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 polyactylate 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 parts per thousand. 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 8 m, its length was shortened by 20 m and the choking zone moved up by 28 m. These changes indicated the improvement of colloid could significantly increase the effect of fire prevention and extinguishing materials. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.