The utilization of metallurgical slags by means of oxidation in the liquid state
In the present contribution, the concept of the slag utilization based on transformation of non-magnetic wüstite (FeO) to magnetic magnetite (Fe3O4) using an oxidizing atmosphere is proposed. In order to verify the feasibility of the proposed way of slag utilization, experiments were performed on the ternary CaO-FeO-SiO2 and quaternary CaO-FeO-SiO2-MnO slag systems, accompanied by thermodynamic and kinetic modelling. The kinetic studies of the oxidation of FeO in liquid synthetic slags were carried out using thermogravimetric technique (TGA) and nucleation / crystal growth of the precipitated phase by confocal scanning laser microscopy (CSLM). Air was used as an oxidizing atmosphere. TGA results indicated that, during the first 10-15 min of oxidation, 80-90％ of FeO in the slag was oxidized. CSLM images showed that crystals grew and agglomerated on the liquid slag surface, reaching 50 μm in length in some cases. Different shapes of crystals were observed at different experimental temperatures. A kinetic analysis of the TGA results indicated that the oxidation process consists of three distinct steps, i.e., nucleation of magnetite/manganese ferrite from the slag, followed by a chemical reaction-controlled stage and later, the diffusion of oxygen through the product layer. Precipitated phases were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis confirmed the presence of magnetite and manganese ferrite in the product layer.
Slag utilization oxidation kinetic studies CSLM
Anna SEMYKINA Jinichiro NAKANO Seetharaman SRIDHAR Volodymyr SHATOKHA Seshadri SEETHARAMAN
Division of Materials Process Science, Royal Institute of Technology, SE-100 44, Sweden National Met URS Corp, P.O. Box 1959, Albany, OR 97321 USA Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, PA 15213 USA National Metallurgical Academy of Ukraine, 4 Gagarin ave., Dnipropetrovsk 49600, Ukraine Division of Materials Process Science, Royal Institute of Technology, SE-100 44, Sweden
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-8
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）