铁酸锌选择性硫化行为与物相转变机制

Selective sulfidation behaviors and phase transformation mechanism of zinc ferrite

为了高效回收含铁酸锌物料中的有价金属,本研究通过硫化焙烧将铁酸锌选择性地转化为硫化锌和铁氧化物或单质铁,再通过常规选矿和湿法冶金的方法实现铁锌分离与回收。利用HSC和Factsage软件研究铁酸锌硫化反应热力学,通过硫化焙烧试验研究了不同工艺条件对铁酸锌硫化行为和物相转变机制的影响。结果表明:在高温条件下,黄铁矿分解产生的气体硫和铁酸锌发生硫化反应,温度、黄铁矿和碳用量均为铁酸锌硫化的主要影响因素,适当提高温度及增加黄铁矿和碳用量可以提高锌的硫化率,添加适量钠盐有助于铁酸锌硫化。在最佳工艺条件下,铁酸锌硫化率可达84%。经XRD和SEM分析,硫化焙烧主要产物为硫化锌和铁氧化物,人造硫化矿的晶粒较小,添加钠盐能够促进人造硫化锌晶粒的长大。

In order to recover valuable metals from zinc ferrites,a sulfidation roasting was developed to selectively convert zinc ferrite into zinc sulfides and iron oxides or metallic iron,after which the separation and recovery of zinc and iron can be achieved by mineral processing and hydrometallurgical process.The thermodynamics of the sulfidation reactions of zinc ferrite was studied by HSC and Factsage calculations,and the effects of different process conditions on the sulfidation behaviors and phase transformations of zinc ferrite were investigated by sulfidation roasting experiments.The results show that the gas sulfur produced by pyrite decomposition reacts with zinc ferrite at high temperatures.The temperature,pyrite dosage and carbon dosage are the main influencing factors for the sulfidation behaviors of zinc ferrite.Appropriately increasing the temperature,the pyrite dosage and carbon dosage,the zinc sulfidation rate can be improved.Adding an appropriate amount of sodium salt is helpful to zinc ferrite sulfidation.Under the optimum conditions,the sulfidation rate of zinc ferrite can reach 84%.The XRD and SEM analysis results indicate that the roasting product is mainly composed of zinc sulfides and iron oxides,which are mainly in the form of fine grains.The addition of sodium salt can promote the grain growth of synthetic zinc sulfides.