Clay resources in the Nelas region (Beira Alta), Portugal. A contribution to the characterization of potential raw materials for prehistoric ceramic production

Clay Minerals ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 353-370 ◽  
Author(s):  
R. Marques ◽  
A. Jorge ◽  
D. Franco ◽  
M. I. Dias ◽  
M. I. Prudêncio

AbstractMineralogical and chemical compositions of residual and sedimentary clays (bulk and <2 μm fraction) from the Nelas region (schist, aplite-pegmatites, granites and Tertiary sediments from both Mondego River margins), Portugal, were studied, aiming to establish indicators for raw materials in ancient ceramic provenance studies. The mineralogy of bulk material does not provide a clear distinction between samples. Among clay minerals, kaolinite dominates, except in the aplite-pegmatites where illite prevails. Smectite was only found in sediments of the left river bank.A more successful result was the geochemical differentiation of clay types. The weathered schist presents greater enrichment in Cr, whereas the clay fraction of aplite-pegmatites shows enrichment in all the chemical elements studied. The sediments and weathered granites are not easy to differentiate; the best geochemical indicators are U (lower contents in clay-size fraction of sediments) and REE patterns in both bulk and clay-size fraction.

2019 ◽  
Vol 11 (7) ◽  
pp. 1995 ◽  
Author(s):  
Sabrina Cajamarca ◽  
Douglas Martins ◽  
Juscimar da Silva ◽  
Mariana Fontenelle ◽  
Ítalo Guedes ◽  
...  

Several agro-industrial, livestock, and food wastes can be recycled to create biofertilizers. This diversity of raw materials can result in nutritional imbalance and an increase in heavy metal content, which could make the final product unfeasible. Thus, the chemical characterization of the raw materials and their influence on the sustainable and safe production of biofertilizers need to be better understood. In this context, the objective of the present study was to evaluate the chemical characteristics of agro-industrial residues used in the manufacture of an aerobic liquid biofertilizer. We analyzed the macronutrient, micronutrient, and trace metal contents of seven waste products used as raw materials to create a biofertilizer. In addition, a survey of secondary biofertilizer data from different residues was carried out that showed great heterogeneity in the chemical compositions of these residues, which has a direct impact on the agronomic efficiency of these biofertilizers. The characterization revealed that some materials may be contaminants of the soil, due to high levels of trace metals, especially cadmium. We conclude that the generation of detailed inventories, such as those of the nutrient and heavy metal contents of the raw materials and biofertilizers produced, is indispensable for the correct recommendation of biologically-based inputs in agriculture.


2019 ◽  
Vol 73 (4) ◽  
pp. 265-274
Author(s):  
Slavica Mihajlovic ◽  
Zivko Sekulic ◽  
Jovica Stojanovic ◽  
Vladan Kasic ◽  
Iroslav Sokic ◽  
...  

Quality of raw materials, including quartz sand and quartzite, varies from one deposit to another. Furthermore, the material quality determines in which industrial branches it can be used after certain preparation processes. Potential applications of quartz raw materials are: in the construction and refractory industry, ceramics and glass industry, then in metallurgy, foundry and also in production of water treatment filters. Geological investigations of the central Serbia region, in the Rekovac municipality, resulted in identification of occurrence of quartz sand ("Ursula") and quartzite ("Velika Krusevica"). Preliminary laboratory tests and characterization of the quartz sand size fraction -0.63+0.1 mm confirmed the possibility of applying this size fraction in the construction materials industry, while the quartzite can be used in refractory, glass and metallurgy industries. After determining the geological reserve of quartz sand "Ursula" and quartzite "Velika Krusevica", detailed investigations are required. Quality conditions from the aspect of chemical composition and physical properties of quartz sand and quartzite are mostly clearly defined by a special standard for this purpose. On the other hand, there are also application areas where standards does not exist, but users define their quality conditions. This example is with the application of quartz sand in the production of water glass. Chemical composition as well is not always the determining factor for the application of quartz raw material. For example, for quartz sand used for sandblasting, grain form is essential. From the economic analysis point of view, the prices of quartz raw materials vary depending on their chemical and physical properties. After all, what needs to be pointed out is the fact that these raw materials are very widespread in nature and that their exploitation is quite simple. After the raw material is excavated, it is stored and further sieved, washed, dried and processed according to customer requirements. All of these processes are cheaper than preparing, for example, limestone, and significaly cheaper than preparation of metal ores.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 779
Author(s):  
David Zemánek ◽  
Karel Lang ◽  
Lukáš Tvrdík ◽  
Dalibor Všianský ◽  
Lenka Nevřivová ◽  
...  

