A mineralogical study of the Guanajuato, Mexico, silver ores

1975 ◽  
Author(s):  
Ivan Franklin Wilson ◽  
Charles Milton ◽  
Joseph Rollins Houston
Keyword(s):  
Mineralogical Study

scholarly journals Phlogopite-pargasite coexistence in an oxygen reduced spinel-peridotite ambient

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Costanza Bonadiman ◽  
Valentina Brombin ◽  
Giovanni B. Andreozzi ◽  
Piera Benna ◽  
Massimo Coltorti ◽  
...  
Keyword(s):  
Oxygen Fugacity ◽  
Upper Mantle ◽  
Mantle Xenoliths ◽  
Spinel Peridotite ◽  
Simultaneous Formation ◽  
Empirical Potentials ◽  
Elastic Data ◽  
Mineralogical Study ◽  
Semi Empirical ◽  
T Locus

AbstractThe occurrence of phlogopite and amphibole in mantle ultramafic rocks is widely accepted as the modal effect of metasomatism in the upper mantle. However, their simultaneous formation during metasomatic events and the related sub-solidus equilibrium with the peridotite has not been extensively studied. In this work, we discuss the geochemical conditions at which the pargasite-phlogopite assemblage becomes stable, through the investigation of two mantle xenoliths from Mount Leura (Victoria State, Australia) that bear phlogopite and the phlogopite + amphibole (pargasite) pair disseminated in a harzburgite matrix. Combining a mineralogical study and thermodynamic modelling, we predict that the P–T locus of the equilibrium reaction pargasite + forsterite = Na-phlogopite + 2 diopside + spinel, over the range 1.3–3.0 GPa/540–1500 K, yields a negative Clapeyron slope of -0.003 GPa K–1 (on average). The intersection of the P–T locus of supposed equilibrium with the new mantle geotherm calculated in this work allowed us to state that the Mount Leura xenoliths achieved equilibrium at 2.3 GPa /1190 K, that represents a plausible depth of ~ 70 km. Metasomatic K-Na-OH rich fluids stabilize hydrous phases. This has been modelled by the following equilibrium equation: 2 (K,Na)-phlogopite + forsterite = 7/2 enstatite + spinel + fluid (components: Na2O,K2O,H2O). Using quantum-mechanics, semi-empirical potentials, lattice dynamics and observed thermo-elastic data, we concluded that K-Na-OH rich fluids are not effective metasomatic agents to convey alkali species across the upper mantle, as the fluids are highly reactive with the ultramafic system and favour the rapid formation of phlogopite and amphibole. In addition, oxygen fugacity estimates of the Mount Leura mantle xenoliths [Δ(FMQ) = –1.97 ± 0.35; –1.83 ± 0.36] indicate a more reducing mantle environment than what is expected from the occurrence of phlogopite and amphibole in spinel-bearing peridotites. This is accounted for by our model of full molecular dissociation of the fluid and incorporation of the O-H-K-Na species into (OH)-K-Na-bearing mineral phases (phlogopite and amphibole), that leads to a peridotite metasomatized ambient characterized by reduced oxygen fugacity.

scholarly journals Removal of Impurities from Shungite Via a Combination of Physical and Chemical Treatments

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 245
Author(s):  
Toyohisa Fujita ◽  
Taichi Aoki ◽  
Josiane Ponou ◽  
Gjergj Dodbiba ◽  
Chunlin He ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Sulfur Removal ◽  
Nitrilotriacetic Acid ◽  
Microwave Treatment ◽  
Magnetic Flux Density ◽  
High Gradient Magnetic Separation ◽  
Chemical Leaching ◽  
Inorganic Acids ◽  
Mineralogical Study ◽  
Physical And Chemical

This study investigated the removal of sulfur and iron from shungite rocks through different methods after fine grinding: flotation, magnetic separation, microwave treatment, and chemical leaching. In this work, first, a mineralogical study of shungite was conducted. The carbon, silica, iron, and sulfur compositions in the as-received shungite were 45.4%, 38.3%, 4.6%, and 2.4%, respectively. In flotation, a sulfur grade of 1.4% was obtained. In the wet high-gradient magnetic separation at a magnetic flux density of 1 tesla, the iron and sulfur grades in the nonmagnetic fraction were 2.8% and 1.9%, respectively. Furthermore, the sulfur reduced to 0.2% by the 9 min microwave irradiation. In addition, chemical leaching using chelating reagents and inorganic acids was utilized to remove iron and sulfur. Nitrilotriacetic acid (NTA) could reduce the iron and sulfur grades to 2.0% and 0.9%, respectively. For leaching using reverse aqua regia, the iron and sulfur grades were reduced to 0.9% and 0.23%, respectively. For leaching using a 6N HCl with H2O2 aqueous solution, the iron and sulfur grades were reduced to 0.8% and 0.34%, respectively. Overall, chemical leaching using HCl with H2O2 was the most effective for iron and sulfur removal from shungite.

