Hobson, AJ, Stewart, DI orcid.org/0000-0001-5144-1234, Mortimer, RJG et al. (3 more authors) (2018) Leaching behaviour of co-disposed steel making wastes: Effects of aeration on leachate chemistry and vanadium mobilisation. Waste Management, 81. pp. 1-10. ISSN 0956-053X
Abstract
Steelmaking wastes stored in landfill, such as slag and spent refractory liners, are often enriched in toxic trace metals (including V). These may become mobile in highly alkaline leachate generated during weathering. Fresh steelmaking waste was characterised using XRD, XRF, and SEM-EDX. Batch leaching tests were performed under aerated, air-excluded and acidified conditions to determine the impact of atmospheric CO₂ and acid addition on leachate chemistry. Phases commonly associated with slag including dicalcium silicate, dicalcium aluminoferrite, a wüstite-like solid solution and free lime were identified, as well as a second group of phases including periclase, corundum and graphite which are representative of refractory liners. During air-excluded leaching, dissolution of free lime and dicalcium silicate results in a high pH, high Ca leachate in which the V concentration is low due to the constraint imposed by Ca₃(VO₄)₂ solubility limits. Under aerated conditions, carbonation lowers the leachate pH and provides a sink for aqueous Ca, allowing higher concentrations of V to accumulate. Below pH 10, leachate is dominated by periclase dissolution and secondary phases including monohydrocalcite and dolomite are precipitated. Storage of waste under saturated conditions that exclude atmospheric CO₂ would therefore provide the optimal environment to minimise V leaching during weathering.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Elsevier Ltd. All rights reserved. This is an author produced version of a paper published in Waste Management. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Steel slag; Vanadium; Leaching behaviour; Alkaline wastes |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Civil Engineering (Leeds) The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Funding Information: | Funder Grant number NERC NE/L01405X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 01 Oct 2018 14:53 |
Last Modified: | 04 Oct 2019 00:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.wasman.2018.09.046 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:136380 |