Preparation of the Environmentally Friendly and High Stable Gel Foam Based on Biomass Xanthan Gum for Inhibiting Coal Spontaneous Combustion

In order to improve the environmental friendliness of inhibiting coal spontaneous combustion, a new environmentally friendly biomass gel foam was successfully prepared by using xanthan gum (XG), aluminum citrate (Alcit), gluconate-δ-Lactone (GDL), alkyl glycoside (APG), and tea saponin (TS). When the concentrations of XG, Alcit, GDL and biomass composite foaming agent were 4, 4, 0.4, and 0.3 wt%, respectively, the gel foam had a half-life of up to 27 days. The gel foam water retention study showed that the water loss rate of its was 60% lower than that of water and 58.6% lower than that of foam after heating at 60°C for 10 h. The temperature-programmed experiment showed that the gel foam could delay the accelerated oxidation temperature of coal from 90°C to 140°C. The fire extinguishing experiment showed that the gel foam could extinguish coal fire quickly, the temperature of coal rapidly dropped from 960°C to 121°C within the first 20 min and the reburning of coal fire was not observed after the extinguishment. This study is useful for the development of environmentally friendly gel foams for inhibiting coal spontaneous combustion.