Molecular structural characterization and model construction of residual carbon in coal gasification fine slag--颗粒学报PARTICUOLOGY

Zhang, N., Zhang, S., Li, X., Li, Z., Zhou, A., Wang, H., & Han, R. (2025). Molecular structural characterization and model construction of residual carbon in coal gasification fine slag. Particuology, 104, 178-189. https://doi.org/10.1016/j.partic.2025.06.015

Molecular structural characterization and model construction of residual carbon in coal gasification fine slag

Ningning Zhang^*, Shuaishuai Zhang, Xinren Li, Zhen Li, Anning Zhou, Hong Wang, Rui Han^*

Key Laboratory of Green Separation and Low-carbon Utilization of Coal-based Resources in Shaanxi Province Higher Education Institutions, College of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, Xi'an, 710054, China

10.1016/j.partic.2025.06.015

Volume 104, September 2025, Pages 178-189

Received 12 April 2025, Revised 15 May 2025, Accepted 26 June 2025, Available online 5 July 2025, Version of Record 11 July 2025.

E-mail: ningningzhang@xust.edu.cn; hanrui0929@163.com

Highlights

• Molecular composition of residual carbon contained in coal gasification fine slag (CGFS-RC) was obtained using HRTEM.

• CGFS-RC molecular modeling method was realized and its validity was confirmed.

• In CGFS-RC, C exists as aromatic, O as ether-oxygen bonded, and N as pyrrole.

• Molecular formula, 2D and 3D models of CGFS-RC were obtained by simulation.

• Wetting property of the CGFS-RC surface was revealed from the molecular level.

Abstract

The residual carbon contained in coal gasification fine slag (CGFS-RC) is a valuable resource with great potential for application, and the elucidation of the macromolecular structural model of CGFS-RC is an important basis for its recovery and utilization. In this paper, CGFS-RC was comprehensively characterized by proximate, ultimate, FTIR, XRD, XPS, and HRTEM analyses, and the macromolecular geometric model of CGFS-RC was constructed and optimized using Materials Studio software. The results show that carbon atoms in CGFS-RC mainly exist in the form of aromatic carbons with a high percentage of 90.7 %, and the ring number of condensed aromatic rings is mainly 3–5. The aliphatic carbon side chain structure on the benzene ring is mainly dominated by cycloalkanes. Among the heteroatoms, oxygen atoms are mainly present in the form of ether-oxygen bonds, (phenolic) hydroxyl groups, carbonyl groups and carboxyl groups, while nitrogen atoms are mainly present in the form of pyrroles. The molecular formula of CGFS-RC can be expressed as C₁₆₅H₄₁O₁₃N, and the density of its geometrical configuration was calculated to be 1.65 g/cm³. The XRD and FTIR simulation confirmed the reasonableness of the constructed model, and the electrostatic potential simulation revealed the hydrophilic properties of CGFS-RC at the molecular level. This study opened up the molecular structure analysis and modeling process of CGFS-RC, which can provide fundamental basis for the reagent design in the flotation recovery of CGFS-RC as well as the resource utilization of CGFS-RC.

Graphical abstract

Keywords

Coal gasification fine slag; Residual carbon; Structural characterization; Molecular simulation; HRTEM

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