scholarly journals Mineralogical Characterization of Dolomitic Aggregate Concrete: The Camarasa Dam (Catalonia, Spain)

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 117
Author(s):  
Encarnación Garcia ◽  
Pura Alfonso ◽  
Esperança Tauler
Keyword(s):  
Portland Cement ◽  
Type A ◽  
Alkali Silica Reaction ◽  
Type B ◽  
Mineralogical Characterization ◽  
Group Mineral ◽  
X Ray ◽  
Concrete Type ◽  
Further Development

The Camarasa Dam was built in 1920 using dolomitic aggregate and Portland cement with two different compositions: type A (dolomite and Portland cement) and type B (dolomite and sand-cement). The sand cement was a finely powdered mixture of dolomite particles and clinker of Portland cement. The mineralogy of concrete was studied by optical microscopy, scanning electron microscopy, and x-ray powder diffraction. Reaction of dedolomitization occurred in the two types of concrete of the Camarasa Dam, as demonstrated by the occurrence of calcite, brucite, and/or absence of portlandite. In the type A concrete, calcite, brucite, and a serpentine-group mineral precipitated as a rim around the dolomite grains and in the paste. The rims, a product of the dedolomitization reaction, protected the surface of dolomite from the dissolution process. In type B concrete, in addition to dolomite and calcite, quartz and K-feldspar were present. Brucite occurred in lower amounts than in the type A concrete as fibrous crystals randomly distributed in the sand-cement paste. Although brucite content was higher in the type A concrete, type B showed more signs of loss of durability. This can be attributed to the further development of the alkali-silica reaction in this concrete type.

scholarly journals The Physico-Chemical and Mineralogical Characterization of Mg-Rich Synthetic Gypsum Produced in a Rare Earth Refining Plant

2021 ◽  
Vol 13 (9) ◽  
pp. 4840
Author(s):  
Fatai Arolu Ayanda ◽  
Mohd Firdaus Mohd Anuar ◽  
Syaharudin Zaibon ◽  
Shamshuddin Jusop
Keyword(s):  
Rare Earth ◽  
Acid Soils ◽  
Acid Neutralization ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Neutralization Capacity ◽  
Acid Neutralization Capacity ◽  
Refining Plant ◽  
Calcium Magnesium

The physical, chemical and mineralogical characterization of the constituents of magnesium-rich synthetic gypsum produced in a rare earth-refining plant located in Gebeng, Pahang, Malaysia was conducted through elemental chemical analysis, scanning electron microscopy with Energy Dispersive X-ray (EDX)-analyzer, thermal analysis, X-ray fluorescence and X-ray diffraction. The crystalline nature of the by-product was studied using FTIR spectroscopy. Elemental analysis confirmed the presence of Ca and Mg, which are essential macronutrients required by plants and this Ca alongside the high pH (9.17) of MRSG may confer on the material a high acid neutralization capacity. From the result, it was observed that the studied by-product is a heterogeneous crystalline material comprising of gypsum (CaSO4.2H2O) and other major components such as calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate) and sulfur. These aggregates may contribute to give an acid neutralization capacity to MRSG. The XRD study of MRSG indicated a high content of gypsum (45.4%), shown by the d-spacing of 7.609 Å (2-theta 11.63) in the diffractogram. The infrared absorption spectra of MRSG indicate close similarities to mined gypsum. The results of the characterization indicated that MRSG has valuable properties that can promote its use in amending soil fertility constraints on nutrient-deficient tropical acid soils.

scholarly journals Mineralogical characterization of clay mineral assemblages from Rio de Janeiro pegmatites to identify kaolinite and/or halloysite deposits

Cerâmica ◽  
2020 ◽  
Vol 66 (380) ◽  
pp. 483-495
Author(s):  
V. M. J. Salgado-Campos ◽  
L. C. Bertolino ◽  
F. J. da Silva ◽  
J. C. Mendes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Analysis ◽  
Rio De Janeiro ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Mineral Assemblages ◽  
Saprolite Zone ◽  
Scanning Electron

Abstract This study reports the mineralogical characterization of kaolin occurrences in the State of Rio de Janeiro, Brazil, to identify new kaolinite and halloysite deposits. Samples were collected in 10 pegmatites with varying sizes for X-ray diffractometry, chemical analysis by X-ray fluorescence, and scanning electron microscopy studies. The results indicated that the kaolin occurrences were of weathered origin, wherein some places there were occurrences of tubular halloysite. Concerning the regolith stratigraphy, samples located in the saprock zone were found to contain kaolinite and/or halloysite contents from 0 to 10.1%, while those located in the saprolite zone contained kaolinite and/or halloysite contents from 16.3% to 34.9%. Kaolinite and/or halloysite-7Å were formed from plagioclase weathering instead of K-feldspar or mica, and the halloysite-7Å occurrence was related to samples in regions with a higher degree of weathering.

