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more on oxidation- again (long)

updated sun 16 nov 97

 

WardBurner@aol.com on fri 14 nov 97

Bill,

This is why I'm leary of posting information.....I don't have time, sorry.
This will be my last post on the subject.

YOU CANNOT OXIDIZE IN AN ELECTRIC KILN.

Now, I know you're not supposed to use uppper case because it's rude, but I'm
feeling a bit of frustration. Some of what you said, I agree with, some I
don't. Step by step here is my reply to your points.

You said;

<<<(to
me) words and definitions are very important. I worked for many years with
combustion processes, including advise and consultation to fuel chemists.
there is a vast difference between "Oxidation" as a process, and
"Oxidizing" as a condition. "Oxidation" means something is happening-
namely, an Oxidizing element is entering into combination with other
elements. "Oxidizing" describes a condition where there is enough
Oxidizing material present to participate, IF (important IF), there is
anything present that is ready to participate. The result of having an
Oxidizing atmosphere in contact with things that are perfectly happy at
their present state of combination is a "neutral" process.

Simple re-statement--- If the material in an Oxidizing atmosphere is
already oxidized to the normal state, the result will be a neutral
exchange.>>>

I agree. The most important point, and one I think you overlook though, is
the last word of your quote; "exchange". Exchange can only happen if
molecular bonds are broken and one atom joins with another. The combustion
process breaks the bonds between the two atoms of oxygen that form a molecule
making this single atom very reactive and ready to bond. There is no
significant bond breaking in the neutral atmosphere of an electric kiln, so
no oxidation takes place. Also neutral process and neutral atmosphere are two
entirely different things. Neutral process means things may change a bit, but
are pretty much happy as they are. This is what happens when you have a
stochiometric burn or excess free oxygen in a gas fueled kiln. It's a neutral
process. A neutral atmosphere is different. The molecular bonds aren't
constantly being ripped apart and reformed like in combustion, the stay the
same or remain neutral and inactive.

You then say;

<<<Oxidizing,
but the process is neutral.>>>>

No, The atmosphere is neutral. Oxidation takes place to the elements because
of electron flow through them, but the atmosphere is neutral because the
molecular bonds are still intact. There is no combustion (rapid oxidation)
taking place.

You further state;

<<<the atmosphere in a fuel burning kiln is THE SAME AS IN AN ELECTRIC KILN!>>>>

Quite true, but the huge difference is that the molecular bonds between atoms
of oxygen are intact in the electric kiln, because no combustion (rapid
oxidation) has taken place. In a fuel fired kiln these bonds are broken,
reform, broken, reform, ect. During this, things are interacting on a
molecular basis. This interaction does not take place to any great degree in
an electric kiln because there is no oxidation (combustion) taking place.

You refered to my post about nothing changing in an electric kiln by saying;

<<<important- **nothing is changing. **>>>>

See what I said above. LOTS of things are changing in a fuel fired kiln on a
molecular level while not much is changing in an electric kiln. I believe the
key misunderstanding is semantic and lies with the use/defination of
oxidation. You pointed out that;

<<<present. The result is a neutral firing, but only because all the
materials are already at their preferred state of Oxidation. If there are
materials present that are not at the preferred state- you had better
believe they WILL oxidize, even in an electric kiln, with or without a
power vent. Try sticking a small piece of paper into your peep hole.>>>>

No, the paper is oxidizing, the atmoshere provides oxygen. Once you use some
of this oxygen, you have a localized reduction atmosphere with a lack of
oxygen. What happens is you have inserted a substance in the form of a
hydrocarbon (paper) that has combusted (rapid oxidizing) thus breaking the
molecular bonds of the hydrocarbons and the molecular oxygen present. That
paper is going through rapid oxidation. If you kept shoveling paper into the
kiln, you would then have a fuel fired kiln with oxidation (or reduction)
taking place and it would no longer be neutral. With nothing burning you have
a neutral atmosphere. Pots, shelves, and bricks are refractory meaning they
are resistant to heat and do not contain many items that can rapidly oxidize
(burn). If you made kiln shelves out of plywood, they'd burn like hell and
then you would have combustion and a atmosphere that would no longer be
neutral.

gas burns.....it's oxidizing
iron rusts.....it's oxidizing
electric elements rust in their own way....they're oxidizing
The atmosphere of an electric kiln has no combustion, no rusting, nothing
going on except molecular vibration (heat). There is radiational heating,
conductive heating, and a tiny amount of convectional heating, but no
oxidizing (burning).

An electric kiln has a neutral atmosphere. The atmosphere we live in is
neutral, it's just cooler where we are. If we were forced to breath elemental
oxygen ( a single atom unbonded from the two atom pair), it would destroy our
lungs (oxidize them).

Marc Ward
Ward Burner Systems
PO Box 333
Dandridge, TN 37725
USA
423.397.2914 voice
423.397.1253 fax
wardburner@aol.com

Vince Pitelka on sat 15 nov 97

>This is why I'm leary of posting information.....I don't have time, sorry.
>This will be my last post on the subject.
>YOU CANNOT OXIDIZE IN AN ELECTRIC KILN.
>Now, I know you're not supposed to use uppper case because it's rude, but I'm
>feeling a bit of frustration.

Geeze, Marc, enough of this BS. We're feeling pretty frustrated here too!
Of course you can oxidize in an electric kiln, when there is anything to
oxidize. All kinds of things oxidize at room temperature, and heat
accelerates the process. The kiln elements are oxidizing. The organics,
sulfates, carbonates, etc. in the claybody or glaze oxidize. In doing so,
if they consume the available oxygen, then no more oxidation can take place,
unless there is a vent system replenishing the fresh air entering the kiln.

Isn't the presence or absence of combustion irrelevant. All we need for
oxidation is ample oxygen and something to be oxidized. Otherwise,
oxidation would not occur at room-temperature. And even if no oxidation is
taking place because everything is oxidized, if there is free oxygen in the
kiln atmosphere, then technically it is still an oxidizing atmosphere (one
capable of oxidizing other materials), right?? Please explain the statement
"With nothing burning you have a neutral atmosphere." Again, if ample
oxygen is present, and adequate heat to accelerate reaction, then any
oxidizeable material will oxidize, right?

You also say "The atmosphere we live in is neutral." If this is true, then
why do so many things oxidize spontaneously - iron to rust, vegetables to
compost, etc?

And then: "The atmosphere of an electric kiln has no combustion, no rusting,
nothing going on except molecular vibration (heat). There is radiational
heating, conductive heating, and a tiny amount of convectional heating, but
no oxidizing (burning)." Wow. This is weird. Of course the atmosphere
itself is not being oxidized. No one said that to my knowledge. The point
is that if oxygen is present, then the atmosphere is CAPABLE of oxidizing
other materials, and is therefore an oxidizing atmosphere. Right?

What we really need here are some definitive, clear, explanation. No one
has provided that yet. That surprises me, considering some of the ace
chemists and engineers on this list.
- Vince

Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166