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Sustainability of gypsum products as a construction material. N. Lushnikova, L. Dvorkin, in Sustainability of Construction Materials (Second Edition), 2016 β-Hemihydrate binder. β-Hemihydrate (also known as plaster of Paris) is the most commonly used gypsum binder in construction.It is produced in an apparatus connected to air. Different equipment is …
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Hemihydrate gypsum whiskers with high aspect ratios were prepared by using phosphogypsum as the raw material through the autoclaved method. The effects of additives containing different carboxyl ...
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Due to its excellent cementitious properties and higher strength, α-calcium sulfate hemihydrate (HH: CaSO 4 ·0.5H 2 O), traditionally known as "plaster of Paris", is widely used in modern construction and ceramics industries [3], [4].Currently, it is commercially produced by dehydration of natural gypsum, or from flue gas …
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ABSTRACT The anhydrous calcium sulfate (AH CaSo4) whiskers were prepared in H2O–H2SO4 autoclave-free hydrothermal system by using flue gas desulfurization gypsum as raw materials.
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Download Citation | ChemInform Abstract: Autoclave-Free Formation of α-Hemihydrate Gypsum. | ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was ...
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The synthesis of hemihydrate gypsum (α-HH) crystals with a low aspect ratio is of great significance to practical production for the effective utilization of flue gas …
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Preparation of α-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum is one of the most promising alternatives and of great value in effectively utilizing the FGD gypsum. Based upon a salt solution method and the optimum operating conditions obtained in the laboratory scale experiments, pilot scale …
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DOI: 10.1016/j.jcrysgro.2021.126360 Corpus ID: 241731164; Preparation of hemihydrate gypsum with controllable morphology in Glycerol-NaCl-Water solutions with maleic acid @article{Chen2021PreparationOH, title={Preparation of hemihydrate gypsum with controllable morphology in Glycerol-NaCl-Water solutions with maleic acid}, …
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Crystal modifier is a significant factor in preparation of α-hemihydrate gypsum (α-HH) from phosphogypsum (PG). The influence of maleic acid, reaction …
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Alpha-calcium sulfate hemihydrate (α-HH) has been prepared from flue gas desulfurization (FGD) gypsum with salt solution method under atmospheric pressure. X-ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG-DSC), optical micrograph, X-ray photoelectron spectroscopy (XPS), energy dispersive spectrometry …
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Phosphogypsum (PG) is a massive industrial solid waste. In this paper, PG was purified by flotation method, and α-hemihydrate gypsum (α-HH) was prepared by the autoclaving method. The morphology ...
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The synthesis of hemihydrate gypsum (α-HH) crystals with a low aspect ratio is of great significance to practical production for the effective utilization of flue gas desulfurization (FGD) gypsum. In this work, the hexagonal prismatic α-HH crystals with controllable morphology were prepared in Glycerol-NaCl-Water solutions with maleic …
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1 a) Represents the solubility curves of gypsum, anhydrite, and hemihydrate while b) represent both nucleation and growth processes [11, 12] ... 3 In-situ ultrasonic speed velocity during the hydration of different types of hemihydrate:a) steam autoclave α-HHb) β-HH. 4 Heat evolution curves of: a) pure steam autoclave α-HH and b) β-HH.
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Phosphogypsum shows different properties with natural gypsum and flue gas desulfurization gypsum due to the existence of a variety of impurities, including phosphorus, fluorine, organic compounds and other ingredients.It has been a barrier for the application of phosphgypsum.In order to explore the ways for its application,the effect …
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Using FGD gypsum as the raw material, short columnar-shaped α-calcium sulfate hemihydrate can be prepared with succinic acid in hydrothermal autoclave method with a low salt content.
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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 autoclaved process, was used to produce α ...
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Calcium Sulfate Hemihydrate, also known as plaster of Paris, is a material made from gypsum that has been used for centuries in construction and various medical applications, including bone repair and growth factor release. ... (17 psi) of pressure, in steam for 5 to 7 hours in an autoclave. Processing gypsum in this way produces more dense ...
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Pressure solution method and high temperature method are used to hydrothermal treatment desulfurization gypsum which is added crystal modifier preparing crystal α-hemihydrate decorative gypsum in ...
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α-Calcium sulfate hemihydrate (α-HH) is an important cementitious material, which can be prepared by hydrothermal method from calcium sulfate dihydrate (DH) in an electrolyte solution. Study of the conversion kinetics of DH to α-HH in NaCl solution is helpful for understanding the control process. In this paper, X-ray diffraction (XRD) …
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Beta hemihydrate is formed when gypsum is heated up to around 100°C in a normal open kettle or rotary kiln. Alpha hemihydrate is formed in an autoclave above …
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LAG is the ideal raw material to replace natural gypsum to produce hemihydrate gypsum (HHG) whiskers, realizing the high-value utilization of industrial by-product gypsum. ... Preparation and surface modification of anhydrous calcium sulfate whiskers from FGD gypsum in autoclave-free hydrothermal system energy sources, …
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The synthesis of hemihydrate gypsum (α-HH) crystals with a low aspect ratio is of great significance to practical production for the effective utilization of flue gas desulfurization (FGD) gypsum. In this work, the hexagonal prismatic α-HH crystals with controllable morphology were prepared in Glycerol-NaCl-Water solutions with maleic …
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a-hemihydrate products with commercially available ma- terials, an autoclave-made a-hemihydrate gypsum product and a plaster of Paris (P-hemihydrate) were included in …
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Crystal modifier is a significant factor in preparation of α-hemihydrate gypsum (α-HH) from phosphogypsum (PG). The influence of maleic acid, reaction temperature, time, and solid–liquid ratio on the preparation of high-strength α-HH from PG was systematically studied herein. The optimum condition for α-HH prepared by …
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Under optimal working conditions the quality of the formed α-hemihydrate gypsum is similar to that of a material produced in an autoclave. References. 1 E. Eipeltauer, " Preparation of Crude Gipseous Rock and Its Conversion into Its Various Hemihydrate Plaster Forms " (in Ger.), Zem.–Kalk–Gips, 11, 264, 304 ( 1958 ).
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In this study, phosphogypsum (PG) is simulated by doping fluorine and phosphorus ions in an analytically pure reagent of gypsum dihydrate. The influence of fluorine and phosphorus impurity and content on the dehydration reaction process of phosphogypsum and its crystalline micromorphology is assessed during the preparation of α‐type gypsum …
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Download Citation | ChemInform Abstract: Autoclave-Free Formation of α-Hemihydrate Gypsum. | ChemInform is a weekly Abstracting Service, delivering concise …
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None of the experiments were performed in an autoclave; gypsum crystals were only heated in a furnace and the crystal seems to be acting as an autoclave. …
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To enable further work to be carried out on the hydration of hemihydrate plasters, materials purer than the available commercial plasters and with reproducible properties were required. As a first stage in the attempted preparation of such materials, the process variables in the autoclave dehydration of gypsum were investigated. Methods …
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Autoclave‐Free Formation of α‐Hemihydrate Gypsum. Flue gas gypsum may be converted to α-hemihydrate by suspending the starting material in inorganic salt …
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