I have a very unexpected result from my rust cleaning exercise. At this moment I have three different experiments running: I have good cast Iron
found on my beach, after removing what was removable by hand I cut into three pieces and placed each piece in the follwing: One electolysis with
sodium carbonate the electrolyte, one in 30% acetic acid, and the other in 80% citric acid. The amount of rust on this Iron is encrusted but NOT
heavy.
Both the Electrolysis and acetic acid solutionss are obviously brown with rust removal. But the citric acid one gives off the exact same smell as I
often smell on some parts of a beach where I live. The solution turned bright yellow and then dull yellow and so it remains bubbling away.
I understand that this yellow solution is referred to as Sunshine? But yes, it is definately the Exact smell I have smelt on a few beaches that I am
aware of, No mistake. I thought that this yellow was a hydrogen sulphide, but there is a subtle difference between this smell and bad egg.
Has anyone any thoughts please? thanks rollercoaster158 - 22-4-2012 at 10:15
There might be some elemental sulfur in there too along with your hydrogen sulfide. It would explain the yellow color.bahamuth - 22-4-2012 at 10:33
As I have used citric acid extensively to remove rust on different types or iron alloys I have also smelled that particular smell.
IIRC the smell is more pronounced in high carbon alloys, and if you let it work it's time you'll get a hard-to-dissolve perfect white crust on your
iron alloy which is very hard to remove.
Since that smell only is observed by the action of citric acid and not by hydrofluoric, hydrochloric, sulfuric, nitric, phosphoric or oxalic acid I
doubt it is a sulfide, arsenide, telluride or phosphide compound.
I myself are really clueless and would gladly "make" a piece of the white "crust" to send off to someone capable to analyse it...CHRIS25 - 22-4-2012 at 10:57
Ok, yes I think I might well try this. The beaches absolutely stink of this same smell certain times of the year. The smell usually next to fresh
running water entering the sea, a tidal estuary actually that is miles and miles from any industry at all. All farmland. So was always surprised by
the smell, and kids swim in this every year, and surfers, and dogs - well they wade through this stench and go back and shake themselves in front of
their happy owners. Could not believe it when I re-created the smell. Will try your suggestion.Pyridinium - 22-4-2012 at 14:52
If the two odors are the same compound, it might be explained by the fact that aerobic organisms produce citric acid as part of the Krebs cycle.
I read that carbon steel has about 0.04-0.05% sulfur as an impurity, but some kinds have up to 0.35% sulfur.
Could be that you're getting a tiny trace of some organosulfur compound forming there, where maybe the same thing is being formed biochemically at the
beach. There are definitely aerobic sulfur bacteria that could be involved at some point (in the beach smell, not your experiment). Maybe someone
else on here would know the species?
CHRIS25 - 22-4-2012 at 22:18
I will look that up about carbon steel, have never ever read that sulphur is in the making of steel. Although this is pure Iron, no steel at all.
The bacteria would make sense, there is something called Iron bacteeria, which turn Ferrous Iron into Ferric Iron.
I am going to read some details about all this see what I can find. But that means that the beaches I am familiar with a laden with buried cast
Iron. this actually would not surprise me for a number of reasons, even though there is no industry around at all.Pyridinium - 26-4-2012 at 17:40
But that means that the beaches I am familiar with a laden with buried cast Iron. this actually would not surprise me for a number of reasons, even
though there is no industry around at all.
Could be scraps of iron somewhere, but iron is actually so abundant in nature that you wouldn't need it. The runoff from freshwater farmlands that
you describe would carry plenty of iron to the beach, if it didn't already have lots of it (many beaches have Fe3O4 in the sand). In the old days
iron used to accumulate at bogs so heavily that it would form beds of mineable iron ore.