scholarly journals Multi-Scale Minero-Chemical Analysis of Biomass Ashes: A Key to Evaluating Their Dangers vs. Benefits

2021 ◽  
Vol 13 (11) ◽  
pp. 6052
Author(s):  
Paola Comodi ◽  
Azzurra Zucchini ◽  
Umberto Susta ◽  
Costanza Cambi ◽  
Riccardo Vivani ◽  
...  
Keyword(s):  
Raw Materials ◽  
Average Diameter ◽  
Rietveld Analysis ◽  
Fly Ashes ◽  
Amorphous Content ◽  
Multi Scale ◽  
Italian Law ◽  
Polycyclic Aromatic ◽  
Mineralogical Study ◽  
The One

A multi-methodic analysis was performed on five samples of fly ashes coming from different biomasses. The aim of the study was to evaluate their possible re-use and their dangerousness to people and the environment. Optical granulometric analyses indicated that the average diameter of the studied fly ashes was around 20 µm, whereas only ~1 vol% had diameters lower that 2.5 µm. The chemical composition, investigated with electron probe microanalysis, indicated that all the samples had a composition in which Ca was prevalent, followed by Si and Al. Large contents of K and P were observed in some samples, whereas the amount of potentially toxic elements was always below the Italian law thresholds. Polycyclic aromatic hydrocarbons were completely absent in all the samples coming from combustion plants, whereas they were present in the fly ashes from the gasification center. Quantitative mineralogical content, determined by Rietveld analysis of X-ray powder diffraction data, indicated that all the samples had high amorphous content, likely enriched in Ca, and several K and P minerals, such as sylvite and apatite. The results obtained from the chemo-mineralogical study performed make it possible to point out that biomass fly ashes could be interesting materials (1) for amendments in clayey soils, as a substitution for lime, to stimulate pozzolanic reactions and improve their geotechnical properties, thus, on the one hand, avoiding the need to mine raw materials and, on the other hand, re-cycling waste; and (2) as agricultural fertilizers made by a new and ecological source of K and P.

Chemical and nano-mineralogical study for determining potential uses of legal Colombian gold mine sludge: Experimental evidence

Chemosphere ◽  
2018 ◽  
Vol 191 ◽  
pp. 1048-1055 ◽  
Author(s):  
Nazly E. Sánchez-Peña ◽  
José L. Narváez-Semanate ◽  
Daniela Pabón-Patiño ◽  
Javier E. Fernández-Mera ◽  
Marcos L.S. Oliveira ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Gold Mine ◽  
Mineralogical Study ◽  
Mine Sludge

Geochemical and mineralogical study of bauxite deposit of Mainpat Plateau, Surguja District, Central India

2013 ◽  
Vol 7 (9) ◽  
pp. 3505-3512 ◽  
Author(s):  
V. N. Patel ◽  
R. K. Trivedi ◽  
S. H. Adil ◽  
R. B. Golekar
Keyword(s):  
Central India ◽  
Bauxite Deposit ◽  
Mineralogical Study

Metabentonite geochemistry: magmatic cycles and graptolite extinctions at Dob's Linn, southern Scotland

1988 ◽  
Vol 79 (1) ◽  
pp. 19-41 ◽  
Author(s):  
R. A. Batchelor ◽  
J. A. Weir
Keyword(s):  
Trace Elements ◽  
Deleterious Effect ◽  
Major Element ◽  
Magma Mixing ◽  
Volcanic Origin ◽  
Intermediate Composition ◽  
Ash Composition ◽  
Mineralogical Study ◽  
Local Extinctions ◽  
Phosphorus Levels

ABSTRACTThe Moffat Shale Group is a condensed, variable and partly pelagic sequence of mudrocks of Llandeilo—Llandovery age. The sequence has a five-fold lithological subdivision based mainly on the occurrence of grey mudstones within a succession otherwise dominated by fully euxinic black graptolitic mudrocks. Associated with the black mudrocks, especially in the Llandovery, are metabentonite beds which achieve a climax, both in thickness and in number, within the top quarter of the mudrock sequence. A geochemical and mineralogical study has confirmed a volcanic origin for the metabentonites. Major element data highlight a carbonate-dominated environment above the gregarius—convolutus Zones boundary. Phosphorus levels reach a peak at the same boundary, as well as at the Caradoc—Ashgill boundary where phosphorite horizons are known from Wales and Norway. Immobile trace elements have highlighted regular changes in source magma composition. Prolonged periods of crystal fractionation in magmas of intermediate composition gave rise, on eruption, to large volumes of silicic ash which had a deleterious effect on graptolite species and led to local extinctions. Regular fluctuations in ash composition from silicic to intermediate are ascribed to alternating fractionation and magma mixing cycles.

scholarly journals The evolved circumbinary disk of AC Herculis: a radiative transfer, interferometric, and mineralogical study

2015 ◽  
Vol 578 ◽  
pp. A40 ◽  
Author(s):  
M. Hillen ◽  
B. L. de Vries ◽  
J. Menu ◽  
H. Van Winckel ◽  
M. Min ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Mineralogical Study
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