نتایج جستجو برای: pyrite

تعداد نتایج: 3387  

2006
Rafael Pérez-López Jordi Cama José Miguel Nieto Carlos Ayora Lluís Solé

A study of sulfur-rich sludge (71.6% pyrite) dissolution at alkaline conditions (pH ca.9) was investigated using non-stirred and stirred flow-through experiments at room temperature (26 ± 1.2oC) and O2 partial pressure of 0.20 atm. The dissolution rate of pyrite-rich sludge was calculated based on the S release (aqueous SO4) at the steady-state. Results show that: (1) in the nonstirred reactor ...

2017
Jianping Liu Raymond M. Coveney

Indium (In) is commonly hosted in Sn-rich deposits but rarely reported in Sn-poor deposits. However, an In-rich and Sn-poor skarn deposit, the Qibaoshan Cu-Zn-Pb deposit, has been identified in south China. Geochemical analyses were undertaken on 23 samples representing the following mineral assemblages: sphalerite-pyrite, pyrite-chalcopyrite, pyrite-sphalerite-galena-chalcopyrite, pyrite, magn...

2014
Baodong Mao Qingfeng Dong Christopher L. Exstrom Jinsong Huang

a r t i c l e i n f o Keywords: Iron pyrite FeS 2 nanocrystals Thin films Ligand exchange Surface stability Photovoltaic Iron pyrite (FeS 2) is a promising photovoltaic absorber material with a high natural abundance and low cost, but surface defects and low photoresponse inhibit sunlight energy conversion. The surface stability of pyrite FeS 2 nanocrystals synthesized in oleylamine (OLA) with ...

2011
Ruoshi Sun M. K. Y. Chan G. Ceder

Despite the many advantages (e.g., suitable band gap, exceptional optical absorptivity, earth abundance) of pyrite as a photovoltaic material, its low open-circuit voltage (OCV) has remained the biggest challenge preventing its use in practical devices. Two of the most widely accepted reasons for the cause of the low OCV are (i) Fermi level pinning due to intrinsic surface states that appear as...

2006
P. Vitorge C. Beaucaire Gregory Druschel Michael Borda

In a recent paper, Descostes et al. (2004) present data on a series of pyrite oxidation batch experiments conducted near pH 2 and 3 where they demonstrate very well the non-stoichiometric dissolution/oxidation of pyrite in acidic solutions through an extensive laboratory investigation of S/Fe ratios. The authors utilized this data to propose a ‘mechanism’ of pyrite oxidation based on these data...

2012

In this research an interfacial characterization of the pyrite was done. Yet, the biooxidation activity is well explained if the interfacial process is carefully analyzed. Thus, I recommended to request to the authors, to include the ESEM-EDX analysis of the pyrite surface after and before the assays, for each trial, vr. gr. C, T1, T2 and T3, in order to improve the surface characterization and...

2011
Wenyi Zhu John R. Reinfelder

Microbial biofilms preferentially colonized pyrite surfaces of black shale incubated in groundwater in the Newark Basin (northeastern United States) for 1 month. SEM observation revealed the co-occurrence of bacteria-shaped pits and secondary iron minerals on pyrite, which indicate biological involvement in pyrite weathering and secondary solid formation. Of the 24 16S rDNA sequences obtained f...

Journal: :The Science of the total environment 2012
Marcos L S Oliveira Colin R Ward Maria Izquierdo Carlos H Sampaio Irineu A S de Brum Rubens M Kautzmann Sydney Sabedot Xavier Querol Luis F O Silva

The extraction of sulphur produces a hematite-rich waste, known as roasted pyrite ash, which contains significant amounts of environmentally sensitive elements in variable concentrations and modes of occurrence. Whilst the mineralogy of roasted pyrite ash associated with iron or copper mining has been studied, as this is the main source of sulphur worldwide, the mineralogy, and more importantly...

Journal: :Geochemical Transactions 2007
Amy L Wolfe Ran Liu Brian W Stewart Rosemary C Capo David A Dzombak

BACKGROUND Standardized sample preparation techniques allow comparison of pyrite dissolution experiments under diverse conditions. Our objective was to assess dry and wet sieving preparation methodologies, and to develop a reproducible technique that yields uniformly size-distributed material within a limited size range of interest. RESULTS Here, we describe a wet sieving preparation method t...

2017
J. Parnell M. Perez J. Armstrong L. Bullock J. Feldmann A. J. Boyce

The Dalradian Supergroup of Britain and Ireland is mineralised by gold-tellurium vein deposits. The host succession includes carbonaceous, pyritic shales (pelites) which were a source of trace elements, including gold and tellurium. LA-ICP-MS mapping of pyrite crystals shows that late stages are enriched in gold, tellurium and lead, representing concentration of these elements during metamorphi...

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