Table 1. The process of degradation
Fe
2+
+ S
2–
→ FeS
(1)
FeS + H
2
S → FeS
2
+ H
2
(2)
FeS
2
+ 7/2O
2
+ H
2
O → Fe
2+
+ 2SO
4
2–
+ 2H
+
(3)
FeS
2
+ 7/2O
2
+ (n+1)H
2
O → FeSO
4
· nH
2
O + H
2
SO
4
(4)