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Model of phosphorus precipitation and crystal formation in Electric Arc Furnace steel slag filters

Dominique Claveau-Mallet, Scott Wallace and Yves Comeau

Article (2012)

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Cite this document: Claveau-Mallet, D., Wallace, S. & Comeau, Y. (2012). Model of phosphorus precipitation and crystal formation in Electric Arc Furnace steel slag filters. Environmental Science & Technology, 46(3), p. 1465-1470. doi:10.1021/es2024884
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Abstract

The objective of this study was to develop a phosphorus retention mechanisms model based on precipitation and crystallization in electric arc furnace (EAF) slag filters. Three slag columns were fed during 30 to 630 days with a reconstituted mining effluent at different void hydraulic retention times. Precipitates formed in columns were characterized by X-ray diffraction and transmission electronic microscopy. The proposed model is expressed in the following steps: 1) the rate limiting dissolution of slag is represented by the dissolution of CaO, 2) a high pH in the slag filter results in phosphorus precipitation and crystal growth, 3) crystal retention takes place by filtration, settling and growth densification, 4) the decrease in available reaction volume is caused by crystal and other particulate matter accumulation (and decrease in available reaction time), and 5) the pH decreases in the filter over time if the reaction time is too low (which results in a reduced removal efficiency). Crystal organization in a slag filter determines its phosphorus retention capacity. Supersaturation and water velocity affect crystal organization. A compact crystal organization enhances the phosphorus retention capacity of the filter. A new approach to define filter performance is proposed: saturation retention capacity is expressed in units of mg P/ mL voids.

Uncontrolled Keywords

phosphorus, apatite, wastewater treatment, slag, removal mechanisms

Open Access document in PolyPublie
Subjects: 1400 Génie minier et minéral > 1400 Génie minier et minéral
1400 Génie minier et minéral > 1402 Traitement des minéraux
Department: Département des génies civil, géologique et des mines
Research Center: Non applicable
Funders: Missouri Remediation Trust, CNSNG/NSERC, Fonds québécois de la recherche sur la nature et les technologies
Date Deposited: 16 Jul 2020 16:25
Last Modified: 08 Apr 2021 10:43
PolyPublie URL: https://publications.polymtl.ca/5302/
Document issued by the official publisher
Journal Title: Environmental Science & Technology (vol. 46, no. 3)
Publisher: ACS Publications
Official URL: https://doi.org/10.1021/es2024884

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