149-7 Influence of Hydration on the Thermochemistry of Rare Earth Nitrates

Session: Research to Accelerate Recovery of Critical Minerals from Primary and Secondary Resources (Posters)

Poster Booth No.: 275

Presenting Author:

Konrad Burkmann

Authors:

Burkmann, Konrad Joerg¹, Agbanga, Godwin Akotenvusi², Loeffelholz, Cayden Thomas³, Scharrer, Manuel⁴, Bohmhammel, Klaus⁵, Navrotsky, Alexandra⁶

(1) School of Molecular Sciences, Arizona State University, Navrotsky Eyring Center for Materials of the Universe, TEMPE, AZ, USA; Fakultät für Chemie, Physik and Biowissenschaften, TU Bergakademie Freiberg, Institut für Physikalische Chemie, Freiberg, Saxony, Germany, (2) Ira A. Fulton School for Engineering of Matter, Transport and Energy, Arizona State University, Navrtosky Eyring center for Materials of the Universe, TEMPE, AZ, USA, (3) Ira A. Fulton School for Engineering of Matter, Transport and Energy, Arizona State university, Navrotsky Eyring Center for Materials of the Universe, TEMPE, AZ, USA, (4) School of Molecular Sciences, Arizona State university, Navrotsky Eyring Center for Materials of the Universe, TEMPE, AZ, USA; University of Tennessee, Knoxville, Tennessee, USA, (5) Fakultät für Chemie, Physik und Biowissenschaften, TU Bergakademie Freiberg, Institut für Physikalische Chemie, Freiberg, Saxony, Germany, (6) School of Molecular Sciences, Ira A. Fulton School for Engineering of Matter, Transport and Energy, School of Earth and Space Exploration, Arizona State University, Navrotsky Eyring Center for Materials of the Universe, Tempe, Arizona, USA,

Abstract:

Rare earth nitrates are common intermediates in the hydrometallurgical separation of rare earth elements. They also serve as important precursors for synthesizing a variety of rare earth compounds significant to industry and geology, such as rare earth carbonates [1-3]. However, their thermodynamic properties are still poorly constrained [3] and their flexible hydration states complicate understanding the energetic driving force of industrial, scientific and geological processes as well as their thermodynamic modelling. Therefore, we determined thermodynamic parameters, namely enthalpies of formation, heat capacity functions, and entropies using several calorimetric techniques as well as established estimation procedures [1,2]. Our results show a clear trend in their enthalpies of dissolution in 5 N HCl decreasing from La to Lu nitrates and in the dependence of their heat capacities and absolute entropies on the water content. By comparing these data with those derived from thermodynamic equilibrium calculations using data of other salt hydrates, we found a consistent influence of crystal water on the properties of metal salt hydrates in general without a clear dependence on structure of the compound and charge of the ions in it. These findings will lead to deeper knowledge of the formation of salt hydrates during industrial processes in general and will help to further understand geological processes in the evolution of hydrated minerals.

 

Literature

[1]   G. A. Agbanga, M. Scharrer, C. G. White, B. F. Woodfield, A. Navrotsky, J. Chem. Thermodyn. 2025, 209, 107529.

[2]   G. A. Agbanga, M. Scharrer, K. Burkmann, C. G. White, B. F. Woodfield, A. Navrotsky, submitted to Inorg. Chem.

[3]   M. Scharrer, G. A. Agbanga, B. L. Brugman, M. Guild, G. Oliveira, J. Liu, X. Guo, A. Navrotsky, Mater. Today 2025, online available: https://doi.org/10.1016/j.mattod.2025.05.010.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7971

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