نتایج جستجو برای: fe oxide gold deposit

تعداد نتایج: 345934  

Journal: :American Journal of Science 1891

Journal: :Applied and environmental microbiology 2000
K P Nevin D R Lovley

Studies with the dissimilatory Fe(III)-reducing microorganism Geobacter metallireducens demonstrated that the common technique of separating Fe(III)-reducing microorganisms and Fe(III) oxides with semipermeable membranes in order to determine whether the Fe(III) reducers release electron-shuttling compounds and/or Fe(III) chelators is invalid. This raised doubts about the mechanisms for Fe(III)...

The origin of the Proterozoic Choghart iron oxide deposit in the Bafq mining district of Central Iran has been the subject of a long-standing dispute. Some authors believe that it was formed from magma, while others suggest metasomatic replacement of preexisting rocks. The present study on the basis of new oxygen isotope, REE and geochemical data concludes that neither of these two hypotheses c...

2016
Timothy Stephen Pasakarnis Timothy S. Pasakarnis Michelle M. Scherer David M. Cwiertny Timothy E. Mattes Michael L. McCormick Edward Abbey

The reaction between aqueous Fe(II) and Fe(III) oxides is extremely complex, and can catalyze Fe(II)-Fe(III) electron transfer, exchange of Fe atoms between the aqueous and solid phases, mineral transformation, and contaminant reduction. Together, these processes represent a phenomenon referred to as Fe(II)-catalyzed Fe oxide recrystallization, which has been observed under controlled condition...

Journal: :nanochemistry research 0
bagher eftekhari-sis department of chemistry, university of maragheh, maragheh, iran somayeh mirdoraghi department of chemistry, university of maragheh, maragheh, iran

a graphene oxide-terpyridine conjugate (gotc) based colorimetric and fluorescent nano-chemosensor was synthesized. it showed high selectivity and sensitivity for fe2+ and fe3+ ions in neutral aqueous solution over other metal ions such as li+, na+, ba2+, ca2+, al3+, cd2+, co2+, cu2+, hg2+, mn2+, ni2+, pb2+, zn2+, cr3+ and ag+. in absorption spectra, upon addition of fe2+ or fe3+, the sensor dis...

2000
Maria Adelaide RV Veado Arno H de Oliveira Julio Cesar C Veado Gilles Revel Guy Pinte

Instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) were used to analyse water and sediment samples of the Paraopeba and the Das Velhas Rivers in the state of Minas Gerais, Brazil to assess the impact of mining activities on the water environment. Elemental concentrations of Cr, Fe, Co, Ni, Cu, As, Cs, Ba, La and Ce were measured in water an...

Journal: :international journal of nano dimension 0
soheila tahmasebi department of chemistry, shahr-e-qods branch, islamic azad university, tehran, iran. omid moradi department of chemistry, shahr-e-qods branch, islamic azad university, tehran, iran. mohammad yari department of chemistry, eslamshahr branch, islamic azad university, eslamshahr, iran.

in this research, graphene oxide- gold nanoparticles (aunp/go) were easily fabricated by a redox reaction between go and chloroauric acid without using any additional reductant and then used to stabilize pickering emulsions. (aunp/go) was investigated by ft-ir spectroscopy. the changes of parameters such as contact time, ph, amoxicillin initial concentration and temperature were tested and inve...

1999
V. Blum J. E. Ortega

The combination of low-energy electron diffraction intensity analyses and scanning tunneling microscopy was used to investigate the morphology and atomic structure of thin Fe films grown on Au~100! at 400 K. Deposition of only about 0.2 monolayers ~ML! Fe is sufficient to lift the reconstruction of the clean substrate. In the initial growth process (<1 ML! place exchanges between Fe and Au lead...

Journal: :Journal of geology, geography and geoecology 2021

&#x0D; The article describes Reza gold deposit of Ugur exploration area located in Geda- bek Ore District the Lesser Caucasus NW Azerbaijan. It is established that main mineralization consists hematite-barite-quartz-kaoline veins- veinlets and breccia, pyrite stock-stockverk quartz-sulfide veins. On orebody surface center secondary quartzites with vein-veinlets barite-hematite have occured over...

The Gandy gold-base metal deposit is located in Tertiary Torud-Chahshirin volcano-plutonic range, north of Central Iran. Various styles of gold mineralization occur throughout the range. Mineralization at Gandy occurs in close spatial relation with rhyolitic domes in a caldera setting in a series of narrow brecciated veins. Two mineralogically and spatially different argillic alterations have a...

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