Experimental investigation of mechanical characteristics of coal samples at different drying temperatures

Abstract

The drying and mechanical properties of long flame coal and anthracite after exposure to various drying temperatures were investigated in this study. Coal samples were processed and screened, treated with a nondestructive water immersion device, and dried separately at different temperatures. Uniaxial compression experiment, acoustic emission tests, and fractal dimension calculation were then conducted. Experimental results show that the degree of drying of coal samples rose as the drying temperature increased. Peak stress and elastic modulus decreased while the damage variables and brittleness rose in dried anthracite samples with increasing drying temperature. The Acoustic emission characteristics were consistent with the mechanical characteristics. The stress-strain curves changed from stepped type to perpendicular type in the post-peak stage. This was accompanied by intense damage of the coal samples and increases in the fractal dimension of the broken blocks. Our findings shed light on how coal samples dry and provide recommendations for enhancing drying methods in laboratory mechanics tests.