molly jones on sun 6 dec 09
This is a questions from my mother Maggie Jones from Turtle Island Pottery.
turtleislandpottery.com
"Anyone know why a glaze that I have been using for several yrs has
suddenly decide to form Lithium Carbonate crystals in the bucket? 6 sided
crystals that get larger ea day, I have been screening them out."
Thanks responders,
Molly M. Jones
William & Susan Schran User on mon 7 dec 09
On 12/6/09 9:19 PM, "molly jones" wrote:
> This is a questions from my mother Maggie Jones from Turtle Island Potter=
y.
> turtleislandpottery.com
>
> "Anyone know why a glaze that I have been using for several yrs has
> suddenly decide to form Lithium Carbonate crystals in the bucket? 6 sided
> crystals that get larger ea day, I have been screening them out."
Has the glaze slurry gotten cold?
Take the crystals mix with a little warm water, add back to glaze.
If they are removed, the glaze will be changed.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
James Freeman on mon 7 dec 09
On Mon, Dec 7, 2009 at 4:43 PM, John Britt wrot=
e:
James,
I hate to say it, but I think you are wrong on this one.
John, Marian, Jess, et alii...
I could very well be wrong, as I am not a geologist, but lithium crystals
are cubic and lithium borate crystals are orthorhombic, so the shape seems
to be wrong. John, I did read your very interesting article many years ago=
,
and just reread it. The fact that Molly's crystals dissolved in warm water
would seem also to eliminate the lithium borate possibility, as lithium
borate is just not very soluble in water. Also, I have grown the same
hexagonal crystals Molly described and you pictured in your article in a
glaze containing no lithium whatsoever. Here is the recipe (I substituted
Gillespie Borate for the Gerstley Borate), which leads me to believe that
they are (mostly) sodium borate crystals (it's a nice glaze, by the way):
Glaze name: White Satin Matte
Cone: 6
Color: Opaque White
Testing: Tested
Surface: semi-matte or satin
Firing: oxidation or reduction
GlazeType:
Recipe: Percent
Gerstley borate 31.60
Soda Feldspar 19.80
Talc 13.95
EPK 5.00
Silica 29.64
Totals: 100 %
Also add:
Zircopax 5.11
John, as I recall from your article, you fished numerous different crystals
out of your various glaze buckets. Are you sure it was the hexagonal,
plate-like crystals that exhibited the lithium? If it was, perhaps any
lithium detected in the crystal was merely a trace contaminant? Marian,
wouldn't the fact that Molly's crystals dissolved when she put them in hot
water argue against the possibility that they were lithium? I'm also not
sure how lithium carbonate, which is only slightly soluble in cool water,
and even less so in warm water, could have dissolved sufficiently to
precipitate out again at the same general temperature at which it allegedly
dissolved. Doesn't seem to make sense. Don't you get crystal precipitates
by making what at one temperature is a saturated solution, then bringing it
back to a temperature at which that solution is now supersaturated? It als=
o
doesn't seem to explain how my glaze with granular lithium carbonate, which
has been sitting for about six years now at temperatures which range from 8=
0
degrees in the summer to 45 degrees in the winter, has not grown any
crystals and has not dissolved the lithium carbonate. The lithium is still
sitting at the bottom of the bucket fully intact. Jess, I have a small pil=
e
of these hexagonal, plate-like crystals. I will try your vinegar test
tomorrow. I will also put them in a flame. If they are some flavor of
sodium borate, which I suspect, they should make a yellow-green flame. If
they are lithium, they should make a red flame. I have also asked Molly fo=
r
the percentage of lithium carb she puts in the glaze. I will mix up two
batches of her glaze tomorrow, one with the lithium, and one without, and
leave them in my marginally heated studio to see what grows. Stay tuned to
this station!
Then again, I guess it ultimately doesn't matter a bit since Molly's
crystals dissolved, thereby eliminating the problem, so maybe it's best to
just let this thread die.
Take care.
...James
James Freeman
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/clayart/
>
molly jones on mon 7 dec 09
Thanks Bill...that was my suspicion, the cold.
