Slag as a Raw Material in the Construction Materials Industry

Calcium Silicate Slag: Sustainable, High-Performance, Forward-Looking

During the production of low-carbon ferrochrome, the Weisweiler electric furnace generates calcium silicate slag (CRS), a byproduct with great potential. Up to 75,000 tons of this valuable material are produced annually – and more than 75% of it is reused as a quality-controlled construction material mixture. This means CRS replaces approximately 56,000 tons of natural rock each year – a significant contribution to resource conservation, CO₂ reduction, and the circular economy.

Versatile Applications

CRS is used in numerous applications, e.g., in road, path, and earthworks as a sub-base layer with or without binders, in the substructure of asphalt and concrete surfaces, or

in noise barriers and as bedding material in sewer construction. Large infrastructure projects such as the “Tivoli” football stadium in Aachen, sections of the A4 motorway, and various logistics and industrial centers have also been successfully realized with CRS.

The Advantages of CRS

Resource-saving and sustainable
High durability and weathering resistance
Consistent quality through quality assurance (RAL)
Available year-round

By recycling calcium silicate slag, EWW demonstrates how industrial byproducts can be meaningfully reintegrated into the circular economy.

A Byproduct Becomes a High-Tech Building Material

The slag is formed at temperatures of up to 1,800 °C during the smelting process from chrome ore and other additives. Through targeted composition and controlled cooling, a material with consistent quality, high compressive strength, and excellent resistance to environmental influences is created. Over time, CRS construction material mixtures continue to harden, further increasing their load-bearing capacity.