Control of the manganese‐oxygen reaction in pure iron melts

EMF sensor measurements using ZrO 2 (CaO) or ThO 2 (Y 2 O 3 ) plug‐type sensors with a Cr‐Cr 2 O 3 reference were performed to redetermine the Mn‐O equilibrium reaction. In these experiments a strong effect of deoxidation of manganese was ascertained at saturation with solid deoxidation products. The measuring interval of the sensors at MnO saturation was limited to about 12 min due to chemical corrosion of the used Al 2 O 3 sheaths. In the case of double saturation with solid MnO · Al 2 O 3 (MA) and Al 2 O 3 (A) the sensors could be used as long as desirable. Moreover, the combined deoxidation of the iron melt with Mn and Al was investigated. An auxiliary electrode at the tip of the sensor ensured rapid saturation of the iron melt with solid MnO or MnO · Al 2 O 3 + Al 2 O 3 .