Bricks used in construction projects can be made out of a troublesome byproduct of the steel industry. Credit: iStock |
Scientists
are reporting development and successful testing of a promising new way
of using a troublesome byproduct of the global steel industry as raw
materials for bricks that can be used in construction projects. Their
study appears in ACS’ Industrial & Engineering Chemistry Research.
In
the report, Ana Andrés and colleagues in Spain 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.
It
showed existing commercial equipment could be used to make bricks with
Waelz slag, and eased concerns about large amounts of potentially toxic
metals leaching out of such bricks. A small amount of potentially toxic
material came out of the slag-made bricks over time, not in excess of
European Union regulations. “Overall, it may be summarized that Waelz
slag containing bricks meet the highest quality standards set for
construction ceramic materials,” the researchers say.
The authors acknowledge funding from the Spanish Ministry for Education and Science and BEFESA Steel R&D.
Study abstract: Incorporation of Waelz Slag into Commercial Ceramic Bricks: A Practical Example of Industrial Ecology
