|
General comment This representative EPD covers air-cooled blast furnace slag (ACBFS), a crystalline by-product formed during the slow cooling of molten blast furnace slag under atmospheric conditions. Once solidified, ACBFS appears as a coarse-grained, rock-like material and is primarily used as a mineral aggregate in the construction industry – for example, in base layers, backfills, or asphalt mixtures.
Its use is governed by the applicable standards:
EN 12620 – Aggregates for concrete
EN 13242 – Aggregates for unbound and hydraulically bound materials for use in civil engineering work and road construction
The specific application of the product is subject to the respective national legal regulations at the place of use, particularly regarding environmental compatibility, installation classes, and approval procedures.
The production of ACBFS takes place as part of the pig iron manufacturing process in the blast furnace.
Iron-bearing input materials (sinter, pellets, ores) are charged into the furnace along with coke. The uniform composition of this charge significantly influences the chemical composition of the resulting slag.
ACBFS can be recycled and reused after (every) excavation.
According to the German Substitute Building Materials Ordinance (EBV), ACBFS is classified as HOS 1.
Key parameters:
pH value: 9–12
Electrical conductivity (µS/cm): < 5000
SO₄ (mg/l): < 1300
Typical chemical composition (by mass %):
Chemical compoundAverage value [%]Fe total0.5CaO42SiO₂34MgO7.2Al₂O₃10
The primary data represent iron and steel production in Germany.
The quality level of geographical representativity can be considered “good,” the quality level of technical representativity can be considered “good,” and the temporal representativity can also be considered “good.” Therefore, the overall data quality for this EPD can be classified as “good.”
To ensure comparability of results, only consistent background data from the ecoinvent database version 3.9.1 was used in the life cycle assessment (e.g. datasets for energy, transport, auxiliary and operating materials), which refer to the reference year 2022. The database is regularly reviewed and thus meets the requirements of EN 15804 (background data not older than 10 years). All consistent datasets contained in the ecoinvent database are documented and can be accessed in the ecoinvent online documentation.
For ACBFS, only modules A1–A3 are declared since the material is integrated into other construction products (e.g., cement, concrete) and cannot be physically separated or identified at end of life. |
