A novel method for purification of phosphogypsum
Nearly 90% calcium was converted into calcium sulfate dihydrate (CaSO4·2H2O) in about 15 min, and after impurity separation the CaSO4·2H2O with about 90% whiteness and 94% purity was effectively ...
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Morphological regulation of calcium sulfate hemihydrate …
The calcium sulfate hemihydrate whiskers were prepared from phosphogypsum at hydrothermal condition. The influences of different organic acid (citric acid and poly (acrylic …
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Utilization of phosphogypsum for the preparation of α‐calcium sulfate …
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. The dehydration of PG in a concentrated Ca(NO 3) 2 solution at 97 °C under atmospheric pressure was analyzed.
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Review on high-value utilization of phosphogypsum: …
O in phosphogypsum own excellent oxygen carrier ability for syngas by CLG. Polymetallic synergy PG can promote the CLG of lignite. Two-step decomposition for CaO …
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The treatment of phosphogypsum leachate is more urgent …
Phosphogypsum(PG) is one of the typical bulk industrial solid wastes generated in the phosphate chemical industry. Due to its huge production volume and immature resource treatment technology, a large amount of PG can only be stored and disposed in slag yards, and its impact on the ecological environment is becoming increasingly significant during long-term …
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The employing of pure calcium sulfate extracted from phosphogypsum …
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 pour caractériser le PG, le sulfate de calcium purifié, le sulfate d'ammonium et le carbonate de calcium.
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The Optimal Conditions of Preparation of Phosphogypsum …
To control the crystallization of calcium sulfate, many researchers have studied the factors that govern the precipitation and dissolution of the sparingly soluble calcium salts, including …
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Gradient Removal of Si and P Impurities from Phosphogypsum …
DOI: 10.2139/ssrn.4372913 Corpus ID: 257272167; Gradient Removal of Si and P Impurities from Phosphogypsum and Preparation of Anhydrous Calcium Sulfate @article{Wang2023GradientRO, title={Gradient Removal of Si and P Impurities from Phosphogypsum and Preparation of Anhydrous Calcium Sulfate}, author={Mingshun Wang …
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Effects of phosphorus impurities on the …
Impurity is an important factor that determines the crystallization process of α-calcium sulfate hemihydrate (α-CSH), but the effects of phosphorus impurities in waste phosphogypsum (PG, >75% CaSO 4 ·2H 2 O) on the α …
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Simultaneous removal of phosphorus and organic …
PG is mainly composed of dihydrate calcium sulfate [25], [6], and can substitute natural gypsum in construction material [22] as raw materials for chemical products [1], [21] and soil amendment [3], [36] after proper treatment. However, various harmful impurities (including phosphate, fluorine, organic matters, and heavy metals), inevitably impose the loss of overall …
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CO2 capture and process reinforcement by hydrolysate of phosphogypsum
Phosphogypsum (PG) is a large-tonnage waste derived from phosphate rock processing for fertilizer production using the "wet acid method,'' as shown in Eq. (1). PG is mainly composed of calcium sulfate dihydrate (CaSO 4 ·2H 2 O) and a lot of impurities [18,19]. Large amounts of PG are produced annually, resulting in environmental and ...
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Preparation and Characterization of Moldable Demineralized …
Calcium sulfate (CS) is a kind of ceramic-based synthetic bone graft material with a long history of use for bone healing since the 19th century . Gypsum mainly consists of calcium sulfate dihydrate (CSD, CaSO 4 ·2H 2 O), which can be a promising raw material to produce calcium sulfate hemihydrate (CSH, CaSO 4 ·0.5H 2 O, Plaster of Paris ...
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Morphology‐Controlled Preparation of α‐Calcium Sulfate …
Phosphogypsum (PG), a by-product of phosphoric acid industry, causes environmental issues. In this paper, PG was effectively transformed into alpha-calcium sulfate hemihydrate (ɑ-CSH) via a semi-liquid method.
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Preparation of α-calcium sulfate hemihydrate from …
Preparation of α-calcium sulfate hemihydrate from industrial by-product gypsum: a review Qingjun Guan 1, Ying Sui 1, Fang Zhang 1, Weijian Yu 1, Yongjie Bo 1, Ping Wang 2, Wenqing ... (FGD) gypsum and phosphogypsum (PG), not only encroaches on lands but also causes serious environmental pollution. The preparation of α-calcium sulfate ...
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Recovery of calcium and sulphur from phosphogypsum …
Approximately 1.6 % of the sulfate in phosphogypsum cannot be dissolved, likely due to the interaction of insoluble sulfate in phosphogypsum with other impurities, such as radium, which results in the formation of radium sulfate that has an even lower solubility constant (K sp = 3.66 × 10-11) and cannot be dissolved through reaction with NaOH ...
