STUDIES ON PHYSICOCHEMICAL CHANGES OF VAN ADIUM CATALYST FOR OXIDATION OF SULFUR-DIOXIDE PROCEEDING DURING PROCESS IN INDUSTRIAL REACTOR

There were tested changes of chemical and phase compositions of vanadi um catylst EASE during work on plates of catalytic reactor intended fo r oxidation of sulfur dioxide. As a result of catalyst work contents o f promoters (potassium, vanadium, iron) decrease and calcium displaces from plates of high temperature and settles on plates of lower temper ature. The increase of temperature increases the rate of phase transit ion of catalyst carrier from alpha-SiO2 (quartz) being the main compon ent of carrier to other form of SiO2. In the fresh catalyst promoters exist in two crystallographic phases: K3V(SO4) and KV(SO4)(2). Relativ e fraction of low potassium content phase increases as temperature on the plate decreases. Amorphous compound of potassium oxides with silic on dioxide is supposed to form. The main changes in promotor phase pro ceed during the first year of work; phase transitions proceed at the s table rate.