ferrous sulfide
ferrous sulfide
(OP)
In the case where ferrous sulfide has been precipitated into a water system due to suspected sulfur corrosion of a pipe...
What does ferrous sulfate look like (outside of being a black precipitate) and how does ferrous sulfide behave? What is the typical particle size range? Does anyone know if it can be physically filtered out of water? Does it smear when warmed and stick to surfaces? (as is the case with the particles I am dealing with-I am trying to identify a black particle found in a drinking water system. It is not manganese).
What does ferrous sulfate look like (outside of being a black precipitate) and how does ferrous sulfide behave? What is the typical particle size range? Does anyone know if it can be physically filtered out of water? Does it smear when warmed and stick to surfaces? (as is the case with the particles I am dealing with-I am trying to identify a black particle found in a drinking water system. It is not manganese).





RE: ferrous sulfide
RE: ferrous sulfide
The property I'm aware of is its dangerous pyrophoricity in petroleum refineries. Hydrochloric acid may dissolve it by releasing H2S. The iron could also be complexed with special chemicals to avoid the release of this gas.
A Google search would most probably give you the details.
RE: ferrous sulfide
In a reducing environment, it's black, insoluble and generally very finely divided. It plugs filters, carbon beds etc. readily. It's frequently present in water drawn from anaerobic aquifers- and it can be an indicator of contaminated water.
RE: ferrous sulfide
There won't be anything you would want to use to dissolve it. It can be reacted with HCL to convert it to H2S (poison gas) and Fe + Cl. That is how we clean some vessels and lines. (A 15% HCL is circulated). For serious cleaning, mechanical scapers must be used. In bulk, FeS is a great fertilizer for crops that need sulphur.
The interesting thing is that it normally coats steel lines stopping futher reactions and corrsion to them by H2S.
RE: ferrous sulfide
Ferrous sulfate FeSO4 is usually greenish (nearly white if extremely pure Reagent grade). Used for fertilizer, wastewater treatment., hexavalent chromium reduction. Converts to ferric sulfate Fe2(SO4)3 (reddish brown) upon oxidation.
FeS2 is pyrite (fools gold), is bright and shiny and yellow gold in color. Is harder (has diamond cubic crystal structure), and is rather non-magnetic.
RE: ferrous sulfide
I would expect to act 'greasy' because of the fine particle size. Stuff like this is very hard to folter out because it will foul filters so fast.
The trick is to control solubility. You can change pH and oxygen potential (H2O2)to keep material in solution until you want it to precipitate.
If you have much of this I would start to worry about underdeposite corrosion in you piping.
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