Performance of Precursor Materials and Fired Ceramics for Structural Blocks

2015 ◽  
Vol 820 ◽  
pp. 13-17
Author(s):  
Neila Gondim Azeredo ◽  
Euzébio Barnabé Zanelato ◽  
Jonas Alexandre ◽  
Afonso Rangel Garcez de Azevedo ◽  
Gustavo de Castro Xavier ◽  
...  
Keyword(s):  
Building Construction ◽  
Structural Ceramic ◽  
X Ray Diffraction ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Physical Chemical ◽  
Ceramic Blocks ◽  
Clay Body ◽  
Structural Blocks

The physical, chemical and mineralogical characterization of a precursor clay body before firing is of relevance for understanding the technological performance of the fired clay ceramic. In particular, structural clay ceramic blocks used in building construction need to attend standard properties specified by the norms. In the present work the precursor clay body, typically used to fabricate structural blocks in Campos dos Goytacazes, state of Rio de Janeiro, Brazil, was characterized in terms of particle size distribution, X-ray diffraction, chemical composition and Atterberg limits. In addition, the performance of structural ceramic blocks, fabricated from the extruded clay body and fired at 850oC, was evaluated. The results indicated that the ceramic mechanical strength complies with the Brazilian norm but the water absorption is higher than the maximum specified by the norm. The characteristic of the clay body contribute to justify the structural blocks performance.

HIGH RESOLUTION MINERALOGICAL CHARACTERIZATION OF SEDIMENTS - LAKE BOLĂTĂU-FEREDEU (ROMANIA)

2021 ◽  
Vol 16 (1) ◽  
pp. 199-210
Author(s):  
Máté Karlik ◽  
◽  
Ildikó GYOLLAI ◽  
Anna VANCSIK ◽  
Krisztián FINTOR ◽  
...  
Keyword(s):  
High Resolution ◽  
Chemical Weathering ◽  
Soil Formation ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Geochemical Conditions ◽  
Formation Conditions ◽  
Physical And Chemical ◽  
Microbial Mediation

The catchment (bedrock and soil) and sediments of lake Bolătău, Romania were studied by high resolution multi-methodological investigations to characterize paleoenvironmental and formation conditions. Particle size analyses, optical and cathodoluminescence microscopy, FTIR-ATR and Raman spectroscopy, X-ray powder diffraction, and XRF were applied for microtextural, chemical, micro-mineralogical and embedded organic material characterization and distribution of the sediments, especially concerning geochemical conditions, like pH and redox potential change. Our results support physical and chemical weathering in the process of soil formation with appearance of the new minerals appear (10Å sized phyllosilicates and clay minerals). Comparison of these studies offer possible differentiation of syn- and diagenetic mineralization, the clarification of debris contribution, microbial mediation and complex mineralization via decomposition of cell and extracellular polymeric substance. Based on the analyses on the abrasives, a suboxic environment prevailed in the depositional area and considerable microbial contribution is proposed via accumulation of lake sediments.

scholarly journals A Tale of Two Tiles: Characterization of Floor Tiles from the Nineteenth-Century Akko Tower Shipwreck (Israel)

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1091
Author(s):  
Alexandra Inberg ◽  
Dana Ashkenazi ◽  
Yishai Feldman ◽  
Omri Dvir ◽  
Deborah Cvikel
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Raw Materials ◽  
Type A ◽  
Raw Material ◽  
Brown Pigment ◽  
Blue Color ◽  
Type B ◽  
Yellow Color ◽  
Floor Tiles

