Yuanbo Zhang, Kun Lin, Zijian Su, Xijun Chen, Ke Ma, Tao Jiang
{"title":"Interface Diffusion and Reaction Mechanisms of Fe3O4–MgO System in Pellets Under Different Atmospheres","authors":"Yuanbo Zhang, Kun Lin, Zijian Su, Xijun Chen, Ke Ma, Tao Jiang","doi":"10.1007/s11663-024-03202-2","DOIUrl":null,"url":null,"abstract":"<p>The proportion of pellets in the blast furnace charge structure is gradually increasing, among which magnesium-bearing fluxed pellets have been widely applied due to their excellent metallurgical properties. To further determine the consolidation mechanism in different reaction layers of magnesium-bearing fluxed pellets, the phase transformation and diffusion behaviors of Fe<sub>3</sub>O<sub>4</sub>–MgO in different roasting atmospheres were investigated in this study. The results showed that Fe<sup>2+</sup> preferentially diffused to the MgO layer and combined with Mg<sup>2+</sup> to form Mg<sub><i>y</i></sub>Fe<sub>1−<i>y</i></sub>O in inert atmosphere, and then, Fe<sup>3+</sup> and Fe<sup>2+</sup> binded to Mg<sup>2+</sup> to form [(MgO)<sub><i>x</i></sub>(FeO)<sub>1−<i>x</i></sub>]·Fe<sub>2</sub>O<sub>3</sub> (0 ≤ <i>x</i> ≤ 1). The increase of roasting temperature was favorable for the entry of Mg<sup>2+</sup> into the spinel phase. In air atmosphere, Fe<sub>3</sub>O<sub>4</sub> was first oxidized to Fe<sub>2</sub>O<sub>3</sub>. Fe<sup>3+</sup> and Mg<sup>2+</sup> counter-diffused and then combined to Mg<sub><i>x</i></sub>Fe<sub>3−<i>x</i></sub>O<sub>4</sub> (<i>x</i> = 1). Fe<sub>3</sub>O<sub>4</sub> reacted more readily with MgO in inert atmosphere than in air atmosphere. It was favorable to increase the oxygen partial pressure for Mg<sub><i>x</i></sub>Fe<sub>3−<i>x</i></sub>O<sub>4</sub> (<i>x</i> = 1) generation. The diffusion rate of Mg<sup>2+</sup> at the interface of Fe<sub>3</sub>O<sub>4</sub>–MgO system in inert atmosphere was 1.88 <i>µ</i>m/min at 1200 °C, which was faster than that of 1.49 <i>µ</i>m/min in air atmosphere.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>\n","PeriodicalId":18613,"journal":{"name":"Metallurgical and Materials Transactions B","volume":"25 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Metallurgical and Materials Transactions B","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s11663-024-03202-2","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The proportion of pellets in the blast furnace charge structure is gradually increasing, among which magnesium-bearing fluxed pellets have been widely applied due to their excellent metallurgical properties. To further determine the consolidation mechanism in different reaction layers of magnesium-bearing fluxed pellets, the phase transformation and diffusion behaviors of Fe3O4–MgO in different roasting atmospheres were investigated in this study. The results showed that Fe2+ preferentially diffused to the MgO layer and combined with Mg2+ to form MgyFe1−yO in inert atmosphere, and then, Fe3+ and Fe2+ binded to Mg2+ to form [(MgO)x(FeO)1−x]·Fe2O3 (0 ≤ x ≤ 1). The increase of roasting temperature was favorable for the entry of Mg2+ into the spinel phase. In air atmosphere, Fe3O4 was first oxidized to Fe2O3. Fe3+ and Mg2+ counter-diffused and then combined to MgxFe3−xO4 (x = 1). Fe3O4 reacted more readily with MgO in inert atmosphere than in air atmosphere. It was favorable to increase the oxygen partial pressure for MgxFe3−xO4 (x = 1) generation. The diffusion rate of Mg2+ at the interface of Fe3O4–MgO system in inert atmosphere was 1.88 µm/min at 1200 °C, which was faster than that of 1.49 µm/min in air atmosphere.