Recycling Waelz Slag

05/26/2011 |


Testing has begun on a promising new way to recycle Waelz slag, turning the harmful steel mill waste material into a useful construction brick.  Though there are concerns over the potentially toxic materials that could be leaked out of the bricks over time, these fears are being investigated with the studies.

The study appears in ACS' Industrial & Engineering Chemistry Research.

In the report, Ana Andrés and colleagues note that steel mills around the world produce vast quantities of waste dust each year — 8 million – 12 million tons in the United States, for instance, and 700,000 tons in the European Union countries. The dust often is converted into a rock-like material known as Waelz slag, which is usually disposed of in landfills.

The slag contains iron, calcium, silicon oxide and other minor oxides as manganese, lead or zinc oxide. Scientists have been searching for practical and safe uses for Waelz slag.

In earlier research, scientists showed that Waelz slag had potential as an ingredient in bricks, roof tiles and other ceramic products.

The new research moves large-scale recycling of Waelz slag closer to reality, establishing at two real-world brick factories that the material can successfully be incorporated into commercial-size bricks.

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