Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition

The removal of Fe from Al alloy scraps is the main challenge for their recycling because the excess of Fe usually forms needle-like phases in the Al alloys, which reduces their mechanical properties. In this study, a combined process of electromagnetic directional solidification and Si addition is p...

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Main Authors: Yakun Zhang, Yun Lei, Yongsheng Ren, Wenhui Ma
Format: Article
Language:English
Published: Elsevier 2023-09-01
Series:Journal of Materials Research and Technology
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2238785423022883
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author Yakun Zhang
Yun Lei
Yongsheng Ren
Wenhui Ma
author_facet Yakun Zhang
Yun Lei
Yongsheng Ren
Wenhui Ma
author_sort Yakun Zhang
collection DOAJ
description The removal of Fe from Al alloy scraps is the main challenge for their recycling because the excess of Fe usually forms needle-like phases in the Al alloys, which reduces their mechanical properties. In this study, a combined process of electromagnetic directional solidification and Si addition is proposed to remove the Fe impurities from Al alloy scraps. The influence of the Si content on the removal and distribution of Fe impurities and the removal mechanism of Fe impurities were studied during the electromagnetic directional solidification of Al alloy scraps. In addition, the precipitation pattern of various phases and the removal mechanism of Cu, Mn, Mg, and Zn impurities were studied. The obtained results showed that adding 5–11.4 wt% Si during the electromagnetic directional solidification of Al alloy scrap can promote the precipitation of large bulk α-Fe (Al15(Fe, Mn)3Si2) phase at the bottom and top of the alloy. In other words, Fe and Mn were mainly enriched at the bottom and top of the alloy, which caused the removal of Fe and Mn impurities (Fe and Mn were reduced from 1.1 to 0.32 wt% and from 0.73 to 0.15 wt%, respectively). After the bulk α-Fe phase precipitated, the Al, Chinese script-like α-Fe, Si, θ (Al2Cu), and Q (Al3Cu2Mg9Si7) phases would sequentially precipitate. In the electromagnetic directional solidification, the Mg impurities (from 1.2 to 0.65 wt%) and Zn impurities (from 1.7 to 0.03 wt%) were also removed. This study provides a new green process for the efficient Fe removal from Al alloy scraps.
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spelling doaj.art-ec6f82d7f47d4b21955325106cafaeda2023-10-30T06:04:48ZengElsevierJournal of Materials Research and Technology2238-78542023-09-012687388747Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si additionYakun Zhang0Yun Lei1Yongsheng Ren2Wenhui Ma3National Engineering Research Center of Vacuum Metallurgy/Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization, Kunming University of Science and Technology, Kunming 650093, ChinaNational Engineering Research Center of Vacuum Metallurgy/Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization, Kunming University of Science and Technology, Kunming 650093, China; Corresponding author. National Engineering Research Center of Vacuum Metallurgy/Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China.National Engineering Research Center of Vacuum Metallurgy/Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization, Kunming University of Science and Technology, Kunming 650093, ChinaNational Engineering Research Center of Vacuum Metallurgy/Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China; State Key Laboratory of Complex Nonferrous Metal Resources Clear Utilization, Kunming University of Science and Technology, Kunming 650093, China; Pu'er University, Pu'er 665000, China; Corresponding author. National Engineering Research Center of Vacuum Metallurgy/Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China.The removal of Fe from Al alloy scraps is the main challenge for their recycling because the excess of Fe usually forms needle-like phases in the Al alloys, which reduces their mechanical properties. In this study, a combined process of electromagnetic directional solidification and Si addition is proposed to remove the Fe impurities from Al alloy scraps. The influence of the Si content on the removal and distribution of Fe impurities and the removal mechanism of Fe impurities were studied during the electromagnetic directional solidification of Al alloy scraps. In addition, the precipitation pattern of various phases and the removal mechanism of Cu, Mn, Mg, and Zn impurities were studied. The obtained results showed that adding 5–11.4 wt% Si during the electromagnetic directional solidification of Al alloy scrap can promote the precipitation of large bulk α-Fe (Al15(Fe, Mn)3Si2) phase at the bottom and top of the alloy. In other words, Fe and Mn were mainly enriched at the bottom and top of the alloy, which caused the removal of Fe and Mn impurities (Fe and Mn were reduced from 1.1 to 0.32 wt% and from 0.73 to 0.15 wt%, respectively). After the bulk α-Fe phase precipitated, the Al, Chinese script-like α-Fe, Si, θ (Al2Cu), and Q (Al3Cu2Mg9Si7) phases would sequentially precipitate. In the electromagnetic directional solidification, the Mg impurities (from 1.2 to 0.65 wt%) and Zn impurities (from 1.7 to 0.03 wt%) were also removed. This study provides a new green process for the efficient Fe removal from Al alloy scraps.http://www.sciencedirect.com/science/article/pii/S2238785423022883Al alloy scrapsFe removalSi additionElectromagnetic directional solidificationWaste disposal
spellingShingle Yakun Zhang
Yun Lei
Yongsheng Ren
Wenhui Ma
Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition
Journal of Materials Research and Technology
Al alloy scraps
Fe removal
Si addition
Electromagnetic directional solidification
Waste disposal
title Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition
title_full Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition
title_fullStr Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition
title_full_unstemmed Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition
title_short Removal of Fe impurities from Al alloy scraps by electromagnetic directional solidification combined with Si addition
title_sort removal of fe impurities from al alloy scraps by electromagnetic directional solidification combined with si addition
topic Al alloy scraps
Fe removal
Si addition
Electromagnetic directional solidification
Waste disposal
url http://www.sciencedirect.com/science/article/pii/S2238785423022883
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AT yunlei removaloffeimpuritiesfromalalloyscrapsbyelectromagneticdirectionalsolidificationcombinedwithsiaddition
AT yongshengren removaloffeimpuritiesfromalalloyscrapsbyelectromagneticdirectionalsolidificationcombinedwithsiaddition
AT wenhuima removaloffeimpuritiesfromalalloyscrapsbyelectromagneticdirectionalsolidificationcombinedwithsiaddition