Ferr-Tech and Danieli Corus have filed a patent application for a technology that removes cyanide in the gas phase using FerSol®, Ferr-Tech’s stable ferrate(VI) solution. The technology helps reduce NOx and CO₂ emissions in the steel industry. The filing follows 3.5 years of development, engineering and extensive testing at a leading European steel producer.
In the steel industry, cyanide is found in coke oven gas and blast furnace gas, which are used as fuel gas in various process installations. When cyanide is combusted, including in the hot blast system, it contributes to additional NOx formation. This directly leads to higher emissions and increased pressure on the available NOx allowance, and indirectly to higher fuel costs. In addition, elevated NOx levels can lead to stress corrosion cracking, which poses an unacceptable risk in pressure vessels.
Cyanide removal in the fuel gas
During the development process, Ferr-Tech and Danieli Corus investigated two routes: treatment of the fuel gas or of the flue gas. Because the flue gas stream is many times larger and requires heavier-duty installations, they chose to treat the fuel gas itself. In this approach, FerSol® is dosed into a packed column, where cyanide is removed within seconds.
Sina Samimi Sedeh, Head of Innovation at Ferr-Tech: “The testing phase required a great deal of perseverance, but that is precisely what gave us valuable insights. By continually refining the design, we arrived at a working solution that stands up in practice.”
More than 99% cyanide removal and a circular residual stream
Following laboratory validation, the module was extensively tested in practice. The results show that more than 99% of the cyanide compounds are removed, without the formation of harmful by-products.
Peter Klut, Manager Technology at Danieli Corus: “This powerful, green oxidant makes it possible to break down cyanide quickly and completely, without the side reactions seen with traditional chemical oxidants. This prevents corrosion issues and reduces emissions. A very promising step forward.”
In addition to clean water, treatment with FerSol® results in a reusable raw material for FerSol® and a sludge stream of iron hydroxide. This sludge stream contains no cyanide and can be reused as a raw material in the steelmaking process. Ferr-Tech and Danieli Corus are also investigating whether the purified water can be reused within the process.
Relevance for the steel industry
According to Richard Willemsen, Business Development Manager at Danieli Corus, this is an important development:
“Steel producers are looking for practical ways to reduce fuel-related NOx, create room within their NOx permit and at the same time reduce CO₂ emissions. This technology contributes to those goals and also lowers operating costs by reducing fuel consumption.”
The solution can be integrated relatively easily into existing installations.
Strategic partnership
Ferr-Tech and Danieli Corus have been working together for some time on applications of FerSol® in the steel industry. The combination of technology and market knowledge is accelerating the move towards practical implementation.
Richard Bruins, CEO of Ferr-Tech: “The collaboration works very naturally. We bring FerSol®, Danieli Corus brings knowledge of the steel-producing industry. Together, we are developing applications that we can now see really make a difference.”
The parties are currently working with several partners to scale up the technology towards commercial application.
