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On the hot metal desulfurization
Author(s) -
Oktay Enver,
Fruehan Richard J.
Publication year - 1995
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199501093
Subject(s) - flue gas desulfurization , carbon fibers , metal , graphite , metallurgy , zirconium , chemistry , materials science , lime , chemical engineering , composite material , engineering , organic chemistry , composite number
Although there is no thermodynamic limitation to the desulfurization of carbon‐saturated iron with CaO, the process is well‐known to be slow. Consequently, the desulfurization of carbon‐saturated Fe‐S, Fe‐S‐Si, Fe‐S‐Si‐Al, Fe‐S‐Zr alloys by CaO, and Fe‐S‐Si alloys by CaO‐10 % CaF 2 were investigated to determine the reaction mechanism. For this purpose, dense CaO and CaO‐10 % CaF 2 discs were cemented to the bottoms of graphite crucibles containing the carbon saturated alloys. The desulfurization experiments were run at 1450°C in an SiC resistance furnace under argon gas atmosphere. The results indicate that the desulfurization of hot metal by CaO is greatly improved by prior addition of aluminum to the hot metal. The addition of 10 % CaF 2 to CaO also increases the rate of desulfurization. Zirconium, which has a stronger affinity for oxygen than aluminum did not increase the rate. SEM and X‐ray diffraction studies on the surfaces of CaO discs used to desulfurize carbon‐saturated Fe‐S, and Fe‐S‐Si alloys showed that solid CaS, and solid CaS plus small amount of solid 2 CaO · SiO 2 compounds form on the lime surface, respectively. The slow reaction rate with CaO is attributed to the solid reaction products which block the reaction by preventing the occurrence of interfacial turbulence.