Sciencemadness Discussion Board - Pottery Chemicals

Pottery Chemicals

MagicJigPipe - 9-12-2007 at 17:41

Today I purchased various pottery chemicals from an extremely elderly lady who was selling all of her pottery stuff. I was wondering if I got a good deal (not like it matters, I only spent $4) and what are the most common uses for these in the lab. I already know about Mn02 but not everything about it. Anyway, here goes.

Lithium Carbonate - 1/4lb (isn't this a mood stabilizer drug?)
Barium Carbonate - 1/2lb
Chromium Oxide - 1/4lb (I think (III) but mine is green and isn't (III) black?)
Manganese Dioxide - 1/2lb
Cobalt Oxide - 3oz (this is what she called it. It's black.)

Grand total: $4USD.

And for those of you who aren't in the US I just say 1/4lb = ~250g and 4oz = 1/4lb. That's close enough for some purposes.

**Edit**
I was thinking o quarter kg... thanks for the corretion... and the chemicals were sold to me in those measurements which is why I used them. It's hard to not use the system since I spent ~20 years of my life learning and using them.

[Edited on 9-12-2007 by MagicJigPipe]

Xenoid - 9-12-2007 at 18:05

Err... 1/4lb is closer to 125g it's 2.2lb to the Kg

God - when will you Americans stop using all those loopy, old fashioned measurements!

Yes, you got a good deal! The Li, Ba, and Co are normally the most expensive!

[Edited on 9-12-2007 by Xenoid]

not_important - 9-12-2007 at 18:25

Cr2O3 - green, dark green trending towards black if prepared in certain ways. Fairly inert stuff.

Li2CO3 may have a percent or two of Na, K, and/or Mg in it. Does no harm in pottery applications.

The cobalt is a mixed oxide, some Co(II) and some Co(III); if you dissolve a bit in string hydrochloric acid some chlorine will be generated. Most simple Co(III) salts are not stable in aqueous solution, gently boiling the chloride solution will result in just CoCl2.

Good prices for getting some fooling around supplies, starting point for other Li, Ba, Co salts; Mn ones too plus its use as an oxidiser.

MagicJigPipe - 9-12-2007 at 19:24

Yes, I figured I could get CoCl2 from the oxide. I just didn't know of the purity of "pottery grade". And I was thinking of 1/4 kg when I wrote the 250g thing. My mistake.

The following is way off topic.... sorry.

Also, I was watching a show on MTV about this girl from the US who moved to New Zealand and a lot of the people at her school were extremely rude and ignorant. They made fun of her for being from the US and were just plain mean. Especially one of her teachers.

What's up with that? Surely not everyone in New Zealand is like that. We NEVER made fun of foreigners at my school. We treated them like everyone else most of the time. Unless they were dicks. Actually, one of my best friends moved here from England 4 years ago. I never treated him like he was inferior because he was from the UK and we make fun of eachother's "cultural differences" only in jest.

Oh, another HILARIOUS thing was when the teacher asked the students what they thought of when they they think of the US they said, "Laguna beach" and "California beaches". Oh my god! My country is being represented by THOSE idiots!

[Edited on 10-12-2007 by MagicJigPipe]

Xenoid - 9-12-2007 at 19:56

Quote:

Originally posted by Xenoid
God - when will you Americans stop using all those loopy, old fashioned measurements!

[Edited on 9-12-2007 by Xenoid]

Yeah! Sorry, but I just couldn't resist it

It really annoys me actually. When I go into a hardware shop here in NZ looking for metric nuts, screws, etc. they have very little range, it's all 3/8" this and 5/32" that!
When I complain, they say it's because the American market is so big, they can get the stuff with loopy measurements, cheaper than metric - go figure!

I personally find all Americans I have met to be extremely nice and pleasant, unfortunately because of your politician's antics and war mongering over the last few years, I think your country has gone downhill in the world's esteem.

Actually, I have a running joke with my son. Whenever we see anything break or crash it's out with "Made in the USA"

MagicJigPipe - 9-12-2007 at 20:12

Really? We do the same thing here except it's "made in New Zealand". Just kidding. Really it's China or Taiwan.

You know what? The old lady was so senile and was taking so long that in my haste to get out of there I forgot to buy her "vanadium yellow" (V2O5). Hopefully she hasn't sold it yet. I'll probably be able to get a pound of it for $5.

