R&D of colloid components of composite material for fire prevention and extinguishing and an investigation of its performance

•This study studied the colloid components of fire prevention material for coalmines.•A colloid recipe was determined considering the cost, environment and technique.•An optimum proportion was obtained by orthogonal tests.•The new material has better performance compared with other four typical materials.•Field test indicates the colloid component is highly effective in fire prevention. Because the existing fire prevention and extinguishing materials for coal mining cannot adhere to coal for long periods of time, this study investigated their colloid components. A colloid recipe of sodium silicate as the base material, sodium bicarbonate as the coagulation accelerator and sodium polyacrylate as the polymer additive was determined. An optimum proportion was obtained by orthogonal tests, whereby the ratio of water to solid was 4:1, sodium silicate accounted for 4%, sodium bicarbonate accounted for 5% and sodium polyacrylate accounted for 0.75‰. Comparing the performance of four other typical materials of fire prevention and extinguishing through contrast experiments, we observed that the new material has advantages of dropping the temperature, lowering the concentration of oxygen and carbon monoxide and increasing the concentration of carbon dioxide. In addition, a field test was conducted with the new material. After injection, three zones of spontaneous combustion showed clear changes: the oxidation temperature rise zone was ahead by 8m, its length was shortened by 20m and the choking zone moved up by 28m. These changes indicated the improvement of colloid could significantly increase the effect of fire prevention and extinguishing materials.