Re: How to supress Pyrophoresis - steaming iron

d buebly wrote:

> On Tue, 09 Sep 2003 16:40:20 GMT, "hanson" <[EMAIL PROTECTED]> wrote:
>
> >Now that the professionals in sci.chem, and sci.environment.waste
> >weren't able to furnish neither clever answers nor solutions, let me
> >repost it with the real, the dedicated to the core specialists, the
> >environmentalists:
> >
> >Machining (turning, shaping, grinding, etc) of steel parts generates
> >iron wastes (chips, spirals, fines) containing small amounts of lubes
> >as mineral oils, glycols and fatty acid amid/amines and water.
> >This iron waste is drained to form sludge cakes that are accumulated
> >in a wet condition in huge piles in open transporter bins (30x12x5 ft).
> >When full, the stuff is hauled to the steel manufacturers for recycling.
> >
> >In all too many cases whenever the stuff is laying there for some
> >weeks it gets so hot that steam and stink begins to rise from the pile.
> >Clearly it's the reaction of the steel with the water.
> >
> >Question: what can be done to prevent this nasty steam occurrence?
> >Out of the question are: Drying, Watering, Covering or Diluting with sand.
> >Any ideas anybody?
>
> seems to be a bacterial sludge generating heat.
> and the stink
>
> Try bleach/Chlorine

Bleach???? I tend to think that would make matters worse. You'd only be adding
a strong oxidant into an environment full of finely divided and readily
oxidizable iron.
The reaction of iron and water is the most likely reason as the original poster
suggested, although oxygen is also necessary. The reaction is used commercially
in disposable theraputic heat pads. You just open them up so air can get in and
voila!
To prevent the reaction, so kind of non-corrosive antioxidant might do the
trick.
Preferably one which is reasonably non-toxic or course. Perhaps something as
simple as calcium ascorbate which is nice and cheap if purchased from stock
feed suppliers. You would need to play around with different ones though since
other unexpected reactions might result. Planting a few zinc bars into the
containers might also help by behaving as sacrificial anodes i.e. the zinc
oxidizes in preference to the iron.
Just a few thoughts. I'm sure there are a lot of other possibilities.