Removal of lead minerals from copper industrial flotation concentrates by xanthate flotation in the presence of dextrin     

Jan Drzymala  Janusz Kapusniak  Piotr Tomasik 《International Journal of Mineral Processing》2003,70(1-4):147-155

Potato starch and dextrins resulting from thermolysis of potato starch in the absence of reagents and presence of -amino acids are promising depressants for separation of lead and copper minerals present in the Polish industrial copper concentrates. The polysaccharides were used for differential xanthate flotation of the final industrial concentrates produced by flotation with sulfhydryl collectors in the absence of depressants. The polysaccharides depressed galena and provided froth concentrate rich in chalcocite and other copper minerals as well as cell product containing lead minerals. The best results of separation were obtained in the presence of plain dextrin prepared by a thermal degradation of potato starch. The industrial concentrate containing 18.5% Cu and 5.5% Pb was divided into a froth product containing 38.1% Cu with 77% recovery of copper and a cell product assaying 7.3% Pb with 83% recovery of lead. It was accomplished using 2500 g/t of dextrin, 50g/t of potassium ethyl xanthate, and 50 g/t of frother (α-terpineol). The pH of flotation was 8.0–8.2.  相似文献   

Fine-grained barite in coal fly ash from the Upper Silesian Industrial Region   总被引：1，自引：0，他引：1  

Mariola Jablonska  Frans J. Rietmeijer  Janusz Janeczek 《Environmental Geology》2001,40(8):941-948

Barite nanocrystals are common and abundant in the troposphere over the Upper Silesian Industrial Region, Poland. The presence of barite nanocrystals is the result of burning Ba-enriched coals (up to 4,260 ppm Ba). ATEM, ASEM and EPMA analyses provided evidence of inefficient coal burning for domestic purposes at temperatures of 800-900 °C as the cause of emissions of barite, which survived unmelted. Much higher temperatures of coal burning for industrial purposes resulted in thermal decomposition of barite into BaO, which could react with airborne sulfuric acid to produce nanometre-sized secondary barite. Formation of both the secondary barite and gypsum in the troposphere contributes to the lowering of acidity of rain over Upper Silesia. Barite nanocrystals are often embedded in sheets of hydrocarbon materials with sizes in the range of respirable aerosols; therefore, they may enter the human respiratory system.  相似文献   

Geochemical characteristics of Archaean and Late Proterozoic to Palaeozoic fine-grained sediments from Southern Africa and significance for the evolution of the continental crust     

Dr. N. Laskowski  Prof. Dr. A. Kröner 《International Journal of Earth Sciences》1985,74(1):1-9

Chemical data for pelitic rocks (shallow-marine platform sediments) of the 2.9 Ga old Pongola Supergroup, South Africa, and the 550–700 Ma old Nama Group, Namibia, revealed clearly different compositions in both groups. A comparison of the Pongola and Nama data with literature values for sedimentary rocks shows a trend for Cr/TiO₂ and Cr/Zn ratios as well as the absolute Cr and Ni concentrations to lower values with decreasing age, whereas the Cr/Ni ratios seem to remain broadly constant through time. REE patterns of Pongola and Nama sediments show no significant difference, thus giving the impression of a post-Archaean origin for the demonstrably Archaean Pongola sediments. However, a plot of the trace element data for these sediments, normalized to the average shale of TuRekian &Wedepohl (1961) shows the Pongola shales to have a clear Archaean pattern whereas the Nama pelites display a typical post-Archaean signature. The results of this investigation confirm a model of rapid evolution of the Earth's upper continental crust from a predominantly mafic composition in the early Archaean to a more felsic character with increasing differentiation. The geochemistry of post-Archaean sediments may reflect the onset of cannibalistic recycling of older crust as proposed byVeizer (1973) and the end of major crustal growth.

