Activity of MnO in Blast Furnace-type Slags

The activity of MnO in blast furnace-typeslags CaO-SiO_2,CaO-SiO_2-Al_2O_3 andCaO-SiO_2-Al_2O_3-MgO at 1500℃ has been measuredin a graphite crucible with Ag and Sn as solventmetals.The agreement between the values ofγMnO obtained from the experimental resultsusing Ag and Sn separately as the solvent metalis excellent.The major errors in the previousstudies have proved to be the failure to takeinto account the exchange reactions involvingSi and Mn and insufficient time for theestablishment of equilibrium between slag andsolvent metal.A new method is suggested for determiningthe activities of elements in metallic solutions.The method involves the separate equilibrationof two metallic alloys,one of which containsthe component of interest at a known activity,with a single slag.