Characteristics of coal thermodynamic under environmental aqueous chemical erosion conditions

Abstract

The raw and treatment samples were studied with X-ray diffractometer, contact angle device, Fourier transform infrared spectrometer and thermogravimetric instrument. The disordered crystalline carbon in coal decreased with acid treatment, whereas the result of alkali treatment contrasted. The calcite can be disappeared in acidic solutions, but alkaline solutions can form new minerals with clay minerals. The breakage of aliphatic side chain in coal with acidic or alkaline treatment could be occurred. The mass of coal samples after burn out decreased in the order of alkali treatment coal > raw coal > acid treatment coal. In the low temperature stage, the alkali treatment coal sample has the highest transformation degree than raw coal and acid treatment coal and the activation energy was the lowest. The acid treatment coal has higher activation energy, which is beneficial for coal spontaneous combustion prevention.