Study of the relationship between the mineralogical composition and the disintegration of shales from Paraíba and Ceará states of Brazil

Author(s):  
Caline Leal ◽  
Matheus Nikolaos Carneiro Brunet ◽  
Luciana Amorim ◽  
Francisco Cézar Costa Nogueira ◽  
Waleska Rodrigues Pontes da Costa ◽  
...  
2021 ◽  
pp. 98-108
Author(s):  
Ali M. Elfeituri ◽  
Ibrahim M. Abou El Leil ◽  
Salah S. El-Elkhfifi

This paper has been carried out to determine the mineralogical and geochemical characteristics of Eocene Darnah limestone which outcrops at Wadi Al Kharsha as an example of the Darnah Formation. The most conspicuous phenomenon is the upward increase of the dolomitization process, whereas, the dolomite content ranges from 4.34 to 15.48 % with an average value of 8.99%. The lime (CaO) represents the major predominant with a high content (48.08%), it can be blend with other carbonates to improve its quality to meet the specifications of raw material for cement manufacture. The relationship between calcium (CaO) and magnesium (MgO) exhibits a significantly strong negative linear correlation coefficient (R2 = 0.967), which emphasizes the dolomitization process, while the relationship between SiO2 and Al2O3 is a positive linear significant relationship with a strong correlation coefficient (R2 = 0.98), whereas, the SiO2 increases with increasing of Al2O3. The calculated mineralogical composition revealed that halite, gypsum, and hematite are considered to be minor constituents, almost less than 1.0%. Keywords: Limestone; Darnah Formation; Mineralogy; Geochemistry; Dolomitization; Characterizations; Cement


Clay Minerals ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 557-564 ◽  
Author(s):  
F. Esenli ◽  
A. Sirkecioğlu

AbstractDiagenetic alteration in two tuff horizons (the lower and upper tuff units) in the GoÈrdes region of Turkey led to the formation of mainly heulandite-clinoptilolite-type zeolites and also clay and silica minerals and K-feldspar. Possible variations in the climate and geological environment followed by variations in the hydrological system and the composition of the Miocene lake water and groundwater at that time resulted in the mineralogical facies. The lower tuffs are unaltered or slightly altered in the northern part and are more altered, particularly to zeolite (clinoptilolite) in the southern part of the study area. Heulandite and K-feldspar are mainly authigenic minerals in the upper tuff unit. The ammonium-exchange capacities of the 16 samples were investigated to understand the effects of the mineralogical composition on their ion-exchange capacities, which vary in the range 0.19-2.00 mEq/g. It is observed that the ion-exchange capacities are strongly dependent on the zeolite contents of the rocks. The correlation coefficient of this linear relation is 0.86. The most significant increase in ammonium-exchange capacity (from 0.2 to ~1.0 mEq/g) was observed when the zeolite contents increased from 0 to 30 wt.%. The second increase in exchange capacity was observed for samples containing >80 wt.% zeolite. Although there is no significant effect from the other authigenic minerals, smectite has a positive effect, and K-feldspar and opal-CT have almost no effect on the ion exchange capacities.


Author(s):  
Зиен Ву Ким ◽  
Dien Vu Kim ◽  
Ван Танг ◽  
Van Tang ◽  
С. Баженова ◽  
...  

Blast furnace slag is a waste of metallurgical industry which can be used in production technology of concretes and mortars. The expedient use of blast furnace slag as a component for new building materials will improve the environmental situation and increase the economic efficiency of production. The authors reaserch blast furnace slag processing technology of factories "Hoa Phat" (Vietnam) and "Thai Nguyen" (Vietnam) to produce mineral additives. As a result of the conducted researches the chemical and mineralogical composition of slags are received, their physical and mechanical characteristics are considered and defined: specific surface area, density, water demand, and others. According to standard of Vietnam and Russia, slag activity index is calculated when considering the possibility of using blast furnace slags to replace part of the binder. The relationship between the strength of the cement-sand mortar and density affected by the binder are reveald (where; binder = Portland cement + Granulated blast furnace slag). Comparison chart of slag activity index IR (%) has been shown. The paper uses the Vietnamese standard TCVN 11586: 2016 to analyze the possibility of using blast furnace slag (Vietnam) in the technology of concrete and mortar construction.


