ArcelorMittal Hamburg utilises residual waste granulate instead of coal

by David Fleschen

Turning waste into raw material - ArcelorMittal's Hamburg steelworks has recently started using granulate from municipal waste instead of coal to produce crude steel from sponge iron and recycled scrap in an electric arc furnace. The crude steel, in turn, is the basis for the production of a wide variety of steels, from reinforcing steel in the construction sector to wire for nails, screws, fences and springs to steel cables that give support to oil rigs, ski lifts and bridges.

Two years of development have been invested in the new process at ArcelorMittal Hamburg, and now around half of the coal previously used in the electric arc furnace is being replaced by a more resource-efficient alternative. "With this project, we are saving 3,500 tonnes of direct CO2 emissions a year from now on," says project manager Dr.-Ing. Michel Wurlitzer happily.

At the beginning of the project, ArcelorMittal engineers tested various substitutes for their suitability together with Stein Injection Technology GmbH from Gevelsberg in the Ruhr region, a technology supplier. "Among other things, we examined sewage sludge and paper fibre residues, processed orange peel and non-recyclable waste. Our colleagues from Stein Injection Technology supported us with their injection technology to guarantee the eligibility of the test materials," explains Wurlitzer.

The most convincing results were delivered by a residual material granulate from waste from private households and similar institutions. The CO2 reduction is made possible by the biogenic carbons contained, which are present in paper or cotton fibres, for example, and by the hydrogen contained. Another advantage: the high temperatures in the steel bath, which exceed 1600 degrees Celsius, lead to complete decomposition of the granulate. Wurlitzer: "Our exhaust gas tests show that the use of the substitute does not produce any measurable emissions."

ArcelorMittal Hamburg Managing Director Dr Uwe Braun is pleased to see so much commitment in-house. "The decarbonisation of steel production is one of the most important cornerstones for achieving the climate targets in Europe."

Souce and Photo: ArcelorMittal Germany

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