青海玛温根矿区氧化铅银矿工艺矿物学特性及分析研究

结合光学显微镜鉴定、扫描电镜、X射线能谱探针、筛析等技术手段,系统研究了青海省玛温根矿区产出的有代表性的氧化铅矿石的工艺矿物学特征。结果表明:矿石主要有价元素是Pb(2. 76%)和Ag(204. 4×10-6);矿石中铅的赋存状态较复杂,主要赋存于铅铁矾等难溶铅中,其次赋存于氧化铅、硫酸铅中,矿石中的铅矿物主要是铅矾、白铅矿、砷铅铁矾,少量方铅矿、砷铅矿等;银的赋存状态亦较为复杂,独立银矿物为硫铜银矿,含量甚微,部分银呈类质同像赋存于其他的金属硫化物中。通过偏光显微镜和扫描电镜分析发现,主要的铅矿物如铅矾、白铅矿等相互交代连生现象明显,且嵌布粒度细小,这与筛析检测结果相一致,同时矿石中As含量较高,达到了5. 43%,含砷矿物主要为毒砂、臭葱石,经X射线能谱分析,部分铅矿物与砷元素关系密切,并形成了砷铅铁矾、砷铅矿等复杂砷铅矿物。所以预测在选矿过程中,砷会随铅矿物同步富集,银的独立银矿物主要是硫铜银矿,且嵌布粒度微细,大部分银矿物以微细粒包裹态赋存于石英、褐铁矿等硅酸盐或氧化物中。根据以上研究成果,可判定该氧化铅银矿属于极难选矿石,建议采用浮选-化学选矿工艺综合回收铅、银金属的技术路线。     

石英流体包裹体的岩相学和热爆参数填图在前河金矿中的应用

文章从石英流体包裹体的研究入手,采用矿物学填图的方法,探讨了流体包裹体的岩相学特征和爆裂温度等热爆参数方面的成因矿物学信息.岩相学填图表明,包裹体大小在8～11μm之间,分布密度越大的样品对应的金矿化越好;依据石英起爆温度、爆裂温度范围、热爆曲线形态及主爆峰值等特点,将矿区所有样品的石英热爆裂归纳为4种基本类型,起爆温度低且具主爆裂峰的Ⅰ型曲线指示有利于金矿化的地段,爆裂峰越高和爆裂温度区间越宽的样品对应的金矿化越好.流体包裹体的爆裂法测温在找矿实践中取得了较好的效果.并通过此方法初步预测了前河金矿区的深部远景.     

福建永定大坪花岗斑岩体的铌钽富集特征研究

福建大坪花岗斑岩体位于永定县城南部的大石凹—蓝地火山喷发盆地,具斑状结构,基质呈霏细结构、细-微粒结构。文章运用电子探针(EMPA)和激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)等技术,对大坪岩体ZK10001钻孔中不同深度的岩石样品进行了矿物和岩石化学分析。分析结果表明,大坪岩体岩性为黑鳞云母碱长花岗斑岩,属于过铝质钙碱性花岗岩,具有较高的分异演化程度,Nb2O5和Ta2O5含量达到了花岗岩型稀有金属矿床的工业品位。铌钽矿物主要与黄玉、萤石的集合体呈稀疏浸染状、星点状产于基质间隙内,其次以星点状存在于石英和长石斑晶中。矿石矿物赋存特征与宜春钽铌矿床类似,可能具有一定的可选性和经济价值。大坪岩体的铌钽富集特征不同于斑岩型铜、钼矿床,与花岗岩型铌钽矿床也存在较大的差别,铌钽的富集过程经历了深部斑晶阶段和浅部基质阶段两阶段岩浆结晶分异作用,F等挥发分促进了铌钽在结晶残余岩浆中富集,在基质间隙间沉淀。大坪矿化岩体的发现暗示斑岩型铌钽矿床存在的可能性。     

REE mineralogy and geochemistry of the Western Keivy peralkaline granite massif,Kola Peninsula,Russia

The authors have studied the geology, geochemistry, petrology and mineralogy of the rare earth elements (REE) occurring in the Western Keivy peralkaline granite massif (Kola Peninsula, NW Russia) aged 2674 ± 6 Ma. The massif hosts Zr- and REE-rich areas with economic potential (e.g. the Yumperuaiv and Large Pedestal Zr-REE deposits), where 25% of ΣREE are represented by heavy REE (HREE). The main REE minerals are: chevkinite-(Ce), britholite-(Y) and products of their metamict decay, bastnäsite-(Ce), allanite-(Ce), fergusonite-(Y), monazite-(Ce), and others. The areas contain also significant quantities of zircon reaching potentially economic levels. We have discovered that behavior of REE and Zr is controlled by alkalinity of melt/solution, which, in turn, is controlled by crystallization of alkaline pyroxenes (predominantly aegirine) and amphiboles (predominantly arfvedsonite) at a late magmatic stage. Crystallization of mafic minerals leads to a sharp increase of K₂O content and decrease of SiO₂ content that cause a decrease of melt viscosity and REE and Zr solubility in the liquid. Therefore, REE and zirconium immediately precipitate as zircon and REE-minerals. There are numerous pod- and lens-like granitic pegmatites within the massif. Pegmatites in the REE-rich areas are also enriched in REE, but HREE prevails over light REE (LREE), about 88% of REE sum.     

