Abstract: The flame-retardant effect, stability in acid or alkaliand thermostability of solutions prepared by three kinds of halogen-free inorganic water solutions were studied in this paper. Results show that through comparative combustion experiments of seven samples, the solution with the best flame-retardant effect is the one with the ratio of Al2(SO4)3·18H2O, Fe2(SO4)3 and Na2SiO3·9H2O as 10:15:5. The paper tissue soaked with this solution did not burn out after 190 s. Its total heat release (THR) and total smoke production (TSP) are only less than 1/4 and 1/46 of those of the comparative sample, respectively. This solution is stable in a small amount of alkali and with temperature under 70 ℃. Moreover, the residual after the combustion is degradable and easy to recycle. This flame-retardant solution is easy to fabricate, low cost, remarkable in flame retardancy and environmentally friendly.

Key words: flame-retardant; environmentally friendly; combustion; THR; TSP