DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Linear Correlations of Gibbs Free Energy of REE Phosphates (Monazite, Xenotime, and Rhabdophane) and Internally Consistent Binary Mixing Properties

Journal Article · · Minerals

Rare Earth Elements (REE) phosphates (monazite, xenotime, and rhabdophane) are critical REE-bearing minerals typically formed in hydrothermal and magmatic ore deposits. The thermodynamic properties of those REE minerals are crucial to understanding the solubility, speciation, and transport of REE complexes. However, the standard-state Gibbs free energy of formation (∆G°f) values reported for these minerals in the literature vary by up to 25 kJ mol−1. Here, we present linear free energy relationships that allow the evaluation and estimation of the ∆G°f values at 25 °C and 1 bar for the three minerals from the ionic radius (rREE3+) and the non-solvation Gibbs free energy contribution to the REE3+ aqua ion (∆G°n, REE3+): ∆G°f,monazite − 399.71 rREE3+ = 1.0059 ∆G°n,REE3+ − 2522.51; ∆G°f,xenotime − 344.08 rREE3+ = 0.9909 ∆G°n,REE3+ − 2451.53; and ∆G°f,rhabdophane − 416.17 rREE3+ = 1.0067 ∆G°n, REE3+ − 2688.86. Moreover, based on the new dataset derived for REE end-members, we re-fitted the binary Margules parameter (W) from previous theoretical calculations into linear correlations: W + 0.00204 ∆G°’n,monazite = 39.3549 ∆V + 0.0641; W + 0.00255 ∆G°’n,xenotime = 25.4885 ∆V − 0.0062. The internally consistent thermodynamic properties of these REE phosphates are incorporated into the computer program Supcrtbl, which is available online at Zhu’s research website.

Sponsoring Organization:
USDOE
Grant/Contract Number:
SC0022269
OSTI ID:
2323941
Journal Information:
Minerals, Journal Name: Minerals Journal Issue: 3 Vol. 14; ISSN MBSIBI; ISSN 2075-163X
Publisher:
MDPI AGCopyright Statement
Country of Publication:
Switzerland
Language:
English

References (66)

