Selective reagent regimes of flotation of non-ferrous and noble metal sulfides from refractory sulfide ores

2016 ◽  
pp. 27-33
Author(s):  
V. A. Ignatkina ◽  
Keyword(s):  
Noble Metal ◽  
Metal Sulfides ◽  
Sulfide Ores ◽  
Selective Reagent

scholarly journals Transition Metal Sulfides- and Noble Metal-Based Catalysts for N-Hexadecane Hydroisomerization: A Study of Poisons Tolerance

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 594
Author(s):  
Aleksey Pimerzin ◽  
Aleksander Savinov ◽  
Anna Vutolkina ◽  
Anna Makova ◽  
Aleksandr Glotov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transition Metal ◽  
Noble Metal ◽  
Flow Reactor ◽  
Fixed Bed ◽  
Chemical Properties ◽  
Pt Catalyst ◽  
Metal Sulfides ◽  
Transition Metal Sulfides ◽  
Nitrogen Containing Compounds

Bifunctional catalysts on the base of transition metal sulfides (CoMoS and NiWS) and platinum as noble metal were synthesized via wetness impregnation of freshly synthesized Al2O3-SAPO-11 composites, supported with favorable acidic properties. The physical-chemical properties of the prepared materials were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), low-temperature N2 adsorption and high resolution transmission electron microscopy (HR TEM) methods. Catalytic properties were studied in n-hexadecane isomerization using a fixed-bed flow reactor. The catalytic poisons tolerance of transition metal sulfides (TMS)- and Pt-catalysts has been studied for sulfur and nitrogen, with the amount of 10–100 ppm addition to feedstock. TMS-catalysts show good stability during sulfur-containing feedstock processing, whereas Pt-catalyst loses much of its isomerization activity. Nitrogen-containing compounds in the feedstock has a significant impact on the catalytic activity of both TMS and Pt-based catalysts.

scholarly journals Palladogermanide Pd2Ge from sulfidized anorthosite of the Yoko-Dovyren intrusion: first finding in Russia

2019 ◽  
Vol 485 (6) ◽  
pp. 741-744 ◽  
Author(s):  
E. M. Spiridonov ◽  
D. A. Orsoev ◽  
A. A. Ariskin ◽  
E. V. Kislov ◽  
N. N. Korotaeva ◽  
...  
Keyword(s):  
Noble Metal ◽  
Layered Intrusion ◽  
Sulfide Ores ◽  
Bottom Part ◽  
First Finding

The Yoko-Dovyren ultramafic-mafic layered intrusion includes the Baikal deposit of Cu-Ni sulfide ores with Pt-Pd mineralization in the bottom part, and “horizons” and pockets of low-sulfide ores with Pt-Pd mineralization at the upper levels of the section. The highest concentration of Pd, Pt, Au, Ag, Hg, and Cd, as well as the widest variability in the noble-metal minerals, is typical of the vein-like bodies of anorthosite and pegmatoid anorthosite in the upper part of the critical horizon at the boundary between troctolite and the overlying gabbronorite. Most of the noble-metal minerals are the postmagmatic pneumatolytic (fluid-metasomatic) phases. Among them are palladogermanide with 19.8 wt % Ge, paolovite with 8.1% Ge, and zvyagintsevite with 0.55% Ge. The composition of palladogermanide is Pd2.03(Ge0.80As0.15Bi0.02)0.97; Ge is significantly replaced with As in this phase, which is typical of endogenic Ge minerals.

scholarly journals Germanium-rich palladium minerals – palladogermanide pd2ge, paolovite pd2 (sn, ge), zvyagintsevite in sulfide-bearing anorthosites of the Yoko-Dovyren pluton, Baikal region

2019 ◽  
Vol 64 (5) ◽  
pp. 554-558
Author(s):  
E. M. Spiridonov ◽  
D. A. Orsoev ◽  
A. A. Ariskin ◽  
E. V. Kislov ◽  
N. N. Korotaeva ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Noble Metal ◽  
Baikal Region ◽  
Sulfide Ores ◽  
Bottom Part ◽  
Sulfide Ore ◽  
Carbonaceous Shales ◽  
Ultramafic Intrusion ◽  
Critical Unit

