Determining the flotation upgrading effect of shale oil on lignite via molecular dynamics simulation and experiment comparisons

ABSTRACT

In this study, we combined experiments with molecular dynamics simulation to investigate the improvement of lignite flotation performance by shale oil and microscopic promotion mechanism. Through FTIR and GC/MS tests, our preliminary findings showed that shale oil contains polar groups and long-chain alkanes. Moreover, XPS tests confirmed that shale oil could render the C–C/C–H and cover the C–O, C=O and O=C–O functional groups. The induction time between lignite particles and shale oil bubbles was 15ms lower than that between kerosene bubbles. Besides, the flotation results indicated that shale oil could improve the yield and reduce the ash content of clean coal significantly. The molecular dynamics simulation results showed that shale oil molecules could preferentially adsorb on lignite pore surface and weak the direct adsorption and seepage of water molecules on lignite surface. This was consistent with the results of an analysis of the whole system’s relative concentration distribution and mean square displacement of water molecules. These data provide further evidence that shale oil can clearly improve the flotation recovery of low-rank coal, which is of great importance for the clean utilisation of low-rank coal.

GRAPHICAL ABSTRACT

KEYWORDS:

• Lignite
• microscopic mechanism
• flotation
• molecular dynamics simulation

Acknowledgements

The authors also thank Advanced Analysis and Computation Center of the China University of Mining and Technology for their technical support.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Xuanchen Guo: Conceptualisation, Methodology, Software, Data curation, Writing – original draft. Yaqun He: Project administration, Resources, Supervision, Writing: Review & Editing, Funding acquisition.

Jie Wang: Investigation, Software, Writing – Review & Editing, Funding acquisition.

Rui Zhou: Supervision, Writing: Review & Editing.

Additional information

Funding

This work was supported by the Key-Area Research and Development Program of Guangdong Province [2020B090919003], the Fundamental Research Funds for the Central Universities [2020QN50] and the Special fund (Social Development) project of key research and development plan of Jiangsu Province [BE2019634].