Study on the synergistic mechanism and high-efficiency inhibition of lignosulfonate-based composite gel for coal spontaneous combustion

Ensuring green and safe mining of coal resources remains a critical challenge in China, particularly due to the issue of coal spontaneous combustion (CSC). To address this, this study developed a lignosulfonate based composite gel with CSC inhibition and air leakage plugging functions. The non-toxic and environmentally friendly gel system includes lignosulfonate, polyacrylamide, modified nano-SiO 2 , DL-malic acid, and epigallocatechin gallate. Comprehensive characterizations and performance optimization were conducted. The gel maintained excellent inhibition properties over a wide temperature range. Synergy of DL-malic acid and EGCG contributed to the high inhibition performance. The inhibition mechanism of lignosulfonate-based gel was elucidated. The LS/PAM/SiO 2 -EGCG/MA gel exhibited a maximum plugging capacity of 1.56 kPa and increased the activation energy of raw coal by 42.41%, reaching 49.73 kJ/mol. Furthermore, the gel achieved an average inhibition rate of 72.80% in the temperature range of 100-200°C, effectively reducing CO emissions and environmental impact. This study provides a promising solution for green and safe coal mining, with significant implications for environmental protection and resource conservation.