Scott North on wed 3 nov 99
Hi Earl,
Since many potters are concerned with the difference between the
old spodumene (gray) and the new spodumene (white), I ran an analysis of
both on the xray fluorescence. The new spodumene that is sold here
(northern California) is mined in New Zealand. The XRF does not detect the
element lithium because it is too light. Anyway, the main difference
between the two is that the new spodumene is much more pure than the old.
The old spodumene contains from 0.5 to 1.5% each of sodium, potassium,
calcium, phosphorus, and iron that is not found in the new spodumene, and
it also has more trace elements. These extra elements can most likely be
attributed to other feldspars usually found in association with spodumene,
which are difficult to separate in the mining process.
Because the XRF does not analyze for lithium, I ran a sample of the
new spodumene on the Xray diffraction, which tells the minerals that are
present. Sure enough, the new spodumene really is spodumene
Scott C. North
Geology Department
Humboldt State University
Arcata, CA 95521
phone: (707) 826-3210
FAX: (707) 826-5241
Paulette Carr on wed 3 nov 99
Dear Mary,
It was descriptions of spodumene vs lithium carbonate is very useful. Can
you shed any light on petalite, since that is what I am using in the high
fire slip glazes on which I am working.
Thanks,
Paulette Carr
Mary's Message below:
Date: Tue, 2 Nov 1999 11:11:21 EST
From: mary simmons
Subject: Re: Lithium glazes --
----------------------------Original message----------------------------
Earl-
Spodumene (LiAlSi2O6) is a lithium-rich pyroxene, which is a silicate, so
there'll be some Si-O and Al-O tetrahedra present. In all silicates silica
and aluminum bond to 3 oxygen atoms in tetrahedrons, which are simply
pyramids where four large oxygen atoms surround a much smaller silica or
aluminum atom. Sodium can substitute for some of the lithium in spodumene.
Lithium carbonate has no silica or aluminum, and firing it breaks down to
LiO + CO2, the CO2 of course goes away as a gas in the kiln atmosphere. In
the natural world of rocks and minerals, there is no such animal :) as
lithium carbonate (that I know of)--so this compound must be synthesized.
Lithium carbonate may be a weathering product of some other lithium-rich
mineral, such as spodumene (which weathers to clay) once the lithium is
liberated, and if it finds its way into water, there are ALWAYS carbonate
ions, with an unbalanced charge, swimming around looking for something to
hook up with. It is more likely that the LiCO3 you are using is
synthesized, and so perhaps relatively pure.
So, no matter how new or old your spodumene is, it is very different from
lithium carb.
your resident geo-geek
Mary
Mary Simmons
Dept of Earth and Planetary Sciences
University of New Mexico
(505)277-9259
piedra@unm.edu
mary simmons on thu 4 nov 99
Paulette-
Petalite is a feldspathoid (as is nepheline) Feldspathoids are similar to
feldspars--these minerals have too little silica to be feldspars. Petalite
is a lithium feldspathoid with the formula Li Al Si4 O10. Minor
replacements of Li by Na and K are possible and some Fe can replace the Al.
Lithium was first discovered in THIS mineral!
Feldspathoids, as you can see from the chem formula are silicates, with our
friends, the Si-O and Al-O tetrahedra. According to a great book called
"The Rock-Forming Minerals" by Deer, Howie and Zussman, the Li content in
petalite is around 4.1 mole%.
Petalite occurs naturally in granite pegmatites. "Pegmatite" means "coarse
crystal" and pegmatites are VERY common in granites--pegmatites are zones
of large crystals of feldspars, quartz, micas and also host unusual
minerals, whose constituents are too big or something to fit into the
granite structures (in a nutshell). One of our favorite pegmatite in New
Mexico, the Harding Mine in the Sangre De Cristos Mountains has ABUNDANT
spodumene, beryl, lepidolite (a Li-rich mica), and a few other rare
minerals that almost no one has ever heard of.
Moren'likely what is sold commercially as petalite is synthesized from
component oxides or from LiOH, Al(OH)3 and silica.
If someone would send me 10 grams or so of NEW and/or OLD Spodumene, I'll
test for the Li content on this department's Atomic Absorption device--as
someone said, Li is too light to be detected on the XRF.......I'll post
results....
