Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
This study presents the results of concentrations of rare earth elements and yttrium (REY), uranium (U), and thorium (Th) in ashes from combustion/co-combustion of biomass (20%, 40%, and 60% share) from the agri-food industry (pomace from apples, walnut shells, and sunflower husks) and hard coal. The study primarily focuses on ashes from the co-combustion of biomass and hard coal, in terms of their potential use for the recovery of rare earth elements (REE), and the identification of the sources of these elements in the ashes. Research methods such as ICP-MS (inductively coupled plasma mass spectrometry), XRD (X-ray diffraction), and SEM-EDS (scanning electron microscopy with quantitative X-ray microanalysis) were used. The total average content of REY in ash from biomass combustion is 3.55-120.5 mg/kg, and in ash from co-combustion, it is from 187.3 to 73.5 mg/kg. The concentration of critical REE in biomass combustion ash is in the range 1.0-38.7 mg/kg, and in co-combustion ash it is 23.3-60.7 mg/kg. In hard-coal ash, the average concentration of REY and critical REY was determined at the level of 175 and 45.3 mg/kg, respectively. In all samples of the tested ashes, a higher concentration of Th (0.2-14.8 mg/kg) was found in comparison to U (0.1-6 mg/kg). In ashes from biomass and hard-coal combustion/co-combustion, the range of the prospective coefficient (Coutl) is 0.66-0.82 and 0.8-0.85, respectively, which may suggest a potential source for REE recovery. On the basis of SEM-EDS studies, yttrium was found in particles of ashes from biomass combustion, which is mainly bound to carbonates. The carriers of REY, U, and Th in ashes from biomass and hard-coal co-combustion are phosphates (monazite and xenotime), and probably the vitreous aluminosilicate substance.
PL
W pracy przedstawiono wyniki stężeń pierwiastków ziem rzadkich i itru (REY), uranu (U), oraz toru (Th) w popiołach ze spalania/współspalania biomasy (udział 20, 40 i 60%) z przemysłu rolno-spożywczego (wytłoki z jabłek, łupiny orzecha włoskiego i łuski słonecznik), i węgla kamiennego. W pracy zwrócono uwagę przede wszystkim na popioły ze współspalania biomasy i węgla kamiennego, pod kątem ich potencjalnego wykorzystania do odzysku pierwiastków ziem rzadkich (REE), oraz identyfikacji źródeł tych pierwiastków w popiołach. Zastosowano metody badawcze takie jak ICP-MS (spektrometria mas ze wzbudzeniem w plazmie indukcyjnie sprzężonej), XRD (dyfrakcja rentgenowska) i SEM-EDS (skaningowa mikroskopia elektronowa z ilościową mikroanalizą rentgenowską). Całkowita średnia zawartość REY w popiołach ze spalania biomasy wynosi 3,55-120,5 mg/kg, a w popiołach ze współspalania od 73,5 do 187,3 mg/kg. Średnie stężenie krytycznych REE w popiołach ze spalania biomasy mieści się w zakresie 1,0-38,7 mg/kg, a w popiołach ze współspalania 23,3-60,7 mg/kg. W popiele z węgla kamiennego średnie stężenie REY i krytycznych REY oznaczono odpowiednio na poziomie 175 i 45.3 mg/kg. W próbkach badanych popiołów oznaczono wyższe stężenie Th (0,2-14,8 mg/kg), w porównaniu do U (0,1-6 mg/kg). W popiołach ze spalania/współspalania biomasy i węgla kamiennego zakres wartości współczynnika perspektywicznego (Coutl) wynosi odpowiednio 0,66-0,82 i 0,8-0,85, co może sugerować potecjalne źródło do odzysku REE. Analiza cząstek popiołów ze spalania biomasy wykazała itr, który związany jest głównie z węglanami. Nośnikami REY, U i Th w popiołach ze współspalania biomasy i węgla kamiennego są fosforany: monacyt i ksenotym, oraz prawdopodobnie szklista substancja glinokrzemianowa.
EN
Ophiolitic blocks, represented by metagabbro and serpentinite containing relict pyroxene, olivine, baddeleyite, zirconolite, Ni-pyrite and pyrrhotite, were found as exotic blocks in an olistostrome in the Magura Nappe, Outer Western Carpathians. The geochemical and isotopic features of the blocks suggest they represent mantle-derived rocks, with within-plate geochemistry signatures, modified by subduction, with lithospheric mantle input. A U-Pb apatite cooling age (614 ±3 Ma) is within age uncertainty of a published U-Pb zircon magmatic crystallization age (~614 Ma) implying rapid post-crystallization cooling. Pervasive alteration with replacement of primary minerals by low-temperature assemblages is observed in all rock fragments and is interpreted as contemporaneous with shearing. The secondary mineral assemblages and temperature modelling allow the interpretation that the pervasive ocean-floor metamorphism is the alteration in these meta-mafic rocks. These ophiolitic fragments can be linked to the Neoproterozoic break up of Rodinia/Pannotia.
EN
In this paper cation arrangement in two samples of aluminoceladonite, emerald green and dark-green were studied by Mössbauer, Raman and X-ray photoelectron spectroscopies. The X-ray photoelectron spectroscopy (XPS) spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p, and O1s core levels provided information, for the first time highlighting a route to identify the position of Si, Al, K, and Fe cations in a structure of layered silicates. The XPS analysis showed the presence of Al in tetrahedral and octahedral coordination while the K2p line indicated the possibility of K+ substitution by other cations in interlayer sites. Mössbauer spectroscopy provided information about crystal chemistry with respect to the local electronic and geometric environment around the Fe atom and to distortions of the polyhedra. It turned out that iron was located mostly in the cis-octahedra position wherein about 75% of iron appeared in the form of Fe3+. The most preferred cation combinations around Fe corresponded to 3Fe3+ ions and MgFe2+Fe3+/2MgFe3+. Raman spectroscopy illustrated aluminium substitution in silicon and iron positions wherein the concentration of the aluminium determined the degree of structural distortion within the layered system. These isomorphic substitutions implied a typical band arrangement in the hydroxyl region, which has not been observed in celadonites so far.
EN
The mineralogical studies of clay from the onshore mud volcanoes discovered in parts of the Upper Benue Trough of Nigeria provide a clue about the geological formation from which the extruded mud originates. The study area is a part of the Cretaceous Upper Benue Trough filled with Early Cretaceous continental deposits and Late Cretaceous marine deposits, having a history of magmatism dating from the Albian to the Pleistocene. The study approach involves integrated inorganic geochemical analysis of the samples to reveal their composition and origin. The results of XRD analysis of the fresh clays from the mud volcano revealed the presence of quartz, kaolinite, and other clay minerals (illite-smectite), feldspars, and in a much lower quantities, other accessory minerals including muscovite, evaporites, calcite and dolomite, trona, barite, goethite. The saprolite samples are composed mainly of quartz, kaolinite, smectite-illite associations, and feldspars, traces of goethite, calcite, and evaporate minerals (sylvite, halite). The presence of calcite, dolomite, sylvite, and halite suggests the marine origin of the rocks, while trona mineral is a non-marine evaporate. The coexistence of these minerals in some of the analyzed samples suggests the deposition of sediments in a transitional environment of deposition. Traces of marine minerals are present in some of the samples but completely absent in others collected from another site. This suggests that the source rock formations from which the material originated are within the Upper Bima Sandstone interpreted as being deposited in a non-marine environment or the Yolde Formation, which is known as a transitional unit (transitional between the outcropping continental Upper Bima Sandstone and marine Pindiga Formation).
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.