Mass Transfer in Slag Refining of Silicon with Mechanical Stirring: Transient Interfacial Phenomena
2014 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 45, no 1, 96-105 p.Article in journal (Refereed) Published
Experiments have been carried out to study the rates of mass transfer between liquid silicon and CaO-SiO2 slag with impeller stirring at 1823 K (1550 A degrees C). The occurrence of transient interfacial phenomena related to the mass transfer of calcium has been observed; the evidence suggests that the reduction of calcium oxide at the interface leads to a rapid, temporary drop in the apparent interfacial tension. At low apparent interfacial tension, mechanical agitation facilitates the dispersion of metal into the slag phase, which dramatically increases the interfacial area; here, it has been estimated to increase by at least one order of magnitude. As the reaction rate slows down, the apparent interfacial tension increases and the metal recoalesces. The incidental transfer of calcium very likely promotes the transfer of boron by increasing the interfacial area. Mechanical mixing appears to be an extremely effective means to increase the reaction rate of boron extraction and could feasibly be implemented in the industrial slag refining of silicon to improve reaction rates.
Place, publisher, year, edition, pages
2014. Vol. 45, no 1, 96-105 p.
Molten Silicon, Boron, Iron, Kinetics, Thermodynamics, Behavior, Removal, Tension
Materials Engineering Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:kth:diva-133689DOI: 10.1007/s11663-013-0010-yISI: 000330735200013ScopusID: 2-s2.0-84895059910OAI: oai:DiVA.org:kth-133689DiVA: diva2:662809
QC 20140306. Updated from accepted to published.2013-11-082013-11-082014-05-21Bibliographically approved