Customer stories: Fiber optics and laser make the steel industry more competitive

In recent years, Acreo Swedish ICT has been involved in several projects that have created value for the Swedish steel industry. The solutions are based on fiber optics and make it possible to measure temperature and atomic composition in real time in different stages of manufacturing and recycling processes. Decreased energy consumption, improved product quality, enhanced proactivity and increased opportunities to recycle are some of the results.

Using the proper temperature is of great importance in different processes in the steel industry. Due to the extreme conditions, relatively few measurements are carried out. In the blast-furnace, with temperatures reaching 2,500 degrees Celsius, measurements have been impossible to perform.

Measurements at several steelworks

In a series of projects, Acreo has managed to implement solutions based on fiber optics for continuous temperature measurement in several large Swedish steelworks. At SSAB Luleå Tunnplåt, measurements have been carried out during production, both in conversion processes and in moulds. In Sandvik’s production of stainless steel, measurements have been carried out in converters. Temperature measurements have also been conducted in LKAB’s experimental blast-furnace.

Work more proactively

In another ongoing project, Acreo will measure the temperature in the ladles, which transport the fuse metal. Over time, the material inside the ladles, the lining, is worn out. But it’s hard to know which ones are at risk of collapse. By measuring the temperature in the lining, it’s possible to work more proactively.

“The fiber optics will be placed in a pattern inside the ladle’s wall. A hole the size of one millimeter in the outer wall is enough to get thousands of measurement points” says Erik Zetterlund, Acreo Swedish ICT.

Laser enables efficient recycling processes

With traditional methods of scrap-metal sorting, it’s impossible to determine the metal composition before the by-product is melted down. LIBS, Laser Induced Breakdown Spectroscopy, enables real-time analysis when the by-products are solid, on the transport band. This knowledge can make the steel industry’s recycling processes more effective, by saving time and energy.

In the LIBS method, the analysis is carried out at a distance. When a short laser pulse hits the scrap-metal, plasma is formed at the surface that emits a spark with a unique color. The light is analysed with a spectrometer, which reveals the atomic composition. 

Real-time analysis

Acreo’s first prototype has been tested at Stena Recycling’s scrapyard. The next step is to integrate a sorting mechanism connected to 10–12 containers. The LIBS system has also been tested at an Outokumpu steelworks.

“Outokumpu wants to reuse certain by-products. We have successfully managed to detect approximately 10 different types of steel without errors.” says Bertrand Noharet, Acreo Swedish ICT.


Erik Zetterlund, erik.zetterlund [at]

Project partners

Acreo Swedish ICT, Swerea Mefos, LKAB, SSAB, Swerea Kimab, Stena Recycling, Outokumpu

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