نتایج جستجو برای: pyrite

تعداد نتایج: 3387  

2018
Yang Li David Selby Xian-Hua Li Chris J. Ottley

Stratabound deposits within late Carboniferous carbonate units in the Middle–Lower Yangtze River metallogenic belt are important copper producers in China. Hitherto, the genesis of these deposits has been debated, due to poor constraints regarding the timing and source of the mineralization. Proposed models include a late Carboniferous seafloor exhalative formation (SEDEX), or an Early Cretaceo...

2016
Christiaan G. C. van Baak Iuliana Vasiliev Dan V. Palcu Mark J. Dekkers Wout Krijgsman

Throughout the Late Neogene, the Black Sea experienced large paleoenvironmental changes, switching between (anoxic) marine conditions when connected to the Mediterranean Sea and (oxic) freshwater conditions at times of isolation. We create a magnetostratigraphic time frame for three sites drilled during Deep Sea Drilling Project (DSDP) Leg 42B to the Black Sea (drilled in 1975). At the time, ma...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
T W Lyons B C Gill

U nless you hang drywall or travel in certain biogeochemical circles, the calcium sulfate mineral gypsum is probably not on your radar—nor is the amount of sulfate (SO4 2 ) dissolved in seawater, which determines how much gypsum is left behind when that seawater evaporates. All the same, sulfate is the second most abundant negatively charged ion dissolved in seawater today, and tracking its cha...

2017
Yongliang Wang Li Xiao Ya Liu Guoyan Fu Shufeng Ye Yunfa Chen

Results & Discussion: The content of arsenic in pyrite cinders was reduced to 0.08% through the investigation of the factors, including particle size, alkaline concentration, temperature, solid-liquid ratio (S/L) and leaching time. Then, the ferric precipitation method was used to remove the arsenic in the leaching solution. More than 99% of the arsenic can be removed by controlling the pH and ...

2015
Liting Song Emanuel Goldman

Gold is rare and precious, while pyrite (FeS2) is abundant and cheap. Pyrite is nicknamed fool9 s gold, since pyrite looks like gold and it is even shinier and brighter than gold. It is very difficult to recognize the differences between a real natural gold and a gold-like rock (pyrite) to non-professional persons [1] , but we know that all that glitters is not gold. Similar mistakes can happen...

1986
C. Lin Y. Ma

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract Hydrogen peroxide (H 2 O 2) at a micromola...

2006
Ian Wark

Sulfide minerals contain sulphur in a large variety of coordination environments. Consequently, the S 2p XPS of various mineral surface states undergo different shifts in binding energy (BE) relative to the bulk, depending on the charge distribution on the surface. This in turn depends on the number, type and position of the atoms on the fracture surface, which is determined by the fracture mec...

In this research work, the dissolution of chalcopyrite was investigated under atmospheric pressure, with sulfate media at low temperatures, in 30°C to 50°C. In the galvanic interaction between chalcopyrite and pyrite, pyrite is used as a leaching catalyst. Effects of different parameters such as temperature, stirring speed, pyrite to chalcopyrite ratio, particle size, and solution potential wer...

Journal: :Anais da Academia Brasileira de Ciencias 2005
André S Mexias Gilles Berger Márcia E B Gomes Milton L L Formoso Norberto Dani José C Frantz Everton M Bongiolo

A geochemical modeling of gold deposition was performed using the EQ3/EQ6 software package using conditions inferred from geological, petrographic, geochemical and fluid inclusion data from the Bloco do Butiá gold mine, Lavras do Sul, RS. Gold in the mine occurs only in the pyrite structure (invisible gold). The pyrite occurs associated with white mica (phengite) in the zone of phyllic alterati...

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