Phosphogypsum is a by-product of phosphoric acid production by a wet-process and can be used to prepare adsorption materials to treat Cd(II) in sewage. Its main component is calcium sulfate dihydrate (gypsum). In the present study, incorporation and adsorption of cadmium on gypsum in an aqueous environment have been investigated …
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Phospho-gypsum is an industrial solid waste discharged from the phosphate production process. The waste includes complex impurities such as phosphoric acid and its salts, fluoride, and organics. Usually, retarders are mixed in gypsum-based building materials to extend setting time. Although the effects of the impurities on hydration …
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THE GEOLOGIC ENVIRONMENT by LEONARD STEVEN ROLNICK A.B., THE JOHNS HOPKINS UNIVERSITY ... Less is known about the problem of post-depositional changes once the gypsum and anhydrite have been formed into deposits. ... Gypsum is composed of calcium sulphate dihydrate (CaSO4.2H20) and has the very useful property of being …
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Co-precipitation of mineral-based salts during scaling remains poorly understood and thermodynamically undefined within the water industry. This study focuses on investigating calcium carbonate and calcium sulfate mixed precipitation in scaling. Scaling is often observed in the produced water supply as a result of treatment …
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Calcium sulfate is widely found in the Earth's crust, in areas such as deserts, lakes and oceans [1,2].Calcium sulfate has three crystalline polymorphs that differ in their degree of hydration, including dihydrate (CaSO 4 ·H 2 O, gypsum), hemihydrate (CaSO 4 ·0.5H 2 O, bassanite) and anhydrite (CaSO 4) [3,4,5,6].Among these polymorphs, …
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The paper assesses the influence of the calcination temperature of synthetic gypsum binder on the binding properties of innovative gypsum pastes, as well as on masonry and plastering …
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We have investigated the solubility behavior of calcium sulfate dihydrate (gypsum, CaSO4·2H2O) in aqueous NaCl solutions upon the addition of ammonium- or imidazolium-based ionic liquids (ILs), viz., ethylammonium lactate (EAL), 1-ethyl-3-methyl imidazolium hydrogen sulfate ([C2mim]HSO4), and 1-butyl-3-methyl imidazolium …
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This Environmental Product Declaration (EPD®) describes the environmental impacts of 1 kg of Gypsum Mineral (Calcium Sulphate Dihydrate). Gypsum Mineral, Calcium Sulphate Dihydrate (CaSO4.2H2O) is a white powder produced from processing high-purity gypsum minerals. Gypsum Mineral has multiple uses in a range of industries.
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Abstract: As a recycled material, flue gas desulfurization gypsum has been used to prepare calcium sulfate hemihydrate whisker (CSHW) through hydrothermal synthesis for several decades. However, the subsequent utilization of this resultant material has not yet received considerable attention. In the present research, CSHW was successfully synthesized at …
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The most prevalent sulfate mineral in the surrounding natural environment is calcium sulfate, which can be found as calcium sulfate dihydrate or gypsum (CaSO 4 ·2H 2 O), hemihydrate (CaSO 4 ·½H 2 O), and anhydrite (CaSO 4). All of these forms have the ability to be crystallized in the presence of water [11, 12]. Numerous industries struggle ...
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The dehydration products of gypsum under different temperature and water vapor pressure were investigated by thermodynamic theory. Additionally, the rehydration mechanism of soluble anhydrite was …
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A review with 9 refs. Calcium sulfate, commonly known as natural gypsum, is found in nature in different forms, mainly as the dihydrate (CaSO4.2H2O) and anhydrite (CaSO4). They are products of partial or total evapn. of inland seas and lakes. Both the dihydrate and the anhydrite occur in nature in a variety of forms.
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While farmers have used gypsum (calcium sulfate dihydrate) for centuries, it has received renewed attention in recent years. This resurgence is due in large part to ongoing research and practical insights from leading experts that highlight the many benefits of gypsum. ... School of Environment and Natural Resources, The Ohio State …
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The measurement of spectra over samples of gypsum in the 1,300–2,500 nm wavelength using a PIMA spectrometer showed the presence of distinct absorptions at 1400–1600, 1750, 1940, 2,100, and 2,400 nm characteristics to O H stretching, H 2 O combinations, and S O bending overtones and stretching, respectively. Studying the …
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calcium sulfate into gypsum dihydrate calcium sulfate in the gypsum board manufacturing process. Carrier solvents occasionally used for silanes and siloxanes should be avoided in wallboard manufacturing due to the volatile emissions at the board mixer where operators are exposed and in the kiln due to VOC stack emissions.
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Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4·2H2O). ... The formation of gypsum involves a sequence of geological and environmental processes: Deposition: Gypsum initially forms as dissolved ... Middle East: Gypsum deposits are common in several …
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This type of gypsum is called "flue gas desulfurization" (FGD) gypsum. Chemically, FGD gypsum is the same as mined gypsum. In the process that scrubs sulfur dioxide from emissions, limestone (calcium carbonate) reacts with sulfur dioxide to form calcium sulfate dihydrate from exhaust gas emissions.
