scholarly journals Bentonites in Southern Spain. Characterization and Applications

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 706
Author(s):  
Jorge Luis Costafreda ◽  
Domingo Alfonso Martín
Keyword(s):  
Chemical Analysis ◽  
Volcanic Glass ◽  
San Jose ◽  
Zeolite Sample ◽  
West Side ◽  
Pozzolanic Reactivity ◽  
Volcanic Glasses ◽  
Thin Section Petrography ◽  
Pozzolanic Properties ◽  
Thermal Stability Of

The objective of this work was to investigate and demonstrate the pozzolanic properties of the bentonites found at the San José–Los Escullos deposit, located in the southeast of the Iberian Peninsula, to be used in the manufacturing of more durable and environmentally compatible pozzolanic cements, mortars and concretes. These bentonites are mainly composed of smectites, with montmorillonite as the main clay mineral. They were formed by the hydrothermal alteration of tuffs, volcanic glasses, dacites, rhyolites and andesites. For this research, samples were taken from outcrops on the south, north and west side of the San José–Los Escullos deposit, and in the Los Trancos deposit located 19.3 km to the northeast. All samples consisted of bentonites, except for a zeolite sample taken from the northern flank of the San José–Los Escullos deposit, which was used to contrast and compare the behaviour of bentonite in some of the analyses that were done. An investigation of the mineralogical, petrological, chemical and thermogravimetric characteristics of the samples was carried out using various methods, such as XRD, OA (Oriented aggregates), TGA, XRF, SEM and thin section petrography (TSP). In addition, a chemical analysis of pozzolanicity (CAP) was done at 8 and 15 days to determine the pozzolanic capacity of the samples. XRD, XRF, SEM and TSP studies showed that these bentonites have a complex mineralogical constitution, composed mainly of smectites of the montmorillonite variety, as well as halloysite, illite, vermiculite, biotite, muscovite, kaolinite, chlorite, mordenite, feldspar, pyroxene, amphibole, calcite, volcanic glass and quartz. Thermogravimetric analysis (TGA) established the thermal stability of the bentonites studied at above 800 °C. Chemical analysis of pozzolanicity (CAP) confirmed the pozzolanic character of the bentonites, exhibited in their reactive behaviour with Ca(OH)2. The pozzolanic reactivity increased significantly from 8 to 15 days. These results show that the materials studied can be used as quality pozzolans for the manufacture of pozzolanic cements, mortars and concretes.

Growth and Stability of MgO/NiO Multilayered Films on Single Crystal NiO(100)

1995 ◽  
Vol 401 ◽  
Author(s):  
S. Imaduddin ◽  
R. J. Lad
Keyword(s):  
Thermal Stability ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Single Crystal ◽  
Lattice Mismatch ◽  
Composition Studies ◽  
Single Crystal Substrate ◽  
Multilayered Films ◽  
Crystal Substrate ◽  
Thermal Stability Of

AbstractThe less than 1% lattice mismatch between MgO and NiO makes them ideal candidates for investigating the growth and stability of multilayered oxide films. Ultra-thin multilayers composed of alternating films of MgO and NiO were deposited onto a stoichiometric NiO(100) single crystal substrate at 250°C by evaporating Mg and Ni in 5×10−7 Torr of O2, respectively. The structure of these multilayers was determined using LEED. Reactivity and chemical composition studies of the MgO/NiO interfaces were carried out using XPS and UPS. The MgO/NiO multilayers grow epitaxially on NiO(100), as evidenced by LEED. XPS and UPS analysis indicates attenuation of the NiO or MgO peaks during growth which is consistent with discrete layering. Chemical analysis also reveals negligible intermixing of the MgO and NiO layers during deposition. Results pertaining to the thermal stability of the multilayers show that UHV annealing above 750°C results in significant diffusion of MgO into the NiO(100) substrate.

scholarly journals Local structures of Zr in impact-related natural glass probed by XAFS

2014 ◽  
Vol 70 (a1) ◽  
pp. C1531-C1531
Author(s):  
Tsubasa Tobase ◽  
Akira Yoshiasa ◽  
Ling Wang ◽  
Hidetomo Hongu ◽  
Tatsuya Hiratoko ◽  
...  
Keyword(s):  
Local Structure ◽  
High Energy Physics ◽  
National Laboratory ◽  
Glass Structure ◽  
Volcanic Glass ◽  
High Energy ◽  
Local Structures ◽  
Geological Processes ◽  
The Earth ◽  
Volcanic Glasses

