20th November 2006 - STEEL INDUSTRY BY-PRODUCT FINDS A NEW USE TREATING CONTAMINATED LAND

Steel slag dust may soon be used to treat contaminated land, making it suitable for redevelopment, if current research trials led by Tarmac Limited and Birmingham University are successful.

Steel slag dust is a by-product produced when manufacturing steel and Corus currently produces about half a million tonnes of it every year. Due to its high lime content the steel slag dust is already widely used as a liming material for farmland.

Having won a contract to recycle all the slag produced by Corus plants around the country in 1999, Tarmac initiated a research partnership with Birmingham University to find new uses for this potentially valuable sustainable material. Backed by the DTI, this research is now reaching an exciting stage and field trials are underway to test the performance of steel slag dust in treating an area of contaminated land on the site of a former open-cast coal mine in Carr Wood, Cumbria.

Dr Howard Robinson, Tarmac's head of product development, 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."

The Carr Wood site has been dormant since the 1920s and as a former coal mine, it has been contaminated with an acidic leachate, making it impossible for plant life to grow. As part of the trials, the steel slag dust, which contains calcium oxide, is being rotivated into the land, so it can be gradually restored to grassland. By monitoring the treated soil pH and chemistry over time, the research aims to provide scientific proof that it is a long term solution.

Commenting on the research, Dr Gurmel Ghataora, senior lecturer at the University of Birmingham, 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.