[Strawbale] Carbide Lime

[Jon Van Eck]

During the 80's I lived in a 150 yr. old farm house with 700 acres
(paradise!!) on the outskirts of Ann Arbor, Michigan.  There was a
barrel buried in the ground approximately 25 ft. from the house.  From
this barrel there was a pipe leading toward the house.  The farm had
been in the same family for over a hundred years but had been sold
before we moved in.  An old family member stopped by one day and during
our conversation we asked about the barrel.  He explained that farm
house used to have carbide lamps and that the barrel was where the gas
was produced.  Unfortunately, I can't remember any of the details of how
the barrel system was constructed; I just remember the barrel and the
pipe.  Now the property has been turned into a huge development for the
Nuevo-rich, with hundreds of oversized million dollar homes and two golf
courses. I just wish I had paid more attention when it existed (I guess
Joni Mitchell was right!!)
~ Jon 

-----Original Message-----
From: strawbale-bounces at listserv.repp.org
[mailto:strawbale-bounces at listserv.repp.org] On Behalf Of Murray Hollis
Sent: Wednesday, April 25, 2007 12:16 AM
To: 'Stone Tool'; strawbale at listserv.repp.org
Subject: Re: [Strawbale] Carbide Lime

Rob
Acetylene (C2H2) production from calcium carbide (CaC2) is achieved by
reacting the carbide with water [CaC2 + H20 = C2H2 + CaO], but the CaO
will
immediately and violently (exothermic) react with the water to produce
'hydrated' lime {Ca(OH)2}  [CaO + H2O = Ca(OH)2]. As I mentioned in
another
communication, the hydrated lime reacts very very slowly with the CO2 in
the
air unless the hydrated lime is continuously maintained wet. I suspect
that
the reaction is still very slow, but I am not sure about that case.
This acetylene production reaction was the basis of the (very) old
carbide
lamps where water was dripped into a chamber containing calcium carbide
to
produce the acetylene gas, which was burnt. The sludge that remained
after
the carbide was exhausted was calcium hydroxide (hydrated lime). 
Murray

> -----Original Message-----
> From: strawbale-bounces at listserv.repp.org [mailto:strawbale-
> bounces at listserv.repp.org] On Behalf Of Stone Tool
> Sent: Wednesday, April 25, 2007 12:38 PM
> To: strawbale at listserv.repp.org
> Subject: Re: [Strawbale] Carbide Lime
> 
> Rob:
> 	Your advice is excellent...... I should have realized what you
said
> without having to be told
> 
> 	The carbide lime is not dry hyrate that requires slaking I
think....
> though I'm not sure.   It was calcium carbide most recently, and
calcium
> carbide is reacted with water to produce acetylene leaving lime
> behind..... which has already been in contact with water in the
previous
> process...... It is at least partially hydrated.  I am not at all sure
> that slaking is a part of the required process.   This carbide lime is
> outdoors in the weather, and exposed to rain and snow, sun and
> wind.......... My question would be to what degree has it already been
> carbonated while living in a heap?   And is it actually useful for
> stucco and plaster without kilning?   If it had been bagged or binned
> after the process it would be a stable and predictable product......
> pushed up into a mountain out doors ?????????  I don't know.
> 
> 	 A small quantity for an experiment is in order methinks!
> 
>                            H.W.


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