Calcium molybdate (CaMoO4) is of significant interest due to its unique properties and numerous industrial applications, such as catalysis, electrochemistry, and optoelectronics. In this study, we developed an economical and environmentally friendly method to …
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Preparation of Calcium Sulfate Whisker by Atmospheric Acidification Method from Flue Gas Desulfurization Gypsum ... Therefore, in recent decades, the preparation of CSW from the industrial by-product, e.g. phosphogypsum [3,4], residue of citric acid [5], waste calcium chloride [6], flue gas desulfurization (FGD) gypsum[7,8], …
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The isothermal kinetics of calcium sulphate hemihydrate hydration have been determined (i) by thermogravimetry and microcalorimetry for water vapour hydration and (ii) by microcalorimetry for liquid water hydration. ... Enhancing the hydration reactivity of hemi-hydrate phosphogypsum through a morphology-controlled preparation technology.
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Phosphogypsum is a by-product of the wet-process phosphoric acid production, and it is rich in Ca and S. Long-term storage of Phosphogypsum can cause serious pollution to the environment; therefore, promoting the sustainable utilization of …
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Phosphogypsum (PG) is a solid waste generated during the production of wet -process phosphoric acid.The silicon and phosphorus impurities in PG greatly affect its resource utilization.In this study, these impurities were removed at atmospheric pressure using a two-step gradient method that simultaneously converted the calcium sulfate …
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The reaction of calcium dihydrogen phosphate solution with sulfuric acid in the presence or absence of HF, H 2 SiF 6, and Al 3+ ions was used to simulate the crystal growth process of α-type hemihydrate calcium sulfate (α-HH) with 30% P 2 O 5 at a reaction temperature of 95 °C. The changes in Ca 2+ ion concentration in the solution …
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This work develops a new class of salt solution method to prepare alpha-calcium sulfate hemihydrate (α-HH) from flue gas desulfurization (FGD) gypsum in trace K 2 SO 4-contained 4.0 M Ca(NO 3) 2 aqueous solution at 95 °C under atmospheric pressure. The driving force for the phase transition is provided by the concentrated Ca(NO 3) 2 …
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The concept of guided tissue regeneration has been with us since the early 1980s. There are a number of techniques available today that each have certain advantages and disadvantages. This article describes one practitioner's experience with a new technique using calcium sulfate as a resorbable barr …
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In this study, calcium sulfate hydrat … Three dimensional of calcium sulfate and mesoporous bioactive glass scaffolds for improving bone regeneration in vitro and in vivo Sci Rep. 2017 Feb 13:7:42556. doi: 10.1038/srep42556. Authors Xin Qi 1 ...
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Phosphogypsum (PG) is a calcium sulphate dihydrate and a by-product of the phosphate fertilizer industry. It is produced in huge quantities (300 MT/year), but only 15% of the PG produced is ...
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Phosphogypsum (PG) is a residue from the fertilizer industry used by Portland cement companies as a source of calcium sulfate to control the setting time during the hydration (or hardening process).
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It also shows that the thermochemical decomposition of calcium sulfate is not complete and that the sulfur present in the residue exists in the form of sulfate and calcium sulfide. It can be concluded that the step in the phosphogypsum conversion scheme then includes the reduction of calcium to calcium sulfide according to the …
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α-calcium sulfate hemihydrate (α-HH) was synthesized by salt solution methods to prepare a promising biomaterial for bone tissue repair and regeneration. The successful synthesis of α-HH was evaluated by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Fourier …
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Phosphogypsum (PG) is a by-product of the wet-process phosphoric acid process, which causes serious environmental issues. In this work, PG was taken as raw material to prepare α-calcium sulfate hemihydrate (α-CSH) at atmospheric pressure using Mg(NO3)2 solution, which is an environmentally friendly chlorine-free salt solution. The …
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Download scientific diagram | Phases of the calcium sulphate/water system. 6,9 from publication: Purification of South African phosphogypsum for use as Portland cement retarder by a combined ...
