不锈钢厂电弧炉粉尘中含铬相的形成

采用SEM-EDS和XPS对粉尘的微观结构和表面元素分布分别进行了检测,然后用FACTSage5.2软件通过热力学平衡计算研究了Cr-Fe-Zn-Mn-Mg-Al-Ca-Ni-O-Cl体系在尾气管中的演变行为,以及温度、氧气含量和粉尘中碱金属元素等对Cr-O2系统的影响.结果表明,计算结果和实验结果基本吻合.在Cr-O2体系中,Cr元素主要以Cr2O3形式稳定存在.在高温区均有少量的CrO3或CrO2生成,并且随着温度的升高,含量不断增加.在尾气系统中,氧势越高或者含氧量越多,越容易在高温区生成CrO3.在氧化性气氛中,碱金属的存在易于与Cr结合形成含Cr(Ⅵ)物相,如K2CrO4和Na2CrO4.

Formation of Cr (Ⅵ)-bearing phases in the EAF dust from stainless steel plant

SEM-EDS and XPS techniques were used to determine the phase and microstructure of the stainless steel plant dust,respectively.FACT Sage 5.2 software was used to thermodynamically study the chemical evolution of the chromium in the Cr-Fe-Zn-Mn-Mg-Al-Ca-Ni-O-Cl system,as well as the effects of temperature,oxygen content and alkali metal elements in the dust on the Cr-O2 system.The results show that the calculated results are basically consistent with the experimental results.In the Cr-O2 system,Cr element are mainly in the form of Cr2O3.In the high temperature zone,small amounts of CrO3 or CrO2 form,and their contents increase as the temperature rising.In the higher oxygen potential or oxygen content zone of the exhaust system,CrO3 forms more easily with temperature rising.Alkali metals are the main elements to form Cr(Ⅵ)-bearing phases.The existence of alkaline metals is helpful to form Cr(Ⅵ)-containing phases,such as K2CrO4 and Na2CrO4 in the oxidizing atmosphere.