Highly targeted stabilization and release behavior of hazardous substances in phosphogypsum

Wu, Fang; He, Minjie; Qu, Guangfei; Zhang, Ting; Ren, Yuanchuan; Kuang, Linrui; Ning, Ping; Li, Junyan; Liu, Ye

doi:10.1016/j.mineng.2022.107866

Cited by 15 publications

(4 citation statements)

References 58 publications

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“…The material composition of phosphogypsum dumps is dominated by gypsum (about 97%, mainly in the form of calcium sulfate dihydrate CaSO 4 •2H 2 O) [10], and about 3% is phosphates of iron and aluminum, orthophosphoric acid, potassium and sodium fluorosilicates, calcium fluorides, heavy metals, and radioactive elements [11][12][13][14]. The main impurities in phosphogypsum fall into three categories: phosphorus, fluorine, and organic impurities.…”

Section: Introductionmentioning

confidence: 99%

Production Waste Management: Qualitative and Quantitative Characteristics and the Calculation of the Hazard Class of Phosphogypsum

Seraya,

Litvinov,

Daumova

et al. 2023

Processes

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Phosphogypsum (PG: CaSO4·2H2O) is a waste product (or by-product) from the production of phosphoric acid, the main component in the production of concentrated simple and complex fertilizers. The world production of phosphogypsum exceeds 200 million tons per year. PG discharged into water bodies (seas, rivers) or disposed of in land dumps may contain elements (including heavy metals and radionuclides) in forms and concentrations that are toxic to ecosystems and human health, which raises concerns about its impact on the environment. The concentrations of these elements vary depending on the region where the raw material is mined and the process used to produce phosphoric acid. Given the significant volumes of phosphogypsum formed, an urgent problem is not only the development of methods for its disposal, but also a special, specific control over its composition after the release of PG and during its use for removal, transportation, and storage in dumps and sludge storages. This article presents the results of comprehensive studies on the determination of the chemical and mineralogical composition of by-products from an experimental plant for the processing of phosphate raw materials of the designed chemical complex of the EuroChem-Karatau company (Republic of Kazakhstan). Based on the conducted studies, it was established that, in terms of the total toxicity index, the studied wastes belong to the fourth hazard class (low-hazardous) with the possibility of processing for the purpose of their further use.

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Section: Introductionmentioning

confidence: 99%

Production Waste Management: Qualitative and Quantitative Characteristics and the Calculation of the Hazard Class of Phosphogypsum

Seraya,

Litvinov,

Daumova

et al. 2023

Processes

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“…2,3 Due to the complex impurities, such as phosphorus, fluorine, residual acid, organic matter, and even heavy metals, it is difficult to recycle it. [4][5][6][7] Especially, the harmful substances existing in the gypsum crystals will be slowly released during the dissolution process, 8,9 seriously affecting the application value of materials. 10 At present, the preparation of α-hemihydrate gypsum (α-HH) from PG has been widely recognized in the field of building materials, α-HH has good workability, and related products have excellent performance in strength, hardness, biocompatibility, and other aspects, with obvious advantages of high value-added.…”

Section: Introductionmentioning

confidence: 99%

“…In general, in the wet process of PG, for every ton of P 2 O 5 produced, 4.5–5.5 tons of PG are produced as by‐products 2,3 . Due to the complex impurities, such as phosphorus, fluorine, residual acid, organic matter, and even heavy metals, it is difficult to recycle it 4–7 . Especially, the harmful substances existing in the gypsum crystals will be slowly released during the dissolution process, 8,9 seriously affecting the application value of materials 10 .…”

Section: Introductionmentioning

confidence: 99%

Effect of mixed cation acetate electrolyte on synthesis of α‐hemihydrate gypsum from phosphogypsum

Min,

Huang,

et al. 2023

J Am Ceram Soc.

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The preparation of α‐hemihydrate gypsum (α‐HH) from phosphogypsum (PG) by atmospheric hydrothermal synthesis is a green and efficient method for the treatment of PG. The commonly used electrolyte solution today is mostly chlorine‐based. The prepared α‐HH based on chlorine salt solution are needle like with a large aspect ratio, low strength, and high impurity. In this study, sodium and calcium mixed cation acetate solution is designed and used as an organic multifunctional electrolyte to synthesis of α‐HH for the first time. The effects of the mixed cation acetate electrolyte on crystal transformation, product morphology, and product purity of the prepared α‐HH were compared with those prepared with chloride solutions with the same mixed cations. Result showed that the morphology of α‐HH crystals prepared in acetate solutions is a stubby hexagonal prism. The aspect ratio of the prepared α‐HH crystals is close to 1, with 3 day compressive strength four times higher than that of α‐HH prepared in chloride solutions. In addition, in comparison with chloride electrolyte, acetate electrolyte showed a complexation effect with impurity metal ions, which realized the efficient removal of impurities from PG and increased the purity of the synthesized α‐HH.This article is protected by copyright. All rights reserved

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“…When the geopolymer is prepared with phosphogypsum, delayed ettringite (AFt) can be continuously generated, which may damage the basic structure of the geopolymer, leading to expansion damage of the material [7][8][9]. In addition, phosphogypsum contains Ba, Cr, Cu, Mn and other heavy metals, and its impact on the environment must be evaluated [10,11]. On the other hand, in China, the annual production of construction waste reaches 3 billion tons, and it is expected to reach a peak emission of 7.5 billion tons by 2035 [12,13].…”

Section: Introductionmentioning

confidence: 99%

The Synergistic Mechanism and Stability Evaluation of Phosphogypsum and Recycled Fine Powder-Based Multi-Source Solid Waste Geopolymer

Liu

2023

Polymers

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Geopolymer prepared from solid waste is a high value-added means. However, when used alone, the geopolymer produced by phosphogypsum has the risk of expansion cracking, while the geopolymer of recycled fine powder has high strength and good density, but its volume shrinkage and deformation are large. If the two are combined, the synergistic effect of the phosphogypsum geopolymer and recycled fine powder geopolymer can realize the complementarity of advantages and disadvantages, which provides a possibility for the preparation of stable geopolymers. In this study, the volume stability, water stability and mechanical stability of geopolymers were tested, and the stability synergy mechanism between phosphogypsum, recycled fine powder and slag was analyzed by micro experiments. The results show that the synergistic effect of phosphogypsum, recycled fine powder and slag can not only control the production of ettringite (AFt) but also control the capillary stress in the hydration product, thus improving the volume stability of the geopolymer. The synergistic effect can not only improve the pore structure of the hydration product but also reduce the negative impact of calcium sulfate dihydrate (CaSO4∙2H2O), thus improving the water stability of geopolymers. The softening coefficient of P15R45 with a 45 wt.% recycled fine powder content can reach 1.06, which is 26.2% higher than P35R25 with a 25 wt.% recycled fine powder content. The synergistic work reduces the negative impact of delayed AFt and improves the mechanical stability of the geopolymer.

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Highly targeted stabilization and release behavior of hazardous substances in phosphogypsum

Cited by 15 publications

References 58 publications

Production Waste Management: Qualitative and Quantitative Characteristics and the Calculation of the Hazard Class of Phosphogypsum

Production Waste Management: Qualitative and Quantitative Characteristics and the Calculation of the Hazard Class of Phosphogypsum

Effect of mixed cation acetate electrolyte on synthesis of α‐hemihydrate gypsum from phosphogypsum

The Synergistic Mechanism and Stability Evaluation of Phosphogypsum and Recycled Fine Powder-Based Multi-Source Solid Waste Geopolymer

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