Desulfurization of iron alloys in vacuo-free energy of formation of SiS (v)

摘要: The rate of desulfurization Fe-C-Si-S meltsin vacua (10 ώm pressure) has been investigated using 15 kg alloys melted by induction heating. For the sulfur contents from 0.008 to 0.1 pct investigated, is a first-order type with respect sulfur. Over this concentration range and in presence carbon up saturation silicon 0 5 pct, activity sufficiently high that fractional surface coverage adsorbed within 0.75 < θS 1. equation derived satisfy experimental findings for limiting case → 1 indicates evolved primarily via two activated reactions involving (SiS2)° (S2)°. These complexes then produce SiS S vapor species. At 1600°C rates formation these volatile species are about one fourth those free vaporization sulfur, respectively. apparent heats activation ∼47 kcal ∼37 vapor. Using an apparatus Knudsen cell Bendix mass spectrometer, enthalpy reaction SiS2(s) + Si(s) = 2SiS(v) measured, giving 102.2 kcal. Combining other thermodynamic data, energy evaluated as 1/2S2(v) SiS(v) δF° 15,500-19.5T 1000° 1686°K Si(l)+ 1/2S2(v)= δF°= 3500 -12.4T above