The local structures of tektites and natural glasses were studied by Zr K-edge XANES and EXAFS in order to provide quantitative data on bonding distances and coordination numbers. The XAFS measurements were performed at the beam line BL-NW10A of the PF-AR in National Laboratory for High Energy Physics (KEK), Tsukuba, Japan. Zr4+ ion in tektite has different kinds of coordination environment. Various natural glasses are formed under different physical conditions. Impact-related glass, fulgurite and volcanic glasses are typical natural glasses. Upon a devastating impact of a giant meteoroid on the Earth, particles of the Earth's surface were melted and catapulted into outer space, where they finally solidified and fell back to the Earth. Tektites should be formed by this series of processes [1]. Tektite has special local structure of Ca[2]. Glass structure is affected by the pressure and temperature conditions during the glass formation and quenching process. This study indicated that different formation process of natural glasses gives different local structure of zirconium ions. The Zr K-edge XANES spectra of tektite have the double post-edge peaks with different heights. The volcanic glasses and other impact-related glasses such as impactite possessed more simple XANES patterns. The average coordination number of Zr4+ in darwin glass, LDG, volcanic glass and tektite are between 6 and 7. The eight-coordinated Zr4+ shows different XAFS pattern in suevite and köfelsite. All tektites are classified in same type. According to EXAFS measurements, Zr-O distances in tektites are 2.198 – 2.215Å and XANES spectra of tektites have similar shape. It indicates that tektites have similar Zr local structure with 7-fold coordination Zr ions. Impact-related glasses are classified to different types. Volcanic glasses are classified to same types. Impact glasses are formed under different geological processes at impact event and are experienced different physical environments.

scholarly journals Application of Concretes Made with Glass Powder Binder at High Replacement Rates

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3796
Author(s):  
M. Isabel Más-López ◽  
Eva M. García del Toro ◽  
Sara García-Salgado ◽  
Daniel Alcala-Gonzalez ◽  
Santiago Pindado
Keyword(s):  
Compressive Strength ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Bulk Density ◽  
Compression Strength ◽  
Glass Powder ◽  
Waste Glass ◽  
Air Content ◽  
Cement And Concrete ◽  
Pozzolanic Properties

Glass is a material that can be reused, except for a small part that, due to its residual characteristics, cannot be reused and becomes a nonbiodegradable waste to accumulate in landfills. The chemical composition and pozzolanic properties of waste glass are encouraging for the use of these wastes in the cement and concrete industries and for providing technically and environmentally viable solutions. In this study, we propose the production of deactivated concretes with a high content of glass powder in the binder. The substitution percentage of glass powder for cement used in this work was between 70% and 80%. Consistency, air content, bulk density, workability, compression strength, and permeability tests were performed. Regarding compressive strength, the results obtained at 90 days for percentages of cement substitution by glass powder of 70 and 80%, respectively, were 14.2 and 8.6. The chemical analysis of leachates showed concentrations of Fe, Cu, V, Ni, and Mo, in mg L−1, of 1.57, 1.38, 0.85, 0.95, and 0.44, respectively. The results obtained, compared with the relevant legislation, have proved that the inclusion of glass powder in a high percentage of substitution and with a granulometry of 20 µm in the manufacture of deactivated concretes is feasible for exterior pavements.

scholarly journals Approximate chemical analysis of volcanic glasses using Raman spectroscopy

2015 ◽  
Vol 46 (12) ◽  
pp. 1235-1244 ◽  
Author(s):  
Danilo Di Genova ◽  
Daniele Morgavi ◽  
Kai‐Uwe Hess ◽  
Daniel R. Neuville ◽  
Nikita Borovkov ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Chemical Analysis ◽  
Volcanic Glasses

scholarly journals Mineralogy and crystallochemical characteristics of HEU-type minerals from zeolitic tuff deposits of Serbia