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Phosphogypsum contains calcium sulfate dehydrate as the main mineral, with small amounts of brushite, quartz, muscovite, and zoisite. Harmful elements, such as silicon, phosphorus, and fluorine, are mainly concentrated in the +0.15 mm and −0.025 …
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BACKGROUND. This work aims to investigate the possibility of recycling by-product phosphogypsum (PG) as raw material for preparing α-calcium sulfate hemihydrate (α-CSH) in chloride-free salt solution under mild conditions.
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Phosphogypsum (PG) is a by-product of wet phosphoric acid during which phosphate rock is reacted with sulfuric acid. ... PG is a chemical compound, which mainly consists of calcium sulfate dihydrate (CaSO 4 ·2H 2 O) and some impurities such as P 2 O 5, F ... Regeneration of sulfided calcium-based sorbents by a cyclic process. Energy …
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Using phosphogypsum-based excess-sulfate cement (PESC) for the preparation of super retarding materials. ... Furthermore, the high calcium sulfate concentration will promote the development of a lot of ettringite, which will soon precipitate on the surface of the unreacted raw material and prohibit its further hydration [34], [35]. …
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As the disposal of phosphogypsum can result in severe contamination of soil and groundwater, several researchers worldwide have devoted efforts toward realizing suitable methods for PG disposal. ... A reaction range for hydration of calcium …
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1. Introduction. Phosphogypsum (PG) is a waste by-product generated during the preparation of phosphoric acid through the reaction of sulfuric acid and phosphate rock (Al Attar et al., 2011).PG is primarily composed of CaSO 4 ·2H 2 O, with small amounts of impurities such as phosphates, heavy metals, fluorides, and organic …
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The main component of PG is calcium sulfate dihydrate (CaSO 4 ·2H 2 O), which undergoes gas–solid and solid–solid redox reactions with reducing agents to achieve the reconstruction of calcium sulfate along with the participation of metal catalysts such as …
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Phosphogypsum waste is environmentally harmful and economically valuable. However, processing phosphogypsum to produce (NH 4) 2 SO 4 and CaCO 3 can solve these environmental and economic issues. ... XRD, SEM-EDS, FTIR et TGA …
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Phosphogypsum is a kind of by-product of the phosphate fertilizer production process, mostly in the form of CaSO4·2H2O, the analytical determination of the content of the main component is the ...
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Nanoparticles of calcium sulfate (nCS) have potential advantages as a ceramic matrix, scaffold and/or vehicle for delivering growth factors for osseous regeneration in a variety of clinical situations. The objectives of this study were to synthesize and characterize nanoparticles of hemihydrate calc …
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Analyzing the results presented in Table 3, all three crystallization processes studied achieved similar values of efficiency of dihydrate calcium sulfate recovery.Since 160 ml of acid solution was used to dissolve the phosphogypsum, in the evaporation and cooling processes 128 ml (80%) and 149 ml (93%), respectively, of the acid solution …
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1. Introduction. Phosphogypsum (PG) is a by-product resulting from the phosphoric acid process for manufacturing fertilizers. It consists mainly of CaSO 4 • 2H 2 O and contains some impurities such as P 2 O 5, F −, and organic substances.The quantity of PG produced is very large: for each 1 ton of phosphate (P 2 O 5) produced, there is a …
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Based on the finding of this study, it can be concluded that microscopic and radiographic findings proposed nanocrystalline calcium sulfate as a cost-effective alternative to conventional microcrystalline form of calcium sulfate in periodontal tissue regeneration regarding new bone formation and cellular proliferation.
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Request PDF | Calcium sulfate-based bioactive cement for periodontal regeneration: An In Vitro study | Background and objective: Various types of osteoconductive graft materials are used for the ...
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Background: Alkaline soils with high calcium carbonate and low organic matter are deficient in plant nutrient availability. Use of organic and bio-fertilizers has been suggested to improve their properties. Therefore, a greenhouse experiment was conducted to evaluate the integrative role of phosphogypsum (PG; added at 0.0, 10, 30, and 50 g PG kg-1), …
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