The present study focused on analyzing these parameters on the metakaolins calcined at 800 °C from three kaolins, and the metakaolins' alkali activation …
The natural kaolin deposits are crystalline inert with low CaO contents and surface area. Therefore, kaolin is not a suitable material used to produce Alkali …
Low-temperature activation of quartz and kaolin, two of the most abundant and affordable raw materials as the sources of alumina and silica for the production of zeolites, is highly desirable but is hampered by several challenges such as incomplete activation and the formation of acid-resistant aluminosilicates.In this paper, the …
Four metakaolins were prepared by calcination of a natural Spanish kaolin (Navalacruz deposit, Zamora province) at 600, 700, 800, and 900 °C. These four …
Scanning electron microscopy. Raw kaolin and kaolin pre-treated in alkali solutions at 20:1 liquor ratio and 4% concentration for 3.5 h are shown in Fig. 1.The unmodified clay SEM image revealed presence of large particles that appeared to have been formed by several flaky particles stacked together in form of densely packed …
Kaolinite, or kaolin (Al 2 SiO 5 (OH) 4), is a clay mineral characterized by its structure 18,19,20,21. This mineral, commonly found in white coloration, is prevalent in soils created through the ...
geopolymeric cement by calcining low-quality kaolin with alkali ... resistant to water. Alkalis seriously alter the thermal decomposition course of kaolin, and the octahedral- ... kaolin with sodium and potassium hydroxide at 550 C. However, the compressive strength was considerably low [10]. Solid-state synthesis through thermal reaction
Jotashield Alkali Resistant Primer protects from alkali attack, helping strengthen concrete, maintain the integrity of the walls while increasing their lifespan and reducing chalking surfaces. It also increases the adhesion of paint to the wall, making it possible to create whatever colour combination is desirable.
This type of raw material is useful because it contains large amounts of silica and alumina, which are the components of geopolymers together with the alkali oxides. Metakaolin is obtained by heating kaolin, which is a natural raw material mainly composed by kaolinite (Al 2 O 3 ·SiO 2 ·2H 2 O). For this reason, in this paper we studied the ...
In response to alkali spills, the basal site density increased to 925 mmol kg−1, and the edge site density increased from 84.8 to 253 mmol kg−1 due to AlOH and SiOH formation; thus, pKa2 ...
In the first step, three sets of three samples were prepared by mixing 1.5 g kaolin and 0.6 g quartz each with 16 mL of 2, 4 or 8 M NaOH aqueous solutions, via vigorous stirring. These three sets of homogeneous mixtures with different amounts of NaOH aqueous solutions were then heated in a closed Teflon-lined stainless steel …
The present study determined the mineralogy and thermal properties of kaolin from Acoculco (Puebla), at the eastern Trans-Mexican Volcanic Belt and …
This paper explores the resistance of alkali-activated concrete mixes to aggressive media that concrete is expected to encounter in-service. Findings indicate that the chloride, freeze-thaw and ...
The stronger acid and alkali resistance of PAMA would broadened its applications for sludge or wastewater with different pH ranges, and thus effectively solved the low acid and alkali stability of existing CPAM. ... study on the effectiveness of hydrophobically modified cationic polyacrylamide groups in the flocculation of kaolin. …
Kaolin deposits are widely distributed in Mexico, mainly in Chihuahua, Guanajuato, Veracruz, Michoacán and Hidalgo and are usually located in the Trans-Mexican Volcanic Belt (TMVB) (De Pablo-Galán, 1979). The exploitation of Mexican deposits, 2015 The …
DOI: 10.1016/j.cscm.2024.e02858 Corpus ID: 266807932; Application of pretreated dealuminated kaolin as a modifier agent for alkali-activated slag cement @article{Alkroom2024ApplicationOP, title={Application of pretreated dealuminated kaolin as a modifier agent for alkali-activated slag cement}, author={Hussein Al-kroom and …
Semantic Scholar extracted view of "Water treatment sludge as precursor in non-dehydroxylated kaolin-based alkali-activated cements" by J. Mañosa et al. Skip to search form Skip to main ... fresh properties, mechanical strength, microstructure, acid and sulfate resistance, high temperature behaviors, impact resistance and interface shear ...
This paper examines the effects of different kaolin qualities on the thermal activation process of metakaolin production. The qualities of kaolin depend on the impurities they contain, such as mica, feldspar and quartz. In this …
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The increase in Na 2 O concentration to 15% decreased the resistance due to the excess of alkali in the system. Besides, there are also attempts to develop one-part AAM from the most common precursors, such as fly ash and granulated blast furnace slag. ... Synthesis, characterization and mechanisms of one-part geopolymeric cement by …
Aust. J. Basic & Appl. Sci., 5(7): 1026-1035, 2011 1027 So far, research work carried out in developing alkali-activated binders has shown that they are likely to
The alkali activation can be carried out via two main pathways; a one-part mix (aluminosilicate precursor and solid alkali activator mix with water) [26][27] [28] or a two-part mix (liquid alkali ...
