Alkali Vapor Corrosion of Spinel (MgAl2O4) and Gahnite (ZnAl2O4) Refractories—A Comparative Study

Rajat Durgesh Ramteke; James G. Hemrick; Manoj K. Mahapatra

doi:10.1111/jace.70773

Alkali Vapor Corrosion of Spinel (MgAl₂O₄) and Gahnite (ZnAl₂O₄) Refractories—A Comparative Study

Rajat Durgesh Ramteke
, James G. Hemrick
, Manoj K. Mahapatra

Ceramics & Ceramic Composites

Research output: Contribution to journal › Article › peer-review

Abstract

Alkali vapor corrosion is critical for refractories used in the kilns and furnaces of diverse high-temperature processing and manufacturing sectors such as gasifiers, cement production, and glass making. Gahnite (ZnAl₂O₄) is being investigated as a potential chrome-free refractory because of its similarity with the structure and properties of magnesium aluminate (MgAl₂O₄) spinel. The alkali vapor corrosion of ZnAl₂O₄, MgAl₂O₄, and Mg_0.5Zn_0.5Al₂O₄ was studied, according to ASTM C987-10, at 1371°C for 24 h using sodium carbonate (Na₂CO₃). The surface and the polished cross-sections of the corroded ZnAl₂O₄, MgAl₂O₄, and Mg_0.5Zn_0.5Al₂O₄ specimens were analyzed using x-ray diffraction (XRD), microscopy, and energy-dispersive spectroscopy (EDS) techniques. MgO in MgAl₂O₄, ZnO in ZnAl₂O₄, Mg_0.77Zn_0.23O, and NaAlO₂ were detected as the corrosion products for these specimens. The extent of corrosion substantially varied among the specimens despite the similarity in the corrosion products. The corrosion resistance increased in the following order: Mg_0.5Zn_0.5Al₂O₄ > MgAl₂O₄ > ZnAl₂O₄. The formation of a dense MgO and Mg_0.77Zn_0.23O layer for MgAl₂O₄ and Mg_0.5Zn_0.5Al₂O₄, respectively, contributed to their superior resistance to alkali vapor corrosion. The underlying corrosion mechanisms are discussed based on experimental observations supported by thermodynamic analysis. Additionally, the results suggest that a partial Zn²⁺ substitution for Mg²⁺ in MgAl₂O₄ can enhance the resistance to alkali vapor corrosion.

Original language	English
Article number	e70773
Journal	Journal of the American Ceramic Society
Volume	109
Issue number	5
DOIs	https://doi.org/10.1111/jace.70773
State	Published - May 2026

Funding

This manuscript has been co‐authored by an employee of UT‐Battelle LLC under Contract No. DE‐AC05‐00OR22725 with the U.S. Department of Energy. The publisher, by accepting the article for publication, acknowledges that the United States Government retains a non‐exclusive, paid‐up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe‐public‐access‐plan ). The US Department of Energy (Advanced Manufacturing Office, AMO) funded this work (grant number: DE‐EE0001761). The authors are grateful to Dr. Andus Buhr (Almatis), Mr. Timothy McGrady, and Ms. Veronica Vasquez (U.S. Zinc) for the generous donation of raw materials. The authors are also grateful to Dr. Daniel J. Delia and Mr. Max C. Modugno at Oak Ridge National Laboratory for meticulously reviewing the manuscript. The US Department of Energy (Advanced Manufacturing Office, AMO) funded this work (grant number: DE-EE0001761). The authors are grateful to Dr. Andus Buhr (Almatis), Mr. Timothy McGrady, and Ms. Veronica Vasquez (U.S. Zinc) for the generous donation of raw materials. The authors are also grateful to Dr. Daniel J. Delia and Mr. Max C. Modugno at Oak Ridge National Laboratory for meticulously reviewing the manuscript.

Keywords

alkali corrosion
gahnite
refractories
spinel

Access to Document

10.1111/jace.70773

Cite this

@article{71471d7f4c9b4d9e96d0d2e1e7981b44,

title = "Alkali Vapor Corrosion of Spinel (MgAl2O4) and Gahnite (ZnAl2O4) Refractories—A Comparative Study",

abstract = "Alkali vapor corrosion is critical for refractories used in the kilns and furnaces of diverse high-temperature processing and manufacturing sectors such as gasifiers, cement production, and glass making. Gahnite (ZnAl2O4) is being investigated as a potential chrome-free refractory because of its similarity with the structure and properties of magnesium aluminate (MgAl2O4) spinel. The alkali vapor corrosion of ZnAl2O4, MgAl2O4, and Mg0.5Zn0.5Al2O4 was studied, according to ASTM C987-10, at 1371°C for 24 h using sodium carbonate (Na2CO3). The surface and the polished cross-sections of the corroded ZnAl2O4, MgAl2O4, and Mg0.5Zn0.5Al2O4 specimens were analyzed using x-ray diffraction (XRD), microscopy, and energy-dispersive spectroscopy (EDS) techniques. MgO in MgAl2O4, ZnO in ZnAl2O4, Mg0.77Zn0.23O, and NaAlO2 were detected as the corrosion products for these specimens. The extent of corrosion substantially varied among the specimens despite the similarity in the corrosion products. The corrosion resistance increased in the following order: Mg0.5Zn0.5Al2O4 > MgAl2O4 > ZnAl2O4. The formation of a dense MgO and Mg0.77Zn0.23O layer for MgAl2O4 and Mg0.5Zn0.5Al2O4, respectively, contributed to their superior resistance to alkali vapor corrosion. The underlying corrosion mechanisms are discussed based on experimental observations supported by thermodynamic analysis. Additionally, the results suggest that a partial Zn2+ substitution for Mg2+ in MgAl2O4 can enhance the resistance to alkali vapor corrosion.",

