Zinc-rich dust is a significant by-product of Höganäs’ melting furnace in Sweden, with limited potential for reuse. However, the metal powder producer states that this could now change, following its collaboration with an ongoing project with a leading research institute that is reported to have already found a solution with clear environmental benefits.
Höganäs has joined the DESULF project, coordinated by the VTT Technical Research Centre of Finland, which aims to reduce the need for virgin zinc. Supported by funding from the EU’s consortium, EIT Raw Materials, the project is planned to run through the end of 2022 and includes partners in the metal industry and gas purification sector.
“We handle a lot of different dusts at Höganäs that go back into our processes or are sent for external metal recovery,” stated Björn Haase, Manager Non-Metal Products at Höganäs. “But we are always looking for new ways to increase the circularity of our dust side streams and reduce the use of virgin materials in any way we can.”
On a small scale, the DESULF project has already shown that side streams containing zinc originating in steel production can be used to remove sulphur from gases almost as efficiently as current commercial zinc oxide products. Its objective is to stimulate new business activity by upscaling the process to an industrial scale.
Haase further explained, “It would mean that material from Höganäs could help to lower environmental impact – not only by increasing the circularity of the zinc-rich dust side stream from its melting furnace in Sweden, but also by reducing the need for virgin zinc and the treatment of zinc-containing dust as hazardous waste.”
Höganäs’ Swedish plant currently sends its zinc-rich dust to a high-tech metal company, where the zinc is recovered and used to dilute virgin zinc. This company is also involved in the DESULF project and Höganäs’ close relationship with them will not change – it will simply supply the dust for another use before it is sent for recovery. This agreement offers other environmental advantages as it effectively doubles the use of this side stream and, again, helps to reduce the need for zinc ore.
The DESULF project also recognises that there is an increasing demand for this kind of circular solution: in the future, an estimated 5,000 tonnes of zinc oxide will be needed in Finland alone to purify synthetic gas which can be used to produce renewable transport fuels and chemicals.
“VTT has already found a network of companies that would be interested in zinc-rich dust by products,” Haase concluded. “This is an important and exciting project that I am happy to be a part of, and I am very confident it will be a success.”