At the voestalpine Group, it is primarily LD slag which is produced and then processed in a resource-efficient manner.
At the voestalpine Group, the conservation of resources has long been an important part of the production process as a whole. This also applies to the slag generated during steel production (LD process). For decades, LD slag has been used not only in Austria but also in many other countries, for use in road construction or general engineering applications. Slag use is subject to strict regulations and controls.
At voestalpine the slag resulting from the steelmaking process is separated into blast furnace and metallurgical slags and then recycled. The slag is processed further into valuable products, particularly for the cement and construction industries.
The metallurgical slags are primarily LD slags which are a byproduct of the Linz-Donawitz process . They are produced at the steel mill in the LD converter as pig iron is processed into steel. The voestalpine Group produces around 650,000 tons a year, of which approximately 500,000 tons are produced in Linz and 150,000 in Donawitz. In comparison: according to the EUROFER and EUROSLAG associations, around 10 million tons of LD slag are produced in Europe each year.
In order to increase raw materials efficiency, a part of the LD slag at voestalpine is fed back into the iron and steelmaking process. This removes the need for considerable quantities of primary sources of iron and lime. To date, a majority of the slag is used externally, in road construction, with a smaller portion going to the cement industry.
Additionally, various R&D projects at voestalpine are constantly working on developing alternative uses for slag.
Further facts and figures on LD slag: http://bit.ly/ld-slag