In‐Situ Separation and Structure Characterization of V‐Cr Spinel in High‐Chromium Vanadium Slag

ABSTRACT The crystal structure of minerals plays a pivotal role in their applications. The V‐Cr spinel is the main crystalline phase of high‐chromium vanadium slag, and its crystal structure is crucial for the extraction of V and Cr resources. In this study, the phase equilibrium experiments were first conducted on vanadium slag with Cr 2 O 3 contents ranging from 0 to 15 wt.% at 1400°C. The results demonstrated that almost all V and Cr elements crystallized as V‐Cr spinel, and the increase in Cr 2 O 3 content promoted the crystallization of V‐Cr spinel. Subsequently, three types of V‐Cr spinel crystals were obtained via in‐situ super‐gravity separation at 1400°C, and the corresponding crystal structures were determined based on structural characterization as (Fe 2+ )(Fe 3+ 0.085 ,V 3+ 0.77 ,Cr 3+ 0.145 ) 2 O 4 , (Fe 2+ )(Fe 3+ 0.01 ,V 3+ 0.625 ,Cr 3+ 0.365 ) 2 O 4 and (Fe 2+ )(Fe 3+ 0.005 ,V 3+ 0.475 , Cr 3+ 0.52 ) 2 O 4 , respectively. On this basis, it was found that Cr 3+ ion migrated into V‐Cr spinel by replacing Fe 3+ and V 3+ ions, thereby enhancing the stability of the V‐Cr spinel and serving as the fundamental reason for the promotion of its crystallization. This study provides additional crystal parameters for V‐Cr spinel, which facilitates an understanding of the physicochemical properties of V‐Cr spinel and is of great significance for the efficient extraction of V and Cr resources from high‐chromium vanadium slag.