Ivor and Olive Lewis on mon 12 jun 06
Dear Friends,
Got the first part of the calculations done, getting values for Delta H, =
Delta G and Delta S for the decomposition reaction of CO2 to CO and O.
Not exciting confirmation that Carbon Dioxide will decompose as =
temperatures get into the glaze maturity region. Disappointing I know, =
but Nature is like that at times.
I will recheck my calculations and explore a bit more, cross referencing =
with thermodynamic values for the reduction of Ferric and Cupric Oxides =
by Carbon monoxide.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Jim Murphy on tue 13 jun 06
Hi Ivor,
A couple of Reduction "water"-related tidbits ... and no calculation is
necessary :o)
Firstly, from ~480-700=BAC, chemical-water ['water smoke'] is available from
within claybody & glaze, perhaps acting as a superheated steam with CO to
form Hydrogen in the presence of iron oxide or copper oxide: CO + H2O -> CO=
2
+ H2
The above equation is important as Hydrogen is good for reduction.
Secondly, in glassmaking "refining", it's well known there's plenty of wate=
r
vapor being formed "in solution" at ~1000-1200=BAC. Similarly, it's likely
"chemical water" is also being formed during our electric ceramic firing
processes possibly through means of gas bubble cavitation & condensation
[within claybody & glaze].
Condensation - during "cooling" - may actually deserve far greater attentio=
n
to revealing the "secrets" of Electric Reduction.
Best wishes,
Jim Murphy
>From: Ivor and Olive Lewis
> I will recheck my calculations and explore a bit more, cross referencing
> with thermodynamic values for the reduction of Ferric and Cupric Oxides b=
y
> Carbon monoxide.
Jim Murphy on tue 13 jun 06
Hi Ivor,
Here's a correction [my own] to my last post:
Actually, the water gas shift reaction "CO + H2O -> CO2 + H2" process would
occur in the higher 1000-1200=BAC temperature range with Hydrogen [H2] being
produced via "thermal water splitting".
So, there's internally produced Hydrogen along with CO [from CO2
decomposition reaction] "driving" Reduction effect reactions ... or so some
think :o)
Best wishes,
Jim
-------------------------
From: "Jim Murphy"
Subject: Re: Reduction , Electric Style.
Date: Tue, Jun 13, 2006, 12:04 AM
........
Firstly, from ~480-700=BAC, chemical-water ['water smoke'] is available from
within claybody & glaze, perhaps acting as a superheated steam with CO to
form Hydrogen in the presence of iron oxide or copper oxide: CO + H2O -> CO=
2
+ H2
The above equation is important as Hydrogen is good for reduction.
Secondly, in glassmaking "refining", it's well known there's plenty of wate=
r
vapor being formed "in solution" at ~1000-1200=BAC. Similarly, it's likely
"chemical water" is also being formed during our electric ceramic firing
processes possibly through means of gas bubble cavitation & condensation
[within claybody & glaze].
Condensation - during "cooling" - may actually deserve far greater attentio=
n
to revealing the "secrets" of Electric Reduction.
Ivor and Olive Lewis on wed 14 jun 06
Dear Jim Murphy=20
Great speculation. Would like to read your research report when you have =
tested your ideas.
That aside, Intertceram are publishing a two part article on the =
development and composition of glaze porosity. Should be interesting and =
valuable since they intend giving analytical results.
Best regards,
Ivor
Jim Murphy on wed 14 jun 06
Hi Ivor,
Well, we can only remain hopeful the new published work [regarding glaze
porosity] has applied Charles' and Boyle's Laws [relating Pressure,
Temperature & Volume] to gaseous bubbles in the glaze matrix.
"Gaseous" as in perhaps containing CO2, CO, Hydrogen and/or the like.
In theory, the Temperature inside a bubble may be hotter than the
surrounding molten - yet highly viscous - glaze matrix. Which, of course,
may help account for discrepency with some other published decomposition
temperatures, e.g., that of CO2.
Best wishes,
Jim
----------
>From: Ivor and Olive Lewis
> Dear Jim Murphy
>
> Great speculation. Would like to read your research report when you have
> tested your ideas.
>
> That aside, Intertceram are publishing a two part article on the
> development and composition of glaze porosity. Should be interesting and
> valuable since they intend giving analytical results.
-----------
Hi Ivor,
I'm not implying any sort of manual steam injection [into the electric
kiln].
"Steam" is already being released & formed naturally as a chemical
by-product - within the claybody/glaze matrix during firing - and much of
this "steam" resides within gaseous bubbles of the molten soup.
Within the vicinity of these gaseous bubbles, one may expect superheated
chemical reactions involving CO & Hydrogen to occur.
If Einstein were a Ceramist, I'd expect him to take a mental journey within
one of these superheated bubbles to form an understanding of Reduction
effects - in Oxidation.
Best wishes,
Jim
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