Why using steel slag as a fertiliser is a win-win
“More widespread use of steelmaking slag in agricultural applications will allow society to solve several important issues at once” – Evgeniy Shidlovskiy, ArcelorMittal
A major by-product of our industry, slag has long been sold by steelmakers for use in construction. Its applications in agriculture are less well known, but ArcelorMittal research in Ukraine is unearthing the true value of slag to famers looking to improve soil properties and crop yield.
One of the main reasons farmers need fertiliser is to reduce the amount of acidity in soil. Thankfully, steel slag has exactly the right chemical composition to do this. It’s been used in agriculture for some time – notably in the USA, Germany, and France. But now technicians at our Kryvyi Rih site in Ukraine have been exploring new ways to sell slag as a fertiliser or soil improver.
The aim of their research? To help transform industrial waste recycling while establishing an effective, cost-efficient fertiliser to rival lime. In other words, to create a win-win for the steelmaking and agriculture industries alike.
A project team in Kryvyi Rih recognised that the first thing we needed to do was to establish a good understanding of what properties farmers are looking for in a fertiliser. This enabled us to ensure the slag delivered by our company would have the best-possible combination of minerals, such as calcium oxide, phosphate, magnesium and sulphur – trace elements support plant growth.
Pilots were conducted in the Volyn and Kharkov regions in partnership with three academic partners. The National Scientific Center based in Kharkov conducted biological investigations, while employees from the Institute of Hygiene and Medical Ecology conducted toxicity studies. Additional environmental research was carried out in partnership with the Institute of Agroecology and Biotechnology, Ukrainian Academy of Agricultural Sciences based in Kiev.
The 2015 field trials confirmed the benefits of using steelmaking slag as a fertiliser for soil deoxidation. Importantly, the study demonstrated that slag represents no threat to the natural fauna and flora so is harmless to the environment.
Tests also showed that corn, beetroot, barley and sunflowers harvests were 230% higher when using slag as a fertliser. Rich in calcium oxide, phosphorus, kalium, sodium and other elements, the slag fertiliser positively affects soil conditions and subsequent crop yields.
Evgeniy Shidlovskiy, chief technical officer at ArcelorMittal Kryvyi Rih, said: “Using steelmaking slag in agricultural applications will allow us to eliminate substantial steelmaking wastes and will allow farmers to optimise the pH levels in their soil, cut costs and improve their harvests”.