scholarly journals Uranium Mineralization of Fossil Wood

Geosciences ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 133
Author(s):  
George E. Mustoe
Keyword(s):  
Fossil Wood ◽  
Metal Sulfides ◽  
Silicate Mineral ◽  
X Ray ◽  
Organic Debris ◽  
Petrified Wood ◽  
Uranium Minerals ◽  
Ancient Wood ◽  
Common Opal ◽  
Ore Zones

Uraniferous sandstone deposits commonly resulted when uranium in groundwater precipitated in reducing environments caused by degradation of ancient wood and organic debris. However, the mineralogy of uranium in fossil wood has received relatively little study. Previous microscopic observations of petrified wood from a few uranium mines have demonstrated that uranium in fossil wood primarily involves the oxide mineral uraninite or the silicate mineral coffinite, often in association with metal sulfides such as chalcopyrite. These observations are applicable to primary ore zones that are located below the water table, where oxidation is inhibited. New analyses utilizing scanning electron microscopy and X-ray fluorescence (SEM/EDS) reveal that fossil wood from oxidized ore zones may contain a diverse variety of uranium minerals, including carnotite, tyuyamunite, and zippeite, as well as various vanadate and sulfate minerals. Uranium-bearing common opalized wood and stratiform common opal from two prospects in Nevada, USA, contain no identifiable uranium minerals. Instead, the element is dispersed in trace amounts within the opal.

scholarly journals The fossil wood of East Cairo, Egypt: A mineralogical view

Mineralogia ◽  
2015 ◽  
Vol 45 (1-2) ◽  
pp. 47-57
Author(s):  
Kamaleldin M. Hassan
Keyword(s):  
Optical Microscopy ◽  
Powder Diffraction ◽  
Xrd Analysis ◽  
Optical Microscope ◽  
Fossil Wood ◽  
X Ray ◽  
Petrified Wood ◽  
Representative Samples ◽  
Petrified Forest

AbstractAs part of the characterization of the petrified wood of East Cairo at the New Cairo Petrified Forest, representative samples collected from the area were studied by X-ray powder diffraction (XRD) and optical microscopy. The samples, as indicated by XRD analysis, are composed of quartz ± some goethite ± minor moganite ± minor gypsum ± trace calcite. The absence of moganite in some samples has been attributed to the transformation of moganite to quartz or to leaching processes. Under the optical microscope, some of the 10 petrified-wood samples are permineralized with mainly microcrystalline quartz (chalcedony), some with a combination of chalcedony and microgranular quartz, and some with microgranular quartz. The sequence of silicification is likely to have been either opaline precursor to chalcedony and quartz, or directly to chalcedony and quartz. The crystallinity indices (C.I.) of the quartz in the samples studied, measured using a standard X-ray powder diffraction procedure, are consistent with the petrographic findings. The chalcedonic samples have the least C.I. values, and the microgranular quartz samples the highest values.

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.

Transferability of phase shifts for extended x-ray-absorption fine-structure studies of metal sulfides and sulfur on nickel surfaces

1992 ◽  
Vol 45 (20) ◽  
pp. 12043-12049 ◽  
Author(s):  
D. R. Warburton ◽  
D. Purdie ◽  
C. A. Muryn ◽  
N. S. Prakash ◽  
K. Prabhakaran ◽  
...  
Keyword(s):  
Fine Structure ◽  
Phase Shifts ◽  
Metal Sulfides ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

Raman and X-ray Photoemission Identification of Colloidal Metal Sulfides as Potential Secondary Phases in Nanocrystalline Cu2ZnSnS4 Photovoltaic Absorbers

2020 ◽  
Vol 3 (6) ◽  
pp. 5706-5717
Author(s):  
Oleksandr Selyshchev ◽  
Yevhenii Havryliuk ◽  
Mykhailo Ya. Valakh ◽  
Volodymyr O. Yukhymchuk ◽  
Oleksandra Raievska ◽  
...  
Keyword(s):  
Metal Sulfides ◽  
Secondary Phases ◽  
X Ray ◽  
Colloidal Metal

Analyses of petrified wood by electron, X-ray and optical microprobes

1999 ◽  
Vol 14 (3) ◽  
pp. 435-446 ◽  
Author(s):  
Andrzej Kuczumow ◽  
Bart Vekemans ◽  
Olivier Schalm ◽  
Walter Dorrin ◽  
Pierre Chevallier ◽  
...  
Keyword(s):  
X Ray ◽  
Petrified Wood

Analysis of Composite Structure and Primordial Wood Remains in Petrified Wood

2007 ◽  
Vol 61 (8) ◽  
pp. 889-895 ◽  
Author(s):  
J. Nowak ◽  
D. Nowak ◽  
P. Chevallier ◽  
J. Lekki ◽  
R. van Grieken ◽  
...  
Keyword(s):  
Cell Walls ◽  
Central Italy ◽  
Global Scale ◽  
Mineralization Process ◽  
Raman Spectrometry ◽  
X Ray ◽  
The Earth ◽  
Geological Past ◽  
Petrified Wood ◽  
Composite Nature