This is a modification of my production white glaze and it works with or
without the addition of the lith carb. It has a broad firing range. I add
the lithium and some rutile to make the white glaze a little more
interesting.
I will warm them up!
maggie
On Mon, Dec 7, 2009 at 7:24 AM, William & Susan Schran User t
> wrote:
> On 12/6/09 9:19 PM, "molly jones" wrote:
>
> > This is a questions from my mother Maggie Jones from Turtle Island
> Pottery.
> > turtleislandpottery.com
> >
> > "Anyone know why a glaze that I have been using for several yrs has
> > suddenly decide to form Lithium Carbonate crystals in the bucket? 6 sid=
ed
> > crystals that get larger ea day, I have been screening them out."
>
> Has the glaze slurry gotten cold?
> Take the crystals mix with a little warm water, add back to glaze.
> If they are removed, the glaze will be changed.
>
> Bill
>
> --
> William "Bill" Schran
> wschran@cox.net
> wschran@nvcc.edu
> http://www.creativecreekartisans.com
>
>
>
>
James Freeman on mon 7 dec 09
On Sun, Dec 6, 2009 at 9:19 PM, molly jones wr=
ote:
>
> "Anyone know why a glaze that I have been using for several yrs has
> suddenly decide to form Lithium Carbonate crystals in the bucket? 6 sided
> crystals that get larger ea day, I have been screening them out."
>
Molly...
The crystals probably aren't lithium carbonate. While lithium carbonate is
listed as being slightly soluble in water, for potters' purposes it can be
thought of as insoluble. Very, very little will dissolve in water. I have
a glaze mixed up with granular lithium carbonate that has been sitting on m=
y
shelf for probably 6 years, and the lithium carb is still not dissolved.
I'm also not sure it even forms crystals.
Is there borax or a borate in your glaze? This is likely your culprit.
Your crystals are probably some type of borate. They are almost certainly
not lithium borate, as the crystal shape is all wrong (lithium borates
produce crystals in the shape of rectangular or parallelogram bars), and th=
e
temperature is much too low (I think lithium borate crystals require
temperatures around 1500 degrees F to form).
I'd follow Bill Schran's advice. If the crystals dissolve, especially if
they dissolve easily, you can be relatively sure they have little to do wit=
h
lithium.
Take care.
...James
James Freeman
"All I say is by way of discourse, and nothing by way of advice. I should
not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/clayart/
John Britt on mon 7 dec 09
James,
I hate to say it, but I think you are wrong on this one.=3D20
I think that they are lithium tetraborate crystals. Even though material=
=3D
s are=3D20
listed as "slightly soluble", like frits, that is under tightly controlle=
=3D
d scientific=3D20
conditions. Many glaze slops are either acidic or basic and temperatures =
=3D
and=3D20
pressures vary, and that effects the solubility.
Here is an article I wrote:
http://www.ceramicstoday.com/articles/flambe_magic.htm
Had them tested at Univ. of Texas and they came in many shapes, mostly=3D20=
=3D
hexagonal flat crystals, but then there were the "jack" shaped ones, etc.=
=3D
Anyway,....just my opinion.... and trying to help,
John Britt
www.johnbrittpottery.com
magzz on mon 7 dec 09
Maggie here...I just reset my mail, I haven't been on in quite a while.
I am positive they are Lithium crystals.
The glaze in the bucket contains:
G-200 spar
Dolomite
Ferro 3195
Talc
Silica
Kaolin epk
zircopax
tin ox
Note: this is my standard "cafeteria white" glaze.
I have added, for interest, lithium carbonate and rutile. I have been
doing this for at least 5 yrs.
I have, in the past, had a small cup with a bit of water and lith carb in
it. A few days later the water had evaporated and left large,
1 inch diameter, flat, six sided, crystals.
These in the bucket are smaller, and do seem to grow both in thickness
and diameter.
If not too big they do not hinder the glaze results. The larger ones,
say, 1/8 inch or more, will flux out a translucent spot.
