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THE ROYAL SOCIETY OF CANADA 



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Ti'na in hour» 



Fig. 1. Rate of Reduction of Hematite in Carbon Monoxide at 850°C. 



The peculiar stepped nature of the curves indicates the different 

 stages of reduction, thus ferric oxide appears to be reduced according 

 to the following equations: 



3Fe203+CO = 2Fe304+CO2 



Fe304+CO = 3Fe0+CO2 



FeO+CO = Fe+C02. 

 The nearly horizontal portion of the CO2 curve in Fig. 1 corre- 

 sponds generally to the reduction of FeO to Fe, the earlier reactions 

 being effected very readily in the initial part of each reduction. The 

 different stages of reduction can be seen more clearly in the equili- 

 brium curves for the reduction of ferric oxide, determined by Mat- 

 subara,- Fig. 2, which show the relation between ^he solid and gaseous 

 phases. 



In this curve the first horizontal line indicates the reduction 

 of Fe203 to Fe304; the second horizontal line the reduction of 

 Fe304 to FeO, and the third the reduction of FeO to Fe. During each 

 of these stages there are present two solid phases. The vertical 

 portions of the curve do not correspond at all closely with the com- 

 pounds Fe304 and FeO. Thus Fe304 contains 26 . 17 per cent, of oxygen, 

 while the vertical line is located at about 28 per cent. Also FeO 



^A. Matsubara, "Chemical Equilibrium between Iron, Carbon and Oxygen," 

 Trans. Amer. Inst. Min. & Met. Eng., February, 1921. 



