含钒钢渣低温钠化焙烧钒浸出效果及其焙砂湿法脱硫作用

Sodium salt roasting of vanadium-containing steel slag at low temperature and application of vanadium calcine for wet desulfurization

含钒钢渣钠化焙烧过程中添加CaF_2等助剂以降低提钒工艺的能耗,分析了不同因素对低温钠化焙烧后钒浸出效果的影响,并将含钒钢渣焙砂配制成吸收浆液以净化烟气中的SO_2。在浸出钒实现其资源化利用的同时,也探索出一种高效烟气脱硫的新方法。添加3.0%CaF_2作为助剂,温度为700℃、焙烧时间为1 h的条件下,所得焙砂中钒浸出率可达68.1%。X射线衍射(XRD)与热重(TG)分析表明,混合物料中添加CaF_2助剂能促进焙烧过程物相的改变,白云母、钛铁矿等衍射峰明显减弱,含钒钢渣混合料在700℃条件下便呈现明显的热失重,在较低温度条件下即可实现钠化焙烧。以此含钒焙砂配制脱硫吸收浆液,脱硫率不低于95%的穿透时间可达125 min,而同样条件下磷矿浆脱硫系统仅为35 min。

In this study,CaF2or other additives were added to the mixture containing vanadium steel slag for energy consumption reduction during vanadium extraction process.The effects of technical parameters on vanadium leaching,as well as the vanadium calcine used as absorption slurry to purify sulfur dioxide in flue gas,were investigated.The results show that vanadium recovery could be successfully achieved,and an innovative approach for efficient flue gas desulfurization was also found.At CaF2addition ratio of 3.0%,the roasting temperature of700℃and retention time of 1 h,the leaching rate of vanadium could reach 68.1%.Based on the analysis of X-ray diffraction（XRD）and thermogravimetry（TG）,the additive CaF2was in favor of the mineral phase change during roasting process,which led to the significant weakening on the diffraction peaks of muscovite and ilmenite.Thus,a remarkable heat loss occurred for the mixing system at the TG temperature of 700℃,then sodium salt roasting of vanadium-containing steel slag could be achieved at a relatively low temperature.The vanadium calcine was used as a kind of wet desulfurization agent,and the breakthrough time reached 125 minutes as desulfurization efficiency was not less than 95%,however,it was only 35 minutes for the desulfurization system with phosphate ore slurry.