keywords = "alkali corrosion, gahnite, refractories, spinel",

author = "Ramteke, \{Rajat Durgesh\} and Hemrick, \{James G.\} and Mahapatra, \{Manoj K.\}",

note = "Publisher Copyright: {\textcopyright} 2026 UT-Battelle, LLC and The Author(s). Journal of the American Ceramic Society published by Wiley Periodicals LLC on behalf of The American Ceramic Society.",

year = "2026",

month = may,

doi = "10.1111/jace.70773",

language = "English",

volume = "109",

journal = "Journal of the American Ceramic Society",

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TY - JOUR

T1 - Alkali Vapor Corrosion of Spinel (MgAl2O4) and Gahnite (ZnAl2O4) Refractories—A Comparative Study

AU - Ramteke, Rajat Durgesh

AU - Hemrick, James G.

AU - Mahapatra, Manoj K.

PY - 2026/5

Y1 - 2026/5

N2 - Alkali vapor corrosion is critical for refractories used in the kilns and furnaces of diverse high-temperature processing and manufacturing sectors such as gasifiers, cement production, and glass making. Gahnite (ZnAl2O4) is being investigated as a potential chrome-free refractory because of its similarity with the structure and properties of magnesium aluminate (MgAl2O4) spinel. The alkali vapor corrosion of ZnAl2O4, MgAl2O4, and Mg0.5Zn0.5Al2O4 was studied, according to ASTM C987-10, at 1371°C for 24 h using sodium carbonate (Na2CO3). The surface and the polished cross-sections of the corroded ZnAl2O4, MgAl2O4, and Mg0.5Zn0.5Al2O4 specimens were analyzed using x-ray diffraction (XRD), microscopy, and energy-dispersive spectroscopy (EDS) techniques. MgO in MgAl2O4, ZnO in ZnAl2O4, Mg0.77Zn0.23O, and NaAlO2 were detected as the corrosion products for these specimens. The extent of corrosion substantially varied among the specimens despite the similarity in the corrosion products. The corrosion resistance increased in the following order: Mg0.5Zn0.5Al2O4 > MgAl2O4 > ZnAl2O4. The formation of a dense MgO and Mg0.77Zn0.23O layer for MgAl2O4 and Mg0.5Zn0.5Al2O4, respectively, contributed to their superior resistance to alkali vapor corrosion. The underlying corrosion mechanisms are discussed based on experimental observations supported by thermodynamic analysis. Additionally, the results suggest that a partial Zn2+ substitution for Mg2+ in MgAl2O4 can enhance the resistance to alkali vapor corrosion.

AB - Alkali vapor corrosion is critical for refractories used in the kilns and furnaces of diverse high-temperature processing and manufacturing sectors such as gasifiers, cement production, and glass making. Gahnite (ZnAl2O4) is being investigated as a potential chrome-free refractory because of its similarity with the structure and properties of magnesium aluminate (MgAl2O4) spinel. The alkali vapor corrosion of ZnAl2O4, MgAl2O4, and Mg0.5Zn0.5Al2O4 was studied, according to ASTM C987-10, at 1371°C for 24 h using sodium carbonate (Na2CO3). The surface and the polished cross-sections of the corroded ZnAl2O4, MgAl2O4, and Mg0.5Zn0.5Al2O4 specimens were analyzed using x-ray diffraction (XRD), microscopy, and energy-dispersive spectroscopy (EDS) techniques. MgO in MgAl2O4, ZnO in ZnAl2O4, Mg0.77Zn0.23O, and NaAlO2 were detected as the corrosion products for these specimens. The extent of corrosion substantially varied among the specimens despite the similarity in the corrosion products. The corrosion resistance increased in the following order: Mg0.5Zn0.5Al2O4 > MgAl2O4 > ZnAl2O4. The formation of a dense MgO and Mg0.77Zn0.23O layer for MgAl2O4 and Mg0.5Zn0.5Al2O4, respectively, contributed to their superior resistance to alkali vapor corrosion. The underlying corrosion mechanisms are discussed based on experimental observations supported by thermodynamic analysis. Additionally, the results suggest that a partial Zn2+ substitution for Mg2+ in MgAl2O4 can enhance the resistance to alkali vapor corrosion.

KW - alkali corrosion

KW - gahnite

KW - refractories

KW - spinel

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DO - 10.1111/jace.70773

M3 - Article

AN - SCOPUS:105038095900

SN - 0002-7820

VL - 109

JO - Journal of the American Ceramic Society

JF - Journal of the American Ceramic Society

IS - 5

M1 - e70773

ER -