湖南仁里5号伟晶岩脉铌钽矿物特征与岩浆热液成因的探讨

湖南仁里5号花岗伟晶岩是1条分异程度很高的伟晶岩脉,其岩相带分为2类:外部带(Ⅰ—Ⅱ)和内部带(Ⅲ—V).文章用电子探针定量分析(EPMA)和背散射电子图像(BSE)研究了 5号脉中的铌钽矿物.研究揭示:铌铁矿-钽铁矿存在于大部分结构带中,而铌锰矿和细晶石主要局限于V带.Ⅰ—Ⅲ带的铌钽铁矿在结构上表现为中心富集Nb元素...     

Optical and infrared photometry of new very low‐mass stars and brown dwarfs in the σ Orionis cluster

We present an RI photometric survey covering an area of 430 arcmin² around the multiple star σ Orionis. The observations were conducted with the 0.8 m IAC‐80 Telescope at the Teide Observatory. The survey limiting R and I magnitudes are 22.5 and 21, and completeness magnitudes 21 and 20, respectively. We have selected 53 candidates from the I vs. R–I colour‐magnitude diagram (I = 14–20) that follow the previously known photometric sequence of the cluster. Adopting an age of 2–4 Myr for the cluster, we find that these objects span a mass range from 0.35 M_⊙ to 0.015 M_⊙. We have performed J‐band photometry of 52 candidates and K_s photometry for 12 of them, with the result that 50 follow the expected infrared sequence for the cluster, thus confirming with great confidence that the majority of the candidates are bona fide members. JHK_s photometry from the Two Micron All Sky Survey (2MASS) is available for 50 of the candidates and are in good agreement with our data. Out of 48 candidates, which have photometric accuracies better than 0.1 mag in all bands, only three appear to show near‐infrared excesses. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

南极格罗夫山普通球粒陨石的岩石学和矿物学特征及分类

从南极格罗夫山地区回收的11个陨石均具有球粒结构,确定为普通球粒陨石。研究了这些陨石的岩相学特征和矿物化学特征,进行了化学群-岩石类型的划分。结果表明,在所研究的11个普通球粒陨石中,4个为H群,6个为L群,1个为LL群。其中GRV 020010（LL3）和GRV 021481（H3）的两个陨石是稀少的、在我国尚末见过的非平衡普通球粒陨石。进行了陨石磁化率的测试,初步探讨了磁化率在陨石化学群分类中的作用。     

Geochemical assessment of a siliceous limestone sample for cement making

A low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, has been investigated for its suitability for cement making. Petrological as well as X-ray diffraction pattern studies indicated that the limestone sample was crystalline and dominantly composed of calcite and quartz. They are simple in mineralogy, and yet they have variable silica and lime contents. Geochemical analysis results of twenty five hand picked samples indicated that the limestone from the Jayantipuram mine shows a wide range of variations in LOI (29.94% to 40.64%), SiO2 (6.14% to 27.18%), CaO (37.93% to 50.78%), Al2O3 (0.49% to 2.27%) and Fe2O3 (0.28% to 2.4%). MgO, K2O, Na2O, TiO2 and MnO2 are present in traces. CaO with LOI shows a strong positive correlation where as CaO with SiO2 shows a strong negative correlation because of mineralogical factors. The chemical composition of the limestone reflects its mineralogical composition. The distribution of various elements in the acid-soluble fraction has been studied by the factor analysis method in order to interpret in terms of their mineralogy, sedimentary environment and diagenesis. Mineralogy, recrystallization and other diagenetic changes are the main factors affecting the distribution of the elements and their mutual relationships in the limestone. The aim of this paper is also to analyze how significantly the two parameters, silica modulus and lime saturation factor, influence this low grade siliceous limestone sample from the Jayantipuram mine of Andhra Pradesh, India, for the cement making process from the geochemical data.     

黄沙坪夕卡岩型多金属矿石中锡的工艺矿物学研究

运用化学分析、X射线衍射分析、化学物相分析、扫描电镜、光学显微镜等手段对黄沙坪夕卡岩型多金属矿石中锡的工艺矿物学特征特别是其赋存状态进行了研究。结果表明:矿区锡主要含在石榴子石夕卡岩型磁铁矿石和夕卡岩型钼矿石中;钙铁榴石和磁铁矿是锡的主要载体矿物,二者晶胞参数随锡含量增大而增大,锡在二者晶体结构中可能以Sn4+置换八面体中的Fe3+;锡的化学物相以石榴子石和磁铁矿结合锡为主,夕卡岩型钼矿石中以"胶态锡"为主,锡石含量较少,粒度较小,解离困难,不具选矿回收价值。     

紫金山金铜矿二元铜硫化物成分特点的初步研究

文章在电子显微成分分析的基础上,结合XRD、振动光谱等研究手段,对高硫型浅成热液形成的紫金山金铜矿床中铜硫化物的成分、物相特点进行了研究.首次在该区找到了久辉铜矿(Cu1.97S)、雅硫铜矿(Cu1.25S)等铜硫二元组分系列矿物,并发现了铜蓝被蓝辉铜矿明显交代的现象,进而推断它们基本上是同期形成的,但其所处的氧化-还...