Table 3 - uploaded by G.E. Christidis
Content may be subject to copyright.
Source publication
Clays have been used by man since prehistoric times. Initially they were used almost entirely in the fabrication of ceramics, nowadays they find numerous industrial and technological applications including the production of materials with large added value such as nanocomposites, cosmetics or pharmaceuticals. The term clay should not be considered...
Citations
... Clays can be divided into families based on their physicochemical properties and atomic structure. This structure depends on the arrangement of tetrahedral and octahedral layers that compose them, formed mainly by Si, Al, Fe, and O atoms in the first case or by Al, Mg, Fe, and O in the second (Christidis, 2011;Huggett, 2013). Species from 4 large groups are generally found in the soils used for construction: smectites (Sm), illites (Ill), kaolinite (K), and chlorites (Cl) (Delinière et al., 2014;Randazzo et al., 2016;Lima, Faria and Santos Silva., 2020;Lagouin et al., 2021a). ...
... A greater number of available exchange sites implies greater cation storage capacity and greater availability (Bueno Buelvas and Fernández Lizarazo, 2019). This property is directly related to the specific surface area, which is why Sm has a higher CEC than Ill and Cl, and these, in turn than K (Christidis, 2011). In this way, the properties of each soil such as its compressive strength, rheology, and its linear shrinkage are associated with this aspect (Delinière et al., 2014;Jia et al., 2024). ...
The clay fraction of earthen plasters is the part responsible for the acquisition of cohesion and adherence that they possess against deterioration factors. Adherence is the property responsible for keeping the plaster together with the wall and is influenced by the percentage content of clay as well as by its mineralogy and the heterogeneity of minerals that may be present. However, it is still unknown in depth how clay minerals perform in the adherent properties of earthen plasters when the composition is heterogeneous in the material. The objective of this study is to evaluate the incidence of the mineralogical complexity of clay mineralogy in the variability of the adherence of earth plasters. To evaluate the variability, considering that the mineralogy of the soils depends directly on the place and the formation processes, eight soils from Tucumán (Argentina) corresponding to different physiographic units were analyzed. A methodology was designed for sample preparation that allows soils to be compared through adhesion tests. They were characterized by XRD to determine their mineralogical composition and by the hydrometric method to determine their granulometry. To evaluate the adherence of mixtures made with the respective soils, it was proposed in the first instance to compensate the granulometry of the soils to equate them and, once the plasters were made, this property was evaluated through shear and pull-off tests. The results showed that they allowed us to identify that the soils presented a pattern of mineralogical composition common to all the physiographic units, made up of the Ill and K pair, the former being predominant. For this pattern, it was observed in particular that there is a positive correlation between the increase in Ill content with the increase in the adhesive strength of the plasters. Clay minerals from the Sm group also contribute to the increase in adherence when the percentage is greater than or equal to 11%. On the contrary, K and Cl do not influence the increase in adhesive strength.The clay fraction of earthen plasters is the part responsible for the acquisition of cohesion and adherence that they possess against deterioration factors. Adherence is the property responsible for keeping the plaster together with the wall and is influenced by the percentage content of clay as well as by its mineralogy and the heterogeneity of minerals that may be present. However, it is still unknown in depth how clay minerals perform in the adherent properties of earthen plasters when the composition is heterogeneous in the material. The objective of this study is to evaluate the incidence of the mineralogical complexity of clay mineralogy in the variability of the adherence of earth plasters. To evaluate the variability, considering that the mineralogy of the soils depends directly on the place and the formation processes, eight soils from Tucumán (Argentina) corresponding to different physiographic units were analyzed. A methodology was designed for sample preparation that allows soils to be compared through adhesion tests. They were characterized by XRD to determine their mineralogical composition and by the hydrometric method to determine their granulometry. To evaluate the adherence of mixtures made with the respective soils, it was proposed in the first instance to compensate the granulometry of the soils to equate them and, once the plasters were made, this property was evaluated through shear and pull-off tests. The results showed that they allowed us to identify that the soils presented a pattern of mineralogical composition common to all the physiographic units, made up of the Ill and K pair, the former being predominant. For this pattern, it was observed in particular that there is a positive correlation between the increase in Ill content with the increase in the adhesive strength of the plasters. Clay minerals from the Sm group also contribute to the increase in adherence when the percentage is greater than or equal to 11%. On the contrary, K and Cl do not influence the increase in adhesive strength.
... As a result, more stable colloids are created. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. ...