Fragments of decorated floor tiles were retrieved from the Akko Tower shipwreck, Israel. Most tiles were made of bright brown fired clay with a white glaze decorated with colored stenciled motifs (Type A); and others consisted of a red-brown fired clay body, coated with a brown pigment covered with transparent brown glaze (Type B). This study aimed to characterize the two tile types; to reveal information concerning the manufacturing process; and to determine the origin of their raw material. A multidisciplinary approach was used, including light microscopy, SEM-EDS, electron probe microanalysis with wavelength-dispersive X-ray spectroscopy (EPMA-WDS), XRD, Raman spectroscopy, and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses. The characterization of both tile types demonstrated the use of different raw materials. The Type A tiles were covered with tin-opacified majolica glaze and colored with various mixtures of pigments. The blue color was due to pigment rich in cobalt; the yellow color was due to Naples yellow and lead-tin yellow I minerals; and the green, orange, and brown colors were all prepared by mixing the Naples yellow pigment with different minerals. These majolica glaze tiles were probably manufactured in Sicily. The brown coating of the Type B tiles was due to pigment rich in lead and iron minerals. These tiles were produced with different manufacturing processes, and apparently made in France.

A Longitudinal Analysis of Methicillin-ResistantStaphylococcus aureusin a Hong Kong Teaching Hospital

2004 ◽  
Vol 25 (2) ◽  
pp. 126-129 ◽  
Author(s):  
Margaret Ip ◽  
D. J. Lyon ◽  
F. Chio ◽  
A. F. Cheng
Keyword(s):  
Hong Kong ◽  
Teaching Hospital ◽  
Dna Typing ◽  
Type A ◽  
University Teaching ◽  
Pfge Type ◽  
Type B ◽  
Isolation And Characterization ◽  
Surgical Units

AbstractObjectives:To review the incidence and trends of MRSA during a 12-year (1989-2000) period at a university teaching hospital and the relationship between strain distribution by antibiogram and molecular typing.Design:Retrospective review of laboratory-based surveillance records on MRSA isolation and characterization of strains by antimicrobial susceptibility and PFGE. A patient episode was counted at the time when MRSA was first isolated.Setting:A 1,350-bed university teaching hospital in Hong Kong.Patients:Those with clinical isolates of MRSA.Results:During 1989 to 2000, the hospital recorded 1,203,175 deaths and discharges (D&D) and encountered 5,707 patient episodes of new MRSA isolation. The overall incidence of patient episodes of MRSA was 0.47/100 D&D. In 1989, the incidence was 0.81/100 D&D and fell to a low of 0.33/100 D&D in 1995, but then rose to 0.50/100 D&D in 2000. Antibiogram and DNA typing identified 5 major types. PFGE type A constituted 68% (211/312) of isolates and was present throughout the 12-year period. PFGE type B constituted 13% (40/312) of isolates and was only present from 1995 to 2000. These isolates form a distinct clone and had unique antibiotic resistance profiles.Conclusions:The study showed the establishment of a dominant MRSA clone (PFGE type A group) in the intensive care, medical, and surgical units and the appearance of a new MRSA strain in 1995 (PFGE type B), which partly explained the rise in incidence of MRSA cases and a disproportionate rise in MRSA bacteremia from 1995 to 2000.

scholarly journals Petrographic and Chemical–Mineralogical Characterization of Mortars from the Cistern at Amaiur Castle (Navarre, Spain)

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 311 ◽  
Author(s):  
Graciela Ponce-Antón ◽  
Maria Cruz Zuluaga ◽  
Luis Angel Ortega ◽  
Juantxo Agirre Mauleon
Keyword(s):  
Organic Additive ◽  
X Ray Diffraction ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Rock Fragments ◽  
Application Techniques ◽  
Aggregate Nature ◽  
Specific Construction ◽  
Selection Of

Mortars from the cistern in Amaiur Castle (Navarre, Spain) were analysed to assess the mortar manufacturing process and application techniques. To this end, optical microscopy, scanning electron microscopy (SEM), thermogravimetric analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman microspectroscopy, and Fourier transform infrared spectroscopy (FTIR) were performed. The study of both structural and plaster mortars from Amaiur Castle cistern show patterns/rules in the mortar manufacture according to the specific construction requirements. A multilayer application technique was used for the construction of the cistern tank. Deliberate selection of the aggregate nature and grading contributed to mortar impermeability. Ceramic and silico-aluminous rock fragments were used as aggregates in the cistern tank to confer hydraulicity to the mortars, instead of carbonated aggregates as used in the vault. Aluminosilicated phases present in the aggregates led to the formation of amesite, which is a magnesium aluminosilicate hydrate (M-A-S-H) phase conferring hydraulicity to the mortar. Two types of additives were identified in the outer pigmented layer of plaster. Beeswax was the identified organic additive used to improve the impermeability of mortar, while hematite was the identified inorganic additive giving rise to the reddish colour of the layer.