Mary
Mary Simmons
Dept of Earth and Planetary Sciences
University of New Mexico
(505)277-9259
piedra@unm.edu
Michael Banks on fri 5 nov 99
Not likely at all Mary. Commercial petalite is natural (not synthesized,
which would be prohibitively expensive). It is mined in Zimbabwe (Bikita
deposit), Namibia and probably other places. It used to be considered a rare
mineral but is now known to occur in significant deposits in many corners of
the world. Vast areas of rare-metal granite (which are likely to contain
lithium aluminosilicates) are little explored in Asia. We are likely to see
continuing falling prices for these minerals and ever-increasing purity. We
geologists are just too damn successful.
When I first started potting about nine years ago, I experimented with
petalite and got some interesting results. For example without coloring
oxides, I got a pale rose pink glaze (though not with lithium carb) and red
to maroon with cobalt! I even won a prize from my local pottery club for a
cobalt maroon pot. Anyone else had any experience with cobalt red?
Petalite gives different effects than lithium carb (like the rose pink) due
probably to trace element contents of natural petalite, which for some will
be a good reason to use the natural material. I would predict that
synthesized petalite (if its ever used) would be too pure like lithium carb.
One interesting fact about petalite, is that it gives off a wonderful blue
phosphorescent light when gently heated. So if you spot a ghostly blue light
emanating from a dark kiln, you're not dreaming!
Michael Banks,
Nelson,
New Zealand
> ----------------------------Original message----------------------------
(Snip)> Moren'likely what is sold commercially as petalite is synthesized
from
> component oxides or from LiOH, Al(OH)3 and silica.
> (chop)
> Mary
>
> Mary Simmons
> Dept of Earth and Planetary Sciences
> University of New Mexico
> (505)277-9259
> piedra@unm.edu
>
Craig Martell on fri 5 nov 99
>Mary explained:
>Petalite is a feldspathoid (as is nepheline) Feldspathoids are similar to
>feldspars--these minerals have too little silica to be feldspars.
Hello Mary:
So now I'm confused. I'm under the impression that petalite is a very
silica rich mineral. I compared petalite to albite, anorthite,
plagiolcase, blah blah and my references say that it has more silica than
any of them. I looked at the seger flux unity formulas for all the spars
and petalite has 8 moles of silica to one mole of flux. The closest
feldspar to that is Custer, which has 7 moles of silica. What am I
missing? I looked at all the stuff I have about petalite and as far as I
can tell it's a naturally occuring substance that isn't altered or
processed with additions of silica. What gives? :>)
later, Craig Martell in Oregon
ACTSNYC@CS.COM on sat 16 dec 00
>
> -----Original Message-----
> From: Khaimraj Seepersad
> To: CLAYART@LSV.CERAMICS.ORG
> Date: 14 December 2000 13:02
> Subject: Re: lithium in glazes
>
> >Hello to All ,
>
> >Barbara ,
> >
> >I stay clear of Lithium anything , because of what I read in the
> >Pharmacopoeia .
> >[ Always read the Martin Dale for Oxide effects e.g Ca0 , Sr0 ]
> >
> >Replaces - sodium in the body's functions , when you notice
> >the symptoms of poisoning , it is usually too late . Therapy is
> >with potassium oxide .
> >Lithium oxide is easily leached out of glass with hot water ,
> >and is available as a trace component in foods and liquids.
> >[ I believe it can be toxic at the mg stage ]
> >
> >The healthy body handles 1 gram easily on a daily basis .
> >[ What is a healthy body ? ] . People on lithium treatment are
> >always at a risk .
> >
> >That said , I am sure testing glazes at Alfred's would save you
> >much grief.
> >
> >Why not master a good Low Borate Multimetal Glaze , high in
> >Silica , for better , safer results , you could work with 3124 or
> >3134 ?
> >Khaimraj
> >
> >-----Original Message-----
> >From: Paul Kirwin
> >To: CLAYART@LSV.CERAMICS.ORG
> >Date: 14 December 2000 4:50
> >Subject: lithium in glazes
> >
> >Does anyone know if a low fire glaze (Cone 06-03) that is 10% lithium
> >carbonate would be food safe? I have gotten conflicting advise, and would
> >love to get some more. I know that I will porbably need to get it tested
> at a lab, but if I can save the expense if it definitely is not food safe,
> then I won't even bother.
