X-ray absorption spectroscopic study of Pd2+ on Ni site in pentlandite

Norilsk sulfide ores are one of the largest known sources of Pd on Earth. Palladium in these ores is presented in platinum-group minerals (PGM) and base metal sulfides (BMS), especially in pentlandite [(Fe,Ni)(9)S-8]. Although several studies demonstrated high concentrations along with heterogeneous...

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Bibliographic Details
Published in:American Mineralogist
Main Authors: Brovchenko, Valeriya, Merkulova, Margarita, Sittner, Jonathan, Shilovskih, Vladimir, Borca, Camelia, Huthwelker, Thomas, Sluzhenikin, Sergey F., Cnudde, Veerle
Format: Article in Journal/Newspaper
Language:English
Published: 2023
Subjects:
Earth and Environmental Sciences
Palladium
pentlandite
platinum-group minerals
XANES
mu XRF
EBSD
EPMA
PLATINUM-GROUP ELEMENTS
J-M REEF
BUSHVELD COMPLEX
PHASE-RELATIONS
MERENSKY REEF
STILLWATER COMPLEX
SULFIDE MINERALS
WHOLE-ROCKS
NORILSK
SYSTEM
norilsk
Online Access:https://biblio.ugent.be/publication/01HNZB6ZJ4TYR9HBR7S6JRQ18H
http://hdl.handle.net/1854/LU-01HNZB6ZJ4TYR9HBR7S6JRQ18H
https://doi.org/10.2138/am-2022-8704
https://biblio.ugent.be/publication/01HNZB6ZJ4TYR9HBR7S6JRQ18H/file/01HNZBFENVKEFE8W8FAS6S931P
Description
Summary:Norilsk sulfide ores are one of the largest known sources of Pd on Earth. Palladium in these ores is presented in platinum-group minerals (PGM) and base metal sulfides (BMS), especially in pentlandite [(Fe,Ni)(9)S-8]. Although several studies demonstrated high concentrations along with heterogeneous distribution of Pd in pentlandites from Norilsk, the form of Pd in pentlandite has not been established. Here, we provide the first evidence for Pd incorporation in the structure of pentlandite from Norilsk ores using X-ray absorption near edge structure (XANES) spectroscopy, synchrotron-based micro-X-ray fluorescence (mu XRF), and electron backscatter diffraction (EBSD). We present the first ever measured XANES spectra of Pd in pentlandite and atokite [(Pd,Pt)(3)Sn] as well as in other common Pd minerals. Divalent Pd in pentlandite was detected by XANES. The Pd spectra in pentlandite show no similarities with Pd spectra in PGM, metallic Pd, PdS, PdCl2, and PdSO4 which signifies that Pd incorporates into the lattice of pentlandite. Substitution of Ni by Pd in the lattice of pentlandite is supported by negative correlations shown by mu XRF and electron probe microanalysis (EPMA) and complies with the previous studies. The additional EBSD study demonstrates a resemblance in cell parameters of the Pd-rich and Pd-poor parts of the pentlandite grains and reflects that Pd incorporation into the pentlandite structure does not imply any notable structure distortion. The combination of analytical techniques used in the present study demonstrates the great potential of these methods for understanding the mechanisms of noble metal incorporation into ore minerals.

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