Potassium Acetate — Frequently Asked Questions

Because chloride is severely corrosive to aluminium and attacks the cadmium-plated fasteners and carbon brake assemblies used on aircraft. The resulting airframe and brake damage was significant enough that acetate and formate de-icers replaced chloride on runways and taxiways, despite costing considerably more per tonne.

To around minus 26 degrees Celsius, which covers most operational conditions at northern European and North American airports. It is applied as a liquid, leaves no gritty residue that could be ingested by engines, and its runoff is less damaging to concrete and to adjacent vegetation than chloride brine.

Because it works by saponification. Sprayed onto burning cooking oil it reacts with the hot fat to form a soapy foam layer that seals the surface, excluding oxygen and preventing reignition as the oil cools. Water alone would flash to steam and spread the fire; a wet chemical agent forms the blanket that actually stops it.

Sealed and dry if supplied as a solid, since it is strongly deliquescent and will absorb atmospheric moisture and liquefy. The liquid concentrate form avoids that issue and is the usual supply route for de-icing, where the material is used in bulk and handling a hygroscopic solid would be impractical.