Effect of low oxygen partial pressure on the chromium partition in CaO-MgO-SiO2-Cr2O3-Al2O3 synthetic slag at elevated temperatures
The objective of the present work is to get an understanding of the impact of Al2O3 addition on the phase relationships in the CaO-MgO-SiO2-Cr2O3 slags at low oxygen partial pressures, with a view to control the precipitation of Cr-spinel in the slag phase since Cr in the spinel phase is expected to have lower leaching levels. The equilibrium phases in CaO-MgO-SiO2-Cr2O3-Al2O3 slag system in the range on 1673-1873 K have been investigated. The Cr2O3 content was fixed at 6wt％ and MgO 8wt％. Al2O3 contents in the slag varied in the range of 3-12wt％. The basicity (CaO/ SiO2) of slag was set to 1.6. Gas/slag equilibrium technique was adopted to synthesize the slag at high temperature. The samples were heated to 1873 K and soaked at this temperature for 24h. The samples were then slow cooled to 1673 K and equilibrated for an additional 24h. The oxygen partial pressure was kept at 10-4 Pa. Gas mixture of CO/CO2 was used to control the oxygen partial pressure. The samples were quenched in water. The chromium distribution and phase compositions in the quenched slag were studied using SEM-WDS and XRD techniques. FACTSAGE software was used for the phase equilibrium calculations. The size of spinel crystals increased drastically after slow cooling followed by annealing compared to samples being quenched after soaking at 1873 K. It was also found that low oxygen partial pressure has a strong impact on chromium partition. The amount of spinel phase increases with increased Al2O3 content.
Phase equilibrium chromium partition spinel scanning electron microscope (SEM) low oxygen partial pressure
Galina Jelkina Lidong Teng Bo Bj(o)rkman Seshadri Seetharaman
Division of Materials Process Science, Royal Institute of Technology (KTH), SE-100 44, Stockholm, Sw Division of Extractive Metallurgy, Lule(a) University of Technology, SE-971 87 Lule(a) 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
1-13
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）