Chemical reactions of iron with sulfur compounds

Taxonomy

• Chemical Treatment
• Inorganic Chemicals
• Sulfates
• Chemical Research
• Chemical Engineering
• Utility Chemicals
• Treatment Chemicals

3 Answers

1. The main issue in pH 3 or less environment of steel is going to be general anodic loss of metal in a rapid manner, leading to pinholes in the pipe or vessel.  This is true even when certain anodic inhibitors are present over a long period of time of exposure.  If a smaller portion of the metal is exposed, then expect the anode reaction to focus on this small area, resulting in faster loss of metal thickness in the area.  The presence of sulfides may have a slight inhibitory effect when the FeS as ions in water is too concentrated to support a solution.  Iron sulfide is considerably more soluble than you may have been led to believe, however.  Certain bacteria have specialized intransporting iron from metal surfaces utilizing sulfides.

2. Once FeS is formed, the pH should be at or below free mineral acidity, which is 3.4.  However, there are a number of things that can keep it bound even at much lower pHs.  This is where you do your testing to confirm your particular water.  Best, Sean

3. There has been considerable work done especially considering that folks have been trying to find better ways to oxidize ferrous to ferric sulfate for a long time. Also the use of Ferric salts to oxidize sulfides.  Much of your question will be determined by which sulfur compounds you may reference. Sulfides, thionates, mercaptans, etc.