Density measurements of low silica CaO-SiO2-Al2O3 slags: slag structure discussions
The density of low silica CaO-SiO2-Al2O3 slags with silica content varying from 5 - 14 ％ was measured using Archimedes Principle. A Pt-30％Rh bob which hung from a balance was then immersed in the slag and the change in mass was measured at temperatures 1410 and 1460 oC. The density values obtained from the measurements were later compared with the model developed by Persson et al. Density values of the corresponding binary silicates as well as higher silica ternary slags were then estimated and compared with the experimental works of other researchers. Some density measurements were also carried out using the X-ray sessile drop technique at higher temperatures which showed good agreement with the results of Archimedes method. Later the density decrease at high temperatures was interpreted based on the silicate structure. As the mole percent of SiO2 was below the 33 pct required for the orthosilicate composition, discrete SiO4-4 tetrahedral units in the silicate melt would exist along with O2- ions. The expansivity curve for the ternary system was plotted against the alumina content. The drooping expansivity curve suggested that the predominant expansions in the bonding were due to Ca-O bonds. The change in melt expansivity may be attributed to the ionic expansions in the order of Al3+ - O2- <Ca2+-O2- <Ca2+-O- Structural changes in the ternary slag also could be correlated to a drastic change in the value of enthalpy of mixing. Similar trend also can be found in the sulphide capacity study of CaO-SiO2-CrOx system at 1873K. The sulfide capacity shows a decreasing trend as Cr2+ replaces Ca2+ in the slag. With further increase of Cr2+ content, there are indications of the occurrence of a minimum point beyond which the sulfide capacities show a slight increasing trend. The latter is attributed, on the basis of slag structure analysis of Gaskell and coworkers, to the increasing extent of the polymerization reaction releasing oxygen ions for sulfide reactions.
Density Measurements Expansivity Archimedes Principle Slag structure
Luckman Muhmood Lijun Wang Seshadri Seetharaman
CSIRO, Process Science and Engineering, Australia Dept. of physical chemistry of metallurgy, University of Science and Technology Beijing, China Royal Institute of Technology, 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
1-9
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）