Flame-retardation characteristics and mechanisms of three inorganic magnesium compounds as fire-retardant for wood

In order to explore the flame-retardation effects and characteristics of inorganic magnesium compounds as wood fire-retardant,cone calorimeter(CONE) and thermal gravity—differential scanning calorimeter analyzer(TG-DSC) were used to analyze the combustion properties,smoke-release properties,and carbonization characteristics of wood powder treated by three important inorganic magnesium compounds——magnesium hydroxide,hydrated magnesium chloride,and basic magnesium carbonate.Results showed that: all of these three magnesium compounds could reduce the heat release rate(HRR) and total smoke production(TSP) of wood,showing good flame-retardation and smoke-suppression effects.Three magnesium compounds exert their flame-retardation effects by different mechanism: magnesium hydroxide could release moisture at a time when wood is going to drastically pyrolyze,and produce melts to protect wood;hydrated magnesium chloride could retard or put out fire at both the solid stage and the gas stage;basic magnesium carbonate protects wood from fire by releasing incombustible gas;basic magnesium carbonate and hydrated magnesium chloride have synergistic flame-retardation and smoke-suppression effects.