Soil–alkali interaction leads to abnormal soil behavior due to significant changes in mineralogy and morphology. The effect of alkali on the swelling behavior of natural clays has been explored in recent years, but the swelling behavior of alkali-transformed clay minerals is still unclear. The objective of the current study was to …
In the present paper, we study the combined effect of thermal activation (600 °C/2 h and 750 °C/2 h) and chemical activation with 1% ZnO on the reactivity of metakaolinite (MK) obtained from natural …
Highlights AAMK system has better acid, seawater attack, sodium sulfate resistance than PC. AAMK system has very good heat resistant up to 1200–1400 °C. Polypropylene and short fibers increase AAMK flexural, strength and impact energy. Replacing 10% MK with FA or lime or 20% with calcite gave higher strength. MK and …
The mechanical properties, fire resistance and alkali resistance and thermal shocking resistance all met the requirements of Chinese standard GB-14907-2002 (Fire resistive coating for steel structure), excerpt for the relatively high density. Zhu et al. (2013) reported the effect of H2O/Al2O3 ratio on the thermal stability of geopolymer.
Metal losses ranged from 5 to 16 microns and thermal cycling resulted in moderately higher corrosion rates compared to isothermal conditions. Type 316 SS was somewhat more corrosion resistant than Type 304 SS in these tests. The effect of carbon content on corrosion resistance was small, as 316L SS corroded only slightly slower …
As a new textile material, silk/PLA mixture combines the outstanding characteristics of silk and PLA fibers, but this mixture is subjected to some problems owing to the poor alkali resistance of PLA fiber during the pretreatment and reactive dyeing processes. In the present work, the alkali resistance of silk/PLA mixture was tested with three alkalis, …
Main conclusion The keys to alkali-stress resistance of barren-tolerant wild soybean lay in enhanced reutilization of reserves in cotyledons as well as improved antioxidant protection and organic acid accumulation in young roots. Abstract Soil alkalization of farmlands is increasingly serious, adversely restricting crop growth and …
An experimental study was carried out to evaluate the effect of several fibers on the mechanical properties, drying shrinkage, and microstructural characteristics of alkali-activated kaolin binders.
In order to develop the alkali resistance property of mullite castable, it was prepared using calcined clay grain, Al2O3 powder, silica fume, calcium aluminate cement as raw materials, and SiC as ...
The resistance to these factors of four different fibres (mineral and kaolin wool, carbon and polypropene fibres) was investigated using X-ray diffraction and scanning electron microscopy (SEM).
The scanning electron microscope (SEM) pattern shows that kaolinite particles contained in these kaolins are very small (<2 µm) and are poorly crystallized due to the impurities they contain. Meka'a kaolin's are extremely weathered (CIA and CIW ≈ 100) and their organic matter content is considerable (1.82-2.54%) and is explain...
Asymmetric stretching of Si-O or Al-O between 900 cm −1 and 1100 cm −1 shows the amorphous nature of geopolymer ceramic (MCGC and MKGC) and absorbed water molecules during geopolymerization.
Alkali leaching was employed to investigate the separation of alumina and silica in roasted kaolin obtained by roasting kaolin alone in air at 1273 K for 60 min and in clinker prepared by roasting the mixed raw meal of kaolin, ferric oxide and coal powder with Fe 2 O 3 /Al 2 O 3 /C molar ratio of 1.2:2.0:1.2 in reducing atmosphere at 1373 K for 60 …
Our previous studies showed that the most effective hydrothermal alkali activation (HAA) conditions for quartz, the mixture of kaolin (1.5 g) and quartz (0.6 g), and kaolin are (1) 6 M NaOH/190 °C/24 h [34], (2) 8 M NaOH/240 °C/8 h [20], and (3) 4 M NaOH/240 °C/3 h [19], respectively. Industrial applications prefer low activation ...
The properties of the product obtained through alkaline activation of metakaolin are directly influenced by the characteristics of the starting kaolin. For the study of this influence, a complete characterization of two spanish kaolins used to synthesised the material has been carried out. A JAF conduction calorimeter was used to follow metakaolin reaction …
The use of kaolin and calcined kaolin (metakaolin: MK) to manufacture geopolymer has attracted worldwide interests. The aim of this paper is to present an overview on the progress of the geopolymer research and development in China in the last 25 years.The works on geopolymerisation mechanisms, microstructure …
