地浸采铀及地浸矿床的条件与评价

主要介绍了地浸采铀的含义及其发展历史,并对地浸矿床的条件进行详细分析,提出地浸矿床评价的三项原则。     

Characterization of Bulgarian oil shale kerogen revealed by oxidative degradation

A 13-step alkaline permanganate degradation of Bulgarian oil shale kerogen concentrate at ambient temperature was carried out. A high yield of oxidation products (90.1%) and a low yield of gaseous products (2.79%) were obtained. IR and ¹H NMR spectroscopic studies have shown that two significantly different types of high molecular products are present in kerogen. Further oxidation of these structures leads to the formation of low molecular aliphatic and aromatic acids, proven by gas chromotography (GC) and gas chromatography-mass spectrometry (GC-MS). The data obtained at these mild conditions allow us to acquire detailed information about the aromatic structures and polymethylene chain lengths in kerogen.The 5-step oxidation of the kerogen at 90 °C provides information about stable aromatic structures. Soluble and insoluble polyfunctional acids in acid medium have close molecular masses and spectral characteristics. The amount of benzene and naphthalene carboxylic acids is 11.3% of the organic matter of the oil shale.     

地浸砂岩型铀矿卵砾石层钻进用钻头的试验研究

介绍了金刚石-硬质合金复合球齿钻头在内蒙古某地区铀矿床卵砾石层中的生产试验情况.在钻进卵砾石层时,保径未做加强的金刚石-硬质合金复合球齿钻头的平均钻进效率为2.50 m/h,钻头的平均寿命为7.34 m/个;保径加强型金刚石-硬质合金复合球齿钻头的平均钻进效率为2.82 m/h,钻头的平均寿命为10.18 m/个;而普通合金钻头的平均钻进效率为1.29 m/h,钻头的平均寿命为1.19 m/个.试验表明金刚石-硬质合金复合球齿钻头是一种理想的钻进卵砾石层的钻头.     

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.     

地浸采铀工艺钻孔施工与成建井技术现状及改进建议

地浸法采铀是铀矿开采的重要方法,地浸工艺钻孔作为溶浸液进入与抽出矿层的通道,在地浸采铀工艺过程中发挥着重要作用。文章介绍了国内地浸采铀工艺钻孔施工与成建井技术现状,针对存在问题,对钻探设备、钻进工艺和成井工艺提出了改进建议。     

铜盐絮凝沉淀法处理含砷浸金溶液试验研究

絮凝共沉法是目前处理含砷废水用得最多的方法。本文对利用铜盐絮凝共沉淀法处理含砷浸金溶液进行试验研究,取得了满意的效果。研究表明,在试验确定的工艺条件下可除去浸金溶液中99.9%以上的砷,同时99.5%以上的金仍保留在溶液中。有利于后续活性吸附和解析工艺,同时避免了砷的环境污染。     

湖南典型地区大气降水与下渗水元素地球化学特征及其影响因素研究

对比了湖南典型地区大气降水与下渗水中阴离子含量、Cd等重金属元素含量特征,并研究了Cd等重金属元素下渗的影响因素。研究表明,郴州市和株洲市大气降水中SO42-含量均比桂东—汝城地区和岳阳市高,郴州市和株洲市大气受到较为严重的污染。郴州市和株洲市大气降水及土壤中Cd等重金属元素含量均明显高于桂东—汝城地区和岳阳市,但下渗水中Cd等重金属元素含量差异不大。用元素浓度下渗比(下渗水中重金属元素含量/大气降水中重金属元素含量)来表征水循环过程中土壤重金属元素的累积性,结果显示郴州市和株洲市降水对土壤Cd等重金属元素累积的贡献大于桂东—汝城地区和岳阳市。综合对比表明郴州市和株洲市表层土壤Cd等重金属元素累积明显。影响Cd等重金属元素下渗的因素非常复杂,其中土壤有机碳和pH是控制As、Cd和Pb下渗的主要因素。     

墨江大平掌岩体岩石地球化学与成因

大平掌岩体为碱性高钠质基性辉绿岩,印支期浅成侵入,大陆环境玄武岩低度部分熔融的产物。     

A preliminary study of PGE in the Late Caledonian Loch Borralan and Loch Ailsh alkaline pyroxenite-syenite complexes,north-west Scotland

