TY - JOUR
T1 - Thermal decomposition of ammonium nitrate on rust surface
T2 - Risk of low-temperature fire
AU - Oluwoye, Ibukun
AU - Mosallanejad, Sara
AU - Soubans, Goruck
AU - Altarawneh, Mohammednoor
AU - Gore, Jeff
AU - Dlugogorski, Bogdan Z.
N1 - Funding Information:
We are grateful to the Australian Research Council (ARC LP160101169 ) and Dyno Nobel Asia Pacific for funding this study. This study has been supported by grants of computing time from the National Computational Infrastructure (NCI), Australia .
Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2021/3
Y1 - 2021/3
N2 - Ammonium nitrate (AN, NH4NO3) remains classified as an oxidising agent for transport, storage and handling purposes. The safe use of ammonium nitrate requires strict procedures as AN is incompatible with many materials. This study investigates the thermal decomposition of AN on surfaces of rust, potentially present on steel in storage facilities of AN. Infrared spectroscopy and X-ray diffraction served to characterise the mineralogy of the rust, relatively to neat iron (III) oxide. Furthermore, simultaneous thermogravimetric measurements and differential scanning calorimetry afforded the isoconversional analysis that yields the activation energies of the decomposition process. The results, in conjunction with the molecular modelling involving oxygen-deficient Fe2O3 clusters, elucidate the effect of rusts, existing on the surface of corroded steel, in reducing the ignition temperature of AN. This process manifests itself by lowering the activation energies of the initiation channels of the decomposition reactions. On the contrary, pure Fe2O3 does not influence the decomposition of AN. The dehydroxylation of hydrated iron (III) oxide, present on surfaces of rust, exposes the Fe sites that react exothermically with AN, before the material assumes the ordered Fe2O3 phase.
AB - Ammonium nitrate (AN, NH4NO3) remains classified as an oxidising agent for transport, storage and handling purposes. The safe use of ammonium nitrate requires strict procedures as AN is incompatible with many materials. This study investigates the thermal decomposition of AN on surfaces of rust, potentially present on steel in storage facilities of AN. Infrared spectroscopy and X-ray diffraction served to characterise the mineralogy of the rust, relatively to neat iron (III) oxide. Furthermore, simultaneous thermogravimetric measurements and differential scanning calorimetry afforded the isoconversional analysis that yields the activation energies of the decomposition process. The results, in conjunction with the molecular modelling involving oxygen-deficient Fe2O3 clusters, elucidate the effect of rusts, existing on the surface of corroded steel, in reducing the ignition temperature of AN. This process manifests itself by lowering the activation energies of the initiation channels of the decomposition reactions. On the contrary, pure Fe2O3 does not influence the decomposition of AN. The dehydroxylation of hydrated iron (III) oxide, present on surfaces of rust, exposes the Fe sites that react exothermically with AN, before the material assumes the ordered Fe2O3 phase.
KW - Ammonium nitrate
KW - Explosion
KW - Rust
KW - Self-heating
KW - Steel
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U2 - 10.1016/j.firesaf.2020.103063
DO - 10.1016/j.firesaf.2020.103063
M3 - Article
AN - SCOPUS:85084381577
SN - 0379-7112
VL - 120
JO - Fire Safety Journal
JF - Fire Safety Journal
M1 - 103063
ER -