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AMA Style. Shen Q, Li B, He W, Meng X, Shen Y. Associated Effects of Sodium Chloride and Dihydrate Gypsum on the Mechanical Performance and Hydration Properties of Slag-Based Geopolymer.
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Abstract The deposition of gypsum (i.e. calcium sulfate dihydrate) on brass heat exchanger surfaces in the presence of homopolymers and copolymers containing different functional groups from aqueous … Expand
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The industrial byproduct gypsum is a general term for byproducts discharged from industrial production with calcium sulfate as the main ingredient. Due to the high number of impurities and production volume, the industrial byproduct gypsum is underutilized, leading to serious environmental problems. At present, only …
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Anhydrite (CaSO 4) and gypsum (CaSO 4 ·2H 2 O) are the two most abundant minerals of ancient marine evaporite deposits and are also common in non-marine evaporite deposits. Sedimentary gypsum forms by direct precipitation out of evaporating seawater under arid climatic conditions in hydrologically restricted marine …
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The most prevalent sulfate mineral in the surrounding natural environment is calcium sulfate, which can be found as calcium sulfate dihydrate or gypsum (CaSO 4 ⋅2H 2 O), hemihydrate (CaSO 4 ⋅ ...
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The axial development of calcium sulfate dihydrate (gypsum) scaling on selected reverse osmosis (RO) membrane surfaces was investigated experimentally in a plate-and-frame RO system. ... The above results suggest that retentate filtration essentially eliminate gypsum crystal scale formation by deposition of bulk crystals. Clearly, with ...
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DOI: 10.1016/j.jwpe.2023.104664 Corpus ID: 266442324; Modeling gypsum (calcium sulfate dihydrate) solubility in aqueous electrolyte solutions using extreme learning machine
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The results show that the main components of natural gypsum minerals were gypsum dihydrate (71%), dolomite (27%) and potassium chloride (2%). ... The physical and mechanical properties of gypsum rocks will change greatly in high-temperature and water environment. ... Due to the obvious deposition weak surface of the sample, the …
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Calcium sulfate occurs in nature mainly in form of three different minerals distinguished by their degree of hydration: gypsum (CaSO 4 ), bassanite (CaSO 4 ⋅0.5H 2 O) and anhydrite (CaSO 4 ...
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Download Citation | Adsorption and solidification of cadmium by calcium sulfate dihydrate (gypsum) in an aqueous environment: a dispersion-corrected DFT and ab initio molecular dynamics study ...
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Gypsum boards also have fire-resistance capacity owing to their phase change from gypsum dihydrate (CaSO 4 ·2H 2 O) to hemihydrate (CaSO 4 ·0.5H 2 O) ... The samples' curing was conducted in an environmental chamber at 20 °C and 97% R.H. The specimens were de-molded after 24 h of curing. Three samples were prepared for …
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Its main component is calcium sulfate dihydrate (gypsum). In the present study, incorporation and adsorption of cadmium on gypsum in an aqueous environment have been investigated using dispersion-corrected density functional theory, and the effect of different vacancy defects on the adsorption and doping of Cd on gypsum was also …
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According to the U.S. Energy Information Administration's statistics, in the 2006–2016 period, approximately 42% of the electricity consumed in the U.S.A was produced by coal combustion (U.S. Energy Information Administration, 2018).The coal combustion process generates various types of residues such as fly ash, bottom ash, …
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Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4·2H2O). It is renowned for its wide use in the manufacturing of plaster, drywall, and fertilizers. Gypsum: mineral ...
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However, laboratory evidence for the synthesis of anhydrite directly from NaCl-rich waters has shown that gypsum is always the stable phase ().. Hardie (1967) converted gypsum to anhydrite in solutions containing high concentrations of H 2 SO 4, and Cruft and Chao (1969) showed that under conditions of very high supersaturation, i.e., high Ca 2+ or …
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Gypsum binders and the products based on them are widely in demand in the construction materials market, which is due to their easy production technology, lower energy consumption, and low environmental impact in relation to Portland cement. Not only natural gypsum (NG), but also phosphogypsum (PG), which is a by-product of the …
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Flue-gas desulphurization (FGD) gypsum is a highly prevalent industrial by-product worldwide, which can be an excellent alternative to natural gypsum due to its high content of CaSO4·2H2O. The preparation of α-calcium sulfate hemihydrate is a high-value pathway for the efficient use of FGD gypsum. Here, a dynamic method, or an improved …
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Calcium sulfate dihydrate (gypsum) loses its water of hydration when exposed to an environment with sufficiently low vapor pressure. At temperatures higher than 80–110 °C, gypsum loses crystalline water to produce hemihydrate, commonly known as plaster of Paris. If hemihydrate is heated above 200 °C, anhydrite II is formed. When …
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