The poisoning effect of chlorine on the fused iron catalyst used for a
mmonia synthesis was studied. Chlorine adsorbs on the catalyst surface
, reacting with potassium contained in the catalyst as well as with ir
on. The chlorine adsorption ability of the passivated catalyst is lowe
r. The poisoning effect of chlorine on the activity of the iron cataly
st is very strong and it is connected with the increase in the apparen
t activation energy of the ammonia synthesis process. Partial regenera
tion of the catalyst is possible by overheating at 920 K. The decrease
of the amount of chlorine after overheating is only 12%. It suggests
that chlorine is bonded not only as chlorides, but also as less volati
le, oxygen-chlorine compounds.