The presented study is focused on optimization and characterization of a high-alumina refractory aggregate based on natural raw materials—kaolins, claystone, and mullite dust by-product (used to increase the alumina and mullite contents, respectively). In total, four individual formulas with the Al2O3 contents between 45 and 50 wt.% were designed; the samples were subsequently fired, both in a laboratory oven and an industrial tunnel furnace. The effects of repeated firing were examined during industrial pilot tests. Mineral and chemical compositions and microstructures, of both the raw materials and designed aggregates, were thoroughly investigated by the means of X-ray fluorescence spectroscopy, powder X-ray diffraction, and optical and scanning electron microscopies. Porosity, mineral composition, and mullite crystal-size development during the firing process were also studied. Based on the acquired results, the formula with the perspective to be used as a new mullite grog, featuring similar properties as the available commercial products, however, with reduced production expenses, was selected. The quality of grog determines to a large extent the properties of the final product. Hence, optimization of aggregates for specific refractories is of a great importance. The production of engineered aggregates provides the opportunity to utilize industrial by-products.


2021 ◽  
Vol 9 (2) ◽  
pp. 95-102
Author(s):  
Sufriadin Sufriadin ◽  
Purwanto Purwanto ◽  
Muhammad Rahmatul Jihad ◽  
Astina Aras ◽  
Angelia Santoso ◽  
...  

Characterization of dolomite samples from Bone Bolango, Gorontalo Province have been performed with the objective to find out their mineralogical and chemical compositions. Observation and mineral analyses were carried out by means of microscopy and X-ray diffraction methods respectively; whereas chemical composition was determined by using X-ray fluorescence spectrometer. Result of XRD analysis shows that samples contain dolomite [CaMg(CO3)2], calcite [CaCO3] and [SiO2]. The proportion of dolomite is about 60.4% in average and its presence is as replacement of calcite in bioclast components and matrices in the rock. Dolomite crystals are characterized by mosaic texture with euhedral – subhedral in shapes. Spacially, dolomite content increase from west to the east of study area. The XRF analysis reveals that dolomite samples contain MgO ranging between 8.07 and 20.78% while CaO ranges between 30.04 and 56.13%. The SiO2 concentration ranges from 3.50 – 7.55%; whereas Al2O3 ranges from 1.07 – 1.84%. The average MgO content of dolomite about 12.89% can be categorized as calcium dolomite. Dolomite within the study area can be used directly in agriculture sector, but it less suitable as raw materials in glass, ceramic and refractory industries because the average content of MgO is less than 17%. However, it can be increased of their MgO with the application of selective mining or beneficiation process.


2021 ◽  
Vol 11 (6) ◽  
pp. 51-53
Author(s):  
Kundan Patil

Calcium is one of the essential elements for living beings. As a supplement, it is used to treat Calcium deficiencies due to a calcium deficient diet. In Rasaratnasamuchchaya Calcium bhasma (Eggshell bhasma) is included as a rich calcium supplement. There is a need for work on the determination of the percentage of Calcium in the eggshell and its limit of acceptance. Easy absorption of bhasma in the body is possible when its preparation is carried out in an acidic medium. Lemon juice is one of the acidic mediums employed for this purpose at pH 2.4. The eggshell powder is subjected to five calcination cycles to convert it into the Bhasma. Analysis of Eggshell Bhasma has been done by various modern analytical techniques to determine its exact chemical compositions. Various instrumental methods like XRD, FTIR, and SEM have been incorporated for analysis of raw materials, intermediates as well as final products. The calcium carbonate present in eggshells is in calcite form. In the present work, structural and chemical characterization of eggshell bhasma was carried out to develop an analytical profile of it.