> >thanks. Barbara in Connecticut. Email address
> >Paul.Kirwin@worldnet.att.net
> >
The original question was about a low fire glaze (Cone 06-03) that contained
10% lithium carbonate. And of course we all know now that there is no way to
answer this question without a great deal more information about the rest of
the glaze formula. Even then, testing is the only way to know for sure.
But I also see why Khaimraj Seepersad, after reading the Pharmacopoeia, would
choose not to use it at all. Lithium in excess causes serious neurological
damage. It is also associated with a skin problem called lithium dermatitis,
it aggravates psoriasis and goiter in some patients, causes kidney
dysfunction in others, and there is strong evidence it can cause a type of
birth defect in pregnant women.
Khaimraj also noted that lithium is used in rather small doses. The pills
come in sizes from 150 mg to 600 mg, but since each person absorbs lithium
differently, patients must have blood tests to assure that the levels are in
the right range for each individual.
The therapeutic range for lithium in the blood for various individuals may
range from 0.5 to 1.25 milliquivalents/liter (meq/L). Unfortunately,
toxicity to the nervous system may occur in various individuals at levels
between 0.75 and 1.7 meq/L. Thus you can see that the that the therapeutic
and the toxic blood lithium levels overlap. This is further complicated by
the fact that the dose at which patients sustain nervous system damage also
varies because they are more susceptible to it during the manic phase of
their illness. These adverse effects can include sedation, mental confusion,
tremors, irregular heart beat, and seizures. Without a reduction in lithium
immediately, this can proceed to coma and death.
The lithium blood levels of each patient must be carefully monitored and
their intake carefully controlled. These people clearly are at great risk
from any unplanned additional lithium from their environment such as from
ceramics. There are literally millions of people taking this drug, and it is
likely that most of us have customers who are on lithium therapy.
So although lithium is far less toxic than lead, cobalt, and other glaze
metals, I would concur with Khaimraj and not use lithium glazes on food
surfaces at all.
Monona Rossol
ACTS
181 Thompson St., #23
NYC NY 10012-2586 212/777-0062
ACTSNYC@cs.com
Snail Scott on sun 17 dec 00
At 06:08 PM 12/17/00 -0500, you wrote:
>Hello all,
>
>do not confuse lead with lithium.
>In case you do not know, which I doubt very much,
>it is an entirely different chemical, at least in my book.
>Edouard Bastarache
Probably no one is too confused about the difference,
but just in case:
There is a a compound called litharge, which is lead monoxide.
One may see it mentioned occasionally, in old glaze recipes.
It has nothing at all to do with lithium.
Both words are derived from the Greek word lithos,
neaning 'rock'.
That's all.
-Snail
ACTSNYC@CS.COM on sun 17 dec 00
> From ClayArt___________
> Here's
> Edouard BastaracheM.D. (Occupational & Environmental Medicine)
> =20
> Hello all,
> =20
> a friend and pharmacist recently did a search for me
> on the subject of lithium intoxication and the use of lithium carbonate
> fluxed glazes, and there is no such thing as a lithium intoxication case
> from using this type of wares.
> I just finished doing a search in different databases we use in
> occupational medicine and there is no such thing as a case of
> lithium intoxication among workers and/or potters using lithium carbonate=
...=20
<
I wouldn't expect that you would, and I'm not impressed by the argument. No=
t=20
being in the literature doesn't mean a thing. For 20 years I was told that=
=20
lead frits were nonsoluble and nontoxic and there were tons of items in the=20
literature to support this position. But it clearly was not true. The=20
ceramic companies said over and over that there was nothing in the literatur=
e=20
to support that their lead frit glazes had ever caused any problem. =20
And they were right because no one looked for the problem. Now there are=20
studies, incidents, and lawsuits showing that the frits are bioavailable. =20
Even the toxicologist that approves labeling for the AP, CP and HL label=20
seals has accepted this fact now--even thought he mislabeled ceramic=20
materials for 20 years based on this misconception.
The literature will only include an incident about lithium from ceramics whe=
n=20
some doctor is alert and open enough to figure out that a patient having=20
trouble getting their lithium dose stable could be getting additional=20
exposure from ceramics. And that's the kind of doctor we all want for our=20
own--not one who closes off an avenue of investigation without question=20
because there is nothing in the literature.
