Blast furnace slag for solar energy

Within the next three years, a new research project aims to make blast furnace slag usable as a raw material for making high-quality finished products for solar thermal processes.

A green circular economy demands sustainable flows of energy and materials and decarbonised industrial processes – those are the only ways to achieve the Paris Agreement’s objectives to reduce greenhouse gas emissions. The project Stars – Solar thermal applications for secondary raw materials from steel production – brings together the project partners the German Aerospace Center (DLR) (project leader), Thyssenkrupp MillServices & Systems and LWK-PlasmaCeramic as they conduct research into sustainable solutions for future-oriented energy storage materials. Fraunhofer UMSICHT provides an ecological rating for the products and processes set to be redeveloped. The reported aim is to use blast furnace slag as a secondary raw material for ceramic components and energetic materials in concentrated solar thermal (CST). Using mirrors and with the aid of special transfer materials, CST attempts to secure an improved proportion of solar heat from solar energy. Besides energy efficiency, product-related features – such as components that offer consistent quality and a long service life, recyclable components or high-temperature materials, for example – are particularly relevant.

Slag exploitation expertise at LCA

This is where the Stars project comes in. The project partners process the blast furnace slag into particles for storing thermal energy, and into ceramic coatings and other components for solar thermal processes. Thyssenkrupp treats the blast furnace slag for the relevant application purposes. DLR and LWK process this slag into innovative products by means of granulation, drop pelletising and sintering or plasma coating. DLR assesses the technical properties of the products, while UMSICHT evaluates the new production processes and components in their early developmental stage from the ecological point of view. Existing experience in rating slag exploitation concepts comes to bear in this context.
Source: Fraunhofer UMSICHT