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Zusammenfassung In der vorliegenden Arbeit werden zwei Plattformsedimente (marine Flachwasserablagerungen) verschiedenen Alters (Pongola 2.9 Mrd. Jahre, Südafrika, Nama 550–700 Mio. Jahre, Südwest Afrika/Namibia) chemisch analysiert und miteinander verglichen. Analysen der Tonmineralfraktion sollten zusätzliche Informationen bereitstellen.Die Pelite der Pongola und Nama Gruppen lassen sich statistisch und nach geochemischen Parametern in Cluster unterteilen. Diese Cluster unterscheiden sich nur gering auf Grund ihrer Hauptelementanalysen, die Spurenelemente hingegen weisen einen altersabhängigen Trend auf. Ganz deutlich kommt dies bei den Cr-Werten zum Ausdruck. Von 545 ppm in dem ersten Cluster der ältesten Gesteine fällt er auf etwa 55 ppm in dem zweiten Nama Cluster der jüngsten Gesteine ab. Um die Entwicklungstendenzen darstellen zu können, wurden X/Y-Diagramme erstellt. Es stellte sich heraus, daß für Proben aus dem südlichen Afrika der Chromgehalt mit jünger werdendem Alter abnimmt. Zn und Ni zeigen deutlich, wie sehr diese Elementkonzentrationen in Sedimenten durch einen langen Transportweg und eine intensive Aufarbeitung beeinflußt werden können. Ein Vergleich der Pongola und Nama Daten läßt den Schluß zu, daß die Seltenen Erden nicht unbedingt zur Unterscheidung archaischer von post-archaischen Sedimente geeignet sind.Die Abnahme der Cr/TiO₂- und der Cr/Zn-Verhältnisse sowei der absoluten Cr- und Ni-Konzentrationen mit abnehmendem geologischen Alter der Sedimente deuten auf eine rasche Entwicklung (von ca. 3.3 Mrd. J. bis ca. 2.3 Mrd. J.) von einer zunächst vorwiegend mafischen oberen Erdkruste zu einer zunehmend felsischen (d. h. stärker differenzierten) Kruste hin. Die relativ geringen Veränderungen in späterer Zeit (d. h. < 2.3 Mrd. J.) lassen auf den Beginn einer Aufarbeitung schon vorhandener Sedimente (recycling) und eine nur untergeordnete Bildung neuer kontinentaler Erdkruste schließen.

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Résumé L'objet de ce travail est de comparer les compositions chimiques de la fraction pélitique (< 2) dans des sédiments de plate-forme, déposés en mer peu profonde, et appartenant respectivement au supergroupe de Pongola (± 2.9 G.a., Afrique du S) et au groupe de Nama (550–700 M.a., Namibie).Cette comparaison, menée par la méthode statistique des «clusters analysis», ne révèle pas de différence entre les deux groupes, en ce qui concerne les éléments majeurs. Pour les éléments en traces, par contre, on constate avec l'âge décroissant des roches une diminution des rapports Cr/TiO₂, Cr/Zn ainsi que des teneurs en Cr et en Ni, tandis que le rapport Cr/Ni reste sensiblement constant.Les distributions des terres rares des deux groupes ne présentent pas de différence significative, donnant l'impression d'un âge post-archéen pour les sédiments du groupe de Pongola (2.9 G.a.). Toutefois, le report de données des éléments en traces, normalisées par rapport au shale moyen deTurekian etWedepohl (1961) montre nettement des distributions archéennes pour le groupe de Pongola et post-archéennes pour le groupe de Nama.Ces investigations confirment le modèle d'une évolution rapide de la croûte continentale supérieure depuis une composition mafique à l'Archéen ancien (3.3 G.a.) vers un caractère plus felsique, c'est-à-dire plus différencié vers 2.3 G.a., le peu de changement au cours des périodes ultérieures (< 2.3 G.a.) indiquant un recyclage continuel des mêmes matériaux sans intervention notable d'un accroissement de la croûte continentale.

