Preparation and Effectiveness of a Nano-Modified Composite Gel Foam in Preventing the Spontaneous Combustion of Coal

In China, coal is considered the cornerstone in the energy mix for ensuring the security of national energy production. With the increasing intensity and depth of coal seam mining in China, spontaneous coal combustion in goaf areas has become a major issue affecting mine safety. The development of a nano-modified composite gel foam to prevent the spontaneous combustion of residual coal was therefore investigated in the current study. Chemical modification through intercalation and grafting was found to significantly enhance the water retention performance of the antioxidant component. In addition, the optimal component ratios were determined using single-factor experiments and response surface methodology. The modified gel foam, consisting of 2.995 wt% gelling agent, 0.25 wt% foaming agent, 0.296 wt% crosslinker, 0.491 wt% foam stabilizer, 3.772 wt% nanoparticles, and 2.964 wt% modified antioxidant, demonstrated environmental friendliness. Thermogravimetric experiments showed that the critical temperature for achieving a significant increase in the dehydration rate rose from 80 to 120°C after modification. Compared with typical inhibitors, the nano-modified gel foam exhibited a superior performance in terms of preventing coal oxidation and spontaneous combustion, particularly at low temperatures. Oxidation during the oxygen absorption and weight gain stages was also effectively inhibited, and the high temperature combustion processes were suppressed.