Determination of dissolved sulfur and Mg‐S, Mg‐O equilibria in molten iron

Experiments on the extraction of sulfur from the sulfides and oxy‐sulfides such as FeS, MgS, CaS, BaS, RE 2 S 3 and RE 2 O 2 S (RE ‐ rare earth metals) by hydrogen reduction were carried out at 600 – 900°C by means of hydrogen reduction‐polarographic analysis method. The reduction degree of various sulfides by H 2 at 800°C is in decreasing order as follows: FeS > MgS ≥ RE 2 S 3 > RE 2 O 2 S ≥ CaS ≅ BaS. The equilibrium constants for reaction MgS(s) = [Mg] + [S] and MgO(s) = [Mg] + [O] obtained by using vapour‐liquid equilibrium method are: K MgS = 2.0·10 −4 at 1873 K, log K MgO = 1.27 ‐ 13670/ T, e O Mg = 644.5 ‐ 1406000/ T .