An Environmentally Friendly Antioxidant Foamed Gel for Inhibiting Spontaneous Combustion of Coal

Coal spontaneous combustion can cause serious coal mine fire and gas explosion. In order to overcome the problem that the effect of existing materials to inhibit coal spontaneous combustion is reduced at high temperature and some environmental protection problems of materials, this study developed an effective, green and environmental protection antioxidant foamed gel (AFG). Modified sodium polyacrylate, konjac glucomannan, sodium dodecyl sulfate, sodium alpha-olefin sulfonate, modified silicone polyether microemulsion, montmorillonite, and tert-butyl hydroquinone were selected as raw materials. A single factor experiment was conducted to determine the appropriate adding proportions for each component. Then, the optimal proportion for the five components were fitted and verified by response surface analysis. The structures of the samples were characterized, and their properties were compared and tested. The fluidity, water loss, and thermogravimetry experiments demonstrated that the effect of AFG was excellent. In the experiment of in situ diffuse reflectance Fourier transform infrared spectroscopy, the AFG inhibition reaction was verified. Finally, combined with the structural characteristics of the AFG, the following inhibiting mechanisms were confirmed: AFG adhered to the coal surface and blocked the coal–oxygen contact; the antioxidant component slowed down chemisorption and the chemical reactions; AFG interrupted the free radical chain reaction.