The fire retardant effects of huntite in natural mixtures with hydromagnesite

Abstract

The fire retardant effects of natural mixtures of huntite and hydromagnesite have been investigated. As well as being entirely natural these mixtures of minerals can be considered "greener" and more environmentally friendly, in their production methods, than alternatives such as aluminium hydroxide and magnesium hydroxide. It has been shown that the release of water and carbon dioxide from hydromagnesite helps to increase the time to ignition and peak heat release in cone calorimeter testing. Huntite has been shown to decrease the average rate of heat release and increase the strength of the residue. Electron microscopy has shown that the huntite particles maintain their platy morphology during combustion in the cone calorimeter. The morphology of these particles helps to reduce the rate of heat release by slowing the release of flammable decomposition products to the flame. The platy shape of the huntite particles increases the strength of the residue containing higher proportions of this mineral. Huntite is shown to play an active part in improving fire retardancy when used in a mixture with hydromagnesite, giving performance for typical mixtures comparable to those of aluminium hydroxide.

Electrophoretic deposition of flame retardant polymer–huntite coatings

“…Huntite offers advantage of lower cost, compared to other FRA, such as aluminium hydroxide and magnesium hydroxide [14]. Moreover, the production of aluminium and manganese hydroxides generates a problem related to the disposal of toxic chemical waste [14]. It is expected that huntite can replace toxic [11,12] halogenated FRA, in many polymer products.…”

Combining product engineering and inherent safety to improve the powder impregnation process

“…This trend may be explained by the fact that the endothermic decomposition of ATH to produce water vapour occurs at 180 °C, which is lower than the decomposition temperature of calcium carbonate in carbon dioxide (450°C) and also lower than the decomposition temperature of the polymer coPe2 (350 °C). Morever, calcium carbonate has a lower heat capacity (840 J.kg -1 .K -1 ) than ATH (1200 J.kg -1 .K -1 ) (Hollingbery and Hull, 2012).…”

“…ATH is commonly used for fibre reinforced plastics and especially in medium and high voltage applications because they have very good thermo-mechanical and dielectric properties. They can be mixed with ammonium polyphosphate or phosphinate organic, which allows a significant reduction of the total flame-retardant ratio (Horrocks and Price, 2001; M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT Hapuarachchi, 2009;Laoutid et al, 2009;Hull et al, 2011;Hollingbery and Hull, 2012;Naik et al, 2013;Zheng et al, 2014).…”

CO2 Absorption and Magnesium Carbonate Precipitation in MgCl2–NH3–NH4Cl Solutions: Implications for Carbon Capture and Storage

“…Dypingite-like Mg-carbonates can serve as a flame-retardant or fire-retardant additive for polymers [81][82][83] or simply as backfill [84]. Hydromagnesite is also a promising material to replace CaO in calcium-based cement, which usually has a net release of CO 2 , as opposed to Mg-based cement, which could potentially absorb nearly as much CO 2 during its service life as was emitted during its manufacture (carbon-neutral) [85].…”