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1. Introduction. The effect of fluoride in water on human health is related to its concentration. The normal growth of bones and teeth requires a certain concentration of fluoride intake (0.4 to 1.5 mg/L) [].However, drinking water with high levels of fluoride (above 1.5 mg/L) can cause many health problems, such as teeth mottling, skeletal fluorosis, and even changes in …
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The radium content of phosphogypsum is 20 to 30 picoCuries Ra-226 per gram (pCi/g), whereas the radium content of most soils and rocks, and of natural gypsum, is on the order of 1 to 2 …
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The thermal treatment method involves the transformation or decomposition of fluorides in phosphogypsum under high-temperature conditions, thereby reducing the fluorine content in phosphogypsum and subsequently mitigating the impact of fluorine on its properties.
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Phosphogypsum (PG), a by-product of phosphoric acid production, contains high levels of fluorine and phosphorus impurities, which negatively impact the strength and setting time of PG-based cement materials and pose environmental risks. This study explores a dual approach combining physical adsorption using zeolite powder and chemical modification with quicklime …
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Phosphogypsum (PG) is a solid waste generated during the wet process of phosphoric acid, the utilization of which is hindered by impurities. Herein, natural gypsum and limestone were replaced by PG as the only source of CaO for the production of sulfoaluminate cement (SAC). ... Results show that with increasing fluoride content, the ...
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The phosphorus content in the slurry solution of PAS was 274.649 ppm, which was 208% higher than PG. The fluorine content in PAS was 0.289 wt%, which was 24.3% lower than PG. The purification effect of phosphogypsum was the best through the micro-environment created by Span-80 and mechanical force.
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This review comprehensively explores fluoride removal from phosphogypsum, focusing on its composition, fluorine-containing compounds, characterization methods, and …
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Results demonstrate that the direct acidification method converts most fluoride into H 2 SiF 6 and HF, which are subsequently released from the PG system after a temperature of 175 °C treatment. ... (Determination of Phosphorus and Fluorine Content in Phosphogypsum). The eutectic phosphorus content was determined by Q/520122 K 003–2020 (The ...
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All content in this area was uploaded by M'nif Adel on Sep 09, 2016 . ... and sodium fluoride. The total phosphogypsum conversion is achieved after reaction time equal to 1.5 h. Generally, this ...
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Phosphogypsum (PG) is an industrial waste residue produced during the wet process of phosphoric acid production in the phosphorus chemical industry. ... [34], reducing the dissolved Ca 2+ content and fluoride removal efficiency of the PG. Therefore, maintaining a relatively low solution temperature (20 ℃) is beneficial for fluoride ions removal.
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phosphogypsum, sodium fluoride, calcium fluoride, sodium sulfate, wet conversion. 1. Introduction. Phosphogypsum (PG) is an acidic by-product resulted during the production of phosphoric acid by the wet process. This …
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PG is a significant industrial by-product generated during the wet production of phosphoric acid [], with 4.5–5.5 tons of PG produced for every ton of phosphoric acid [].The global production of PG waste is estimated to exceed 280 million tons per year [].PG stockpiles are primarily found in the USA, China, Morocco, Tunisia, and numerous other countries worldwide [].
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Abstract: The resource utilization of phosphogypsum is confronted with great challenge. Of all the different methods for phosphogypsum resource utilization, using phosphogypsum to fabricate calcium fluoride (CaF 2) is an effective resource utilization method. In this work, high-quality nano-calcium fluoride was successfully prepared
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Phosphogypsum, a typical by-product in the phosphorus chemical industry, could generate a large amount of leachate containing phosphate and fluoride in the process of …
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Using phosphogypsum (PG) as the aggregate of cemented backfill is an economical and effective method of PG utilization. However, the stability and performance of cemented backfill are challenged by the rich fluoride content in PG.
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The high concentration of fluoride and phosphate in phosphogypsum leachate is harmful to the environment and ecosystem. Thus, there is a need to develop feasible materials or technologies to ...
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backfill technique to some extent, especially the fluoride impurity which has a content of up to 3.6% of the mass of PG [15,16]. The presence of fluoride in PG in both soluble and
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This study investigates the impact of initial fluoride content (IFC) in PG samples on the strength and leaching behavior of PCPB to establish appropriate pretreatment standards. …
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Phosphogypsum (PG) is a waste by-product generated during the wet process manufacture of phosphorus fertilizer, which is mainly composed of gypsum (CaSO 4 ·2H 2 O) but also contains some impurities of environmental concern, such as P 2 O 5, fluorides and metal elements (e.g., Fe, Mn, Al, Mg, etc.) [1], [2].Worldwide PG production is very large, it is …
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This review comprehensively explores fluoride removal from phosphogypsum, focusing on its composition, fluorine-containing compounds, characterization methods, and …
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Research has proved that the use of modified materials can not only effectively reduce the soluble phosphorus and F-content in PG, but also promote the hydration reaction. ... Control of fluoride pollution in cemented phosphogypsum backfill by citric acid pretreatment. Materials, 16 (19) (2023), 10.3390/ma16196493. Google Scholar [13]
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Phosphogypsum, which contains more than 90% of the calcium sulfate dehydrate (CaSO4 · 2H2O), is a kind of important renewable gypsum resources. ... content and phase distribution of trace fluoride in phosphogypsum has important theoretical values in removing trace fluoride effectively. In this present paper, the main existence form and phase ...
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Using phosphogypsum (PG) as the aggregate of cemented backfill is an economical and effective method of PG utilization. However, the stability and performance of cemented backfill are challenged by the rich fluoride content in PG. In this study, the ...
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The high concentration of fluoride and phosphate in phosphogypsum leachate is harmful to the environment and ecosystem. Thus, there is a need to develop feasible materials or technologies to remove both fluoride and phosphate in acidic phosphogypsum leachate. In this study, sulfoaluminate cement (SC) was used to simultaneously remove fluoride and phosphate in …
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Request PDF | On Jan 1, 2025, Daolin Wang and others published Enhanced immobilization of fluoride in phosphogypsum-based cement-free paste backfill modified by polyaluminum chloride and its ...
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The resource utilization of phosphogypsum is confronted with great challenge. Of all the different methods for phosphogypsum resource utilization, using phosphocypsum to fabricate calcium fluoride (CaF 2 ) is an effective resource …
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The conversion of calcium sulfate to calcium fluoride in acidic medium was reported using phosphogypsum as a source of CaSO 4 . The reaction was successfully achieved using reagents such as HF ...
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Phosphogypsum (PG) is a typical by-product of phosphoric acid and phosphate fertilizers during acid digestion. The application of cemented paste backfill (CPB) has been feasibly investigated for the remediation of PG. The present study evaluated fluorine immobilization mechanisms and attempted to construct a related thermodynamic and …
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The dependence of the content of Ca 2+, SO4 2-, NO3ions in the temperature range of 20-80°C at the ratio CaSO4:NH4NO3= 1:0.5 was studied. The optimal temperature for the fertilizer obtaining was established at 60°C. ... The conversion of phosphogypsum to calcium fluoride (solid phase) and sodium sulfate (liquid phase) was carried out using a ...
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Fluoride Release from Phosphogypsum Sudhakar M. Rao1 and K. Asha2 ... (G content −10−40%) exhibited radioactivity much lower than international reference levels, indicating G-blended
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