2017 ◽  
Vol 71 (1) ◽  
pp. 49-60
Author(s):  
Vladan Kasic ◽  
Vladimir Simic ◽  
Dragana Zivotic ◽  
Ana Radosavljevic-Mihajlovic ◽  
Jovica Stojanovic
Keyword(s):  
Crystal Structure ◽  
Cation Exchange Capacity ◽  
Raw Materials ◽  
Volcanic Glass ◽  
Exchange Capacity ◽  
Exchangeable Cations ◽  
Zeolitic Tuff ◽  
Pyroclastic Rocks ◽  
Zeolitic Tuffs ◽  
Thermal Stability Of

The results of perennial research of several Serbian zeolitic tuffs enriched with HEU-type minerals are presented in this paper. There are several recognized zeolitic tuff deposits containing HEU-type minerals: Zlatokop, Igros, Beocin, Toponica, Slanci, but their comparative mineralogical and crystallochemical features have not been studied in detail so far. These zeolitic tuff deposits are spatially and genetically connected to volcanic and pyroclastic rocks of marine and lake environments of Senonian and Eocene, and Neogene age, respectively. As a result of devitrification and diagenesis process of volcanic glass within zeolitic tuffs hypocrystalline porphiry and vitroclastic textures occur. The studied zeolitic tuffs are mainly composed of heulandite occuring in a form of needle- to plate-like crystals of 0,1 do 100 ?m in length, associated with other silicates. Depending on the type and content of exchangeable cations as well as the thermal stability of these raw materials, 24 clinoptilolite-Ca and heulandite-Ca can be distinguished. The values of cation exchange capacity and surface area capacity range from 96 to 166 meq/100 g, and from 8,0 to 10,5 meq/100 g, respectively. HEU-type minerals can be distinguished either by a Si/Al ratio or arrangement of extra framework cations within the crystal structure of these minerals.

scholarly journals Altered Volcanic Tuffs from Los Frailes Caldera. A Study of Their Pozzolanic Properties

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5348
Author(s):  
Jorge Costafreda ◽  
Domingo Martín ◽  
Leticia Presa ◽  
José Parra
Keyword(s):  
Electrical Conductivity ◽  
Portland Cement ◽  
Mechanical Strength ◽  
Iberian Peninsula ◽  
Volcanic Glass ◽  
Petrographic Analysis ◽  
High Mechanical Strength ◽  
Physical Chemical ◽  
Strength Tests ◽  
Pozzolanic Properties

This work presents the results of the study of the physical, chemical, mineralogical and pozzolanic properties of the altered volcanic tuffs (AVT) that lie in the Los Frailes caldera, south of the Iberian Peninsula, and demonstrates their qualities as pozzolans for the manufacturing of mortars and pozzolanic cements of high mechanical strength. The main objective of this research is to show to what extent the AVTs can replace portland cement (PC) in mortars, with standardised proportions of 75:25% and 70:30% (PC-AVT). To achieve these objectives, three AVT samples were studied by a petrographic analysis of thin section (PATS), DRX, FRX and MEB. The pozzolanic properties were determined by three methods: electrical conductivity (ECT), chemical pozzolanicity tests (CPT) at 8 and 15 days and mechanical strength tests (MS) of the specimens at 2, 7, 28 and 90 days. Studies of a PATS, DRX, FRX and MEB showed that the AVT samples’ constitutions are complex where smectite (montmorillonite), mordenite, quartz, halloysite, illite, kaolinite, volcanic glass and lithic fragments coexist. The results of the ECT and CPT tests confirmed the pozzolanic properties of the samples analysed and proved an increase in mechanical strength from 2 to 90 days of testing.

scholarly journals A review of the Effect of Calcination Temperature on the Properties of Calcined Clay Concrete

2021 ◽  
Vol 2 (3) ◽  
Keyword(s):  
Compressive Strength ◽  
Calcination Temperature ◽  
Hydration Kinetics ◽  
Structural Reorganization ◽  
Calcined Clay ◽  
Calcination Temperatures ◽  
Pozzolanic Reactivity ◽  
Partial Cement Replacement ◽  
The Right ◽  
Pozzolanic Properties

Naturally occurring clays can produce an amorphous siliceous material possessing pozzolanic properties if is heated at an appropriate temperature. Calcination at the right temperature is crucial since it affects the formation of relevant phases, pozzolanic reactivity, hydration kinetics and consequently, increase the strength and durability of concrete. This paper reviews the effect of calcination temperature on the properties of mortar and concrete corporating calcined clay as partial cement replacement. It is observed that calcination temperatures close to 900°C decrease the specific surface and represent the onset for the structural reorganization of aluminosilicates. Both factors limit the pozzolanic reactivity and can consequently compromise compressive strength. The results show that mortar containing 20% calcined clay obtained compressive strength of 63MPa when calcined at 800oC, surpassing the reference cement by about 8MPa.

