Leaching behavior and release mechanism of pollutants from different depths in a phosphogypsum stockpile
Copyright © 2024 Elsevier Ltd. All rights reserved.
| Veröffentlicht in: | Waste management (New York, N.Y.). - 1999. - 189(2024) vom: 01. Dez., Seite 230-242 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2024
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| Zugriff auf das übergeordnete Werk: | Waste management (New York, N.Y.) |
| Schlagworte: | Journal Article Geochemical modeling Leaching test Phosphogypsum Release mechanism Stack depth Calcium Sulfate WAT0DDB505 Phosphorus 27YLU75U4W mehr... |
| Zusammenfassung: | Copyright © 2024 Elsevier Ltd. All rights reserved. Phosphogypsum (PG), a byproduct during the production of phosphoric acid and phosphate fertilizers, is predominantly stockpiled with a height greater than hundreds of meters. In this study, the leaching behavior of pollutants from PG stored at different depths was systematically investigated through batch tests, column tests, and geochemical modeling. PG samples were collected at different depths within a range of 48 m from a large-scale PG stack in China. The results showed that the pH, electrical conductivity, and elemental concentration of the leachate exhibited spatial variability in terms of the depth distribution, with evident bottom enrichment effects for metals and soluble salts. The pH-dependent leaching tests investigated the impact of pH variations on the solubility of various elements in PG, with a specific focus on elements precipitation occurring within the natural pH range. The geochemical modeling of leaching tests conducted by PHREEQC enabled the identification of the dominant phases controlling the solubilization of the elements, as well as the dynamic process of changes in element forms and concentrations with pH variation. Column leaching tests reveal the differences in pollutant properties between the unsaturated and saturated zones within the PG stack and categorize the leaching mechanisms of elements into three models including dissolution, diffusion, and wash-off. This study aims to reveal the leaching characteristics of PG at different depths, so as to provide a data foundation for the design of liner system, leachate management strategies, and remediation of heavy metal pollution of PG stack sites |
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| Beschreibung: | Date Completed 13.09.2024 Date Revised 13.09.2024 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1879-2456 |
| DOI: | 10.1016/j.wasman.2024.08.035 |