Xenoid - 9-12-2007 at 20:27

1.1 Kg for $5, now that's good value....

The local pottery place here sells 500g for about NZ$50...

Edit: Changed price, looked it up wrongly in catalogue! Still expensive though!

[Edited on 9-12-2007 by Xenoid]

woelen - 10-12-2007 at 05:14

The black Co3O4 is very inert. I also have that material and I hardly could dissolve this. I tried concentrated hot HCl, concentrated hot H2SO4 and the same, with reductors like Na2SO3 added. No success. Only after an hour of refluxing or so in very hot H2SO4 (30%) with some Na2SO3 added, I obtained a very faint pink color, almost invisible. I turned away from using that oxide, in the meantime I also found cobaltous sulfate and cobaltous chloride.

12AX7 - 10-12-2007 at 10:04

The chrome oxide is definetly extremely green, and definetly on the inert side. You're better off fusing it with an oxidizer (see chromate thread) to get it into solution, then if you want Cr(III) again, reduce it to a salt or reactive Cr(OH)3.

Tim

len1 - 10-12-2007 at 17:59

Quote:

Originally posted by MagicJigPipe

The following is way off topic.... sorry.

Also, I was watching a show on MTV about this girl from the US who moved to New Zealand and a lot of the people at her school were extremely rude and ignorant. They made fun of her for being from the US and were just plain mean. Especially one of her teachers.

What's up with that? Surely not everyone in New Zealand is like that. We NEVER made fun of foreigners at my school. We treated them like everyone else most of the time. Unless they were dicks. Actually, one of my best friends moved here from England 4 years ago. I never treated him like he was inferior because he was from the UK and we make fun of eachother's "cultural differences" only in jest.

You never made fun of foreigners at your school, we never had any foreigners at our school to make fun of. The most exotic was one Australian to a school of 1000+. And yes he was taken the micky out of, but not seriously. That was 20 yrs ago, maybe there are more foreigners in NZ schools these days. Its a great place to live, a darn awful place if you want to do science in. We lived in the second biggest city and there was one place were you could buy analytical chemicals over the counter (in NZ even HCl was not stocked in hardware) and two were you could purchase transistors, all at exhorbitant prices (NZ was all about middlemen). I remember walking two hours there and back to the industrial zone (there was no public transport) to be told that I need a note with my parents permission to buy a chemical. So it all had to be repeated the next day. At the electronics shop they refused to give me a price list, lest I should see their trade prices. Kids have to pay full price.

chloric1 - 10-12-2007 at 18:16

Quote:

Originally posted by Xenoid
Err... 1/4lb is closer to 125g it's 2.2lb to the Kg

God - when will you Americans stop using all those loopy, old fashioned measurements!

[Edited on 9-12-2007 by Xenoid]

When American business and government stops using them! I get so exhausted converting fahrenheit to celsius, square decimeters to square inches, grams to ounces etc etc. I am technically progessive enough to accept America going TOTALLY metric, unfortunately too many prom queens and football heads are NOT ready for this.

12AX7 - 10-12-2007 at 22:39

By admitting you cannot handle imperial measurements, you are conceding you have no capacity for fundamental arithmetic, approximating values and remembering simple numbers.

I pity you.

Tim, sometimes works in electronvolts. OMG, it's so non-SI!!!!!!1

Xenoid - 10-12-2007 at 23:38

Quote:

Originally posted by 12AX7
By admitting you cannot handle imperial measurements, you are conceding you have no capacity for fundamental arithmetic, approximating values and remembering simple numbers.

This is a rather silly statement, I'll leave it at that!

When US Mars missions, miss their mark, because some twat forgot to convert miles to Km or some such, don't you think it's a serious problem.

This thread is going to get canned fairly soon!...

MagicJigPipe - 11-12-2007 at 00:35

Quote:

This thread is going to get canned fairly soon!...

Why?

not_important - 11-12-2007 at 08:40

Quote:

Originally posted by MagicJigPipe
... I forgot to buy her "vanadium yellow" (V2O5). Hopefully she hasn't sold it yet. I'll probably be able to get a pound of it for $5.

