It is a by-product produced when manufacturing steel and Corus currently produces half a million tonnes of it a year.
While it is already widely used as a liming material for farmland, current research being led by Tarmac and Birmingham University could see it put to an altogether different use.
Having won a contract to recycle all the slag produced by Corus plants around the country in 1999, Tarmac initiated a research partnership to find new uses for the potentially valuable sustainable material.
Backed by Department of Trade and Industry funding, the research is reaching an exciting stage with field trials underway to test performance on an area of contaminated land on the site of a former open-cast coal mine in Carr Wood, Cumbria.
Tarmac head of product development doctor Howard Robinson said: This is very exciting research which could open up a new market for steel slag dust. While farmers have used it to maintain grassland areas for livestock for some time, it has not been clear until now how long term the liming effect will last.
The field trials at Carr Wood will prove that this is a sustainable, long term solution. With hundreds of acres of contaminated land in the UK, steel slag dust could be utilised to create new areas of development land from brownfield sites.
Carr Wood is a former coal mine that has been dormant since the 1920s and has been contaminated with an acidic leachate making it impossible for plant life to grow. The research is aiming to prove that calcium oxide from the steel slag dust can provide a solution.
Birmingham University senior lecturer doctor Gurmel Ghataora said: The field trials at Carr Wood are now more than one year old and are progressing very well indeed adding further proof the slag is able to maintain soil pH between 6-8 so that it can support vegetation such as grasses and trees.
The research will conclude in March 2007.