The influence of iron compounds in the sulfuric acid catalyst on the SO 2 oxidation process The catalytic oxidation process of SO 2 to SO 3 is the main stage of sulfuric (VI) acid production. The process run could be disordered by reason of the increased inactivation of sulfuric acid catalyst during SO 2 oxidation process. This paper includes the influence study of the iron quantity and forms, which is introduced into the catalyst active phase, on the reaction rate of the SO 2 oxidation process.