نتایج جستجو برای: pyrite

تعداد نتایج: 3387  

2006
K. Nowaczyk F. Domka

This paper reports results of studies on the influence of the crystallographic mineral structure on the process of pyrite and marcasite leaching. Kinetic studies show that the crystallographic structure of minerals like FeS2 type does not influence the efficiency of the process.

2002
HEINRICH D. HOLLAND

This paper proposes that gradual changes in the composition of volatiles that have been added to the atmosphere-ocean system are responsible for the Great Oxidation Event (G.O.E.) ca. 2.3 Ga. Before ca. 2.3 Ga, the composition of these volatiles was probably such that 20% of the carbon gases could be reduced to organic matter and all of the sulfur gases could be reduced to pyrite. Since 2.3 Ga,...

2013
F. W. Herbert A. Krishnamoorthy B. Yildiz

a r t i c l e i n f o The interfacial electronic properties and charge transfer characteristics of pyrite, FeS 2 , are greatly influenced by the presence of electronic states at the crystal free surface. We investigate the surface electronic structure of FeS 2 (100) using scanning tunneling spectroscopy (STS) and interpret the results using tunneling current simulations informed by density func...

ملک‌زاده شفارودی, آزاده, مظاهری, سید احمد , کریم‌پور, محمدحسن ,

MA-II area is one of the most important parts of Cu-Au porphyry mineralization at Maherabad prospect area. Subvolcanic intermediate intrusive rocks (Upper Eocene), monzonite to diorite in compositions, intruded telescopically and are mostly altered. Monzonitic porphyries had major role in mineralization. These intrusive rocks are highly altered, have dense stockwork veinlets, and show highest g...

Massive Zn-Cu-Fe sulfide deposits at the Garon Lake Mine occur in three sulfide lenses in a group of metamorphosed rhyolite crystal tuffs, metasediments and basalts. The major ore minerals are sphalerite, chalcopyrite, pyrrhotite and pyrite. Minor associated silicates are actinolite, tremolite, chlorite, albite and quartz. Rounded detrital pyrite, magnetite and chert grains and diagenetic p...

Journal: :international journal of mining and geo-engineering 0
soghra salehi student mohammad noaparast phd seyed ziaodin shafaie phd

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: :Geochemical Transactions 2004
Gregory K Druschel Brett J Baker Thomas M Gihring Jillian F Banfield

The Richmond Mine at Iron Mountain, Shasta County, California, USA provides an excellent opportunity to study the chemical and biological controls on acid mine drainage ~AMD! generation in situ, and to identify key factors controlling solution chemistry. Here we integrate four years of field-based geochemical data with 16S rRNA gene clone libraries and rRNA probe-based studies of microbial popu...

2004

The sulfur-bearing minerals which predominate in coal seams are the iron sulfide ores pyrite, marcasite, amorphous 'sulfur-balls', and less commonly the monosulfide pyrrhotite. Excluding pyrrhotite, all have the same ratio of sulfur to iron but have different crystalline properties. The amorphous structure is reported to be the most reactive due to its large surface area, followed by pyrrhotite...

Journal: :journal of particle science and technology 0
yasser vasseghian chemical engineering department, faculty of engineering, razi university, kermanshah, iran mojtaba ahmadi chemical engineering department, faculty of engineering, razi university, kermanshah, iran mohammad joshaghani faculty of chemistry, razi university, kermanshah 67149, iran

this study investigates removing ash and pyrite sulphur from bitumen by column flotation process. central composite design (ccd) of response surface methodology (rsm) was applied for modeling and optimization of the percentage of ash and pyrite sulphur removal from bitumen. the effects of five parameters namely the amounts of collector and frother agents, particle size, wash water rate and feed...

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