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40Ar39Ar dating of glauconites: Measured 39Ar recoil loss from well-crystallized specimens     

K.A. Foland  Jeffrey S. Linder  Thomas E. Laskowski  Norman K. Grant 《Chemical Geology》1984,46(3):241-264

Nine glauconite samples with relatively high K concentrations and which appear to be well crystallized using normal X-ray diffraction techniques have been studied using the ${}^{40}\text{Ar}{}^{39}\text{Ar}$ method. The glauconite ${}^{40}\text{Ar}{}^{39}\text{Ar}$ apparent ages exceed their KAr, RbSr and, in most cases, stratigraphic ages by substantial amounts. ${}^{40}\text{Ar}{}^{39}\text{Ar}$ release spectra sometimes yield plateaus but these apparent ages have no geological significance. The results indicate that ³⁹Ar is lost by recoil from mineral grains during neutron irradiation, consistent with previously reported observations. The amount of ³⁹Ar loss was measured by isotope dilution for four samples and varied from 29% to 17%. In contrast, radiogenic ⁴⁰Ar is quantitatively retained during irradiation. The very fine blades which make up glauconite grains yield the mineral susceptible to large amounts of ³⁹Ar loss and unsuitable for ${}^{40}\text{Ar}{}^{39}\text{Ar}$ dating.  相似文献   

Investigating landslides with space-borne Synthetic Aperture Radar (SAR) interferometry   总被引：7，自引：0，他引：7  

Carlo Colesanti  Janusz Wasowski   《Engineering Geology》2006,88(3-4):173-199

This paper is addressed to readers without advanced knowledge of remote sensing. It illustrates some current and potential uses of satellite Synthetic Aperture Radar interferometry (InSAR) for landslide assessment. Data acquired by SAR systems can provide 3D terrain models and be used to assist in regional scale investigations, e.g. aimed at evaluation of susceptibility of slopes to failure. Under favourable environmental conditions, the innovative Permanent Scatterers (PS) technique, which overcomes several limitations of conventional SAR differential interferometry (DInSAR) applications in landslide studies, is suitable for monitoring slope deformations with millimetric precision. The PS technique combines the wide-area coverage typical of satellite imagery with the capability of providing displacement data relative to individual image pixels. With the currently available radar satellites, however, only very slow ground surface displacements can be reliably detected and measured. The presented case study of a landslide from the Liechtenstein Alps indicates that the most attractive and reliable contribution provided by this remote sensing technique lies in the possibility of (i.) wide-area qualitative distinction between stable and unstable areas and (ii.) qualitative (relative) hazard zonation of large, slow landslides based on the identification of segments characterised by different movement rates. Since only the radar line of sight projection of the displacements can be detected, a quantitative exploitation of the PS data is possible only where sufficient ground truth is available. In site specific or single landslide investigations the PS data can represent a very useful complementary data source with respect to the information acquired through ground based observations and in situ surveying. However, the difficulties associated with the feasibility assessments of the applicability of SAR data to local scale problems, as well as with the interpretation of PS results, require a close collaboration between landslide experts and specialists in advanced processing of radar satellite data. The interpretation of the exact geotechnical significance of small, radar sensed ground surface deformations is challenging, especially where ground truth is lacking. Although any ground deformation is potentially of interest to an engineering geologist, detection of movements in both vertical and horizontal directions is needed in the case of landslides to evaluate slope failure mechanisms. With their high radar viewing angles, however, the current space-borne systems can detect only a fraction of the horizontal component of movement. It is expected that the upcoming SAR dedicated missions with new sensors and different acquisition geometries, combined with the rapid developments in the field of advanced radar data processing, will allow a full 3D reconstruction of deformation data and help to further reduce the current limitations of the PS and similar DInSAR approaches.  相似文献   

Field report:Research along the Yarlung Suture Zone in Southern Tibet,a persistent geological frontier     

Andrew K.Laskowski  Lin Ding  Fu-Long Cai  Yao-Fei Chen  Song-Lin He 《地学前缘(英文版)》2018,9(2):591-594