2019 ◽  
Vol 34 (1) ◽  
pp. 163
Author(s):  
Helen Jamil Khoury ◽  
Roberto Araújo ◽  
Sandra De Brito Barreto ◽  
Viviane Khoury Asfora

No presente trabalho são 1 apresentados os resultados de estudos por fluorescência de raios X de tijolos brasileiros. Neste estudo foram avaliados 22 tijolos, sendo sete de Igarassu, dois do Forte do Brum e 13 de Olinda. Um equipamento portátil de fluorescência de raios X por dispersão de energia foi desenvolvido para este estudo. Análises por difração de raios X também foram efetuadas para determinar as fases cristalinas presentes nos tijolos. Os resultados mostraram a existência de fases minerais, como quartzo, em todos os tijolos avaliados. A Análise da Componente Principal foi aplicada aos dados dos espectros de fluorescência de raios X obtidos. Os resultados mostraram que a partir do gráfico de scores das componentes principais CP1 e CP3, respectivamente representadas pelo Fe e Ca, foi possível separar os tijolos de Igarassu e do Forte do Brum em cinco grupos, que estavam associados com o século de fabricação. Por sua vez, os tijolos de Olinda foram separados em dois grupos, sendo um formado por um único tijolo e o outro grupo pelos demais tijolos. Estes resultados sugerem que os tijolos foram produzidos com diferentes matérias primas ou em diferentes locais. ENERGY DISPERSIVE X-RAY FLUORESCENCE APPLIED TO THE CHARACTERIZATION OF BRICKS OF PERNAMBUCO HISTORICAL SITESABSTRACTThis work presents the results of X-ray fluorescence analysis of Brazilian bricks, collected from several historical sites of the State of Pernambuco, Brazil. In this study, twenty two bricks were analyzed; seven from Igarassu, two from Forte do Brum in Recife, and thirteen from Olinda. A portable X-ray fluorescence system was assembled and used for the qualitative determination of the chemical elements present in the samples. X-ray diffraction analysis was also carried out to determine the crystal mineral phases in the bricks. All the bricks studied showed several minerals, such as quartz A Principle Component Analysis was applied to the full X-ray fluorescence spectra. In the score plot of principal components PC1 and PC3, represented by Fe and Ca respectively, it can be seen that the results for the bricks from Igarassu and Forte do Brum may be grouped in five clusters corresponding to the bricks´ century and manufacture locations. The analysis of the Olinda bricks yielded two separate groups, one with a single brick and the second group with the other eleven bricks. These results suggest that the bricks were produced with different raw-materials or manufactured in different locations.KEYWORDS: non-destructive analysis; X-ray fluorescence; cultural heritage; bricks; X-ray diffraction.


2017 ◽  
Vol 866 ◽  
pp. 191-194
Author(s):  
Kantamard Lamasai ◽  
Nittaya Jaitanong ◽  
Suparut Narksitipan

The influence of aluminium dross on the phase compositions and microstructure of cement composites were studied in this research. The cement/aluminium dross composites were prepared by adding ground granulated blast-furnace slag (GGBS) from aluminium casting industrial. The sample was added fiber optic and mixed with aluminium dross at 0.1-0.8 wt% of cement. Then, the mixture was poured into a metallic mold (5mm*5mm*5mm). After incubation with saturated lime water for 3 days, the samples were wrapped with plastic films for 7 and 28 days. The chemical compositions of raw materials were characterized by using x-ray fluorescence spectrometry (XRF). The phase compositions and crystalline structure cement/aluminium dross composites were studied by using x-ray diffraction (XRD) technique. Scanning electron microscopy (SEM) was used for characterization of microstructure of these composites.