Mineralogical and geochemical studies of hardened subsurface layers in soils of the Azufres and Atecuaro volcanic calderas, southwestern Mexico

2005 ◽  
Vol 85 (5) ◽  
pp. 611-624 ◽  
Author(s):  
Mikhail Ostrooumov ◽  
Victor Hugo Garduño Monroy ◽  
Alise Servenay
Keyword(s):  
Chemical Analysis ◽  
Volcanic Glass ◽  
Climatic Conditions ◽  
Crystalline Silica ◽  
Infrared Spectrometry ◽  
X Ray ◽  
Molar Ratios ◽  
Ash Fall ◽  
Free Silica ◽  
Subsurface Layers

Free silica and halloysite-bearing hardened subsurface layers in the ash fall deposits of the Azufres and Atecuaro volcanic calderas (Michoacan State, southwestern Mexico), known as “tepetates”, have been characterized by chemical analysis, X-ray diffraction (XRD), Raman and Infrared spectrometry, optical (OM) and scanning (SEM) microscopy with energy dispersive X-ray analysis (EDXRA). Chemical analysis of these weathered and hardened formations shows the oxidation of Fe2+, enrichment of Al, Fe3+ and Ti, loss of Si, Na, Ca, K, Mg, and formation of minerals with hydroxyls groups. Tepetates are characterized by elevated SiO2/Al2O3 molar ratios (4.86–8.82) that show part of the SiO2 has crystallized in free siliceous phases. X-ray analysis reveals hydrated (1.0 nm) and dehydrated halloysite (0.7 nm), sanidine, plagioclases, cristobalite, and tridymite. Raman and infrared spectra confirm the presence of these mineral phases and show that the structural transformations occur in opal neoformations. SEM shows a compact matrix with a skeleton of different phenocrysts (aluminosilicates, ferromagnesian minerals and various crystalline silica phases) and the presence of non-crystalline silica (volcanic glass and opal with different degrees of crystallinity). The tepetates form by interaction of two processes: volcanic ash fall then subsequent weathering under variable climatic conditions. These indurated horizons are partly or totally cemented by the diagenetic secondary minerals: non-crystalline silica with variable crystal chemical characteristics and clay minerals. Key words: Ash fall, tepetates, volcanic soil, mineralogy, geochemistry

Stone Drugs and Calamine Lotion: Chemical Analysis of Residue in Nineteenth-Century Glass Bottles, Market Street Chinatown, San Jose, California

2015 ◽  
Vol 7 (1) ◽  
pp. 93-118 ◽  
Author(s):  
Barbara L. Voss ◽  
Ray von Wandruszka ◽  
Alicia Fink ◽  
Tara Summer ◽  
S. Elizabeth Harman ◽  
...  
Keyword(s):  
Nineteenth Century ◽  
Chemical Analysis ◽  
San Jose ◽  
Glass Bottles

scholarly journals Further Tests of Dry Sulfur Compounds for the Control of the San Jose Scale

1920 ◽  
Vol 13 (1-16) ◽  
pp. 339-343
Author(s):  
Wesley Flint
Keyword(s):  
Sulfur Compounds ◽  
Field Conditions ◽  
Present Writer ◽  
San Jose ◽  
The West ◽  
West Side ◽  
University Of Illinois ◽  
San Jose Scale ◽  
Series Of Experiments ◽  
The University

During the season of 1919 a series of experiments for the control of the San Jose scale was conducted in two orchards on the west side of the state. The object of these experiments was to make a thorough test, under field conditions, of several widely advertised dry sulfur compoundsintended for the control of the San Jose scale. A description of these experiments and the results have been published in Experiment Station Circular No. 239, this work being conducted by W. S. Brock, of the Horticultural Department of the University of Illinois, and the present writer.

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