Experimental Investigation of a Novel Zn Foam for Preventing the Spontaneous Combustion of Coal

Fire hazards caused by the self-ignition of coal are perennial disasters, which constitute a severe threat to the global environment. In this study, an innovative Zn foam material, mainly comprising water, foaming agents, zinc acetate, diethanolamine, and hydroxyethyl cellulose, was developed for controlling the spontaneous combustion of coal. These Zn foams exhibited a foaming multiple greater than 30 and a half-life greater than 7 h, indicative of excellent performance. The inhibition mechanism for the spontaneous combustion of coal after the addition of Zn foam was investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Results indicated that after treatment, ultrafine zinc oxides are uniformly deposited on the coal specimen surface, and functional groups, such as C-O and -OH, in the coal significantly decrease, which effectively inhibit the oxidation of coal.