钒渣物相结构及钙化焙烧相变对钒转化率的影响因素探讨

运用马弗炉焙烧钒渣得到不同温度阶段的熟料,采用偏光显微镜、扫描电子显微镜、电子探针以及能谱仪等对钒渣物相结构、形貌以及焙烧过程中物相组成变化规律等进行详细分析。通过偏光显微镜观察得出钒渣主要由钒尖晶石、金属铁、硅酸盐及钛铁矿等物相组成;通过能谱成分分析得出钒尖晶石为主要含钒物相;通过扫描电镜和电子探针观察钒渣焙烧过程形貌变化,得出钒尖晶石最终氧化分解形成铁板钛矿、氧化铁以及钒酸钙相,认为钒渣物相结构(钒尖晶石晶粒大小、硅酸盐粘结相分布和分散金属铁量的多少)、熟料中钒的存在形式、钒酸钙相的生成含量以及高熔点硅酸盐的形成等都可能会影响钒的转化率高低。

Discussion on the influence factor of vanadium slag phase structure and calcification roasting phase transition on vanadium conversion rate

The vanadium slag was roasted in muffle furnace to produce clinkers with different temperature stages. The vanadium slag phase structure, morphology and change law of phase composition in roasting process were systematically analyzed by polarizing microscope, scanning electron microscope, electronic probe and energy disperse spectroscopy. It was found from polarizing microscope observation that the vanadium slag was mainly composed of vanadium spinel, metallic iron, silicate and ilmenite. The energy disperse spectroscopy results indicated that the vanadium spinel was mainly the vanadium-containing phase. The morphology change of vanadium slag in roasting process was observed by scanning electron microscope and electronic probe, and it was found that the vanadium spinel was finally oxidized and decomposed to form pseudobrookite, iron oxide and calcium vanadate. The vanadium conversion rate was possibly affected by the vanadium slag phase structure (the grain size of vanadium spinel, the binding phase distribution of silicate and the content of disperse metallic iron), the existence form of vanadium in clinkers, the content of generated calcium vanadate and the formation of high melting point silicates.