Atomic-Scale Insights into the Surface Chemistry, Surface Stability, and Floatability of Spodumene and Montebrasite with Fatty Acid Collectors

@misc{murhula2026atomicscale,
  title = {{Atomic-Scale Insights into the Surface Chemistry, Surface Stability, and Floatability of Spodumene and Montebrasite with Fatty Acid Collectors}},
  author = {Espoir M. Murhula and Charlotte E. Gibson and Wennie Wang and Lebogang Babedi and Jing Lian Ng and Suk Gyu Lim},
  howpublished = {ChemRxiv},
  year = {2026},
  month = oct,
  doi = {10.26434/chemrxiv.15010231/v1},
  url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010231/v1},
  note = {CC BY-NC},
}

TY  - UNPB
TI  - Atomic-Scale Insights into the Surface Chemistry, Surface Stability, and Floatability of Spodumene and Montebrasite with Fatty Acid Collectors
AU  - Espoir M. Murhula
AU  - Charlotte E. Gibson
AU  - Wennie Wang
AU  - Lebogang Babedi
AU  - Jing Lian Ng
AU  - Suk Gyu Lim
PY  - 2026
DA  - 2026/10/11
PB  - ChemRxiv
DO  - 10.26434/chemrxiv.15010231/v1
UR  - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010231/v1
AB  - Spodumene and montebrasite are minerals that contain significant quantities of lithium and are often found together in phosphate-rich lithium pegmatites. Separating these two minerals by flotation is key to efficient downstream lithium extraction from each. Understanding the crystal and surface properties of both minerals is an important step towards their separation by flotation. We present a systematic study of the surface properties of spodumene and montebrasite, and their interactions with fatty acid collectors, using density functional theory calculations. Our results showed that, for montebrasite, the most dominant surfaces were (110) ≈ (012̅) > (102̅) > (12̅0) > (212̅), with (110) ≈ (012̅) being the most represented (56 %). The Al-terminated (110) surface was the dominant surface on spodumene, accounting for 70 % of the crystal surface area, followed by (111̅) > (111) > (101̅) > (001), consistent with available experimental data. The Wulff equilibrium morphology showed that both minerals are elongated/prismatic, consistent with their naturally occurring crystals, but spodumene is less reactive to flotation reagents than montebrasite. Surface electronic density of states showed that Li and Al states dominate the bottom of the conduction band of spodumene (110) and montebrasite (110) and are available to hybridize with oxygen states of the COO- functional group of fatty acid collectors. Energetics calculations show that both minerals interact with fatty acid collectors via surface Al and Li, but more strongly for montebrasite than spodumene (–18.6 kcal/mol vs +11.05 kcal/mol). Therefore, montebrasite is more floatable with fatty acid collectors than spodumene, making it convenient to separate these two minerals by first recovering montebrasite to the flotation concentrate, resulting in a spodumene-enriched tailings product. Less favorable adsorption energies explain the need to activate/pretreat spodumene before flotation to overcome the energy barrier for fatty-acid adsorption, with spodumene activation by high-density conditioning performed only after montebrasite flotation. This study further demonstrates that the interaction energy of fatty acids with mineral surfaces does not depend on chain length, regardless of mineral type. Our findings open a new direction for efficient lithium production from phosphate-rich lithium pegmatites by generating a montebrasite concentrate while simultaneously upgrading the feed to the spodumene flotation circuit.
ER  -