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Ettringite is a hexacalcium aluminate trisulfate hydrate, of general formula: (CaO) 6 (Al 2 O 3)(SO 3) 3 · 32 H 2 O, or; (CaO) 3 (Al 2 O 3)(CaSO 4) 3 · 32 H 2 O. Ettringite, a naturally-occurring mineral, is formed in hydrated Portland cement system as a result of the reaction of calcium aluminate with calcium sulfate, both present in Portland cement. [1]
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Ettringite is a mineral with formula of Ca 6 Al 2 (S 6+ O 4) 3 (OH) 12 ·27H 2 O or Ca 6 Al 2 (SO 4) 3 (OH) 12 ·27H 2 O. The corresponding IMA (International Mineralogical Association) number is IMA1962 s.p.. The IMA symbol is Ett. RRUFF Project. 1 Structures. 1.1 2D Structure. Structure Search. Get Image.
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Cement, en viktig beståndsdel i betong, innehåller vanligtvis cirka 8 % trikalciumaluminat, inom byggkemin förkortat C 3 A. För att hindra en alltför snabb stelning vid kontakt med vatten, på grund av bildning av kalciumaluminathydrat, tillsätts en andel gips (ca 6 %), med vilket C 3 A istället bildar ettringit. Detta medför en tillfällig volymmässig expansion i och med dess stora ...
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Ettringite (or aft phase) can also be produced in the laboratory by reacting stoichiometric amounts of calcium, aluminium and sulfate in water. In the cement system, the presence of ettringite depends on the ratio of calcium sulfate to aluminate; when this ratio is low, ettringite forms during early hydration and then converts to the calcium ...
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Ettringite $ 85.00 Original price was: $85.00. $ 68.00 Current price is: $68.00. Specimen # 215179. Specimen Locality: Wessels Mine, Kuruman, South Africa. Mineral Description: A matrix piece dusted with numerous small black crystals of specular hematite and several translucent yellow ettringite crystals. Height: 5.5 Width: 4 Depth: 1.8 cm
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Ettringite synthesis was carried out by precipitation from solution, which is considered the most optimal way because of the simplicity of the technique and low energy consumption. To obtain ettringite in the laboratory, the following materials were used: sugar; Ca(OH) 2; Al 2 (SO 4) 3 ·18H 2 O and sodium hydroxide. The method of obtaining the ...
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Ettringite. specimen number: 1341774. location: N'Chwaning mines, Kuruman, South Africa. description: A brilliant yellow lustrous crystal of ettringite 0.6 cm across set nicely up on matrix. In terrific condition. Watch Specimen Video. Size: 2.6 x 2.5 x 2.0 cm (thumbnail) Collection: Jan Dietrich. Purchase With Layaway
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Ettringite Formula Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O Crystal System Hexagonal Crystal Habit Acicular Cleavage Perfect, None, None Luster Vitreous (Glassy) Color colorless, white Streak white Class Hexagonal - Dihexagonal Dipyramidal Hardness 2 …
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Ettringite always exists in cement based materials, it begins to form during cement hydration process [1]. Ettringite is also applied to the shrinkage compensation and hardening accelerating and set accelerating of concrete [2]. However, formation of excess ettringite has negative effect on durability of cement based materials.
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Ettringite Formula Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O Crystal System Hexagonal Crystal Habit Acicular Cleavage Perfect, None, None Luster Vitreous (Glassy) Color colorless, white Streak white Class Hexagonal - Dihexagonal Dipyramidal Hardness 2-2.5 . Data courtesy of Webmineral. Mineralpedia View Ettringite
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The specimen is a cluster formation of ettringite with a shallow domed shaped form with hexagonal yellow crystals having grown more or less vertically. The largest crystal to 0.6cm. Mineral Data. What's on the rock. Ettringite. Formula: Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O. Strunz: 7.DG.15. Hardness:
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With more SCMs addition, the aluminate containing hydration products are increasing and accounts for more than 25 % of the solid volume of Portland cement pastes from thermodynamic calculations [11], [12].The aluminate containing hydration products of Portland cement mainly include ettringite, monosulfate (AFm), monocarbonate (Mc), hemicarbonate …
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This specimen contains over 10 crystals of Ettringite, a rather unusual sulfate mineral from South Africa. They are in generally good condition, though some of the crystasls show obvious …
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Mineral Description: A matrix piece dusted with numerous small black crystals of specular hematite and several translucent yellow ettringite crystals. Height: 5.5 Width: 4 Depth: 1.8 cm
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colloidal solution formed when selenate ettringite was soaked in butanol. This is because the surface of the columnar parts in ettringite is surrounded by structural water molecules that can interact with OH groups of strongly polar solvent molecules to form hydrogen bonds that can directly exfoliate selenate ettringite and convert to ...