Among all the fossils, petrified wood belongs to the most impressive and most common of materials. Still, its study has not exceeded the purely phenomenological level. The recognition of the conserved structure of petrified wood seems to be of meaning for understanding the geological past, the complete carbon cycle inside the Earth, and the structure of potential new materials. The first ever published spatial distributions of the remains of the primordial organic material (lignin, cellulose, pectins) in the cells of permineralized wood, from Dunarobba (Central Italy), are presented here. They were collected using μ-Raman spectrometry. The composite nature of the petrified material (calcite located in the lumena of cells and goethite located in the cell walls) was confirmed by electron, proton, and X-ray microprobes. The structure of the cell walls was well preserved. The mineralization process was induced by the tracheidal water flow and was stopped after formation of pipe-like goethite shielding of the cell walls on the cellulose scaffolds. The chemical (Eh and pH ranges) and probable microbial conditions for such a pattern of mineralization were determined. We estimate that substantial amounts of the primordial organic matter were preserved in bodies of petrified wood on a global scale. The wood petrifaction process, if well understood, can be a basis for the production of “everlasting” organic–inorganic composite compounds.

scholarly journals Secondary Iron Minerals Present in AMD Sediments from Smolník Abandoned Mine

2012 ◽  
Vol 11 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Zuzana Dakos ◽  
Daniel Kupka ◽  
Michal Kovařík ◽  
Katarína Jablonovská ◽  
Václav Krištúfek ◽  
...  
Keyword(s):  
Mine Drainage ◽  
Solid Phase ◽  
Metal Sulfides ◽  
X Ray Diffraction ◽  
Mine Area ◽  
X Ray ◽  
Sulfur Oxidizing ◽  
Term Monitoring ◽  
Sequential Formation

Abstract The genesis of acid mine drainage (AMD) is conditioned by existence of indigenous chemolithotrophic iron and sulfur oxidizing bacteria, especially of genus Acidithiobacillus. The result of the oxidizing weathering of metal sulfides is a sequential formation of ochreous precipitates in drainage systems and in the surroundings of AMD seepage on the surface. The long-term monitoring of AMD waters collected at the shaft Pech that receives the majority of waters draining the flooded Smolník mine area point out the enduring contamination risk of particular components in the environment of Smolník mine area. Elemental analysis, X-ray diffraction, Mossbauer spectroscopy and scanning electron microscopy of the ochreous precipitates formed from Smolník AMD stream revealed schwertmannite as the dominant solid phase in the precipitates. The chemical analysis of AMD effluents and the elemental composition of related sediments indicated considerable scavenging potential of the ochreous precipitates towards metal cations and oxyanions of arsenic and sulfate

Effect of Adding Sago and Sintering to the Properties of Geopolymer Mortar

2020 ◽  
Vol 1010 ◽  
pp. 659-664
Author(s):  
Mohamad Abdul Zahari Aziz ◽  
M.M.R. Faizal ◽  
Izwan Johari ◽  
Shah Rizal Kasim
Keyword(s):  
Compressive Strength ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Content Increase ◽  
Curing Time ◽  
Sintering Process ◽  
Silicate Mineral ◽  
Pore Former ◽  
X Ray ◽  
Alkaline Activator

Geopolymer is an alternative cementitious material produced by rich Alumino Silicate mineral materials (Si-Al) combine with alkaline activator. The objectives in this study are to introduce pores by using sago as pore former and to determine the effect of curing time and sintering process to geopolymer mortar properties. There are three compositions of mortar used in this study with different sago content (10%, 20%, and 30%) and each composition of mortar have different curing time (1, 3 and 7 days). Fly ash, silica powder, alkaline activator (sodium silicate solution (Na2SiO3) and sodium hydroxide (NaOH) and sago were mixed together based on their composition and the mixture were put into steel cubic mould (50 mm x 50 mm x 50 mm) and left at room temperature for curing process. After the mortar reaches their curing time, it will be sintered at 1000 °C. The physical changes of the mortar were analysed before and after the sintering process. The microstructure of mortar was observed using Scanning Electron Microscope (SEM). Compression test was done to geopolymer mortars by using ADR-Auto 3000 from ELE instrument (ASTM C109 standard) to determine the mechanical properties. Fourier-transform infrared (FTIR) analysis used to determine the functional group exist in geopolymer mortar and X-ray Diffraction (XRD) was used to determine the phase. Besides that, Energy dispersive X-ray spectroscopy (EDX) use to measure percentage elements exist in a mortar. Geopolymer mortar with 10% sago content, 7 days of curing and undergo sintering process have the highest compressive strength (13.46 N) compare to the other geopolymer mortar composition. The 30% sago mortar contain many pores after sintering contributes its brittleness and cannot be tested for compressive strength. Longer curing days give enough time for the geopolymerisation process to create strong Si-O-Al bond or Jadeite (N-A-S-H gels) while sintering process helps to speed up the geopolymerisation process take place in a mortar. Formation of jadeite (N-A-S-H gels) influenced the strength of the mortar. The increasing phase of jadeite increases the strength of the mortar. As sago content increase, the pores in geopolymer also increase but the ratio Al2O3:SiO2 decrease resulting low formation of Jadeite. Hence the compressive strength of geopolymer mortar decrease.

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