In this work, we investigate the capability of a waste bentonite from the Polycanthos quarry in Cyprus, as a low-density
solid additive to create colloids that are used in water-based drilling fluid systems (WBF) in drilling operations. Repurposing waste bentonite aligns with environmental sustainability and when properly processed can serve as a cost-effective solution to achieve the desired colloidal properties for WBF. Samples were obtained from waste stockpiles and were mechanically processed to a size < 63 μm. The material was activated with soda
ash via three different methods investigating optimum soda ash percentage and curing time. Standard tests were performed for the rheological behavior and filtration properties and the results indicated that the quality of the activated clay dispersions improved slightly but the desired colloidal properties were not obtained. This can be attributed to the K+-rich clay and non-clay impurities that are inherent in the material so further amendment
with xanthan gum polymer was conducted, at various concentrations. Results of this work show that with minor
polymer addition, the material under investigation reaches the desired colloidal properties and qualifies according to API standards for WBF. Exploiting local waste clay material in WBF application leads to the development and sustainability of local resources thus contributing to the circular economy principle.
... Bentonite is a crystalline clay mineral. The nano-Bentonite consists of fine, rounded particles with particle size in the range 50-150 nm and a maximum particle size of 25 mm [42,43]. ...
h i g h l i g h t s Rheological behavior of alkali activated low-calcium fly ash (AAF) binder pastes investigated. The constant strain rate response of AAF binder pastes varies between Yield-type and Maxwell flow behaviors. Stable cellular structure created in AAF binder pastes with yield type behavior. Addition of nano-clay transforms the behavior of AAF binder paste from Maxwell flow to yield-type response. Nano-clay enhances the yield stress of AAF binder pastes. a b s t r a c t An efficient method of production for cellular geopolymer from an alkali-activated fly ash (AAF) binder paste by controlling its rheological behavior is presented. The AAF binder paste exhibits a complex rhe-ological behavior, which is influenced by the solids loading and the composition of the activating solution. The constant strain rate response of the AAF binder paste varies between a yield-type and Maxwell flow behavior. Entrained porosity created in the hardened geopolymer matrix with the use of Aluminum powder exhibits a dependence on the constant strain rate response of the AAF binder paste. A cellular structure is achieved in pastes which exhibit a yield-type behavior. The addition of nano-clay fundamentally alters the constant strain rate response of AAF binder pastes producing a yield-type response in suspensions that exhibit a Maxwell flow behavior. There is also an increase in the peak stress in the constant strain rate response with nano-clay. A stable cellular structure is produced in the AAF binder pastes which exhibit a Maxwell-flow type response with the addition of clay. Montmorillonite is more effective than Bentonite in enhancing the yield stress of the AAF binder pastes. The importance of identifying the yield stress of the AAF binder pastes for creating a stable cellular structure within the hardened geopolymer matrix is established. The cellular structure in the geopolymer matrix can be tailored with the rheology control of the AAF binder pastes using nano-clay.
... Initially, they were mostly used in the manufacture of ceramics, but recently they are being utilised in other industries. These industries include agriculture, engineering, construction, environmental remediation and the focus of this research paper; catalysis [1]. It should be noted that the term clay should not be mistaken for clay mineral; a clay mineral is a group of hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earth and other cations found on or near some planetary surfaces that form in the presence of water [2]. ...
The operational effectiveness of a fluid catalytic cracking unit largely depends on its catalyst , which is a mixture of zeolite, binder, matrix and filler. The filler plays an active role as it provides the catalyst with physical strength and integrity and also presents a heat exchange platform where more imperative and costly zeolite component can be incorporated. In Nigeria, foreign kaolin clay is used as fillers because it contains lesser impurities when compared to the one indigenous to the country. In contrast, Nigeria bentonite clay have unique properties that can be processed and used as an alternative. This paper evaluates the suitability of kaolin and sodium bentonite from southern Nigeria as fillers in the Fluid Catalytic Cracking Unit. Initial characterisation with the aid of an XRF analysis confirmed the presence of iron oxide impurity on both the local and foreign crude clay (Bavaria, Germany). Wet beneficiation processes were carried out on all clay samples with different reaction times, temperatures and amounts of reagents to reduce impurities. Reaction time at 8 h proved more effective as 77% of iron oxide were removed from both the local and foreign clays. The product properties of the beneficiated samples also revealed iron oxide impurities that reduce impurities from 5.62% to 1.41% for kaolin clay and from 9.84% to 2.77% for bentonite clay. Samples of crude oil and products were tested to determine their physical properties using an Emmetteller Brunauer, a scanning electron microscope, a viscometer, and a pH meter to reveal the impact of the benefits on compliance with API standards. Aside from the increase or decrease of particulate or grain size, the structural modifications reflect the impact of mineral clay in retaining exchangeable cations (nutrients)
... The na-Journal of Power and Energy Engineering ture of plasticity is related to the water molecules which are adsorbed on the clay mineral surfaces forming a rigid film with a certain order, which links together clay particles (Grimshaw, 1971). The clay particles form coherent networks, which can deform and retain their shape after the stress is removed) [14]. ...
