A new slurry foam gel material based on CaCl2 inhibition and its coal spontaneous combustion prevention performance study

Spontaneous combustion of coal is a major safety hazard currently facing coal mining operations. However, the existing fire prevention and extinguishing technology faces limitations including limited coverage and environmental hazards. In this paper, a new slurry foam gel material (SFGM) is proposed and developed for the technical bottleneck of coal spontaneous combustion prevention and control. The response surface method was used to optimize the material ratio. The foaming ratio of the new SFGM reached 5 times, and the stability coefficient reached 85.44. In simulated coal seam sealing tests, the sealing pressure stabilized at approximately −77.6 kPa, demonstrating a 45.3 % improvement in sealing capacity compared to conventional slurries. In the TG-DSC-GC coupled experiment, the mass loss of the coal sample decreased by 0.397 mg, representing a reduction of approximately 59.5 %. The carbon monoxide concentration decreased from 0.73 ‰ to 0.41 ‰. The DTA data at 250 °C decreased from 0.76 °C/mg to −1.1 °C/mg, with the peak exhibiting a delayed trend. The SFGM overcomes the disadvantages of traditional inhibition techniques, including the inability to cover high-position cracks and the weak ability to interrupt chain reactions. SFGM plays a crucial role in ensuring safety in coal mine production. Furthermore, it provides a scientific basis for selecting and applying effective prevention and control technologies against spontaneous combustion of coal seams in deep mining operations under complex environmental conditions.