iandol on sat 17 jun 00
Kelly,
As far as I am aware the jury is still out on this one. There may be no =
modern research on which to base a valid argument. I have the firm =
conviction that what is written as acceptable chemistry explaining the =
rapid reaction of Soda, as Sodium Carbonate or Sodium Bicarbonate, is =
not possible. See P. J. Durrant, General and Inorganic Chemistry, 2nd =
Ed,1952. Footnote, P 319. Longman Green and Co. London. In addition the =
commonly accepted action of Sodium Chloride, which suggests that this =
compound breaks down under the influence of water before it reaches the =
clay, is also unproven. The record for the interaction of common salt, =
called Sel de Marin by Alex. Brongniart, can be traced back to Rudolph =
Glauber. All the experimental work used to support the idea that salt =
and steam give either Hydrogen Chloride or Chlorine and Sodium or Sodium =
Oxide might not pass scrutiny. Treat it with healthy scepticism. It is =
full of inconsistencies.=20
To get any valid information you need to get into the research archives =
of the British Ceramic Society and the American Ceramics Society. Then =
be a critical reader. There are papers which record data analysing =
effluent from industrial heavy clay factories which used Salt Glaze, mid =
Twentieth Century. These records shows that almost fifty percent of the =
effluent is Potassium Chloride, almost fifty percent Sodium Chloride. =
The rest of the chemicals are those which react with water, forming =
Hydrated oxides and hydrochloric acid. This takes place outside the =
kiln.
Potassium chloride is a fertiliser, and sodium chloride is essential to =
many plant species. We dress out asparagus bed with it every year. I =
fired a 12 Cu ft Salt kiln of several years on a regular basis. Never =
found any dead sparrows in the paddock. But as participants at Jane =
Hamlyn's workshop at Macgregor College will attest, I insist on wearing =
a respirator with acid and particulate filters when I am near a kiln =
during salting.
I think you may have to do some research to find if anything has been =
done since 1988. I closed my account on the process that year.
Hope that helps.
Best regards,
Ivor Lewis. Redhill, S.Oz
Chris Trabka on sun 18 jun 00
There was an article in Ceramics Monthly in the past few years. The gasses emitted from the kiln were measured for various elements. It did have some surprising results; salt firing is not as bad as one would expect.
Chris
WHC228@AOL.COM on sun 18 jun 00
Chris
There were several production studios shut down in New Hampshire a few years
back until they put bag houses over their stacks. The emission that they were
concerned about was the salt, not the chlorine or HCl. The bags stopped the
salt.
Bill
Lynne at The Pottery Web on tue 20 jun 00
At 10:03 AM 06/18/2000 -0400, you wrote:
> >bag houses over their stacks<
Dumb question: What are "bag houses"?
Lynne in Atlanta
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WHC228@AOL.COM on wed 21 jun 00
Lynne
Bag houses are in principle like a big vacuum cleaner bag. They are made to
take the heat and remove all of the particulate in the air that shouldn't be
floating around the neighborhood. The Dept. of Environment whatever can tell
you about them. They are used regularly in industry so that companies can
comply with emission standard rules.
There are also some other kinds of scrubbers that are in use that work. The
environmental folks are just getting started and I expect that someday that
there will be a requirement for all vapor and wood kilns to either have Some
kind of scrubber or a catalytic converter like are required on wood stoves in
one of the North eastern states.
Like everything else it will require us to spend too much money to do the
things that we want to do.
There may come a time when we will not be allowed to use our vapor kilns. I
understand that there is a ban in Kyoto Japan that limits the firing, and
building of new wood kilns because of the pollution.
If you need further information about bag houses I can give you the names of
two potters that have them. One is in New Hampshire, and the other is in
Maine. I am reluctant to put there names out on clay art without asking them
first.
My phone number is 814 398 2148
Bill Campbell
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