Sphalerites (Tn-Usa)

Optical cathodoluminescence microscopy (CLM) can provide very useful information both on mineral zoning formed during crystal growth and on variations in chemical composition of sphalerites which is reflected by their visible colors. Gem quality sphalerite crystals associated with dolomite, calcite and fluorite having 3 different visible colors - green, honey and brown - were studied to compare their mineral chemistry and CL characteristics. Electron microprobe analyses indicated essentially no significant differences in terms of major components. Although the common CL-quencher ferrous iron contents of all three were lower than 0.25 wt %, none of the sphalerites cathodoluminescenced: two (brown and honey) were non-CL, the green sphalerite showed very week CL in faint brown color. Other trace elements that were analyzed include Fe, Cd, Mn, Ag, Hg, In, Bi, Cu, Ge, and Ga. Fe, Cd, Ga and Cu were relatively higher than the others. Most significant differences with respect to the common trace elements include honey colored sphalerites are essentially Fe- and Cd-poor but rich in Ga, green sphalerites are Fe- and Cd- rich but poor in all the others, and brown sphalerites are rich in Cd. No conclusive relation between non-CL behavior of all three sphalerites and their trace element chemistry was established, however; low quantities of common CL activators in sphalerite crystal structures such as Mn, Cu, and In were the main cause of the non-CL behavior.