Waelue

Holistic Recovery of Recyclable Materials from Rolling Slags

Time span

From 01.01.2023 to 31.12.2025

Abbreviation

Waelue

Project type

Holistic Recovery of Recyclable Materials from Rolling Slags

The aim of the Waelue project is to fully utilize the recycling potential of Waelue slag. Waelz slag is a product that is produced during the recycling of galvanized steel scrap, particularly from the automotive industry. During recycling, fly ash containing heavy metals (Zn and Fe, but also Pb) is produced, which is reworked using the Waelz process. Around 90% of the zinc contained can be recovered in this process. Iron and other secondary components are transferred to the so-called Waelz slag. The Waelz process produces approx. 650 kg of Waelz slag per ton of fly ash (approx. 2 million tons per year worldwide). Further use of the very iron-rich Waelz slag is problematic due to the remaining heavy metal content, which is why it is currently landfilled.

Due to the complex chemical and mineralogical composition, it is not possible to purify the rolling slag using metallurgical processes at moderate temperatures. For this reason, the Waelue project will use melt reduction in a high-temperature furnace (e.g. plasma furnace) as a recycling method for Waelue slag. The resulting products are pig iron, a residual slag and a zinc-rich flue dust. In the spirit of the circular economy, all the resulting products are to be reused. The energy costs during the remelting process are offset by the production of marketable products. The resulting pig iron can be used in the steel industry and zinc is recovered as a product from theflue dust. An alkali-activated binder (AAB) is to be produced from the residual slag for the manufacture of chemically resistant manhole bases. The use of AABs opens up new fields of application and can also make a significant contribution to reducing CO2 emissions.

Contact

Helmholtz Institute Freiberg for Resource Technology

Prof. Dr. Ajay Patil

+49 351 2604411

a.patil@hzdr.de

Pollutants

Pb

Resources

Zn

Fe
Pb

Partners

Logo HIF

Helmholtz-Institut Freiberg für Ressourcentechnologie

Logo FV Montanregion

Förderverein Montanregion Erzgebirge e.V.

Welterbe Montanregion Erzgebirge e.V.