Study on the Differences in the Microstructure between Outburst and Nonoutburst Coal.

Area of Science:

• Geology
• Materials Science
• Chemical Engineering

Background:

• Coal outbursts pose significant safety risks in mining.
• Understanding the microstructural factors influencing coal outburst propensity is crucial for prevention.

Purpose of the Study:

• To investigate the microchemical and pore structure characteristics of coal samples.
• To elucidate the influence of these microstructural features on coal outburst propensity.

Main Methods:

• Comparative experimental investigations of typical outburst and nonoutburst coal samples.
• Characterization using Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and low-temperature liquid nitrogen adsorption.

Main Results:

• Outburst coal shows higher aromaticity, increased nascent primary aromatic hydrocarbons, and substantial methane (CH4) generation.
• Outburst coal has fewer oxygen-containing functional groups, stronger gas adsorption capacity, chaotic macromolecular structures, and increased micropore content.
• Outburst coal exhibits higher total pore volume, more pore content per unit volume, a thinner skeleton, and a higher proportion of fine-necked bottleneck and wedge-shaped pores.

Conclusions:

• Microstructural differences, particularly increased aromaticity and microporosity, are key indicators of coal outburst propensity.
• Specific pore structures in outburst coal hinder gas desorption, increasing residual gas content and the risk of coal and gas outbursts.
• This research provides a theoretical foundation for predicting and mitigating coal outbursts based on microstructural analysis.