Determination of the Solubility of Rhabdophanes LnPO 4 ·0.667H 2 O (Ln = La to Dy) : Determination of the Solubility of Rhabdophanes LnPO journal August 2016
Mixtures and Mineral Reactions book January 1987
Measurements of the relative permittivity of liquid water at frequencies in the range of 0.1 to 10 kHz and at temperatures between 273.1 and 373.2 K at ambient pressure journal July 1995
On the miscibility gap in monazite–xenotime systems journal February 2007
Thermochemistry of monazite-(La) and dissakisite-(La): implications for monazite and allanite stability in metapelites journal January 2007
Reaction relationships in the Bayan Obo Fe-REE-Nb deposit Inner Mongolia, China: implications for the relative stability of rare-earth element phosphates and fluorocarbonates journal February 1999
Monazite chemical composition: some implications for monazite geochronology journal December 1999
The Rare Earth Elements: Demand, Global Resources, and Challenges for Resourcing Future Generations journal April 2017
Some linear and non-linear problems in petrology journal December 1979
Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: Correlation algorithms for ionic species and equation of state predictions to 5 kb and 1000°C journal August 1988
Estimation of surface precipitation constants for sorption of divalent metals onto hydrous ferric oxide and calcite journal August 2002
Prediction of trace metal partitioning between minerals and aqueous solutions: a linear free energy correlation approach journal May 2001
Inorganic species in geologic fluids: Correlations among standard molal thermodynamic properties of aqueous ions and hydroxide complexes journal March 1997
Rare earth and yttrium phosphate solubilities in aqueous solution journal April 1997
Use of linear free energy relationship to predict Gibbs free energies of formation of pyrochlore phases (CaMTi2O7) journal November 1999
Use of linear free energy relationship to predict Gibbs free energies of formation of zirconolite phases (MZrTi2O7 and MHfTi2O7) journal November 1999
SUPCRTBL: A revised and extended thermodynamic dataset and software package of SUPCRT92 journal May 2016
The solubility of xenotime-(Y) and other HREE phosphates (DyPO 4 , ErPO 4 and YbPO 4 ) in aqueous solutions from 100 to 250 °C and p sat journal April 2015
Hydrothermal transport, deposition, and fractionation of the REE: Experimental data and thermodynamic calculations journal November 2016
Hydrothermal solubility of TbPO4, HoPO4, TmPO4, and LuPO4 xenotime endmembers at pH of 2 and temperatures between 100 and 250 °C journal April 2021
Optimized thermodynamic properties of REE aqueous species (REE3+ and REEOH2+) and experimental database for modeling the solubility of REE phosphate minerals (monazite, xenotime, and rhabdophane) from 25 to 300 °C journal January 2024
Solid solutions of monazites and xenotimes of lanthanides and plutonium: Atomistic model of crystal structures, point defects and mixing properties journal February 2019
Large Scale Simulation of Nuclear Waste Materials journal September 2017
Coprecipitation in the barite isostructural family: 1. binary mixing properties journal August 2004
Experimental determination of synthetic NdPO4 monazite end-member solubility in water from 21°C to 300°C: implications for rare earth element mobility in crustal fluids journal May 2004
The solubility of monazite (CePO4), SmPO4, and GdPO4 in aqueous solutions from 100 to 250 °C journal December 2018
The solubility of monazite (LaPO4, PrPO4, NdPO4, and EuPO4) endmembers in aqueous solutions from 100 to 250 °C journal July 2020
From mantle to critical zone: A review of large and giant sized deposits of the rare earth elements journal May 2016
The low temperature heat capacity of LaPO4 and GdPO4, the thermodynamic functions of the monazite-type LnPO4 series journal February 2005
High-temperature calorimetry of (La1−xLnx)PO4 solid solutions journal February 2007
Thermodynamics of solid phases containing rare earth oxides journal September 2015
Thermochemistry of La1−xLnxPO4-monazites (Ln= Gd, Eu) journal February 2017
Fractionation of REE, U, and Th in natural ore-forming hydrothermal systems: Thermodynamic modeling journal January 2019
Relationship between the thermodynamic excess properties of mixing and the elastic moduli in the monazite-type ceramics journal July 2016
Heat capacities of xenotime-type ceramics: An accurate ab initio prediction journal October 2017
Ab initio calculation of excess properties of La 1 − x ( Ln , An ) x PO 4 solid solutions journal December 2014
In pursuit of the rhabdophane crystal structure: from the hydrated monoclinic LnPO 4 .0.667H 2 O to the hexagonal LnPO 4 (Ln = Nd, Sm, Gd, Eu and Dy) journal May 2017
Separation and recovery of valuable metals from low-grade REE–Nb–Fe ore journal May 2016
The story of rare earth elements (REEs): Occurrences, global distribution, genesis, geology, mineralogy and global production journal July 2020
Role of critical metals in the future markets of clean energy technologies journal September 2016
High-temperature heat capacities of EuPO4 and SmPO4 synthetic monazites journal June 2006
Heat capacity and thermodynamic functions of LuPO4 in the range 0–320K journal September 2006
Thermodynamic functions of erbium orthophosphate ErPO4 in the temperature range of 0–1600K journal May 2012
Experimental determination of the high temperature heat capacity of a natural xenotime-(Y) solid solution and synthetic DyPO4 and ErPO4 endmembers journal March 2016
Thermodynamic functions of holmium orthophosphate HoPO4 in the range 9–1370 K journal January 2020
Crystal Chemistry and Thermodynamics of HREE (Er, Yb) Mixing in a Xenotime Solid Solution journal May 2022
Monoclinic Form of the Rhabdophane Compounds: REEPO 4 ·0.667H 2 O journal September 2014
A linear free energy relationship for crystalline solids and aqueous ions journal March 1992
VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data journal October 2011
Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides journal September 1976
Effective ionic radii in oxides and fluorides journal May 1969
Crystal chemistry of monazite and xenotime from Saxothuringian-Moldanubian metapelites, NE Bavaria, Germany [Crystal chemistry of monazite and xenotime from Saxothuringian-Moldanubian metapelites, NE Bavaria, Germany] journal October 1996
Heat capacity and thermodynamic functions of xenotime YPO4(c) at 0–1600 K journal September 2010
Heat capacity and thermodynamic properties of GdPO4 in the temperature range 0–1600 K journal July 2012
Low-temperature heat capacity and thermodynamic properties of PrPO4 journal April 2016
High-temperature thermodynamic properties of LuPO4 journal July 2012
Heat capacity and thermodynamic functions of YbPO4 from 0 to 1800 K journal June 2013
The heat capacity and thermodynamic functions of EuPO4 over the temperature range 0–1600 K journal January 2009
Use of Linear Free Energy Relationship to Predict Gibbs Free Energies of Formation of MUO4 Phases journal September 1999
Thermochemistry of rare-earth orthophosphates journal September 2001
Thermodynamic Stability of Actinide Pyrochlore Minerals in Deep Geologic Repository Environments journal January 1999
Mineralogy, Chemistry, and Fluid-Aided Evolution of the Pea Ridge Fe Oxide-(Y + REE) Deposit, Southeast Missouri, USA journal November 2016
Crystal chemistry of the monazite and xenotime structures journal February 1995
Solid-Solution Solubilities and Thermodynamics: Sulfates, Carbonates and Halides journal January 2000
Apatite, Monazite, and Xenotime in Metamorphic Rocks journal January 2002
Theoretical prediction of the thermodynamic behavior of aqueous electrolytes by high pressures and temperatures; IV, Calculation of activity coefficients, osmotic coefficients, and apparent molal and standard and relative partial molal properties to 600 degrees C and 5kb journal December 1981