I screened them out, put them in Hot water , some dissolved slowly and
later in the day put them in a blender.
Thanks Bill, James and John for your input!
I thought it was an interesting phenomenon.
Maggie
On Mon, 7 Dec 2009 16:43:21 -0500 John Britt
writes:
> James,
>
> I hate to say it, but I think you are wrong on this one.
>
> I think that they are lithium tetraborate crystals. Even though
> materials are
> listed as "slightly soluble", like frits, that is under tightly
> controlled scientific
> conditions. Many glaze slops are either acidic or basic and
> temperatures and
> pressures vary, and that effects the solubility.
>
> Here is an article I wrote:
>
> http://www.ceramicstoday.com/articles/flambe_magic.htm
>
>
> Had them tested at Univ. of Texas and they came in many shapes,
> mostly
> hexagonal flat crystals, but then there were the "jack" shaped ones,
> etc.
>
> Anyway,....just my opinion.... and trying to help,
>
> John Britt
> www.johnbrittpottery.com
>
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Jess McKenzie on mon 7 dec 09
I suggested this almost-definitive test to Otto, and
he promised to try it, except his crystals haven't
returned.
Li2CO3 will fizz when an acid is applied due to the
formation of CO2
Li2B4O7 placed in acid will just form H3BO3
So, one needs only to wash a few crystals in cold
water, blot, then drop on a bit of household vinegar.
If they fizz, they're probably a carbonate.
As a Texas U grad, I can't very well argue with the
alma mater, but John's crystals might not be
identical to others.
~jess
John Britt
wrote
James,
I hate to say it, but I think you are wrong on this
one.
I think that they are lithium tetraborate crystals.
Even though materials are listed as "slightly
soluble", like frits, that is under tightly
controlled scientific conditions. Many glaze slops
are either acidic or basic and temperatures and
pressures vary, and that effects the solubility.
Here is an article I wrote:
http://www.ceramicstoday.com/articles/flambe_magic.ht
m
....
Had them tested at Univ. of Texas and they came in
many shapes, ...
Neon-Cat on mon 7 dec 09
I wasn=3D92t going to say anything because we don=3D92t have the glaze reci=
pe
and ingredients. However, I can remind you, James, that lithium
carbonate acts a little differently than other compounds when it comes
to being soluble. It is most soluble at lower temperatures and
decreases in solubility as the temperature increases. So, it is
partially soluble in cold water and very slightly soluble in hot
water. About one gram of lithium carbonate dissolves in 78 ml of cold
water and in 140 ml of boiling water.
Lithium carbonate solubility in water:
1.52% at 0 C; 1.31% at 20 C; 1.16% at 40 C; 1.00% at 60 C; 0.84% at 80
C; 0.71% at 100 C.
It is soluble in acids.
So, if Li2CO3 can be soluble it can precipitate back out as a
crystalline solid. Unless combined with other things it won=3D92t make
large crystals because of its combined ionic and covalent bonding; it
will just clump together to make a granular mass or powder when dry.
When combined with other glaze batch components there is no reason why
a new lithium compound won=3D92t go ahead and precipitate out and
crystallize at the colder temperature that caused the lithium
carbonate to become available as a solute and reactant in the glaze
batch (solvent). Knowledge of solubility and solubility rules can help
us predict or know what kinds of precipitation reactions are possible.
Marian
Neon-Cat
Jess McKenzie on tue 8 dec 09
James Freeman wrote
"... lithium crystals are cubic and lithium borate
crystals are orthorhombic, so the shape seems to be
wrong. ..."
Is it a lithium salt? We won't guess, but the
question is beginning to border on the moot. Maggie
just told us that she tried the vinegar test--no
fizz. I think we must conclude it isn't a carbonate.
We guess you and John are both right. It seems
likely to be a borate, fed by one of the components
that releases borate ion very slowly, to combine with
some cation to form an equally not-very-soluble
compound that appears as if by magic. In Maggie's
case source could be the borate frit; in other cases,
maybe it's one of those complex borate minerals like
Gillespie.
~joan and jess
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