For over 25 years, despite the general use of slag products in construction, there has been an on-going argument about whether slag is a waste or a by-product. Still today, the situation concerning the classification of slag is not uniform within European member states. In various countries some of the slag types are considered as by-products; however in others they have a waste status.

Before the revision of the Waste Framework Directive – WFD – (Directive 2008/98/EC) in 2008, there was no definition of by-products in European legislation. The WFD now allows for a clear definition of criteria characterising a by-product as well as a material that shall cease to be regarded as waste and finally becomes a useful product.

Ferrous slag placed on the market meets the requirements of national as well as European harmonised standards and specifications related to both technical and environmental aspects with regard to the intended use. For this reason, the European steel and slag industry considers slag to be a by-product.

In order to support the standardisation work of the EU Commission and in this respect to express the opinions of the European steel industry, its affiliates and downstream users, EUROSLAG (the European Slag Association, a body for the promotion of slag producers’ interests in the EU and member countries) frequently elaborates position papers. In 2006, a position paper “The legal status of slag” was written, where arguments and applied measures were summarised to demonstrate that slag is produced parallel to steel as a product (and not as waste.) It was stressed that slag that is intentionally generated by controlling and modifying its composition, its cooling conditions, its physical properties, etc., has to be accepted as a product.

The European Regulation No. 1907/2006 for Registration, Evaluation, Authorisation and Restriction of Chemicals (REACh) was adopted by the European Parliament and the European Council in December 2006 and came into force on 01 June 2007. The European Chemicals Agency (ECHA) manages the technical, scientific and administrative aspects of the REACH system.

The REACH regulation replaces a number of national regulations and directives with a single system. Just after implementation of the REACH regulation, the members of the FEhS-Institute (monitors and tests industrial by-products, e.g. ferrous slag, and other construction products and certifies their manufacturers) and EUROSLAG initiated – in agreement with EUROFER (the European Steel Association) – the registration of iron and steel slags as substances. Assuming that slag in general is not a waste but a by-product or product/secondary raw material, in 2009 the REACH Ferrous Slag Consortium (RFSC) was founded to prepare the registration of ferrous slag before 01 December 2010.

During the registration process the available data on slag compositions and corresponding production processes from all European countries were evaluated and intensively discussed. It was agreed to register all slag types as UVCB substances (Substances of Unknown and Variable composition, Complex reaction products or Biological materials) that are best described by their production processes. Other identifiers are the most frequently found mineral components and, as additional information, the chemical composition.

At the end of 2010, the registration was successfully filed by RFSC members, which altogether represented 97% of the European steel production at the time.

Key EU Statistics

Production of blast furnace slag in 2010: 23.5 million tons (Data from A, B, FIN, F, D, I, L, PL, E, SK, S, NL, UK)

Use of blast furnace slag in 2010: 25,6 million tons (Data from: A, B, FIN, F, D, I, L, PL, E, SK, S, NL, UK)

Production of Steel slag in 2010: 21.8 million tons (Data from: A, B, DK, FIN, F, D, GR, I, L, PL, RO, E, SK, SLO, S, NL, UK)

Use of Steel slag in 2010: 22.3 million tons (Data from: A, B, DK, FIN, F, D, GR, I, L, PL, RO, E, SK, SLO, S, NL, UK)