Abstract:In order to uncover the intrinsic reasons for spontaneous combustion of sulfide minerals, representative samples were collected from typical metal mines to carry out the mechanical activation experiment. The structures and heat behaviors of activated samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, and simultaneous thermal analysis (STA). It is found that the sulfide minerals after mechanical activation show many changes with increased specific surface areas, aggregation phenomenon, decreased diffraction peak intensity, broadened diffraction peak, declined initial temperatures of heat release and self-ignition points. A new theory for explaining the spontaneous combustion of sulfide minerals is put forward: the chemical reaction activity of sulfide minerals is heightened by all kinds of mechanical forces during the mining, and the spontaneous combustion takes place finally under proper environment.

Key words: metal mines; mining; sulfide minerals; spontaneous combustion; mechanical activation; reaction mechanism; chemical reaction activity