The term "Eco-lodge" is used to identify a type of nature-based tourism facility that will respond to the principles of ecotourism. The research aims to study, develop and design such types of facilities in an environmentally sensitive manner, using local materials or recycled materials, with a design that serves the environment and is consistent with the nature and cultural background of the place, through Energy Efficiency and Renewable Energies. This leads us to the ideas and foundations of seeking to preserve natural energy, respect the environment and reduce the impact of construction thereon. The research applies environmental and sustainable design standards to a proposed model designed by the Author for desert lodges, and the most important advantages of supporting ecotourism, by observing the principles of good design consistent with the local environment and culture, preventing the use of internal pollution sources, adapting to the climate, using alternative environmentally friendly materials, the efficiency of production and use of energy to promote the use of clean renewable energy. As important elements in the development of tourism and to help to preserve natural heritage and biodiversity. Such architectural solutions aim to achieve the objectives of eco-design, in terms of reducing the cost of energy in buildings, using natural energy instead of mechanical power systems, in addition to creating a healthy and comfortable environment.
... landfills to impede migration of inorganic and organic pollutants into neighbouring soil, groundwater and surface water (Vimonses et al., 2009;Naganathan et al., 2010;Brown et al., 2011. The variability of physical properties of sedimentary kaolins and, hence, of its industrial uses depends on the depositional environment and post-depositional modifications (Hurst & Pickering, 1997;Ekosse, 2000;Nyakairu et al., 2001;Sousa et al. 2007;Christidis, 2011) which affect the mineralogical and chemical composition, the kaolinite crystal size and order, the colour (brightness/whiteness) and the firing characteristics (Grim, 1962;Pinheiro et al., 2005;Siddiqui et al., 2005;Murray, 2007;Christidis, 2011). ...
... landfills to impede migration of inorganic and organic pollutants into neighbouring soil, groundwater and surface water (Vimonses et al., 2009;Naganathan et al., 2010;Brown et al., 2011. The variability of physical properties of sedimentary kaolins and, hence, of its industrial uses depends on the depositional environment and post-depositional modifications (Hurst & Pickering, 1997;Ekosse, 2000;Nyakairu et al., 2001;Sousa et al. 2007;Christidis, 2011) which affect the mineralogical and chemical composition, the kaolinite crystal size and order, the colour (brightness/whiteness) and the firing characteristics (Grim, 1962;Pinheiro et al., 2005;Siddiqui et al., 2005;Murray, 2007;Christidis, 2011). ...
Detailed multi-scale characterization of the kaolin quality and the controlling depositional environment is crucial for optimal quality upgrading and for prioritizing potential exploitation areas. In the present work, the quality of El-Tih kaolin, Egypt, was investigated using the chemical/mineralogical
characteristics as well as the field observations of the clay. Chemical analysis of major oxides was carried out using energy dispersive X-ray fluorescence (EDS-XRF) spectrometry. Mineralogical analyses were carried out using X-ray diffraction (XRD) and scanning electron microscopy coupled
with wavelength-dispersive X-ray spectroscopy (SEM-WDS). Spatial heterogeneity of the quality was evaluated applying kriging geostatistical techniques and potential zones were identified. Results clarified an upward gradual deterioration of the quality via a decrease in the Al2O3
content and thickness of the clay layers, and an increase in the TiO2 content. According to the kriging maps, areas of high potentiality indices (PI) characterized by high Al2O3 and low SiO2 content and maximum thickness of the kaolin are located
to the west and east, and decrease toward the central part of the study area. The high PI zones are dominated by pseudo-hexagonal platy kaolinite, often forming accordion- and book-like aggregates with subordinate quartz and traces of Fe and Ti oxides, yielding minimal TiO2 and
Fe2O3 contents. These zones of high PI are considered optimal for exploitation. Kaolinite was formed as a result of intensive weathering of rhyolite/granite and basalt in the source area, and subsequent erosion, transportation and deposition of the weathering mantles
in a flood environment with marked depositional energy variations. Results allowed comparison with worldwide kaolin occurrences, and suggested the suitability of the studied kaolins for use in paper coating and filling and in higher-grade ceramics, after removal of free Fe- and Ti-oxide impurities.
Clays with various chemical and mineralogical compositions are an increasingly important mineral source for producing sustainable cements, mortars, and concretes. Numerous studies have recently been conducted to expand the scope of widespread and potentially suitable clays, including bentonite clays. The composition and unique structural characteristics of bentonite clay facilitate their application in cement-based materials in raw, activated, and modified forms as a supplementary cementitious material, micro-and nano-pore-forming agent, pore structure and engineering property modifier, and aluminosilicate precursor. This review analyses recent studies on the growing role of montmorillonite (MM) clays in the design and exploration of Portland clinker-reduced cements, non-clinker alternative cements, and various cement composites. In addition, this review presents the advances in the theoretical investigation of MM reactivity enhancement using activation and modification techniques and reagents, and the interactions of MMs and superplasticisers.
