Regional-Scale Characterization of REE Abundances in Pennsylvania Iron Slag from the 18th to Early 20th Century

Rare earth elements (REE) are recognized as critical minerals which are necessary components of more than 200 products across a wide range of applications, particularly high-tech consumer products and magnets for wind turbines. Waste product reclamation potentially offers an environmentally favorable source of raw materials as an alternative to extracting REE from virgin sources. The concept of utilizing slag from Pennsylvania cold blast iron furnaces as a source of REE is promising but has yet to be studied extensively. Slag samples from five historic PA cold blast furnaces (in operation from 1771-1921, collectively) were analyzed using an Electron Probe Microanalyzer (EPMA) to determine major element abundances and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to determine trace element abundances. The slag samples, composed primarily of Si, Al, and Ca with variable Mg contents, were found to contain 348 – 1362 ppm total REE. The slag contains up to ten times the concentration of REE compared to average upper continental crust. Slag from furnaces in Central PA, where sedimentary iron ore was processed, contain little Mg and are less enriched in the light REE compared to middle and heavy REE, while slag from furnaces in Southeastern PA, where skarn ore was processed, contain more Mg and show more consistent enrichments with respect to light, middle, and heavy REE. Although no correlation between REE abundance and visual appearance (color or porosity) was observed, the observed correlation between REE and Y may be useful for field identification using a handheld X-ray Fluorescence analyzer. Future work should investigate the methodology for extracting REE from slag to determine if slag is an economically feasible source of REE for use in industry.

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Work Title Regional-Scale Characterization of REE Abundances in Pennsylvania Iron Slag from the 18th to Early 20th Century
Access
Open Access
Creators
  1. Noah Sheldon
  2. Maureen Feineman
  3. Joshua Garber
Keyword
  1. Rare Earth Elements
  2. Slag
  3. Critical Minerals
  4. Pennsylvania Iron Industry
  5. Pennsylvania Geology
License CC BY-NC-ND 4.0 (Attribution-NonCommercial-NoDerivatives)
Work Type Research Paper
Publication Date 2024
DOI doi:10.26207/q4ve-h050
Deposited May 31, 2024

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Version 1
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  • Updated
  • Updated Keyword, Description, Publication Date Show Changes
    Keyword
    • Rare Earth Elements, Slag, Critical Minerals, Pennsylvania Iron Industry, Pennsylvania Geology
    Description
    • Rare earth elements (REE) are recognized as critical minerals which are necessary components of more than 200 products across a wide range of applications, particularly high-tech consumer products and magnets for wind turbines. Waste product reclamation potentially offers an environmentally favorable source of raw materials as an alternative to extracting REE from virgin sources. The concept of utilizing slag from Pennsylvania cold blast iron furnaces as a source of REE is promising but has yet to be studied extensively. Slag samples from five historic
    • PA cold blast furnaces (in operation from 1771-1921, collectively) were analyzed using an Electron Probe Microanalyzer (EPMA) to determine major element abundances and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to determine trace element abundances. The slag samples, composed primarily of Si, Al, and Ca with variable Mg contents, were found to contain 348 – 1362 ppm total REE. The slag contains up to ten times the concentration of REE compared to average upper continental crust. Slag from furnaces in Central PA, where sedimentary iron ore was processed, contain little Mg and are less enriched in the light REE compared to middle and heavy REE, while slag from furnaces in Southeastern PA, where skarn ore was processed, contain more Mg and show more consistent enrichments with respect to light, middle, and heavy REE. Although no correlation between REE abundance and visual appearance (color or porosity) was observed, the observed correlation between REE and Y may be useful for field identification using a handheld X-ray Fluorescence analyzer. Future work should investigate the methodology for extracting REE from slag to determine if slag is an economically feasible source of REE for use in industry.
    Publication Date
    • 2024
  • Added Creator Noah Sheldon
  • Added Creator Maureen Feineman
  • Added Creator Joshua Garber
  • Added Sheldon_Sp2024.pdf
  • Updated License Show Changes
    License
    • https://creativecommons.org/licenses/by-nc-nd/4.0/
  • Published
  • Updated