The Yarlung Suture Zone in Southern Tibet marks the boundary between India and Asia-formerly separated by an ocean basin-and is a critical record of the tectonic processes that created the Tibetan Plateau. The Yarlung Suture Zone is also a frontier research area, as difficulty of access has limited research activity, providing ample opportunities for new discoveries. This paper documents field research conducted by the authors along the Yarlung suture zone in eastern Xigaze(Shigatse, Rikaze)County, ~250 km west of the city of Lhasa, in July 2017. The goal of this research was to map the Suture Zone structure in detail, and more specifically to understand the branching relationships between two major fault systems-the Great Counter Thrust and Gangdese Thrust. A summary of early geological exploration is included to provide context for this research.  相似文献   

Variable stars in the globular cluster NGC 6362     

Beata Mazur  Janusz Kaluzny  Wojciech Krzemi&#;ski 《Monthly notices of the Royal Astronomical Society》1999,306(3):727-735

We report the results of a CCD search for short-period variables in the field of a southern globular cluster NGC 6362. We identified 19 new candidate variables, five of which are cluster RR Lyraes, four are probable SX Phe-type stars and eight are eclipsing binaries. Of the discovered binaries, three are EA-type systems, two of which are located on the cluster CMD in the turn-off region and the third 1 mag above the turn-off point, in the yellow straggler region. Five other systems are of W UMa type, three of which are foreground objects and two are likely cluster members. The remaining two candidates exhibit a modulation of the brightness level with an amplitude of 0.1–0.2 mag; further observations are needed to reveal the nature of their variability. Phased VI light curves for 20 variables (18 RR Lyrae stars and two blue stragglers) located in the central region of the cluster are presented.  相似文献   

Evolution of the Upper Rhone River discharge and suspended sediment load during the last 80 years and some implications for Lake Geneva   总被引：1，自引：0，他引：1  

Jean-Luc Loizeau  Janusz Dominik 《Aquatic Sciences - Research Across Boundaries》2000,62(1):54-67

: During this century, the characteristics of the Upper Rhone River discharge, flowing into Lake Geneva, have been altered in response to the changes which have occurred in its watershed. Principally, numerous hydroelectric dams have been constructed on the course of the Rhone River tributaries. At present the major reservoirs can hold about 122010⁶m³ of water, which represents 1/5 of the total annual Rhone River flow. Flow regime characteristics of the river have been modified by the dam operations. Water is released from reservoirs during winter and stored in summer. Large floods have also been reduced in amplitude and frequency. From the available literature data, sediment rating curves have been calculated and used to estimate the evolution of the sediment load from the Rhone River to Lake Geneva. They show that sediment input has decreased by at least a factor 2. This reduction has impacted the occurrence of underflows along the lake bottom, due to the reduction of sediment-laden floods, which in turn may have considerable negative effects on the reoxygenation of Lake Geneva deep waters.  相似文献   

The use of a novel Vibrio harveyi luminescence mutagenicity assay in testing marine water for the presence of mutagenic pollution     

Podgórska B  Pazdro K  Pempkowiak J  Wegrzyn G 《Marine pollution bulletin》2007,54(6):808-814

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Coupled weather research and forecasting–stochastic time-inverted lagrangian transport (WRF–STILT) model     

Thomas Nehrkorn  Janusz Eluszkiewicz  Steven C. Wofsy  John C. Lin  Christoph Gerbig  Marcos Longo  Saulo Freitas 《Meteorology and Atmospheric Physics》2010,107(1-2):51-64

This paper describes the coupling between a mesoscale numerical weather prediction model, the Weather Research and Forecasting (WRF) model, and a Lagrangian Particle Dispersion Model, the Stochastic Time-Inverted Lagrangian Transport (STILT) model. The primary motivation for developing this coupled model has been to reduce transport errors in continental-scale top–down estimates of terrestrial greenhouse gas fluxes. Examples of the model’s application are shown here for backward trajectory computations originating at CO₂ measurement sites in North America. Owing to its unique features, including meteorological realism and large support base, good mass conservation properties, and a realistic treatment of convection within STILT, the WRF–STILT model offers an attractive tool for a wide range of applications, including inverse flux estimates, flight planning, satellite validation, emergency response and source attribution, air quality, and planetary exploration.  相似文献