##tihuan2##The retarding effect of phosphogypsum pretreated with washing Islam et al. (2017) removed impurities and water in the raw PG by washing and drying. Then, the setting time of cement and the compressive strength of mortar and concrete containing different contents of treated PG were tested, and the results are shown in Table 2 .
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##tihuan2##PG-3 needed fewer washing times to remove the imp urities. e 5% di erence in removal e ciency between two adjacent washes is de ned as the stab ilization of PG in this study . As seen in Fig. 5 b ...
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##tihuan2##Phosphogypsum circular economy considerations: A critical review from more than 65 storage sites worldwide ... The treatment methods vary and may include washing, filtration, calcination, neutralization, leaching, and purification, among others, to remove impurities and further reduce the radioactivity levels. The specific process used …
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##tihuan2##Phosphogypsum is a solid waste byproduct from processing phosphate ore to make phosphoric acid that is later used in fertilizer. Phosphogypsum contains radium, which decays to form radon gas. Both radium and radon are radioactive and can cause cancer. The Clean Air Act regulations require that phosphogypsum be managed in …
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##tihuan2##The impurities in PG can be removed easily and affordably by washing it with water. The microstructure and sizes of PG have changed because of the deionized …
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##tihuan2##Water washing could remove the majority of residual acids in PG. As the pH value of the pretreated PG reached 3.50 and 5.00, the pH value of the slurry reached …
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##tihuan2##Phosphogypsum, as a byproduct of wet-process phosphoric acid reaction, has caused many environmental pollution problems. To improve the property and purity of phosphogypsum in the wet-process phosphoric acid process, a liquid–solid–liquid three-phase acid hydrolysis synergistic extraction reaction system was established by adding …
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##tihuan2##Phosphogypsum (PG), a byproduct during the phosphoric acid production process, also known as the wet process, contains complex and diverse impurities, resulting in low utilization and considerable accumulation. This leads to a massive waste of land resources and a series of environmental pollution problems. Given the current urgent …
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##tihuan2##Phosphogypsum (PG) is an industry solid waste produced from phosphoric acid manufacture. To reduce environmental pollution of the PG, H2C2O4 was employed to purify it, which then can be used for ...
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##tihuan2##In this study, a water-washing pre-treatment was used to purify OPG, aiming to optimize the transport performance and mechanical properties of backfills. The overall results proved that in treated phosphogypsum-based cemented paste backfill (TCPB), the altered particle size distribution can alleviate the shear-thinning characteristic.
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##tihuan2##Based on our results, we propose a simple and efficient impurity removal method that can be used to remove almost all impurities in PG.
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##tihuan2##Figure 11 a–d shows further that the phosphogypsum, after grading and flotation of the gypsum concentrate, dispersed and had a smooth crystal surface, which indicates that the phosphogypsum through classification of pre-treatment using direct flotation can effectively remove impurities in the phosphogypsum concentrate, thus …
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##tihuan2##Zhang et al. showed that the soluble fluorine content in phosphogypsum can be reduced from 0.250% to 0.023%, 0.02%, and 0.018%, respectively, when treated …
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##tihuan2##The current trends focus on purifying PG by different methods: (1) water washing, which could remove dissolved phosphorus and fluorine, but wastewater treatment as a byproduct is a major …
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##tihuan2##Utilisation of Water-Washing Pre-Treated Phosphogypsum for Cemented Paste Backfill. March 2019; Minerals 9(3):175; ... Therefore, the water-washing pre-treatment can effectively remove some of .
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##tihuan2##In this study, we investigated a coarse phosphogypsum containing 49.63% SO3, 41.41% CaO, 10.68%, 4.47% SiO2, 1.28% P2O5, 0.11% F, CaSO4·2H2O purity of 80.65%, and whiteness of 27.68. Phosphogypsum contains calcium sulfate dehydrate as the main mineral, with small amounts of brushite, quartz, muscovite, and zoisite. Harmful …
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##tihuan2##The raw material was treated to remove additional water and impurity by washing, air drying and oven drying. Both treated and untreated materials were used in experimental work.
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##tihuan2##The use of heat treatment can remove all impurities by subjecting the phosphogypsum to a temperature between 130 and 150 °C [125]. However, soluble phosphates are difficult to remove, and for this reason they affect the setting time and the level of strength of the cement [ 126 ].
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##tihuan2##Phosphogypsum (PG) represents the typical secondary gypsum material; its main composition is also of dihydrate calcium sulphate. At present, the world's PG pile stock has reached 6 billion tons, and is still being added at the rate of 150 million tons every year. ... Washing can remove most of the soluble impurities, but in terms of the ...
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##tihuan2##Phosphogypsum is currently marketed in Brazil, China, Spain, India, Kazakhstan, the Netherlands, and the United States of America. ... (Mesi´cetal. 2016), but other acids (hydrochloric or nitric acids) can also be used instead of sulphuric acid (Pereira 2003). Moreover, the temperature of the acid attack is a determinant factor in the degree ...
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##tihuan2##The current trends focus on purifying PG by different methods: (1) water washing, which could remove dissolved phosphorus and fluorine, but wastewater treatment as a byproduct is a major concern, and the solution is not effective for eutectic phosphorus removal 4; (2) floatation method can remove the organic matter but the …
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##tihuan2##Compared with the post-treatment of pollutants, such as the removal of phosphate from wastewater, it is more important to develop effective emission control strategies to reduce phosphate pollution. Phosphogypsum (PG) is a typical solid waste byproduct of phosphate production and contains high amounts of residual phosphate. In …
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##tihuan2##Phosphogypsum (PG) is a radioactive industrial by-product produced in large quantities when processing phosphate ores into fertilizers. With rapid growth of high concentration phosphate and compound fertilizers production in China, PG production is increasing every year. Phosphogypsum is usually stored in such a way that it not only …
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##tihuan2##(3) Water washing pre treatme nt signi can tly reduce d the impurities c ontent in the bleed in g water and the leachates of back ll. Eventually, almost of PO 4 3- -P, mor e than 99.3% of F ...
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##tihuan2##Among the methods of physical decontamination, washing is the most effective. Washing can remove most of the soluble impurities, but in terms of the environment, the sewage after washing must be …
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##tihuan2##The proper reutilization of the phosphogypsum (PG) by-product derived from the production of phosphoric acid and recycled concrete aggregate (RCA) from waste concrete in roadbase materials is of great necessity and importance. This investigation tried seeking a new approach to reuse them to high quality, including turning PG into …
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##tihuan2##The stockpiling of phosphogypsum is a waste of land resources and also causes serious pollution to natural resources such as water and atmosphere. This paper explores the mechanism of efficiently modified phosphogypsum and constructs a model and evaluation system for heavy metal leaching and migration transformation. The …
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##tihuan2##Figure 3 Washing of phosphogypsum prior to the storage or disposal 7 Figure 4 Conveyance of phosphogypsum to the stack area by 'Belt Conveyor'Figure 5 10 Figure 6 Phosphogypsum loading to truck in phosphoric acid plant and unloading in phosphogypsum stack area (Dry stacking) 11 Figure 7 Figure 8 Phosphogypsum …
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##tihuan2##Radioactive waste roads in Florida: Phosphogypsum can be tested in paving Conservation groups had urged the governor to veto the bill, saying phosphogypsum would hurt water quality and put road ...
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