Dynamics of metals in backfill of a phosphate mine of guiyang, China using a three-step sequential extraction technique

Shi, Ying; Gan, Lei; Li, Xibing; He, Suya; Sun, Cheng; Gao, Li

doi:10.1016/j.chemosphere.2017.10.161

Cited by 24 publications

(11 citation statements)

References 29 publications

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“…Compared with the 50% water-soluble fraction of arsenic in PG, the water-soluble fraction of arsenic in the backll decreased to 27% aer PG inclusion into the backll matrix. 17 This was similar to previous study in which the water-soluble arsenic in contaminated sediments decreased by about 20% aer S/S treatment. 11 However, most studies have focused on the leaching amount of arsenic by conducting leaching tests on solidied structures.…”

Section: Introductionsupporting

confidence: 92%

“…22 In PG-based backll process, Shi et al used BCR sequential extraction to measure the dynamic behaviors of metals in PG-based backll and found that metals present in backll were effectively solidied aer about 10 years. 17 However, due to high water-soluble arsenic concentrations, the solidication degree of arsenic should also be considered during backlling. The arsenic dynamics in both bleeding water and leaching water should also be studied.…”

Section: Introductionmentioning

confidence: 99%

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Effects of acid and phosphate on arsenic solidification in a phosphogypsum-based cement backfill process

Yin

Yang

et al. 2019

RSC Adv.

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Section: Introductionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Effects of acid and phosphate on arsenic solidification in a phosphogypsum-based cement backfill process

Yin

Yang

et al. 2019

RSC Adv.

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“…The cumulative leaching quantity of SO 4 2− in PG is 5 times as much as that in backfill, the cumulative leaching quantity of F − in PG is 81 times in backfill, and the cumulative leaching quantity of PO 4 3− in PG is 1678 times in backfill. The reason for this is that, when PG formed a dense structure, the impurities were precipitated and/or incorporated in the hydration products, and thus impurities were less likely to escape from the cemented PG backfill [46].…”

Section: Cumulative Effects Of Impurities On the Environmentmentioning

confidence: 99%

Slurry Preparation Effects on the Cemented Phosphogypsum Backfill through an Orthogonal Experiment

Zhou

Zhu

et al. 2019

Minerals

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The cemented phosphogypsum (PG) backfill technique provides a new method for massive consumption of PG, and therefore alleviating the environmental pollution of PG. This study considered the effects of slurry preparation on the performance of cemented PG backfill. A L 16 (4 4 ) orthogonal experiment was designed to analyze four factors, namely the solid content, phosphogypsum-to-binder ratio (PG/B ratio), stirring time and stirring speed, with each factor having four levels. According to the range analysis, the solid content played the dominant role in controlling the bleeding rate, while the setting times strongly depended on the PG/B ratio. In terms of strength development of the backfill, the PG/B ratio was shown to be the most significant factor determining the unconfined compressive strength (UCS), followed by the solid content, stirring time and stirring speed. Furthermore, the results showed that the slurry preparation affected the environmental behavior of impurities that originated in PG. By analyzing the concentrations of impurities in the bleeding water of the slurry as well as the leachates of the tank leaching test, the results showed that the release of F − and SO 4 2− was aggravated clearly with the increase in the PG/B ratio, while the release of PO 4 3− always remained at relatively low levels.

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“…As a typical solidification/stabilization (s/s) process, cemented backfill technology can effectively immobilize the impurities in PG, alleviating environmental pollution [22]. In the cement-based s/s process, chemical adsorption and physical adsorption are primary fixation mechanisms [23].…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, leaching of toxic impurities from cement-stabilized soil increases noticeably in an acidic environment [25]. However, studies on the leaching of hazardous impurities from PG-based backfill are still limited [7,22]. Therefore, research on the dynamics of impurities in backfill should be conducted under unfavorable conditions.…”

Section: Introductionmentioning

confidence: 99%

Durability Evaluation of Phosphogypsum-Based Cemented Backfill Through Drying-Wetting Cycles

Zhou

et al. 2019

Minerals

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In this study, the durability of phosphogypsum (PG)-based cemented backfill was investigated by drying-wetting cycles to explore deterioration of its strength and the release of impurities. The leachates in this test were composed of deionized water, 5% Na2SO4 solution, 5% NaCl solution, and a range of sulfuric acid solutions with pH values of 1.5, 3, and 5. After drying-wetting cycles, unconfined compressive strength (UCS), visual deterioration, porosity, microstructure and concentrations of phosphate and fluoride in the leachates were measured. The results showed that both saline and acidic solutions could lead to strength reduction of PG-based cemented backfill under different deterioration mechanisms. The mechanical damage of salinity was caused by micro-cracking and degradation of C–S–H. However, the H+ broke the backfill by dissolving hydration products, leaving the conjunctures between PG particles weakened. Furthermore, the environmental impact was investigated by measuring the concentration of phosphate and fluoride in the leachates. In acidic solutions, the release of phosphate and fluoride was greatly enhanced by H+. Compared to the great strength deterioration in saline leachates, the concentration of phosphate and fluoride were similar to that of deionized water, indicating that saline solutions had little impact on the release of hazardous impurities.

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Dynamics of metals in backfill of a phosphate mine of guiyang, China using a three-step sequential extraction technique

Cited by 24 publications

References 29 publications

Effects of acid and phosphate on arsenic solidification in a phosphogypsum-based cement backfill process

Effects of acid and phosphate on arsenic solidification in a phosphogypsum-based cement backfill process

Slurry Preparation Effects on the Cemented Phosphogypsum Backfill through an Orthogonal Experiment

Durability Evaluation of Phosphogypsum-Based Cemented Backfill Through Drying-Wetting Cycles

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