{"title":"Influence of substituting B2O3 with Li2O on the viscosity, structure and crystalline phase of low-reactivity mold flux","authors":"Rongzhen Mo, Xubin Zhang, Ying Ren, Junjie Hu, Lifeng Zhang","doi":"10.1007/s12613-023-2621-x","DOIUrl":null,"url":null,"abstract":"<div><p>The low-reactivity mold flux with low SiO<sub>2</sub> content is considered suitable for the continuous casting of high-aluminum steel since it can significantly reduce the reaction between Al in steel and SiO<sub>2</sub> in mold flux. However, the traditional low-reactivity mold flux still presents some problems such as high viscosity and strong crystallization tendency. In this study, the co-addition of Li<sub>2</sub>O and B<sub>2</sub>O<sub>3</sub> in CaO–Al<sub>2</sub>O<sub>3</sub>–10wt%SiO<sub>2</sub> based low-reactivity mold flux was proposed to improve properties of mold flux for high-aluminum steel, and the effect of Li<sub>2</sub>O replacing B<sub>2</sub>O<sub>3</sub> on properties of mold flux was investigated. The viscosity of the mold flux with 2wt% Li<sub>2</sub>O and 6wt% B<sub>2</sub>O<sub>3</sub> reached a minimum value of 0.07 Pa·s. The break temperature and melting point showed a similar trend with the viscosity. Besides, the melt structure and precipitation of the crystalline phase were studied using Raman and X-ray diffraction spectra to better understand the evolution of viscosity. It demonstrated that with increasing Li<sub>2</sub>O content in the mold flux from 0 to 6wt%, the degree of polymerization of aluminate and the aluminosilicate network structure increased because of increasing Li<sup>+</sup> released by Li<sub>2</sub>O, indicating the added Li<sub>2</sub>O was preferentially associated with Al<sup>3+</sup> as a charge compensator. The precipitation of LiAlO<sub>2</sub> crystalline phase gradually increased with the replacement of B<sub>2</sub>O<sub>3</sub> by Li<sub>2</sub>O. Therefore, Li<sub>2</sub>O content should be controlled below 2wt% to avoid LiAlO<sub>2</sub> precipitation, which was harmful to the continuous casting of high-aluminum steels.</p></div>","PeriodicalId":14030,"journal":{"name":"International Journal of Minerals, Metallurgy, and Materials","volume":"30 7","pages":"1320 - 1328"},"PeriodicalIF":5.6000,"publicationDate":"2023-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Minerals, Metallurgy, and Materials","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s12613-023-2621-x","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 2
Abstract
The low-reactivity mold flux with low SiO2 content is considered suitable for the continuous casting of high-aluminum steel since it can significantly reduce the reaction between Al in steel and SiO2 in mold flux. However, the traditional low-reactivity mold flux still presents some problems such as high viscosity and strong crystallization tendency. In this study, the co-addition of Li2O and B2O3 in CaO–Al2O3–10wt%SiO2 based low-reactivity mold flux was proposed to improve properties of mold flux for high-aluminum steel, and the effect of Li2O replacing B2O3 on properties of mold flux was investigated. The viscosity of the mold flux with 2wt% Li2O and 6wt% B2O3 reached a minimum value of 0.07 Pa·s. The break temperature and melting point showed a similar trend with the viscosity. Besides, the melt structure and precipitation of the crystalline phase were studied using Raman and X-ray diffraction spectra to better understand the evolution of viscosity. It demonstrated that with increasing Li2O content in the mold flux from 0 to 6wt%, the degree of polymerization of aluminate and the aluminosilicate network structure increased because of increasing Li+ released by Li2O, indicating the added Li2O was preferentially associated with Al3+ as a charge compensator. The precipitation of LiAlO2 crystalline phase gradually increased with the replacement of B2O3 by Li2O. Therefore, Li2O content should be controlled below 2wt% to avoid LiAlO2 precipitation, which was harmful to the continuous casting of high-aluminum steels.
期刊介绍:
International Journal of Minerals, Metallurgy and Materials (Formerly known as Journal of University of Science and Technology Beijing, Mineral, Metallurgy, Material) provides an international medium for the publication of theoretical and experimental studies related to the fields of Minerals, Metallurgy and Materials. Papers dealing with minerals processing, mining, mine safety, environmental pollution and protection of mines, process metallurgy, metallurgical physical chemistry, structure and physical properties of materials, corrosion and resistance of materials, are viewed as suitable for publication.