The basic oxygen furnace (BOF) is the dominating primary steelmaking process. It is an autothermal process where hot metal and scrap are used as charging materials. The decarbonization and transformation of integrated BOF steelmaking will be the most important challenge in the coming years. Steel scrap is a charge material without new CO₂ emissions, whose availability is expected to grow significantly and will play a key role in this decarbonization process. Several solutions have been developed by Primetals Technologies to provide additional energy for processing higher scrap rates in integrated BOF steelmaking. Such solutions include simple upgrade packages installed on existing converters such as process models for heat optimization, post-combustion, and scrap preheating lances. For higher scrap rates from 30% to 50%, a combination blowing converter and JET converter is required to provide sufficient mixing during scrap melting and the highest heat transfer from the increased post-combustion. Hybrid EAF–BOF operation and limitations regarding scrap quality also need to be considered for the transformation of steelmaking. Scrap sorting and processing can be a solution to reduce residual levels in crude steel for high scrap rates. Based on reference plant data, the CO₂ reduction potential of the presented solution versus the effort and complexity of implementation is compared.

The system steel-slag-refractory and reactions of non-metallic inclusions at its interfaces are decisive in numerous metallurgical processes. In order to obtain the desired steel cleanness level, a detailed understanding of the occurring interactions is needed. This study focuses on the in-situ observation of different reactions of non-metallic inclusions in steel and slag. For this purpose a Confocal Scanning Laser Microscope attached to a high temperature furnace is applied which enables the visualization of metallurgical phenomena at steelmaking temperatures up to 1700 °C. Two different examples are discussed: First, the agglomeration of different inclusion types in a Ca-treated steel is described and corresponding attraction forces are calculated. Secondly, the dissolution of Al 2 O 3 and MgOAl 2 O 3 in two slags of the system CaO-Al 2 O 3-MgO-SiO 2 is examined, including the evaluation of the governing dissolution mechanism. Finally, an outlook on further experimental possibilities is given.

An increased interest for high temperature metallurgical processes appeared during the last decades, in order to achieve the high quality requirements in steel products. A defined steel cleanness and microstructure essentially influence the final product quality. The high temperatures involved in metallurgical processes and the lack of in situ observations do not only complicate the verification of simulation model predictions but also make significant conclusions regarding the industrial processes difficult. For that reason, new tools and techniques are necessary to develop. By combining the advances of a laser, confocal optics and an infrared image furnace, the High Temperature Confocal Scanning Laser Microscopy (HTCSLM) is a strong tool which enables high temperature in situ observations of different metallurgical phenomena. Next to solidification processes and phase transformations also the behavior of inclusions at different interfaces in the system steel-slag-refractory can be observed. The present study focuses on the aspects of inclusion agglomeration in the liquid steel and the inclusion behavior at the steel/refractory interface in two different steel grades. Out of the obtained experimental data, attraction forces are calculated and compared. This information provides an important basis for a better understanding of inclusion behavior in industrial processes and the therewith related process optimization, like for example the clogging phenomenon during continuous casting.