Melting and Crystallization Behaviors of Modified Vanadium Slag for Maintenance of MgO-C Refractory Lining in BOF

摘要

Vanadium extracting BOF suffers serious corrosion from slag. Maintenance on MgO-C refractory based on slag splashing has not been applied because of high oxidizability, low CaO content and dispersed distribution crystalline phase of slag. The present study proposed MgO addition and iron oxides reduction for component modification. Crystallization behaviors were expectantly optimized on the premise of reducing corrosion and ensuring reasonable melting temperature. The results showed [Fe04]-tetrahedral increased from 0 to 19.1% in the slag structure with the increase of MgO content, and MgO played a role in motivating FeO change into Fe_2O_3. Pleonaste (MgO.Fe_2O_3) and solid solution (MgO-FeOss) with high melting temperature generated and FeO.V_2O_3 precipitation weakened. The melting temperature increased with the increase of MgO content and decreased with the decrease of TFe content. MgO addition reduced the polymerization degree of slag and TFe decrease reduced the precipitation of crystalline phases, which led to decreasing of crystallization activation energy. Vanadium slag with MgO=12 wt% and TFe=16% satisfied the demands on melting temperature and crystallization tendency for slag splashing. Microstructure changed from dispersed distribution to blocky crystals combined with banded solid solution which greatly promoted the corrosion resistance of slag splashing layer.