The bottom part of the Yoko-Dovyren layered mafic–ultramafic intrusion hosts the Baikalskoe deposit of Cu–Ni sulfide ores with Pt–Pd mineralization, and the stratigraphically higher portion of the intrusion includes units and pockets with low-sulfide ore with Pt–Pd mineralization. The maximum Pd, Pt, Au, Ag, Hg, and Cd concentrations and the greatest number of noble-metal minerals, including those containing Ge, are typical of vein-shaped sulfide-bearing anorthosite bodies and pegmatoid anorthosites in the upper part of the Critical Unit, at the boundary between the troctolite unit and overlying gabbronorite. The noble-metal minerals were produced mostly by postmagmatic pneumatolytic (fluid–metasomatic) processes. These minerals are kotulskite, moncheite, zvyagintsevite, telargpalite, paolovite, and other Pd and Pt chalcogenides and intermetallic compounds, including palladogermanide that contains 19.8 wt % Ge (the first find in Russia), paolovite with 8.1 wt % Ge (first find), and Au-rich zvyagintsevite that bears 0.55 wt % Ge. The palladogermanide has the composition Pd2.03(Ge0.80As0.15Bi0.02)0.97, and much of its Ge is substituted for As, as is typical of endogenic Ge minerals. The composition of the Ge-paolovite isPd2.02(Sn0.54Ge0.35Sb0.05As0.04)0.98. The possible source of the germanium is contact-metasomatic pyrite-bearing paralic carbonaceous shales hosting the intrusion.

scholarly journals Adhesion to Mineral Surfaces by Cells of Leptospirillum, Acidithiobacillus and Sulfobacillus from Armenian Sulfide Ores

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 69 ◽  
Author(s):  
Arevik Vardanyan ◽  
Narine Vardanyan ◽  
Anna Khachatryan ◽  
Ruiyong Zhang ◽  
Wolfgang Sand
Keyword(s):  
Biofilm Formation ◽  
Ferrous Iron ◽  
Extracellular Polymeric Substances ◽  
Ferric Iron ◽  
Metal Sulfides ◽  
Mineral Surfaces ◽  
Sulfide Ores ◽  
Bacterial Origin

Bioleaching of metal sulfides is an interfacial process where adhesion and subsequent biofilm formation are considered to be crucial for this process. In this study, adhesion and biofilm formation by several acidophiles (Acidithiobacillus, Leptospirillum and Sulfobacillus) isolated from different biotopes with sulfide ores in Armenia were studied. Results showed that: (1) these bacteria adhere to pyrite surfaces to various extents. A correlation between pyrite biooxidation and adhesion of S. thermosulfidooxidans 6, L. ferriphilum CC, L. ferrooxidans ZC on pyrite surfaces is shown. It is supposed that bioleaching of pyrite by S. thermosulfidooxidans 6, L. ferriphilum CC, L. ferrooxidans ZC occurs by means of indirect leaching: by ferric iron of bacterial origin; (2) cells of At. ferrooxidans 61, L. ferrooxidans ZC and St. thermosulfidooxidans 6 form a monolayer biofilm on pyrite surfaces. The coverage of pyrite surfaces varies among these species. The order of the biofilm coverage is: L. ferrooxidans ZC ≥ At. ferrooxidans 61 > St. thermosulfidooxidans 6; (3) the extracellular polymeric substances (EPS) analysis indicates that the tested strains produce EPS, if grown either on soluble ferrous iron or solid pyrite. EPS are mainly composed of proteins and carbohydrates. Cells excrete higher amounts of capsular EPS than of colloidal EPS. In addition, cells grown on pyrite produce more EPS than ones grown on ferrous iron.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

Interlayer confinement synthesis of Ir nanodots/dual carbon as an electrocatalyst for overall water splitting

2020 ◽  
Author(s):  
Yaru Li ◽  
Yu-Quan Zhu ◽  
Weili Xin ◽  
Song Hong ◽  
Xiaoying Zhao ◽  
...  
Keyword(s):  
Water Splitting ◽  
Noble Metal ◽  
High Efficiency ◽  
Overall Water Splitting ◽  
Highly Dispersed

Rationally designing low-content and high-efficiency noble metal nanodots offers opportunities to enhance electrocatalytic performances for water splitting. However, the preparation of highly dispersed nanodots electrocatalysts remains a challenge. Herein, we...

Identification of acid-insoluble filter-plugging compounds and optimal acid-washing procedures for tubular backpulse pressure filters

TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER
Keyword(s):  
Calcium Sulfate ◽  
Membrane Filter ◽  
Sulfamic Acid ◽  
Xrd Analysis ◽  
Metal Sulfides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gypsum Formation ◽  
Acid Washing ◽  
Hydrolysis Of

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.

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