Basic Oxygen Furnace: Assessment of Recent Physicochemical Models
- PDF / 1,754,144 Bytes
- 20 Pages / 593.972 x 792 pts Page_size
- 31 Downloads / 251 Views
I.
INTRODUCTION
TODAY’S crude steel production has reached 1689 million ton[1] worldwide. About 70 pct of this steel is produced via the basic oxygen furnace (BOF) steelmaking process. The main goal of this process is to reduce carbon and impurity content of the hot liquid metal by blowing oxygen through the metal bath. Over the past few decades, BOF steelmaking has been extensively researched. Both the metallurgical aspects of the process and the design and configuration of the installation, known as the converter, have been addressed in several studies. However, due to the harsh conditions of the process (i.e., high temperatures and the presence of multiple liquid phases) and its dimensions, experimental approaches to reveal the mechanisms of the BOF process and steel refining are extremely difficult. Modeling offers an elegant solution for the problems encountered during experimental approaches. Models are especially appealing to link changes in critical process parameters to the final obtained amount of steel, its composition, and the process temperature.
LOTTE DE VOS, INGE BELLEMANS, and KIM VERBEKEN are with the Department of Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 903, Zwijnaarde, 9052 Ghent, Belgium. Contact e-mails: [email protected], [email protected], and [email protected] CARINA VERCRUYSSEN is with the ArcelorMittal Gent, John Kennedylaan 51, 9042 Gent, Belgium. Manuscript submitted May 29, 2019.
METALLURGICAL AND MATERIALS TRANSACTIONS B
The BOF process was introduced in the 1950s in Austria at Linz and Donawitz.[2,3] In the batch process, the hot liquid metal, tapped from the blast furnace with main relevant impurities Si, C, and P, is refined. As a result, both metal and slag phases are present in the converter. In general, the process is known under various names: basic oxygen process (BOP), basic oxygen steelmaking (BOS), and basic oxygen furnace (BOF) process.[4] However, in practice, all these processes use pure oxygen and basic slag, which if formed during the process, to convert the hot metal to steel. This in contrast to much older processes where air was used for this purpose. A schematic representation of the BOF process is shown in Figure 1. In conventional oxygen steelmaking, scrap and liquid hot metal are charged together in the converter. Pure oxygen is blown through a top lance on the metal bath. As a result, a CO-rich gas phase is formed together with a metal phase and a slag phase containing impurities such as silicon, phosphorus, and manganese. In addition, a metal–slag emulsion is formed during the process. Emulsification is believed to occur through the formation of metal droplets which subsequently circulate through the slag phase. This emulsion has been reported[5–11] to play a crucial role in the refining process. During the oxygen blow, fluxes can be added to the process to obtain optimal process conditions. Some fluxes, mainly CaO, are added to obtain an optimal slag, while others, e.g., FeSi, are added to control the final tempera
Data Loading...
