Some Cansiderations on the Chemical Reactions in Cupola Based on the Results of Gas Analysis Obtained by a Mass Spectrometer

Abstract

  Gases on various levels of cupola stack were taken through the wall and determined with a mass spectrometer. On the bases of the determinations the reaction of moisture in blast with coke and the oxidizing and reducing reactions of metals were discussed. At the later discussion, the variation of total oxygen in gases; To₂ calculated from the following equation were remarked.
    To₂={(O₂%)+(CO₂%)+1/(2) (CO%)}×78.1/(N₂%)×{100−(H₂O%)}+1/(2)(H₂O%)
  where; (    %) represents the determined value of each gas, and (H₂O%) represents the calculated value from (H₂%) and humidity of blast.
  On the behaviour of moisture in blast, it was revealed that while the moisture reacted with incandescent coke generating H₂ and CO₂ on the levels of 0 to 550 mm above tuyeres, a part of the H₂ gas on the higher level of the cupola turned into H₂O owing to the reaction with CO₂.
  By investigating the distribution of To₂ in cupola, it was clarified that the To₂ decreased on the levels of 0 to 350 mm above tuyere because of the oxidation of molten iron. On the levels of 550 to 750 mm above tuyere, however, the increase of the To₂ was recognized. In this zone the iron began to melt and its contact area with coke increased considerably, so that FeO on the surface of iron were reduced with coke. Moreover, in the preheating zone the decrease of To₂ appears which introduce by the oxidation of solid iron.