1997 ◽  
Vol 48 (3) ◽  
pp. 313-325 ◽  
Author(s):  
James L. Bischoff ◽  
Kirsten M. Menking ◽  
Jeffrey P. Fitts ◽  
John A. Fitzpatrick

Chemical analyses of the acid-soluble and clay-size fractions of sediment samples (1500-yr resolution) reveal oscillations of lake salinity and of glacial advances in core OL-92 back to 155,000 yr B.P. Relatively saline conditions are indicated by the abundance of carbonate and smectite (both pedogenic and authigenic), reflected by Ca, Sr, and Mg in the acid-soluble suite, and by Cs2O, excess MgO, and LOI (loss on ignition) in the clay-size fraction. Rock flour produced during glacial advances is represented by the abundance of detrital plagioclase and biotite in the clay-size fraction, the ratio of which remains essentially constant over the entire time span. These phases are quantitatively represented by Na2O, TiO2, Ba, and Mn in the clay fraction. The rock-flour record indicates two major ice-advances during the penultimate glacial cycle corresponding to marine isotope stage (MIS) 6, no major advances during the last interglaciation (entire MIS 5), and three major advances during the last glacial cycle (MIS 2, 3, and 4). The ages of the latter three correspond rather well to36Cl dates reported for Sierra Nevada moraines. The onset of the last interglaciation is shown by abrupt increases in authigenic CaCO3and an abrupt decrease in rock flour, at about 118,000 yr B.P. according to our time scale. In contrast, the boundary appears to be gradual in the δ18O record in which the change from light to heavy values begins at about 140,000 yrs B.P. The exact position of the termination, therefore, may be proxy-dependent. Conditions of high carbonate and low rock flour prevailed during the entire period from 118,000 yr B.P. until the glacial advance at 53,000 yr B.P. signaled the end of this long interglaciation.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Celina Luízar Obregón ◽  
Marco A. Zamalloa Jara ◽  
Flor L. Rojas Arizapana ◽  
Yuri J. Chura Huayllani ◽  
Janet F. Gonzales Bellido ◽  
...  

AbstractThe Regional Archive of Cusco in Peru guards valuable history collections with exceptional regional and international value dating from the sixteenth century to the present. Historical manuscripts are part of the identity of all people; they constitute a tangible cultural heritage that must be studied, valued, and protected. In this sense, the objective of this research was to identify the chemical compositions of inks and paper, with the goals of setting the background of their originality, identifying relationships between them, and glimpsing antecedents that generated degradation due to the compositions of the inks. This study is the first of its kind in Peru and reveals the chemical elements present in the writing ink, the seal, and the paper of five documents from the late eighteenth and early nineteenth centuries. Duplicate in situ nondestructive analyses were carried out using a hand-held X-ray fluorescence spectrometer under ambient conditions in soil mode, configured with three sequential shots, and energies from zero to 40, 40, and 15 keV, respectively. The elements S and Fe were present as components of iron gall inks. Cu and Zn were less abundant; probably, they provided less corrosion and more color intensity to the inks. The minor elements Pb, As, and especially Ag in all manuscripts differentiate them from European inks of the same period. Additionally, the five documents reflect the same elemental compositions but with different concentrations. This could mean that writers used local raw materials and Spanish ink recipes. Finally, the analyses of standard reference material, SRM 1646a and SRM 196b, gave results with acceptable precision. Graphical Abstract


Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 563-577 ◽  
Author(s):  
A. Nzeukou Nzeugang ◽  
M. El Ouahabi ◽  
B. Aziwo ◽  
J.R. Mache ◽  
H.S. Mefire Mounton ◽  
...  

ABSTRACTA kaolin deposit from Mankon (northwest Cameroon) was prospected and studied for potential applications in ceramics. Six samples were investigated with X-ray diffraction (XRD), infrared (IR) spectroscopy and scanning electron microscopy (SEM) to determine the mineralogical composition and with X-ray fluorescence (XRF) to determine the chemical composition and properties for ceramic applications. The main minerals in the clays are kaolinite/halloysite and anatase associated with alunite, illite, gibbsite and maghemite. The kaolin samples have abundant organic matter (4–10%) and low absorption of methylene blue (0.2–2.5 meq/100 g), while SiO2 (33.28–56.31%) and Al2O3 (19.26–35.87%) are major oxides. The particle-size distribution derived from sieving and the hydrometer method indicates that 12–38% of the samples are in the <2 μm clay fraction. The clays have low to moderate plasticity (7–21%). One sample with K-feldspar and plagioclase displays the necessary properties for red ceramic products. SEM confirmed the occurence of halloysite in sample M9. The high kaolinite/halloysite content (64–97%), associated with low Fe2O3 content (0.5–1.4%) demonstrates that five samples are suitable raw materials for white firing industrial kaolin.


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