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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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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The principle of water washing method: the main impurity affecting the phosphogypsum can dissolve in water.The organic impurities mainly for oily substances above can float on
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The contact angle between the superhydrophobic phosphogypsum coating (SPG coating) and water was 156°, and the coating reached a superhydrophobic state with good self-cleaning ability. Even when sandpaper was used to polish the coating, the water contact angle of the coating was still greater than 150°, indicating that the coating had …
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The treatment methods vary and may include washing, filtration, calcination, neutralization, leaching, and purification, among others, to remove …
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Abstract Red mud and phosphogypsum are staple solid wastes, with considerably large annual emissions. Improving their comprehensive utilization is the key to addressing the large accretion of both red mud and phosphogypsum. They have great utilization potential and can be collectively modified to expand the utilization field and …
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Utilisation of Water-Washing Pre-Treated Phosphogypsum for Cemented Paste Backfill Yikai Liu 1, Qinli Zhang 1 ... water-washing, was proposed to remove impurities from PG. The pre-treatment of adding water and separating supernatant and precipitate by centrifuge is widely used as an effective and simple method of impurity removal in various ...
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The washed phosphogypsum (PGW) was obtained by washing the PGF; this was placed in a large sieve and washed several times until the wash water obtained a neutral pH (between 6.7 and 7). The PGW was left to dry in the open air for 7 days. ... Based on our results, phosphogypsum can be considered to be a source of gypsum …
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"The generation of acidic leachates from phosphogypsum (PGL) stacks is a global problem due to their high pollutant concentrations (As, Cr, Cd, Cu, Ni, Zn, F-, PO 4 3-, SO 4 2-, 210 Po and 238,234 U). The cleaning treatment of the PGL by neutralization with alkaline reagents is a proper option for removal of pollutants by (co)-precipitation.
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In this research, thus, a pre-treatment method, water-washing, was proposed to remove impurities from PG. The pre-treatment of adding water and separating supernatant and precipitate by …
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The physical methods are based on particle size separation mainly including sieving and washing (Andrade Neto et al., 2021; Potgieter et al., 2003). The thermal method can remove organic matter from phosphogypsum and obtain hemihydrate or anhydrous gypsum using high-temperature calcination (Taher, 2007).
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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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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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The calcination treatment for recycling phosphogypsum (PG) is very promising, which can transform PG into a binder material and remove harmful impurities. To effectively recycle and reutilize PG, the influence of calcination temperatures on the properties of calcined and hydrated PG with and without pretreatment should be …
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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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The current impurity removal methods include: (1) water washing can remove the acidic and soluble impurities of phosphogypsum, but it is difficult to remove insoluble impurities, and the water resource consumption is serious . (2) Flotation can only remove organics .
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Physical methods are categorized as water washing, flotation, screening, etc. [20, 21]. The soluble impurities in phosphogypsum can be effectively removed . 95% of phosphorus can be removed after taking the removal rate of soluble phosphorus as the target and determining the optimum process .
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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 …
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This study contributes to sustainable construction practices by exploring the use of phosphogypsum, a commonly discarded byproduct, in the production of recycled aggregates. Addressing both environmental and economic aspects of sustainability, we investigate the feasibility of employing phosphogypsum as a primary raw material, in …
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The salts or a²cids not removed during washing of the PG in the filtration step represent soluble impurities, including soluble P 2 O 5 in the form of H 3 PO 4 or H …
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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 around 12.8, which...
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Further, as can be seen in Fig. 11 (c), with the increase of pH value of pretreated PG, the concentration of SO 4 2− in the bleeding water of PG-1 and PG-2 groups gradually decreased from 4000 to 5000 mg/L to about 1300 mg/L. Overall, the water washing of PG could well remove the impurities, leading to lower concentrations of …
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Phosphogypsum is the radioactive waste from phosphate ore processing that can contain carcinogens and toxic metals. Learn why conservation groups are petitioning the EPA to …
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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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Phosphogypsum (PG) is a massive industrial solid waste. ... and using citric acid solution pretreatment to convert phosphorus and fluorine in PG into citrate that can be removed by water washing ...
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PDF | Recycling phosphogypsum (PG) for cemented paste backfill (CPB) has been widely used at phosphate mines in China. ... Therefore, the water-washing pre-treatment can effectively remove some of ...
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(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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As can be seen from the above, phosphogypsum has a good solidification effect on the washed MSWI fly ash, and the use of washed MSWI fly ash as an auxiliary material for phosphogypsum is safe ...
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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 …
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Phosphogypsum (PG) waste is a by-product generated from wet-process phosphoric acid (H 3 PO 4) manufacturing during phosphate rock decomposition.Worldwide, the annual production of PG ranges between 100 and 300 million tons, with only a few quantities utilized in several application domains (about 15%), the …
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Phosphogypsum can be chemically treated and become more suitable for the use of cementitious systems at a large scale in a more economical way. ... simple water washing or wet sieving, but all impurities are not removed ... The use of heat treatment can remove all impurities by subjecting the phosphogypsum to a temperature between 130 …
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Minerals 2019, 9, 175 4 of 20 2. Materials and Methods 2.1. Raw Materials and Water-Washing Pre-Treatment OPC 42.5R (similar to ASTM C150 Type I cement [35]) and OPG with moisture content of
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1. Introduction. Phosphogypsum (PG) is a bulk industrial solid waste of wet-process phosphoric acid production. Every ton of phosphoric acid production generates as many as 4–6 tons of PG, including more than 90% of CaSO 4 ·2H 2 O, a small amount of phosphorus, fluorine, organic matter, oxides, heavy metals, radioactive substances …
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DOI: 10.1016/j.cej.2022.138594 Corpus ID: 251523098; Usage of biowashing to remove impurities and heavy metals in raw phosphogypsum and calcined phosphogypsum for cement paste preparation
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phosphogypsum calcination temperature increases the pH. The water washing method can adequately remove phosphogypsum-soluble P 2 O 5, fluorine, organic matter and other impurities, however, the washing method will induce a huge amount of wastewater discharge, causing severe secondary pollution with adverse environmental impacts.
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Abstract. Phosphogypsum (PG: CaSO 4 ·2H 2 O) is a waste product generated by the phosphate industry. World production of this waste exceeds 200 million tonnes per year. PG, discharged into the sea, watercourses or in wilderness stocks, contains toxic elements harmful to ecosystems and human health, including heavy …
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The principle of water washing method: the main impurity affecting the phosphogypsum can dissolve in water.The organic impurities mainly for oily substances above can float on water.Therefore, the water washing method can remove most of the phosphorus gypsum soluble impurities, including phosphorus, fluorine, most alkali metal salts and organic ...
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DOI: 10.1016/j.jece.2023.111485 Corpus ID: 265318021; Evolution of the waste generated along the cleaning process of phosphogypsum leachates @article{PrezMoreno2023EvolutionOT, title={Evolution of the waste generated along the cleaning process of phosphogypsum leachates}, author={S.M. P{'e}rez Moreno and …
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