Fire-retardant composition derived from agricultural waste materials and production method thereof

Abstract

The invention relates to a fire-retardant composition derived from agricultural waste materials and production method thereof. The composition comprises water (80–89 % wt), diammonium phosphate (10–15 % wt), sodium silicate (0.5–3 % wt) obtained from silica extracted from agricultural residues, a fire-retardant agent (0.1–0.5 % wt) selected from magnesium hydroxide, aluminum hydroxide, zinc borate, or calcium carbonate and a bio-based binder (0.1–2 % wt) chosen from guar gum, xanthan gum, methylcellulose, or carrageenan. Agricultural silica is purified through a sequential process of washing, acid leaching, incineration at 630–700 °C, and conversion to sodium silicate by reacting with sodium hydroxide at 50–70 °C. The resulting sodium silicate is combined with diammonium phosphate and selected hydroxides to yield a biodegradable, non-toxic flame-retardant. Upon thermal exposure, the composition demonstrates multi-stage flame suppression within the temperature range of 500 °C to 1000 °C, operating through endothermic cooling, gas-phase dilution, and the formation of a protective mineral–glass layer that resists oxygen and heat transfer. This synergistic process results in stable char formation and sustained fire resistance under high-temperature conditions. The product is biodegradable, free of heavy-metal residues, and retains its fire-resistant effectiveness for no less than four months when applied to vegetation or wooden surfaces, providing a sustainable and conventional phosphate-based fire retardant.

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