2021 ◽  
Vol 1 (2) ◽  
pp. 012-023
Author(s):  
Benson Chinweuba Udeh ◽  
Chidinma Lovelyn Ani ◽  
Monday Omotioma

Calcination of Nkalagu limestone for the production of agricultural quicklime is presented. It entails improving the quality of limestone through calcination process. Appropriate scientific instruments/techniques (x-ray diffractometer and scanning electron microscopy) were used for the characterization of the uncalcined and calcined limestone samples. Effects of calcination variables on the quicklime yield were examined. Central composite design of design expert software was used to optimize the calcination process. Analyses of the results revealed that calcite was the major limestone’s mineralogical composition. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. Quadratic model adequately described the relationship between quicklime yield and calcination factors of temperature, particle size and time. The optimum yield of 74.00% was obtained at optima operating conditions; temperature of 937.41 0C, particle size of 85.99µm and time of 3.7 hrs. Characteristics of the quicklime showed that the calcination improved the quality of the sample in terms of mineralogical properties. It is recommended that the generated model should be used to develop chemical plant/equipment for limestone calcination process.


Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 381 ◽  
Author(s):  
Isabel Sonsoles de Soto García ◽  
María de los Reyes de Soto García ◽  
Rosario García Giménez

The present article evaluated the mineralogical composition of 85 mortar samples from some emblematic monuments of Ávila city (Spain), which were collected during the restoration of the monuments. The aim of this article is to try to extract the relationship between the composition and the origin of the raw materials, as well as to identify possible alterations in the samples. The study of the samples was carried out using visual and petrographic techniques such as stereoscopic microscope, XRD, and SEM/EDX analysis. The main components of the mortars were calcite, feldspar and quartz, although small amounts of phyllosilicates were also identified. The minerals of the mortars came from the surroundings of the city, and some of the samples presented evident alteration of the original materials due to humidity, salt concentration, and biological weathering, possibly inducted by unfortunate effects of the restoration. Finally, a study of the salts present in some mortars showed that most samples display contamination of soluble salts such as halite, thenardite, hexaedrite, and carnalite. This investigation offers fresh insight into historic building activity and related techniques, and should provide knowledge useful for restoration and conservation processes.


2021 ◽  
Vol 2 (1) ◽  
pp. 021-029
Author(s):  
Benson Chinweuba Udeh

This study focused on processing of Yandev quicklime for potential amelioration of acidic soil. It involved production of quicklime from the Yandev limestone, characterization and slaking of the quicklime. In a batch process, 10g of the limestone (90mm particle size) was calcined for 3hrs to produce the quicklime. Mineralogical composition of the quicklime was determined by X-ray Diffractometer (XRD), while scanning electron microscope (SEM) was used to examine its surface morphology. The CaO was hydrated for the production of slaked lime (Ca (OH) 2). The slaking process was carried out by digesting CaO in distilled water. During the slaking/hydration process, values of reactivity (rise in temperature) were recorded. Central composite design (CCD) tool of Design Expert Software 11 was used to design the experiment of the slaking process. Quicklime/water ratio, particle size and time were the considered slaking variables, while reactivity was considered as the response. Analysis of the results quicklime is made up of pure calcite with visible pores. Quadratic model adequately described the relationship between reactivity and the considered slaking factors of quicklime/water ratio, particle size and time. Optimum reactivity was obtained as 58.4 0C with the corresponding optimal factors of quicklime/water ratio (0.26 g/ml), particle size (93.0 µm) and time (16.4 minutes). Properties of the slaked lime showed that it is suitable for acidic soil amelioration.


Author(s):  
Isabel López ◽  
José Ignacio Pagán ◽  
Antonio J. Tenza-Abril ◽  
Luis Aragonés ◽  
Luis Bañón

The main objective to this work is to establish a relationship between shoreline evolution and sediment wear. The shoreline evolution trend is similar to of the results obtained by the accelerated particle wear test (APW). However, the relationship between the number of APW test cycles and the years of shoreline evolution is not clear. In Guardamar beach the ratio (years/cycles) is 9.7, in Marineta Casiana beach (it is 5.6, and in Arenal beach it is 3. Differences may be due to the different mineralogical composition and morphology of the sand particles.


1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.


Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.


2020 ◽  
Vol 43 ◽  
Author(s):  
Thomas Parr

Abstract This commentary focuses upon the relationship between two themes in the target article: the ways in which a Markov blanket may be defined and the role of precision and salience in mediating the interactions between what is internal and external to a system. These each rest upon the different perspectives we might take while “choosing” a Markov blanket.


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