نتایج جستجو برای: pyrite polymetallic
تعداد نتایج: 4006 فیلتر نتایج به سال:
Abstract The Huayangchuan ore belt is located in the western segment of Xiaoqinling Orogen southern margin North China Craton (NCC), and hosts voluminous magmatism significant U?REE?Mo?Cu?Fe polymetallic mineralization. However, geochronological framework various mineralization phases this region poorly understood. Here, we present new Re?Os isochron ages on magnetite from Caotan Fe deposit (2 ...
In the case of pyrite bioleaching by Leptospirillum ferrooxidans, an organism without sulfur-oxidizing capacity, besides the production of tetra- and pentathionate, a considerable accumulation of elemental sulfur occurred. A similar result was obtained for chemical oxidation assays with acidic, sterile iron(III) ion-containing solutions. In the case of Thiobacillus ferrooxidans, only slight amo...
Elevated arsenic concentrations have been observed in shallow groundwater in the Cold Lake-Beaver River Basin (CLBR) of Alberta. The geology of this area includes up to 200 m of unconsolidated glacial deposits, with six regional interglacial sand and gravel aquifers, underlain by marine shale. Arsenic concentrations in unconsolidated sediment samples ranged between 1 to 17 ppm. Mineralogical ch...
The origin in rocks of the common iron sulphides, pyrrhotine, Fe 1 xS and pyrite, FeS2 and their behaviour during geochemical processes is best considered using the simplified redox reaction: 2FeS ~-~ FeS2 + Fe 2 + + 2e . Thus pyrrhotine is more reduced than pyrite and is the stable iron sulphide formed from magmas except where relatively high oxygen fugacities result from falling pressure or h...
A novel, anaerobically grown microbial biofilm, scraped from the inner surface of a borehole, 1474 m below land surface within a South African, Witwatersrand gold mine, contains framboidal pyrite. Water flowing from the borehole had a temperature of 30.9 degrees C, a pH of 7.4, and an Eh of -50 mV. Examination of the biofilm using X-ray diffraction, field emission gun scanning electron microsco...
Acid mine drainage (AMD) from abandoned coal mines continues to be one of the most significant environmental problems. Remediation of AMD requires an addition of lime source to decrease the acidity, and grouting the entire mine and encapsulating the pyrite by calcium-rich additives is often employed. Utilization of alkaline coal combustion by-products (CCBs) has gained acceptance in such remedi...
Citation Sun, Ruoshi et al. " Intrinsic stoichiometry and oxygen-induced p-type conductivity of pyrite FeS_{2}. " Physical Review B 84 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. ...
Black shales in the geologic record have long been considered to reflect deposition under anoxic or even euxinic conditions. Although bottom-water anoxia favors deposition of black shales, certain biological indicators, such as benthic fossils and bioturbation, suggest that bottom-water conditions may not have been as persistently anoxic as commonly presumed. Examination of twelve marine carbon...
Commercial-scale mining for polymetallic nodules could have a major impact on the deep-sea environment, but the effects of these mining activities on deep-sea ecosystems are very poorly known. The first commercial test mining for polymetallic nodules was carried out in 1970. Since then a number of small-scale commercial test mining or scientific disturbance studies have been carried out. Here w...
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