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Synergistic preparation and application in PCU of α-calcium sulfate
Introduction. Phosphogypsum (PG) is an industrial byproduct primarily composed of calcium sulfate dihydrate (DH, CaSO 4 ·2H 2 O), generated from the wet process production of phosphoric acid. Currently, the global annual production of PG is approximately 2.8 million tons, and it can be utilized as a soil conditioner, for the production of ammonium sulfate, and as a …
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FIC-Figthers project homepage
FIC-FIGHTERS is an EU-funded initiative aimed at creating sustainable economic models to manage waste that threatens our natural and cultural heritage. 🌍♻️ This project fosters dialogue on innovative solutions for long-standing waste accumulation issues near urban areas. 🏙️ By engaging local actors, industries, authorities, SMEs, RTD centers, and universities, 🧑🔬 we aim to ...
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Effects of phosphorus impurities on the preparation of α-calcium …
Impurity is an important factor that determines the crystallization process of α-calcium sulfate hemihydrate (α-CSH), but the effects of phosphorus impurities in waste phosphogypsum (PG, >75% CaSO 4 ·2H 2 O) on the α-CSH prepared using the salt solution method are still not well known. In this context, the phase transformation of PG to α-CSH was …
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Preparation of calcium sulfate whisker from phosphogypsum …
The performance characteristics and growth mechanism of CSW were reviewed in this paper.The preparation methods of CSW,hydrothermal synthesis and atmospheric acidification method were also introduced,especially the influence of preparation process on the growth of CSW by hydrothermal synthesis was detailed.The pretreatment method of phosphogypusm and its …
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Study on the composite compatibility and interfacial …
Releasable sulfate contained in the Excess Sulfate Phosphogypsum Cementing System (ESPCS) potentially degrades interfaces when contacted with conventional cements, raising incompatibility concerns. This work evaluated fresh connection, adhesion, and aggregate embedment of ESPCS to ordinary Portland cement (OPC) and Calcium sulfoaluminate …
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Composite Design of a Phosphogypsum Whisker–Based …
AbstractThis research aimed to develop a superior asphalt rejuvenator characterized by its resistance to aging by utilizing phosphogypsum whiskers (PSWs) derived from phosphogypsum (PSP) waste. Initially, the ratios of components in the rejuvenator were ...
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Morphology‐Controlled Preparation of α‐Calcium …
In this paper, PG was effectively transformed into alpha-calcium sulfate hemihydrate (ɑ-CSH) via a semi-liquid method. The phase evolution and the effects of different organic acids and pH values on crystal morphology of the α …
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Preparation of alpha-calcium sulfate hemihydrate from …
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 solution through …
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Preparation of α-Calcium Sulfate Hemihydrate by Reaction …
Direct preparation of α-calcium sulfate hemihydrate out of sulfuric acid solution by reaction with lime under atmospheric pressure conditions is systematically investigated. Two preparation methods are investigated: one involving addition of dry lime to sulfuric acid solution (standard procedure) and the other involving addition of sulfuric acid solution to slaked lime …
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regeneration of sulfuric acid from by-product calcium sulfate
Match case Limit results 1 per page. ENGINEERING, DESIGN, AND PROCESS DEVELOPMENT Regeneration of Sulfuric Acid from By-product Calcium Sulfate EXPLORATORY STUDIES OF DESULFURIZATION J. M. STINSON AND C. E. MUMMAl Tennessee Volley Authorify, Wilson Dum, Ala. N THE wet process for the production of …
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Sustainable Approach for Recovery of Sulfur from …
It seems that bentonite clay is an adjuvant that promotes, in a remarkable way, the decomposition of calcium sulfate. It follows from these tests that, through appropriate …
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Alpha-calcium sulfate hemihydrate blends incorporated with tri-calcium
Calcium sulfate hemihydrate (CSH) is one of the bioceramic materials with a long-standing clinical application due to good biocompatibility and osteoconduction. 4 Once implanted, CSH appears to be a biocompatible agent that is completely absorbed over a period of several weeks, leaving behind a calcium-rich environment to stimulate the growth of osteoblasts, …
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Ammonium sulfate preparation from phosphogypsum waste
The obtained precipitate is the highly purified phosphogypsum which is used to obtain the highly purified ammonium sulfate fertilizer, the preparation of ammonium sulfate process is applied using suspended 500 g purified phosphogypsum which is contained 410.6 g calcium sulfate in 2 L of 3% ammonium sulfate solution (as initiator), 1/4 solid ...
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Innovative strategy of turning waste into treasure: High …
In the present work, phosphogypsum (PG) waste was used as a calcium source, and integrated with 2-hydroxyphosphonoacetic acid (HPA) doping, modified inorganic-organic amorphous calcium phosphate hybrid composite was prepared, to remove Cd 2+ and Co 2+ in aqueous solution. The study demonstrated that when pH=8, the equilibrium adsorption …
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Preparation and Characterization of Moldable Demineralized Bone …
Calcium sulfate (CS) is a kind of ceramic-based synthetic bone graft material with a long history of use for bone healing since the 19th century . Gypsum mainly consists of calcium sulfate dihydrate (CSD, CaSO 4 ·2H 2 O), which can be a promising raw material to produce calcium sulfate hemihydrate (CSH, CaSO 4 ·0.5H 2 O, Plaster of Paris ...
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