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Ettringite is generally considered to be stable up to a temperature of 110°C; however, some investigators claimed that ettringite may already decompose at even ambient temperatures.
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Over 30 hexagonal prismatic Ettringite crystals rest on the dark brown host rock of this thumbnail specimen. These crystals range in size from a few millimeters along each axis to 0.4 x 0.3 x 0.3" (1.0 x 0.8 x 0.7 cm). Though a few are obviously broken and mostly incomplete, those that are intact are in excellent condition and have excellent ...
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The hydration degrees of clinkers and ettringite stability in calcium sulfoaluminate (C S ‾ A) cements in the presence of externally supplied dolomite were investigated in this study. The mineralogical and microstructural characteristics of C S ‾ A cements containing different dosages of dolomite were characterized using X-ray diffractometry, Rietveld refinement-based …
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In the case of the sample characterized by the ratio of 1:1 (typical of monosulfate), a considerable portion of ettringite (27.9%) was present in the final products along the AFm phase. Therefore ...
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Hydrous calcium sulfo-aluminate From Wikipedia, the free encyclopedia. Ettringite is a hydrous calcium aluminium sulfate mineral with formula: Ca 6 Al 2 (SO 4) 3 (OH) 12 · 26H 2 O.It is a colorless to yellow mineral crystallizing in the trigonal system.The prismatic crystals are typically colorless, turning white on partial dehydration.
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In addition, endothermic peak ranges for ettringite or calcium silicate hydrates and gypsum were found as 88°C-105°C and 120°C-134°C, respectively. DSC was found to be a reliable technique in ...
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Ettringite Group. Although it is generally assumed that a solid solution series between ettringite and thaumasite exists, both species have different space groups and a possible discontinuity was identified, characterised by a gap in the a-dimension of the solid-solution phases (Barnett et al., 2000).Further work showed a miscibility gap in the solid solution (Barnett et al., 2003): …
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Ettringite is a hydrous calcium aluminum sulfate mineral that typically bears colorless to yellow coloration. It was first described by J. Lehmann in 1874 from an occurance at Ettringer …
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Though pure ettringite is rarely faceted, you can find various faceted gemstones composed of ettringite and other minerals. Almost all of these are yellow, with some colorless exceptions. These faceted ettringite gemstones range from around $60 to $250 per carat, or around $90 to $1,200 each.
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The formation of ettringite crystals between particles can be modelled as randomly throwing rectangles based on Monte Carlo simulation, typically used in simulating aggregate distribution in concrete. A MATLAB program was used to implement this simulation as shown in Appendix 1. Ettringite rectangles are throwed in an 8μm × 1 μm area.
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Media in category "Ettringite" The following 200 files are in this category, out of 220 total. (previous page) ()
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A.9 presents the distribution of ettringite, calcite, and portlandite in the mixed system at a 30% addition ratio. For ettringite, areas containing sulfur indicate ettringite, whereas regions with silicon correspond to C-S-H, as only ettringite contains sulfur and …
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The sturmanite forms yellowish coatings, with ettringite cores. Stone Sizes. Material from Ettringen and Franklin is microscopic. A 2.5 carat pale yellow ettringite was faceted from material found in the center of a mass of …
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Ettringite là một khoáng chất calci nhôm sulfat với công thức: Ca 6 Al 2 (SO 4) 3 (OH) 12 ·26H 2 O. Nó là một khoáng chất từ không màu đến màu vàng kết tinh hệ tinh thể lục phương.Các tinh thể lăng trụ này thường không có màu, biến thành màu trắng khi mất nước một phần. Nó là một phần của nhóm ettringite bao gồm các ...
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اترینگایت یافت‌شده در معدن نچوانینگ آفریقای جنوبی. اترینگایت (به انگلیسی: Ettringite) یا هگزاکلسیم آلومینات تری‌سولفات هیدرات یک کانی با ترکیب شیمیایی تقریبی Ca 6 Al 2 (SO 4) 3 (OH) 12 ·[30-32](H 2 O) [۱] یا Ca 6 Al 2 (SO 4) 3 (OH) 12 ·[26](H 2 O) [۲ ...
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The generation of ettringite was mainly responsible for the compressive strength and water resistance improvements of nano-modified CSA. The hydration process of nano-modified CSA was clarified and the corresponding micro-mechanism model was proposed. Furthermore, the benefits and challenges of using nano-modified CSA were also analyzed ...
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Ettringite formation was evidenced in all lime-treated samples, whenever sulfates were present. A non-expansive monosulfate calcium-aluminum-hydrate forms first in the high alumina content lime ...
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"Ettringite" (AFt) تولید کند که تاثیر قابل توجهی بر مقاومت سیمان دارد. ... که همواره در تلاشند تا اطلاعات فنی دقیق در مورد محصولات ساختمانی، قیمت های رقابتی، به روز و شفاف و کیفیت های برتر بازار را ...
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