As long as the numbers support the fact that this kind of incident is=20
possible, we should act. To do otherwise is to wait for the supporting body=
=20
count. Prevention is the way to go.
Monona Rossol
ACTS
181 Thompson St., #23
NYC NY 10012-2586 212/777-0062
ACTSNYC@cs.com
answering:
Edouard BastaracheM.D. (Occupational & Environmental Medicine)
> Irr=E9ductible Qu=E9becois
=20
Edouard Bastarache on sun 17 dec 00
Hello all,
do not confuse lead with lithium.
In case you do not know, which I doubt very much,
it is an entirely different chemical, at least in my book.
Secondly, hypotheses are there to be proved,
so, where are the facts and data????
That is your problem not mine; it is your
hypothesis, prove it.
Later,
Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----- Message d'origine -----
De :
=C0 :
Envoy=E9 : 17 d=E9cembre, 2000 13:40
Objet : Re: Lithium glazes
> From ClayArt___________
> Here's
> Edouard BastaracheM.D. (Occupational & Environmental Medicine)
>
> Hello all,
>
> a friend and pharmacist recently did a search for me
> on the subject of lithium intoxication and the use of lithium carbonat=
e
> fluxed glazes, and there is no such thing as a lithium intoxication ca=
se
> from using this type of wares.
> I just finished doing a search in different databases we use in
> occupational medicine and there is no such thing as a case of
> lithium intoxication among workers and/or potters using lithium
carbonate.
<
I wouldn't expect that you would, and I'm not impressed by the argument.
Not
being in the literature doesn't mean a thing. For 20 years I was told t=
hat
lead frits were nonsoluble and nontoxic and there were tons of items in t=
he
literature to support this position. But it clearly was not true. The
ceramic companies said over and over that there was nothing in the
literature
to support that their lead frit glazes had ever caused any problem.
And they were right because no one looked for the problem. Now there are
studies, incidents, and lawsuits showing that the frits are bioavailable.
Even the toxicologist that approves labeling for the AP, CP and HL labe=
l
seals has accepted this fact now--even thought he mislabeled ceramic
materials for 20 years based on this misconception.
The literature will only include an incident about lithium from ceramics
when
some doctor is alert and open enough to figure out that a patient having
trouble getting their lithium dose stable could be getting additional
exposure from ceramics. And that's the kind of doctor we all want for ou=
r
own--not one who closes off an avenue of investigation without question
because there is nothing in the literature.
As long as the numbers support the fact that this kind of incident is
possible, we should act. To do otherwise is to wait for the supporting b=
ody
count. Prevention is the way to go.
Monona Rossol
ACTS
181 Thompson St., #23
NYC NY 10012-2586 212/777-0062
ACTSNYC@cs.com
answering:
Edouard BastaracheM.D. (Occupational & Environmental Medicine)
> Irr=E9ductible Qu=E9becois
_________________________________________________________________________=
___
__
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
ACTSNYC@CS.COM on wed 20 dec 00
> ---------- Forwarded message ----------
> Date: Wed, 20 Dec 2000 09:12:22 -0800
> From: Hank Knaepple
> Reply-To: Ceramic Arts Discussion List
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: lithium carbonate
>
> I have read several postings concerning the possible
> toxicity of lithium carbonate being released from
> glazes.
> I have taken lithium carbonate as a treatment for
> bi-polar disorder for a number of years, in quantities
> that would far exceed any anmounts that may leach out
> of a glaze with only one side effect, you get happy!
> I was taking about 900 milligrams a day and could
> barely get a blood level. <
According to the Physicians Desk Reference, many people can maintain their
blood level with around 300 mg/day. And there are even warnings that this
dose can be very toxic to some people.
> Until 1974 lithium carbonate was an ingredient in the
> soft drink seven up. The 7-up folks dropped the
> ingredient due to its negative association with
> "mental illness". <
You defend giving lithium to people unknowingly in their 7-up? That's really
public-spirited of you.
And up to the middle 1980s they added cobalt to beer to stabilize the
foam--until it was proved to cause serious heart damage and the lawsuits
started to fly. Food companies did a lot of dumb things years ago. Lithium
in 7-up apparently is another.
Monona Rossol
ACTS
181 Thompson St., #23
NYC NY 10012-2586 212/777-0062
ACTSNYC@cs.com
answering:
> Zatheros
> zatheros7@yahoo.com
| |
|
