Evaluierung der Unterschiede zwischen sequenzieller chemischer und elektrolytischer Extraktion anhand von Seltene Erden (SE)-haltigen Einschlüssen

In metallurgical applications, rare earth elements (REEs) play an increasingly significant role. They are not only used as grain refinement agents but also for marking deoxidation products in modern steelmaking processes. Marking (tracing) the inclusions allows monitoring and investigating the modification of substances such as aluminum oxides throughout the process. Due to partial reduction of existing deoxidation products, changes occur in the exsisting non-metallic inclusions (NMIs) concerning their chemical and physical properties and morphology.

Modifying inclusions using REEs also may influence their solubility in various chemicals. Therefore, one focus of the study conducted is the examination of the stability of complex multiphase REE-Al-oxides with commonly used extraction methods.

This involves assessing the applicability of electrolytic and sequential chemical extraction techniques for REE-containing inclusions. The samples used in this study are Ultra-Low Carbon (ULC) steels containing aluminum oxides modified with cerium (Ce). The objective is to verify the stability of these multiphase inclusions in different extraction methods and to predict the number of inclusions per unit volume. This is achieved by calculating the NMI concentration using the Woodhead model, then by comparing the results of this model calculation with a measured number of NMIs per unit volume.