Ready for take-off

Even in winter

Product Stories

With its caustic potash solutions for de-icing, Evonik keeps airports operating safely in frosty conditions.



Every time winter comes around, airport operators are faced with the exceptionally challenging job of keeping take-off and landing strips free from snow and ice. In addition to employing specially trained personnel and the requisite machinery to clear the runways, it is also important that they utilize the right de-icing agent. Evonik's caustic potash solutions as a basic component in the manufacture of efficient and environment-friendly de-icers help to keep runway traffic operating smoothly and safely.


When temperatures plummet in winter, it marks the onset of the hot phase on Roland Schwarz's calendar. As head of Site Infrastructure, Surfaces and System Technology at Germany's largest airport in Frankfurt am Main, Schwarz is in charge of safeguarding that traffic operations at his airport are maintained in events such as the incidence of snow and ice on runways. He heads a team of 450 experienced people who operate a fleet of 243 special-purpose  vehicles. "More than 1,200 planes come and go every day in Frankfurt," he explains. "The take-off and landing strips alone add up to a total surface of 750,000 square meters that need to be kept cleared for traffic; that’s the equivalent of more than 100 soccer fields. It is imperative that we always get the job done quickly and reliably."
To maintain such an enormous volume of traffic throughput in adverse weather conditions requires sending whole batteries of vehicles out to clear the runways, taxiways, and other tarmac areas. "Our convoys can easily comprise as many as 21 vehicles," says Schwarz. "At the head of the convoy is a service car, usually followed by up to 14 sweeper-blower machines, two snow ploughs and three dispersion machines. Once all these vehicles have completed their various tasks, a surface friction tester is sent out to make sure the tarmacs provide sufficient frictional resistance to guarantee safe landings."
The winter maintenance crew at Frankfurt Airport requires about 30 minutes to simultaneously clear two take-off and landing strips of snow and ice. That is a very impressive feat. "Ours is a collaborative effort by excellently trained personnel, modern machinery and the efficient, dependable de-icing agents we use on all our tarmacs," says the seasoned expert. “The agents we use have to be fast-acting and have good adhesive qualities, even in extremely cold temperatures." 
Efficient, environment friendly, safe
De-icing agents made using caustic potash solutions satisfy all these stringent criteria. Evonik runs a production plant for inorganic and organic chemicals at its Lülsdorf site, where a large chloralkali electrolysis facility manufactures hydrogen, chlorine, alkoxides, and caustic-potash solutions.
Caustic potash solution (potassium hydroxide) is obtained from potassium salt (potassium chloride) and is usually sold in the form of a 50-percent solution. The combination of this solution and formic acid results in the de-icer potassium formate. Compared with other defrosting products, potassium formate is the more efficient solution on icy runways and also has better adhesive qualities. Moreover, chlorides are eliminated in the electrolytical production of caustic potash, meaning that this de-icing agent is minimally corrosive, which is good for the aircraft.
De-icing products made with caustic potash from Evonik are biodegradable. "Potassium formate consumes relatively little oxygen during the degrading process," explains Hans Put, who is in charge of the Chlor-Alkali Chemicals Product Unit at Evonik. "The less oxygen it consumes in water and wastewater, the more ecologically  tolerable the de-icing agent is.
Tried and proven
Used at many airports around the globe, potassium formate has already proven to be an efficient, environment-friendly and safe de-icer. In Europe it has become the standard solution. Roland Schwarz and his team certainly appreciate the qualities of this agent. "We have mobilized our winter clearing services countless times in varying weather conditions. Even when the task seemed particularly daunting, we have always managed to maintain traffic flow on our tarmacs."

Further information

Photo: Fraport AG