To investigate the influence law of soluble organic matter in coal on coal resistivity

briquette coals of three different metamorphic grades made of 60~80 purpose raw coal grains were selected and tested. Ethyl acetate was used as solvent to dissolve soluble organic matter in the coals at 4

8

2

6

0

4 h. The coals before and after dissolution were made into sample coals. The current vs. voltage curves of the sample coals were obtained at 10 ℃~90 ℃ using CHI660E electrochemical workstation and their resistivity were calculated. Based on this

the influence mechanism and rule of the soluble organic matter on coal resistivity at different temperatures were analyzed. Results show that the presence of soluble organic matter in coal increased coal resistivity for 1.31~1.74 times at temperatures from 10 ℃~90 ℃ in 0 ~24 h dissolution time. The rule that coal resistivity increased with the increase of dissolution time conforms to the Sigmoid Function relation

and coal resistivity only changed according to this rule within a certain range. Coal resistivity increasing with temperature rise exhibits parabolic rule. The ratio of coal resistivity before and after dissolution increasing with temperature rise approximately presents Lorentzian distribution with a turning point at 40 ℃~50 ℃. The sensitivity and correlation of the influence of soluble organic matter on coal resistivity gradually weakened with the increase of the degree of coal metamorphism.