The Effect of Ag-Addition on Precipitation Sequence in Al-1.0mass%Mg2Si-Excess 0.4mass%Si Alloy

2007 ◽  
Vol 561-565 ◽  
pp. 239-242 ◽  
Author(s):  
Kenji Niwa ◽  
Kenji Matsuda ◽  
Junya Nakamura ◽  
Tatsuo Sato ◽  
Susumu Ikeno
Keyword(s):  
Metastable Phase ◽  
Type A ◽  
Precipitation Sequence ◽  
Type B ◽  
X Ray ◽  
Β Phase ◽  
Transmission Electron ◽  
Alloy Type ◽  
Type C ◽  
Study Type

It is well known that Ag additional Al-1.0mass%Mg2Si-excess0.4mass%Si alloy (ex. Si-Ag alloy) has higher hardness and elongation than those of Al-1.0mass%Mg2Si-excess 0.4mass%Si alloy (ex. Si alloy). However, precipitation sequence of ex. Si-Ag alloy is not clear yet. In this work, precipitation sequence of ex. Si-Ag alloy has been investigated using high resolution transmission electron microscopy and X-ray energy dispersive spectroscopy. Precipitates were classified into several kinds by HRTEM images and SAED patterns, and relative frequencies of precipitates were also investigated. Its precipitation sequence was compared with that of ex. Si alloy. Type-A, Type-B and Type-C precipitates as special metastable phase in excess Si type Al-Mg-Si alloy, has been observed in ex. Si-Ag alloy, but β’ phase increased and Type-A and Type-B precipitate decreased in this study. Type-A precipitate was found at only grain boundary.

Physico-Mineralogical Characterization: Bentonitic Clays Recently Found in Olivedos, Paraíba, Brazil

2015 ◽  
Vol 820 ◽  
pp. 56-59
Author(s):  
F.K.A. Sousa ◽  
I.A. Silva ◽  
W.S. Cavalcanti ◽  
Gelmires Araújo Neves ◽  
Heber Carlos Ferreira
Keyword(s):  
Cation Exchange Capacity ◽  
Petroleum Industry ◽  
Specific Area ◽  
Exchange Capacity ◽  
X Ray Diffraction ◽  
Mineralogical Characterization ◽  
X Ray ◽  
Petroleum Wells ◽  
The Town

Used in various branches of the industry, bentonitic clays are considered a valuable mineral, used specially in the petroleum industry for manufacturing of fluids used the drilling of petroleum wells in long depth. Recently, a deposit of this valuable mineral was discovered in the town of Olivedos-PB. There are data that prove that this is a very poor and underdeveloped town. So, this work aims at the physico-mineralogical characterization of clays recently discovered and, this way, verify if they present similar characteristics which allow them to replace the clays from Boa Vista-PB, and if they can be used by the industry, thus bringing social development for that town. The characterization was made by means of the analysis of chemical composition by X-ray fluorescence (EDX), thermogravimetric and thermal differential analyses (TG and DTA), X-ray diffraction (XRD), cation-exchange capacity (CEC) and specific area (SA). The results show that the clays recently discovered in Olivedos-PB are polycationic clays, presenting MgO, CaO and K2O content, and that they are constituted by smectitic clay mineral, by quartz and kaolinite.

Mineralogical characterization of a lignite gasification ash from a low-BTU fixed-bed gasifier I. X-ray phase analysis

1984 ◽  
Vol 14 (4) ◽  
pp. 479-484 ◽  
Author(s):  
Gregory J. McCarthy ◽  
Lindsay P. Keller ◽  
Paul J. Schields ◽  
Mark P. Elless ◽  
Keven C. Galbreath
Keyword(s):  
Phase Analysis ◽  
Fixed Bed ◽  
Mineralogical Characterization ◽  
X Ray
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