The Siluro-Ordovician Loch Borralan (c. 430 Ma) and Loch Ailsh Complexes (c. 439 Ma) comprise a suite of intrusive rocks ranging in composition from clinopyroxenites, through potassic melasyenites to quartz syenites. The rock suite at Loch Borralan also includes nepheline syenite. Geochemical data in the literature indicate that the intrusions are alkaline, with pronounced enrichments in LILE and LREE relative to contemporaneous calc-alkaline magmatic centres further to the south-east, although they share similar high LILE/Nb, subduction-related characteristics. The Loch Borralan Complex is associated with marginal gravity and magnetic anomalies which can be interpreted in terms of a shallow body less than 400 m thick. Analysis of rocks and drill core revealed widespread elevated Pt and Pd values in pyroxenites and syenites in both complexes. The highest concentrations, up to about 900 ppb Pt+Pd, occur in pyroxenites in the Loch Borralan Complex. Extensive archived drill core provides an excellent section through the marginal pyroxenites, which host the PGE at Loch Borralan. The pyroxenites show unusual petrological features; early clinopyroxene is followed by biotite, apatite, magnetite, sphene and plagioclase with later garnet, which might be metasomatic in origin. Sulphides occur in minor amounts. High-temperature shearing produced local granulation and mylonitisation. Later brittle deformation caused extensive micro-fracturing and the introduction of minor carbonate veining. Platinum-group minerals (PGM) were located in a number of samples with high PGE assay values. These occur as clusters of grains around 1–2 m in diameter, and are difficult to identify uniquely. A few grains appear to be magmatic; these are Pt and PtPd sulphides that occur enclosed in clinopyroxene or garnet. All other grains occur in late fractures or along grain boundaries. These include sperrylite (PtAs₂), Pd antimonides and PdBi tellurides, along with hessite (Ag₂Te). They occur in microfractures accompanied by carbonate and barite and fine-grained sulphides and are probably of secondary origin. The PGE in the pyroxenites may have been introduced during the magmatic phase of the intrusion but the observed distribution of PGM results from low-temperature, hydrothermal remobilisation following brittle deformation and introduction of fluids.

The mineral isotope composition of two Precambrian carbonatite complexes from the Kola Alkaline Province – Alteration versus primary magmatic signatures

We investigated the isotope composition (O, C, Sr, Nd, Pb) in mineral separates of the two Precambrian carbonatite complexes Tiksheozero (1.98 Ga) and Siilinjärvi (2.61 Ga) from the Karelian–Kola region in order to obtain information on Precambrian mantle heterogeneity. All isotope systems yield a large range of variations. The combination of cathodoluminescence imaging with stable and radiogenic isotopes on the same samples and mineral separates indicates various processes that caused shifts in isotope systems. Primary isotope signatures are preserved in most calcites (O, C, Sr, Pb), apatites (O, Sr, Nd), amphiboles (O), magnetites (O), and whole rocks (Sr, Nd).

The primary igneous C and O isotope composition is different for both complexes (Tiksheozero: δ¹³C = − 5.0‰, δ¹⁸O = 6.9‰; Siilinjärvi: δ¹³C = − 3.7‰, δ¹⁸O = 7.4‰) but very uniform and requires homogenization of both carbon and oxygen in the carbonatite melt. The lowest Sr isotope ratios of our carbonates and apatites from the Archaean Siilinjärvi (0.70137) and the Palaeoproterozoic Tiksheozero (0.70228) complexes are in the range of bulk silicate earth (BSE). Positive ε_Nd values of the two carbonatites point to very early Archaean enrichment of Sm/Nd in the Fennoscandian mantle. No HIMU components could be detected in the two complexes, whereas Tiksheozero carbonatites give the first indication of Palaeoproterozoic U depletion for Fennoscandia.

Sub-solidus exchange processes with water during emplacement and cooling of carbonatites caused an increase in the oxygen isotope composition of some carbonates and probably also an increase of their ⁸⁷Sr/⁸⁶Sr ratio. A larger increase of initial Sr isotope ratios was found in carbonatized silicic rocks compared to carbonatite bodies. The Svecofennian metamorphic overprint (1.9–1.7 Ga) caused reset of Rb/Sr (mainly mica) and Pb/Pb (mainly apatite) isochron systems.