Fluoride sorption and mineral stability in an Alberta soil interacting with phosphogypsum leachate

Luther, S. M.; Poulsen, L.; Dudas, M. J.; Rutherford, P. Michael

doi:10.4141/cjss96-012

Cited by 27 publications

(24 citation statements)

References 17 publications

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“…High concentrations of soluble phosphate, sulfate, and fluoride were present in unreacted PW (Table 2). Over the pH range described in the present study, Ca activity may be controlled by fluorapatite (Ca 5 (PO 4 ) 3 F), gypsum (CaSO 4 2H 2 O), or fluorite (CaF 2 ) (Murray and Lewis 1985;Kennedy et al 1991;Ball 1994;Luther et al 1996). Other Ca compounds may have formed in conjunction with calcite and prevented calcite alone from controlling pH.…”

Section: Solid Phase Analysesmentioning

confidence: 99%

“…Fluoride concentrations decreased from 4700 to 18 mg L -1 , where they stabilized. Using a thermodynamically based geochemical model, Ball (1994) predicted CaF 2 controlled F solubility above pH 3.6; at lower pH values, aluminum complexes with F were hypothesized to control F. Luther et al (1996) repeatedly equilibrated PG leachate containing 31 mg F L -1 with calcareous and noncalcareous soils and reported that concentrations of 11 and 22 mg F L -1 persisted, respectively. Geochemical modeling predicted leachates were at or above saturation with respect to fluorite and fluorapatite for calcareous and noncalcareous soils, respectively.…”

Section: Total Soluble Fluoridementioning

confidence: 99%

“…1). Luther et al (1996) reviewed attenuation processes for F and identified precipitation as a major mechanism for F removal in soil-PW systems. As leachates had to be destructively sampled to determine F concentrations below the effective detection limit of 10 mg L -1 (log [F] = -3.3 mol L -1 ), no F concentrations were recorded for PW solutions between the 16th equivalent depth interval and the conclusion of the experiment (Fig.…”

Section: Total Soluble Fluoridementioning

confidence: 99%

“…Impurities associated with PG limit its potential uses (Rutherford et al 1994) and the byproduct will likely remain stockpiled at plant sites indefinitely. Process water used to slurry PG to stockpiles is recycled and becomes extremely acidic (pH <2) as well as concentrated with trace elements, radionuclides, fluoride, sulfate and phosphate which originate from the raw phosphate rock used in the manufacturing process.Concerns about the leaching of trace constituents below PG repositories have led to various studies on the fate of fluoride and other elements in solid PG and in leachates derived from solid PG (Kennedy et al 1991;Ball 1994;Rutherford et al 1995), and in leachates and PW equilibrated with pure phase minerals and soils (Murray and Lewis 1985;Arocena et al 1995;Luther et al 1996). These studies have shown a need for an understanding of the long-term leaching potential of PW-derived contaminants from PG repositories.…”

mentioning

confidence: 99%

“…Concerns about the leaching of trace constituents below PG repositories have led to various studies on the fate of fluoride and other elements in solid PG and in leachates derived from solid PG (Kennedy et al 1991;Ball 1994;Rutherford et al 1995), and in leachates and PW equilibrated with pure phase minerals and soils (Murray and Lewis 1985;Arocena et al 1995;Luther et al 1996). These studies have shown a need for an understanding of the long-term leaching potential of PW-derived contaminants from PG repositories.…”

mentioning

confidence: 99%

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Attenuation of cadmium, fluoride and uranium in phosphogypsum process water by calcareous soil

Poulsen¹,

Dudas²

1998

Can. J. Soil. Sci.

