Leaching Kinetics of Iron Collector Containing PGMs

The leaching kinetics of an industrial iron collector containing PGMs (Pd, Pt, Rh) in HCl and HF solutions were investigated. The effects of the HCl concentration (2.74–6.86 mol/L), the HF concentration (1.46–7.50 mol/L), temperature (323–363 K), and leaching time (0–210 min) on the extraction of Fe...

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Main Authors: Evgeniy Kuzas, Ivan Sandalov, Aleksei Kritskii, Kirill Karimov
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/14/12/1416
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author Evgeniy Kuzas
Ivan Sandalov
Aleksei Kritskii
Kirill Karimov
author_facet Evgeniy Kuzas
Ivan Sandalov
Aleksei Kritskii
Kirill Karimov
author_sort Evgeniy Kuzas
collection DOAJ
description The leaching kinetics of an industrial iron collector containing PGMs (Pd, Pt, Rh) in HCl and HF solutions were investigated. The effects of the HCl concentration (2.74–6.86 mol/L), the HF concentration (1.46–7.50 mol/L), temperature (323–363 K), and leaching time (0–210 min) on the extraction of Fe into the solution and Si into the gas phase from the iron collector were studied. The HCl concentration had a negative effect on the extraction of Si, which decreased from 78.2% to 58.1% and from 97.4% to 87.2% in the time ranges of 0–30 min and 30–120 min, respectively. This occurred due to the accumulation of Fe<sup>2+</sup> in the solution and its interaction with HF, which led to a reduction in both the HF concentration and the extraction of Si. In addition, there were diffusion difficulties of the Fe and Si extraction because Fe precipitated on the surface of the cakes in the form of thin-film conglomerates of FeF<sub>2</sub>. This was confirmed by the XRF and EDS results, indicating that F was present on the surface of the cakes. The processes of the Fe and Si extraction were diffusion-chemically controlled and diffusion controlled—the apparent activation energies decreased from 26.9 kJ/mol to 7.8 kJ/mol and from 2.2 kJ/mol to 2.0 kJ/mol in the time range of 0–120 min, respectively. Using the shrinking core model and the full factorial experiment model, the kinetic equations, the optimal parameters of iron collector leaching, and the extraction rates of Fe and Si were determined. These optimal parameters ensure the extraction of Fe and Si at the level of 95% with high leaching rates: the HCl concentration of 4.36 mol/L, the HF concentration of 6.93 mol/L, temperature of 363 K, and leaching time of 80 min.
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spelling doaj-art-864d5077a1d44f8e8632fec219188e092024-12-27T14:40:01ZengMDPI AGMetals2075-47012024-12-011412141610.3390/met14121416Leaching Kinetics of Iron Collector Containing PGMsEvgeniy Kuzas0Ivan Sandalov1Aleksei Kritskii2Kirill Karimov3Department of Non-Ferrous Metals Metallurgy, Ural Federal University, 620002 Yekaterinburg, RussiaDepartment of Rare Metals and Nanomaterials, Ural Federal University, 620002 Yekaterinburg, RussiaLaboratory of Advanced Technologies in Non-Ferrous and Ferrous Metals Raw Materials Processing, Ural Federal University, 620002 Yekaterinburg, RussiaLaboratory of Advanced Technologies in Non-Ferrous and Ferrous Metals Raw Materials Processing, Ural Federal University, 620002 Yekaterinburg, RussiaThe leaching kinetics of an industrial iron collector containing PGMs (Pd, Pt, Rh) in HCl and HF solutions were investigated. The effects of the HCl concentration (2.74–6.86 mol/L), the HF concentration (1.46–7.50 mol/L), temperature (323–363 K), and leaching time (0–210 min) on the extraction of Fe into the solution and Si into the gas phase from the iron collector were studied. The HCl concentration had a negative effect on the extraction of Si, which decreased from 78.2% to 58.1% and from 97.4% to 87.2% in the time ranges of 0–30 min and 30–120 min, respectively. This occurred due to the accumulation of Fe<sup>2+</sup> in the solution and its interaction with HF, which led to a reduction in both the HF concentration and the extraction of Si. In addition, there were diffusion difficulties of the Fe and Si extraction because Fe precipitated on the surface of the cakes in the form of thin-film conglomerates of FeF<sub>2</sub>. This was confirmed by the XRF and EDS results, indicating that F was present on the surface of the cakes. The processes of the Fe and Si extraction were diffusion-chemically controlled and diffusion controlled—the apparent activation energies decreased from 26.9 kJ/mol to 7.8 kJ/mol and from 2.2 kJ/mol to 2.0 kJ/mol in the time range of 0–120 min, respectively. Using the shrinking core model and the full factorial experiment model, the kinetic equations, the optimal parameters of iron collector leaching, and the extraction rates of Fe and Si were determined. These optimal parameters ensure the extraction of Fe and Si at the level of 95% with high leaching rates: the HCl concentration of 4.36 mol/L, the HF concentration of 6.93 mol/L, temperature of 363 K, and leaching time of 80 min.https://www.mdpi.com/2075-4701/14/12/1416automotive catalystiron collectorplatinum group metalskineticsshrinking core model
spellingShingle Evgeniy Kuzas
Ivan Sandalov
Aleksei Kritskii
Kirill Karimov
Leaching Kinetics of Iron Collector Containing PGMs
Metals
automotive catalyst
iron collector
platinum group metals
kinetics
shrinking core model
title Leaching Kinetics of Iron Collector Containing PGMs
title_full Leaching Kinetics of Iron Collector Containing PGMs
title_fullStr Leaching Kinetics of Iron Collector Containing PGMs
title_full_unstemmed Leaching Kinetics of Iron Collector Containing PGMs
title_short Leaching Kinetics of Iron Collector Containing PGMs
title_sort leaching kinetics of iron collector containing pgms
topic automotive catalyst
iron collector
platinum group metals
kinetics
shrinking core model
url https://www.mdpi.com/2075-4701/14/12/1416
work_keys_str_mv AT evgeniykuzas leachingkineticsofironcollectorcontainingpgms
AT ivansandalov leachingkineticsofironcollectorcontainingpgms
AT alekseikritskii leachingkineticsofironcollectorcontainingpgms
AT kirillkarimov leachingkineticsofironcollectorcontainingpgms