The Phase Rule and Its Applications

by Alexander Findlay

Fe + CO = FeO + C

This reaction is succeeded by the two reactions

FeO + CO = Fe + CO₂
CO₂ + C = 2CO

The former of these reactions is not complete, but leads to a definite equilibrium. The result of the different reactions is therefore an equilibrium between the three solid phases, carbon, iron, and ferrous oxide, and the gas phase consisting of carbon monoxide and dioxide. We have here four phases; and if the total pressure is maintained constant, equilibrium can occur only at a definite temperature.

Since, under certain conditions, we can also have the reaction

Fe₃O₄ + CO = 3FeO + CO₂

a second series of equilibria can be obtained of a character similar to the former. These various equilibria have been investigated by Baur and Glaessner,[^[378]] and the following is a short account of the results of their work.