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Mass transfer of sulfur from liquid iron into lime‐saturated CaO‐Al 2 O 3 ‐MgO‐SiO 2 slags
Author(s) -
Deng Jianxiong,
Oeters Franz
Publication year - 1990
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199000376
Subject(s) - chemistry , mass transfer , metal , slag (welding) , sulfur , mass transfer coefficient , analytical chemistry (journal) , sulfide , lime , metallurgy , materials science , chromatography , organic chemistry
Laboratory experiments on the kinetics of sulfur transfer from aluminium‐deoxidized liquid iron into lime‐saturated CaO‐Al 2 O 3 ‐MgO‐SiO 2 slags were carried out at 1600°C in MgO crucibles with 1500 g iron and 180 to 250 g slag. The mass‐transfer coefficients of sulfur were determined under defined flow conditions of liquid metal induced by gas stirring. A square‐root dependence of measured rate constants on flow velocity of metal was found. This is interpreted as normal liquid‐liquid mass transfer caused by the forced convection of gas stirring. It could be described by boundary‐layer theory applied to the metal‐slag interface. With increasing sulfur contents of metal mass‐transfer coefficients became larger. This is interpreted as mass transfer by interfacial convection superimposed to normal mass transfer. Interfacial convection was confirmed by microscopic observation of quenched metal‐slag interface samples. If the sulfur content in liquid iron exceeds a critical value, calcium sulfide crystals precipitate in slag at the slag‐metal interface. The precipitation inhibits generation of interfacial convection.