Preparation and fire extinguishing characteristics of inorganic solidified foam with large amount of slag

ABSTRACT

Aiming at the problems of conventional cement-based foam plugging and filling materials, such as large amount of cement, low utilization rate of solid waste, unclear bonding, and plugging mechanism, it was proposed that a kind of plugging and preventing fire material named inorganic solidified foam was prepared from industrial slag, cement, and water-based foam as the main raw materials. Based on the fluidity, expansion ratio and mechanical strength of solidified foam, it was determined that S105 slag powder with high content of 60%~65% and the optimal content of the chemical activator 6%. The dry density of solidified foam was about 410~450 kg/m³, and the compressive strength reached 0.5~0.55 MPa. The formation process, the bonding-reinforcement mechanism, and the fire prevention characteristic fire of solidified foam were explored. The results showed that solidified foam could significantly improve the pozzolanic activity of solid waste under the effect of physical and chemical synergy, promoted the hydration reaction of the material, increased the structural compactness of the hydration product of the material, further improving the strength. Fire-fighting experiments and field application exhibited that solidified foam could rapidly diffuse and accumulate to high places through crack channels, quickly extinguish and cool down, and coat loose high-temperature coal piles, showing excellent effect of preventing coal spontaneous combustion. Moreover, the field test results showed that the solidified foam could quickly plug the air leakage, and reduce the CO concentration in the air leakage are. Specifically, the CO concentration of high falling area decreased from 315 ppm to 22 ppm in 3 days, eventually stabilizing below 10 ppm, thereby timely inhibiting the development of spontaneous combustion fire.

KEYWORDS:

• Coal spontaneous combustion
• solidified foam
• mine plugging
• bond and reinforce
• extinguishing and cooling

Acknowledgements

The project was funded by the Engineering Technology Research Centre for Safe and Efficient Coal Mining (Anhui University of Science and Technology) (NO. SECM2204); the Natural Science Foundation of Jiangsu Province [BK20231070]; the China Postdoctoral Science Foundation [2023M733768]; the Fundamental Research Funds for the Central Universities [2023QN1068].

Credit authorship contribution statement

Xian Xi: Data curation, Formal analysis, Resources, Investigation, Roles/Writing - original draft. Cuiping Xia: Resources, Investigation, Roles/Writing. Chenchen Yin: Formal analysis. Shuguang Jiang: Conceptualization, Methodology, Review & editing

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The project was supported by the Engineering Technology Research Centre for Safe and Efficient Coal Mining (Anhui University of Science and Technology) (NO. SECM2204); the Natural Science Foundation of Jiangsu Province [BK20231070]; the China Postdoctoral Science Foundation [2023M733768]; the Fundamental Research Funds for the Central Universities [2023QN1068].

Notes on contributors

Xian Xi

Xian Xi is a research assistant at the Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization, China University of Mining & Technology, Xuzhou. Her research focuses on mine fire, solid waste utilization and CO2 emission reduction technology.

Cuiping Xia

Cuiping Xia is a teaching assistant at Engineering Technology Research Centre for Safe and Efficient Coal Mining, Anhui University of Science and Technology, Huainan. Her research focuses on mine fire.

Chenchen Yin

Chenchen Yin is a PhD candidate at the School of Safety Engineering, China University of Mining & Technology, Xuzhou. Her research focuses on mine fire.

Shuguang Jiang

Shuguang Jiang is a professor at the School of Safety Engineering, China University of Mining & Technology, Xuzhou. His research focuses on mine fire and safety monitoring in mine.