Evolution of Inclusions in Steelmaking Process of Rare Earth Steels Containing Arsenic with Alumina Crucibles

• Main Authors: Hongpo Wang, Peng Yu, Silu Jiang, Bin Bai, Lifeng Sun, Yu Wang
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Metals
• Subjects: rare earth; inclusion; arsenic; refractory; evolution
• Online Access: https://www.mdpi.com/2075-4701/10/2/275

In order to determine strategies for removing arsenic from rare earth arsenic-containing steels, the evolution of inclusions in the whole steelmaking process with alumina crucibles was investigated. It has been proven that adding lanthanum has a significant effect on both the existing state and content of arsenic in steel. The content of arsenic steeply decreased after adding 0.148% lanthanum by generating La−S−As inclusions. The addition of 0.054% lanthanum did not dramatically affect the content of arsenic. Both 0.148% and 0.054% additions of lanthanum modified the existing Si−Mn−Al−O inclusions, making them first change to La-containing inclusions, and then change back to Si−Mn−Al−O inclusions. During this process, the compositions of inclusions changed from (SiO₂−MnO)-rich to Al₂O₃-rich ones, owing to the reactions between lanthanum and alumina crucibles. The addition of 0.148% lanthanum resulted in a relatively severe reaction with the alumina crucible. This led to the decomposition of a part of the existing La−S−As inclusions and a slight increase in the arsenic content. Therefore, it is noted that choosing an appropriate holding time after adding rare earth elements to molten steel has a significant effect on the arsenic removal and saving the consumption of rare earth elements.