Alloy selective optical sorting of mixed post-consumer aluminum scrap streams

Efe, Mert; Rohatgi, Aashish; Dai, Qiang; Stapleton, Brian; Rader, Katherine E.; Lipson, Albert L.; Spangenberger, Jeffrey S.

doi:10.1016/j.resconrec.2025.108500

Alloy selective optical sorting of mixed post-consumer aluminum scrap streams

Journal Article · Fri Jul 11 00:00:00 EDT 2025 · Resources, Conservation and Recycling

DOI:https://doi.org/10.1016/j.resconrec.2025.108500· OSTI ID:3021470

^[1]; ^[1]; Dai, Qiang ^[2]; Stapleton, Brian ^[2]; ^[1]; Lipson, Albert L. ^[2]; Spangenberger, Jeffrey S. ^[2]

Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Argonne National Laboratory (ANL), Argonne, IL (United States)

Shredded post-consumer non-ferrous scrap stream, also known as Zorba, contains a mixture of cast and wrought aluminum pieces with very different compositions. Cast Al pieces, with their high Si, Cu and Fe content, are a major contaminant in wrought scrap fraction, which results in downcycling of the mixed cast + wrought scrap into non-structural cast Al alloys and parts. Here, in this paper, we introduce a chemical treatment method to color-code scrap aluminum pieces by alloy family and demonstrate low-cost optical sorting of cast from wrought pieces to upgrade the scrap stream. We utilized non-acidic chemical solutions that react with (i.e., etch) the scrap pieces to produce colors based on the Al alloy chemistry of a given piece. Cast pieces with high Si and Cu fractions turned black, whereas the much leaner wrought pieces remained unreacted. We showed > 95% sorting efficiency of mixed cast and wrought pieces using a repurposed low-cost optical sorter originally designed for food sorting. We also colored wrought Al pieces by alloy families, such as 5xxx and 6xxx, using a two-step chemical etching technique, which has the potential to create a circular supply chain in which wrought aluminum alloys are sorted from the mixed scrap stream and recycled back to high-value wrought products such as sheets, extrusions, and forgings with minimal contamination from cast scrap.

View Accepted Manuscript (DOE)

Research Organization:: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)

Sponsoring Organization:: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO)

Grant/Contract Number:: AC02-06CH11357; AC05-76RL01830

OSTI ID:: 3021470

Report Number(s):: PNNL-SA--208489

Journal Information:: Resources, Conservation and Recycling, Journal Name: Resources, Conservation and Recycling Vol. 223; ISSN 0921-3449

Publisher:: ElsevierCopyright Statement

Country of Publication:: United States

Language:: English

References (15)

