Mechanisms of Heterogeneous Fe(ii) Oxidation in Acid Mine Drainage

Park, Byungtae; Dempsey, Brian A.

doi:10.21000/jasmr0401408

Cited by 4 publications

(1 citation statement)

References 8 publications

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“…Consequently, the overnight air bubbling of AMD was sufficient to ensure the nearly complete oxidation of iron. It is reported that the abiotic oxidation of ferrous iron to ferric iron proceeds very slowly at pH<3 (Park and Dempsey, 2004). Also, the oxidation of iron is limited by the availability of dissolved oxygen.…”

Section: Iron Oxidationmentioning

confidence: 99%

Acid mine drainage: Sludge dewatering, metal recovery and synthesis of magnetite nanoparticles

Wei¹

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Acid mine drainage (AMD) is one of the significant environmental challenges for the coal and hard-rock mining industry. Traditional AMD treatment generates large volumes of sludge with low solids which are difficult to dewater. In this study, a systematic investigation was carried out on the characteristics and dewaterability of AMD sludge produced from an ammonia neutralization operation, and the dewatering performance of different treatment options. In order to mitigate the AMD sludge problem, a selective precipitation process was developed to recover Fe and Al while AMD was treated simultaneously. In conjunction, a low-cost synthesis approach was examined to prepare magnetite nanoparticles with the recovered iron from AMD, and its implication in environmental engineering was discussed. The AMD sludge from ammonia neutralization was characterized by high pH and alkalinity, high total Fe and Al, elevated sulfate, and low solids (0.72 ± 0.24%). Compared to other AMD sludges and metal hydroxide sludges, ammonia-treated AMD sludge demonstrated relatively good dewaterability in terms of specific resistance to filtration. Coagulation and flocculation treatment did not effectively reduce the final volume of the settled sludge. Sludge cakes with 6.2% solids and a filter yield of 3.04 kg/m 2 h were achieved by vacuum filtration. Additionally, a belt filter press showed a good performance in improving solids content of the sludge cake. Simultaneous metal recovery and AMD treatment were achieved using a selective precipitation process based on solubility characteristics of the major and minor metals in the AMD. Separate iron and aluminum hydroxide products with relatively high purity were successfully recovered via iron precipitation at pH 3.5-4.0 followed by aluminum precipitation at pH 6.0-7.0, while simultaneously meeting the NPDES effluent discharge standards. The proposed metal recovery process was relatively easy to implement in the field. An approach to synthesize low-cost magnetite nanoparticles via coprecipitation was developed with the recovered ferric iron from AMD as the iron source. Through scanning and transmission electron microscopic studies, it was demonstrated that most of the magnetite nanoparticles ranged from 10 to 15 nm and were spheroidical or cubic in shape. Consequently, the recovered ferric iron from AMD could be used as a low-cost substitute feedstock for reagentgrade chemical for magnetite nanoparticle preparation, which provided great opportunity for the application of magnetite nanoparticles in environmental engineering.

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Section: Iron Oxidationmentioning

confidence: 99%

Acid mine drainage: Sludge dewatering, metal recovery and synthesis of magnetite nanoparticles

Wei¹

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An approach to total synthesis of the cylindricine B pyridoquinoline subclass of tricyclic marine ascidian alkaloids

Chao

Mahajan

Weinreb

2006

Tetrahedron Letters

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Electrochemical Impedance Spectroscopic Study of Passive Zirconium

Chen

Urquidi‐Macdonald

et al. 2007

J. Electrochem. Soc.

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The development of deterministic models for predicting the accumulation of corrosion damage to zirconium and Zircaloys in boiling water reactor coolant environments requires the acquisition of values for various model parameters. In the present work, the point defect model ͑PDM͒ was further developed to account for the properties of passive films comprising oxide barrier layers and porous oxide outer layers that form on zirconium and Zircaloys in high-temperature, deaerated aqueous solutions. The model parameter values were extracted from electrochemical impedance spectroscopic data for zirconium in deaerated, borate buffer solution ͓0.1 M B͑OH͒ 3 + 0.001 M LiOH, pH 6.94͔ at 250 °C by optimization. The results indicate that the corrosion resistance of zirconium in high-temperature, deaerated aqueous solutions is dominated by the porosity and thickness of the outer layer. The impedance model based on the PDM provides a good account of the growth of the bi-layer passive films described above, and the extracted model parameter values might be used, for example, for predicting the accumulation of general corrosion damage to Zircaloy fuel sheath in BWR operating environments.

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Mechanisms of Heterogeneous Fe(ii) Oxidation in Acid Mine Drainage

Cited by 4 publications

References 8 publications

Acid mine drainage: Sludge dewatering, metal recovery and synthesis of magnetite nanoparticles

Acid mine drainage: Sludge dewatering, metal recovery and synthesis of magnetite nanoparticles

An approach to total synthesis of the cylindricine B pyridoquinoline subclass of tricyclic marine ascidian alkaloids

Electrochemical Impedance Spectroscopic Study of Passive Zirconium

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