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Wyświetlanie 1-2 z 2
Tytuł:
Alunogen from the sulfate efflorescence of the Stone Town Nature Reserve in Ciężkowice (the Outer Carpathian Mountains, Poland)
Autorzy:
Marszałek, Mariola
Gaweł, Adam
Powiązania:
https://bibliotekanauki.pl/articles/27310118.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
sulfate efflorescence
alunogen
thermal analysis
Raman spectroscopy
unit-cell parameters
the Carpathian Mountains
Polska
Opis:
Alunogen (Al2(SO4)3∙17H2O), a rare secondary mineral, has been found in the efflorescence on sandstones from the Stone Town Nature Reserve in Ciężkowice, southeastern Poland. This is probably the first find of this salt on such rocks in Poland. Alunogen forms in various geological environments, but mainly from the oxidation of pyrite and other metal sulfides in ore deposits and Al-rich Earth materials under low-pH conditions. Its crystallization at this particular site depends on a set of necessary physicochemical (pH, concentration), climatic (season, temperature, humidity), site-related (location and protection of efflorescence), and mineralogical (the presence of pyrite) conditions. This paper presents the mineralogical and geochemical characteristics of the alunogen from the Stone Town Nature Reserve (based on SEM-EDS, XRPD, EPMA and Raman spectroscopy methods) as well as of the efflorescence itself (based on XRPD and STA coupled with QMS and FTIR for the analysis of gas products). Crystals of alunogen take the shape of flakes, often with a hexagonal outline, clustered in aggregates forming a cellular network. Its calculated formula is (Al1.96Fe3+ 0.01)∑1.97(SO4)3∙17H2O (based on 12 O and 17 H2O). The unit-cell parameters refined for the triclinic space group P1 are: a = 7.423 (1) Å, b = 26.913 (5) Å, c = 6.056 (1) Å, α = 89.974 (23)°, β = 97.560 (25)°, γ = 91.910 (22)°. The Raman spectra (SO4) bands are: intensive 995 cm−1 (ν1); low-intensive 1069, 1093 and 1127 cm−1 (ν3); low-intensive 419 and 443; medium-intensive 470 cm−1 (ν2); and medium-intensive 616 cm−1 (ν4). Those at 530, 312 and at 338 cm−1 are assigned to water vibrations and those at 135, 156, 180 cm−1 to the lattice modes. Although the efflorescence contained an admixture of other minerals (pickeringite, gypsum and quartz), the predominant alunogen is almost chemically pure and the above parameters are consistent with the values reported in the literature for alunogen from different locations and of various origins.
Źródło:
Geology, Geophysics and Environment; 2023, 49, 2; 139--156
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Secondary sulphate minerals from Bhanine Valley coals (South Lebanon) : a crystallochemical and geochemical study
Autorzy:
Kruszewski, Łukasz
Powiązania:
https://bibliotekanauki.pl/articles/2058616.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
iron sulphates
aluminium sulphates
coquimbite
coal
unit cell parameters
standardized Energy Dispersive Spectroscopic analysis
Opis:
Rich efflorescences of various Fe and Al sulphate mineral mixtures on coal seams of Bhanine, South Lebanon, were examined using (1) Powder X-Ray Diffraction (with the Rietveld method and unit cell parameters calculation), (2) Scanning Electron Microscopy with standardized Electron-Dispersive Spectroscopy system, and (3) Inductively-Coupled Plasma Mass Spectroscopy. The sulphates most likely originated from coal-contained pyrite to form Fe(II) sulphates (melanterite, rozenite, and the most common szomolnokite), followed by Fe3+-rich sulphates (coquimbite group, copiapite group) and Al sulphates (alunogen, tamarugite). The halotrichite group and minor voltaite, metavoltine, and possibly secondary rozenite and szomolnokite were the last species to be formed. Strong enrichment in Al in copiapites and coquimbites, common occurrence of aluminocoquimbite, and Al likely entering the structure of Fe(II) sulphates makefurther phenomena, during which the initial ferrous copiapites were oxidized in the presence of Al-rich solutions, not out of the question. The obtained unit cell parameters sometimes stand for threshold values in the literature-based ranges drawn, but the values are usually below the 2% discrepancy. The Bhanine sulphates bear relatively large amounts of Tl, Hg, and Co when compared to Coal Clarke and mean crustal abundancies, being also moderately enriched in Ni and As.
Źródło:
Geological Quarterly; 2019, 63, 1; 65--87
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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