铁矾渣熔化-烟化过程中铅元素的挥发性质研究

Study on volatilization of lead in melting-fuming process of iron vanadium slag

采用火法中的熔化-烟化法回收铁钒渣中的有色金属铅,并通过热力学计算在还原焙烧过程中金属铅所需的反应条件。探究回收铅过程中不同工艺参数对铅回收率的影响,并确定回收的较优工艺条件。用扫描电子显微镜、能谱仪和X射线衍射技术对收集到烟尘的形貌、成分和结构进行表征。结果表明:铁钒渣中的铅物相在熔化-烟化过程中,当温度高于1 000℃时,PbS最先开始挥发进入烟尘中;烟尘中回收的铅主要以PbO和PbS形式富集,其中PbO是单质铅挥发后被氧化的产物,呈四棱柱形状;在较优反应温度1 242℃下铅的回收率达99.70%。

In this paper, the melting-fuming method, a type of pyrometallurgy, was used to recover the nonferrous metal lead(Pb) in iron vanadium slag, and the reaction conditions required for reducing metallic Pb during the roasting process were calculated by thermodynamic software. In addition, the effects of different process parameters during the recycling process on the lead Pb recovery ratio were investigated, the optimal conditions for comprehensive Pb recovery ultimately obtained, and the morphology, elemental composition and structure of the collected smoke dust characterized by scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS)/energy spectrometry and X-ray diffraction(XRD). The results show that in the melting-fuming process, lead sulfide(PbS) in the iron vanadium slag first volatilizes into the form of soot when the reaction temperature is above 1 000 ℃. The Pb recovered in soot is mainly enriched in the form of lead oxide(PbO) and lead sulfide(PbS), in which lead oxide(PbO) is the oxidized product of lead single after volatilization, contained a quadrilateral shape. Pb recovery reaches 99.70% at the optimal reaction temperature of 1 242 ℃.