Elke Blodgett on tue 9 nov 99
from Monona
> ---------- Forwarded message ----------
> Date: Sun, 7 Nov 1999 17:24:24 EST
> From: "I.Lewis"
> Reply-To: Ceramic Arts Discussion List
> To: CLAYART@LSV.UKY.EDU
> Subject: Fumes.
> Resent-Subject: Fumes.
>
> ----------------------------Original message----------------------------
> ------------------
> To Subscribers clayart@lsv.uky.edu
>
> Fumes.
>
> There are often interesting postings about fumes and fume extraction and
> recent
> dialogues about those issuing from electric kilns attracted my attention
> even
> though I do not have an electric kiln. However, when teaching I always
> noticed
> that the metal casings of electric kilns around the spy holes were often
> corroded. I always attributed this to the effects of hot steam on steel.
>
> I would like to know if the following notions are tenable.
>
> Given that the original rocks were granite intrusions they would have been
> in contact with crustal rocks which metamorphosed. Volatiles in the rising
> magma
> would react with such things as limestone producing gypsum and fluorite.
> Weathering and further metamorphism change the rocks, forming clays.
> Transport
> would degrade the size of the particles.
> Hence, it is reasonable to suppose that ball clays and other sedimentary
> deposits also have a percentage of sulphate, sulphide and fluoride
minerals.
> When heated to a high enough temperature these minerals break down
releasing
> fluorine, sulphur and chlorine (NaCl get everywhere) as elements or through
> reaction with water vapour, Hydrofluoric acid, Sulphuric acid and
> Hydrochloric acid.
> Should this be possible, it might be that emanations from kilns may be a
> greater hazard than we might believe.
> Can some one satisfy my curiosity and confirm that firing out of doors is
a
> safe thing to do.
> Ivor.
---------------------------------------------------------------
The corrosion on the metal parts of the kiln are not from just steam and
heat. The steam contains compounds containing sulfur, chloride, fluoride,
and carbon. EPA has recognized this problem and is proposing regulations on
emissions from brick kilns for the sulfur oxides, hydrochloric acid, and
hydrofluoric acid. And all clays contain some or all of these impurities.
In fact, several kaolins even contain one of the dioxins. And no one knows
why!
Mom Nature was not interested in quality control.
Monona Rossol
Ron Roy on thu 11 nov 99
When I was part of workshop in Minissota last spring I noticed - a vent
pipe from an electrick kiln which exited from a window. Above the pipe the
glass was etched for many feet.
RR
>----------------------------Original message----------------------------
>
>from Monona
>
>
>> ---------- Forwarded message ----------
>> Date: Sun, 7 Nov 1999 17:24:24 EST
>> From: "I.Lewis"
>> Reply-To: Ceramic Arts Discussion List
>> To: CLAYART@LSV.UKY.EDU
>> Subject: Fumes.
>> Resent-Subject: Fumes.
>>
>> ----------------------------Original message----------------------------
>> ------------------
>> To Subscribers clayart@lsv.uky.edu
>>
>> Fumes.
>>
>> There are often interesting postings about fumes and fume extraction and
>> recent
>> dialogues about those issuing from electric kilns attracted my attention
>> even
>> though I do not have an electric kiln. However, when teaching I always
>> noticed
>> that the metal casings of electric kilns around the spy holes were often
>> corroded. I always attributed this to the effects of hot steam on steel.
>>
>> I would like to know if the following notions are tenable.
>>
>> Given that the original rocks were granite intrusions they would have been
>> in contact with crustal rocks which metamorphosed. Volatiles in the rising
>> magma
>> would react with such things as limestone producing gypsum and fluorite.
>> Weathering and further metamorphism change the rocks, forming clays.
>> Transport
>> would degrade the size of the particles.
>> Hence, it is reasonable to suppose that ball clays and other sedimentary
>> deposits also have a percentage of sulphate, sulphide and fluoride
>minerals.
>> When heated to a high enough temperature these minerals break down
>releasing
>> fluorine, sulphur and chlorine (NaCl get everywhere) as elements or through
>> reaction with water vapour, Hydrofluoric acid, Sulphuric acid and
>> Hydrochloric acid.
>> Should this be possible, it might be that emanations from kilns may be a
>> greater hazard than we might believe.
>> Can some one satisfy my curiosity and confirm that firing out of doors is
>a
>> safe thing to do.
>> Ivor.
>---------------------------------------------------------------
>
>The corrosion on the metal parts of the kiln are not from just steam and
>heat. The steam contains compounds containing sulfur, chloride, fluoride,
>and carbon. EPA has recognized this problem and is proposing regulations on
>emissions from brick kilns for the sulfur oxides, hydrochloric acid, and
>hydrofluoric acid. And all clays contain some or all of these impurities.
>In fact, several kaolins even contain one of the dioxins. And no one knows
>why!
>
>Mom Nature was not interested in quality control.
>
>Monona Rossol
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
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