(1. 东北大学 冶金学院,沈阳 110819; 2. 东北大学 多金属共生矿生态化利用教育部重点实验室,沈阳 110819; 3. 攀钢集团 西昌钢钒有限公司,西昌 615012)
摘 要: 采用X射线衍射、扫描电镜及能谱分析对钒渣钙化焙烧相变机理进行研究。结果表明:钒渣主要物相为不规则多边形铁钒尖晶石和铁橄榄石,660 ℃时均已开始氧化分解,前者产物为固溶体R2O3和部分铁板钛矿微晶聚体及晶间少量钒酸锰,铁橄榄石740 ℃时已显著分解、结构破坏。随着温度的提高(660~900 ℃),氧化产物逐渐增多,微晶粒长大聚合,钒酸盐形态由少量浸染状逐渐向微质点、无定形熔态带状变化,并向渣粒外侧迁移。低于900 ℃时,钒酸盐中Mn含量较高,Ca含量偏低,实际生成的为钒酸锰盐;900 ℃以上时,Mn和Ca含量则逆向变化,形成焦钒酸钙;940 ℃时,渣粒出现液相,使部分焦钒酸钙与R2O3和玻璃相混杂,阻碍氧化反应。
关键字: 钒渣;钙化焙烧;相变;钒酸锰;钒酸钙
(1. School of Metallurgy, Northeastern University, Shenyang 110819, China; 2. Key Laboratory for Ecological Utilization of Multimetallic Mineral, Ministry of Education, Northeastern University, Shenyang 110819, China; 3. Xichang Iron and Steel Co., Ltd., Pangang Group, Xichan 615012, China)
Abstract:The mechanism of phase transformations in calcified roasting vanadium slag was studied by XRD, SEM and EDS analyses. The results indicate that the major phases in the vanadium slag are irregular and polygonal iron-vanadium spinel and fayalite, both of which have been the beginning of oxidation decomposition at 660 ℃. The decomposition products of the former are the micro crystalline aggregate of solid solution R2O3 and partial pseudobrookite with small amount of manganese vanadium distributing on the micro crystalline boundary. Fayalite is evidently decomposed at 740 ℃, resulting in its structure failure. With the temperature (660-900 ℃) raising, the oxidation products gradually increase, and the micro crystallines grow and aggregate. Also, the vanadate transforms in morphology from a small amount of dissemination to micro particles and to amorphous and molten zone, which migrates to the outside of the slag particles in the meantime. Below 900 ℃, Mn content in the vanadate is higher and Ca content is lower, indicating that it is manganese vanadate. Above 900 ℃, the contents of Mn and Ca in the vanadate vary reversely, indicating that the calcium pyrovanadate forms. The liquid phase occurs in slag particles at 940 ℃, which results in mixing the partial calcium pyrovanadate with R2O3 and glass phase to hinder the oxidation reaction.
Key words: vanadium slag; calcified roasting; phase transformation; manganese vanadate; calcium pyrovanadate