The development of recycle-friendly automotive aluminum alloys Das, Subodh K.; Green, J. A. S.; Kaufman, J. Gilbert JOM, Vol. 59, Issue 11 https://doi.org/10.1007/s11837-007-0140-2	journal	November 2007
Aluminum recycling—An integrated, industrywide approach Das, Subodh K.; Green, John A. S.; Kaufman, J. Gilbert JOM, Vol. 62, Issue 2 https://doi.org/10.1007/s11837-010-0026-6	journal	February 2010
The Potential for XRF & LIBS Handheld Analyzers to Perform Material Characterization in Scrap Yards Brooks, Leslie; Gaustad, Gabrielle Journal of Sustainable Metallurgy, Vol. 7, Issue 2 https://doi.org/10.1007/s40831-021-00361-3	journal	June 2021
Hot-crush technique for separation of cast- and wrought-aluminum alloy scrap Ambrose, Fred; Brown, R. D.; Montagna, Dominic Conservation & Recycling, Vol. 6, Issue 1-2 https://doi.org/10.1016/0361-3658(83)90018-8	journal	January 1983
Recycling of aluminum and caustic soda solution from waste effluents generated during the cleaning of the extruder matrixes of the aluminum industry Tansens, Pieter; Rodal, Alberto T.; Machado, Carina M. M. Journal of Hazardous Materials, Vol. 187, Issue 1-3 https://doi.org/10.1016/j.jhazmat.2011.01.048	journal	March 2011
Performance evaluation of optical sorting in mineral processing – A case study with quartz, magnesite, hematite, lignite, copper and gold ores Gülcan, Ergin; Gülsoy, Özcan Y. International Journal of Mineral Processing, Vol. 169 https://doi.org/10.1016/j.minpro.2017.11.007	journal	December 2017
Making sustainable aluminum by recycling scrap: The science of “dirty” alloys Raabe, Dierk; Ponge, Dirk; Uggowitzer, Peter J. Progress in Materials Science, Vol. 128 https://doi.org/10.1016/j.pmatsci.2022.100947	journal	July 2022
Automatic sorting of lightweight metal scrap by sensing apparent density and three-dimensional shape Koyanaka, Shigeki; Kobayashi, Kenichiro Resources, Conservation and Recycling, Vol. 54, Issue 9 https://doi.org/10.1016/j.resconrec.2009.10.014	journal	July 2010
Deep learning computer vision for the separation of Cast- and Wrought-Aluminum scrap Díaz-Romero, Dillam; Sterkens, Wouter; Van den Eynde, Simon Resources, Conservation and Recycling, Vol. 172 https://doi.org/10.1016/j.resconrec.2021.105685	journal	September 2021
Analysis of scrap flows from recycling aluminum-intensive vehicles in the United States: Insights from a case study on the F-150 Zhu, Yongxian; Khan, Omer; Heidari, Mohammadreza Resources, Conservation and Recycling, Vol. 217 https://doi.org/10.1016/j.resconrec.2025.108199	journal	May 2025
Research on the process of small sample non-ferrous metal recognition and separation based on deep learning Chen, Song; Hu, Zhili; Wang, Chao Waste Management, Vol. 126 https://doi.org/10.1016/j.wasman.2021.03.019	journal	May 2021
Deep learning approaches for classification of copper-containing metal scrap in recycling processes Koinig, G.; Kuhn, N.; Fink, T. Waste Management, Vol. 190 https://doi.org/10.1016/j.wasman.2024.10.022	journal	December 2024
Long-Term Strategies for Increased Recycling of Automotive Aluminum and Its Alloying Elements Løvik, Amund N.; Modaresi, Roja; Müller, Daniel B. Environmental Science & Technology, Vol. 48, Issue 8 https://doi.org/10.1021/es405604g	journal	March 2014
Super-High-Purity Seed Sorter Using Low-Latency Image-Recognition Based on Deep Learning Heo, Young Jin; Kim, Se Jin; Kim, Dayeon IEEE Robotics and Automation Letters, Vol. 3, Issue 4 https://doi.org/10.1109/LRA.2018.2849513	journal	October 2018
Classification of Shredded Aluminium Scrap Metal Using Magnetic Induction Spectroscopy Williams, Kane C.; Mallaburn, Michael J.; Gagola, Martin Sensors, Vol. 23, Issue 18 https://doi.org/10.3390/s23187837	journal	September 2023

Similar Records

Upcycling of Mixed Aluminum Alloy Shredder Scrap using Shear Processing

Journal Article · Fri Jul 05 00:00:00 EDT 2024 · Advanced Materials and Processes · OSTI ID:2506684

Highly Efficient Vacuum Smelting of Aluminum

Technical Report · Sat Mar 09 23:00:00 EST 2024 · OSTI ID:2322347

Upcycling of aluminum Twitch scrap via Shear Assisted Processing and Extrusion (ShAPE)

Journal Article · Fri Jul 18 20:00:00 EDT 2025 · Manufacturing Letters · OSTI ID:3006406

Related Subjects

Aluminum
Domestic resources
Optical sorting
Recycling
Surface coating
Twitch
Wrought

Alloy selective optical sorting of mixed post-consumer aluminum scrap streams

Citation Formats

References (15)

Similar Records

Related Subjects