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Poulsen, L. and Dudas, M. J. 1998. Attenuation of cadmium, fluoride and uranium in phosphogypsum process water by calcareous soil. Can. J. Soil Sci. 78: [351][352][353][354][355][356][357]. Concerns about contaminant migration from phosphogypsum (PG) repositories prompted the present study. A sequential batch procedure, in which acidic process water (PW) from a phosphate fertilizer plant was reacted with samples of a calcareous till, was employed to determine the attenuation of environmentally sensitive elements by reaction with typical subsoils at PG waste repositories. PW leachates were monitored for total soluble fluoride (F) and pH during the experiment. Soil samples were analyzed for pH, F, cadmium (Cd), uranium (U), and calcium carbonate (CaCO 3 ) equivalent at the end of the study. Leachate pH increased from <2 to 5.5 where it stabilized; soil pH stabilized at 6.5. Fluoride solution concentrations were reduced within regulatory limits. Soils accumulated Cd, F, and U in excess of background concentrations (up to 99×, 83×, and 12.5×, respectively). Soil carbonates persisted after leachate was buffered near pH 4.5, and played a major role in Cd attenuation. The results of this laboratory analog of a PW leaching gradient suggest contamination of groundwater is unlikely but accumulation of toxic elements in soil is an issue that may require consideration in the long-term decommissioning of PG waste repositories. Les travaux dont nous faisons état ont été inspirés par les risques de migration des contaminants à partir des dépôts de phosphogypse. Une méthode séquentielle en discontinu, dans laquelle l'eau technique acide (ET) d'une usine d'engrais phosphaté était mise en réaction avec des échantillons de till calcaire, a été utilisée pour déterminer l'atténuation des éléments à risque pour l'environnement par réaction avec les sous-sols typiques des emplacements choisis comme sites de stockage du phosphogypse. Les lessivats d'eau technique étaient suivis quant à leur teneur totale en fluorures (F) et à leur pH durant l'expérience. Au terme de l'expérience, les échantillons de sol étaient analysés sur le pH, les teneurs en F, en cadmium (Cd) et en uranium (U) ainsi que sur l'équivalent en carbonate de calcium (C a CO 3 ). Le pH du lessivat remontait de moins de 2 à 5,5, niveau auquel il se stabilisait. De son côtés le pH du sol se stabilisait à 6,5. Les concentrations en fluorures de la solution étaient ramenées dans les limites réglementaires. Les concentrations de Cd, de F et de U dans les sols excédaient celles des sols naturels environnants dans des proportions allant respectivement, jusqu'à 99, 83 et 12,5 fois). Les carbonates du sol qui persistaient après que le lessivat ait été tamponné aux alentours de pH 4,5, jouaient un rôle de premier plan dans l'atténuation du Cd. À partir des résultats de cette réplique en laboratoire d'un gradient de lessivat de ET, on peut conclure qu'il y a peu de risques de contamination de la nappe mais l'accumulation d'éléments toxiques dans le sol est une question dont il faud...

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Section: Solid Phase Analysesmentioning

confidence: 99%

Section: Total Soluble Fluoridementioning

confidence: 99%

Section: Total Soluble Fluoridementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Attenuation of cadmium, fluoride and uranium in phosphogypsum process water by calcareous soil

Poulsen¹,

Dudas²

1998

Can. J. Soil. Sci.

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Fluoride in Groundwater

Sabti

Samayamanthula

Dashti

et al. 2022

Hydrogeochemistry of Aquatic Ecosystems

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Soil Washing of Fluorine Contaminated Soil Using Various Washing Solutions

Moon

Koutsospyros

et al. 2015

Bull Environ Contam Toxicol

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Bench-scale soil washing experiments were conducted to remove fluoride from contaminated soils. Five washing solutions including hydrochloric acid (HCl), nitric acid (HNO3), sodium hydroxide (NaOH), sulfuric acid (H2SO4) and tartaric acid (C4H6O6) were tested. The concentration of the washing solutions used ranged from 0.1 to 3 M with a liquid to solid ratio of 10. The soil washing results showed that the most effective washing solution for the removal of fluoride from contaminated soils was HCl. The highest fluoride removal results of approximately 97 % from the contaminated soil were obtained using 3 M HCl. The fluoride removal efficiency of the washing solution increases in the following order: C4H6O6 < NaOH < H2SO4 < HNO3 < HCl.

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Fluoride sorption and mineral stability in an Alberta soil interacting with phosphogypsum leachate

Cited by 27 publications

References 17 publications

Attenuation of cadmium, fluoride and uranium in phosphogypsum process water by calcareous soil

Attenuation of cadmium, fluoride and uranium in phosphogypsum process water by calcareous soil

Fluoride in Groundwater

Soil Washing of Fluorine Contaminated Soil Using Various Washing Solutions

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