Make sure that it is really V2O5 and not a vanadium based pigment. Example

http://store.ceramicstoreinc.com/vanadiumyellow.html

http://pangea-intl.com/glaze/ceramic-stain-PANGEA-INTERNATIO...

There's still vanadium in it, but not as much as if it were V2O5 and you'll have to work to extract the vanadium.

MagicJigPipe - 12-12-2007 at 11:24

Ooooh... Yeah, didn't think of that. I just remember seeing , on another site, what they said was V2O5. It didn't say "vanadium yellow". I suppose they are two different things.

12AX7 - 12-12-2007 at 15:48

Innit lead metavanadate?

Tim (I've never metavanadate I didn't like)

not_important - 12-12-2007 at 22:14

Quote:

Originally posted by 12AX7
Innit lead metavanadate?

No, lead is pretty much verboten in pottery these days. Tin or zirconium base is common. Zirc is used a lot, the mixed alkoxides are sprayed either mixing with water spray or into steam, the ZrO2 formed protects the colour formers from dissolution in glazes.

MagicJigPipe - 14-12-2007 at 20:37

Most sites list vanadium yellow as Sn and V. Which compounds of the two I don't know. But the only V compound I know of that is yellow is V2O5. Maybe it's a mixture of V2O5 and Sn.

Uranium

MadHatter - 14-12-2007 at 21:04

It was used in pottery glazes in the 70s because of the extremely black color it
produced. The EPA and the NRC would lose their collective minds if a pottery supplier
tried to sell it now. Still my pottery supplier is a good source of OTC chemicals.

not_important - 14-12-2007 at 23:39

Not just blacks, but more famously for light greens, yellows, and orange glazes, before and after WW-II.

http://people.umass.edu/emartz/martzpots/gallery/uranium.htm

http://www.orau.org/PTP/collection/consumer%20products/urani...

microcosmicus - 4-1-2008 at 00:21

Quote:

Originally posted by MagicJigPipe
Today I purchased various pottery chemicals from an extremely elderly lady who
was selling all of her pottery stuff. I was wondering if I got a good deal
(not like it matters, I only spent $4) and what are the most common uses for
these in the lab.
[Edited on 9-12-2007 by MagicJigPipe]

Having come back from a run to the friendly local pottery shop for some
of the same chemicals you bought (BaCO3 and MnO2), I can answer your
question. You were at the right place at the right time and got an
awesome deal!!!! While manganese dioxide and barium carbonate are
relatively cheap, the other three chemicals are not definitely not. In fact,
ordinarily your $4 would only buy you one of them in the quantities you
obtained so you got something like a "three for the price of one liquidation
sale" discount with two cheap chemicals thrown into the bargain.

Speaking of my trip, every time I go to the pottery store, I feel like the
proverbial kid in the candy shop and it is extremely difficult to restrain
myself from grabbing everything in sight

Nothing like walking down an
aisle of shelves packed with all sorts of goodies from the usual compounds
of silicon, aluminum and copper to the exotic, like praesodymium and
vanadium oxides, not to mention the refractories and knick-knacks like
nichrome wire and rod or drills for glass and ceramic. In addition, my
local pottery shop has a once-a-month event where there is some sort
of ceramic demonstration or workshop coupled with discounts on
refractories, books, and other items (but no discount on chemicals

）.

At one of these sales, I picked up an interesting book called "Ceramic
Science for the Potter" by W. G. Lawrence and R. R. West, which describes
the physics and chemistry of clay and glass and relates it to the practical
issues of making stuff out these materials. One of these years, I hope
to build some of the apparatus described therein, such as a thermal
gradient furnace or a differential thermocouple and carry out some of the
measurements described in the book for various ceramic compositions.
Also, reading their account of slip pouring and casting suggests some
interesting problems in mathematical physics involving Pfaffian systems
and fractional calculus which I will also have to look into. On a somewhat
different note, when I build up some skills in the arts of melting and
sintering and build myself some better equipment, it might be fun to try
making some ferrites, rare-earth magnets (got to something with that
praesodymium, you know), and other ceramic materials. Right now, I am
at the level of slip-casting mullite and alumina crucibles and am fiddling
around with carbon-clay mixtures.

As for use of common uses of the chemicals you purchased, I can think of
two uses for barium. Firstly, it is often used to precipitate sulphate and
other anions. For instance, the old book "Qualitative Analysis as a Laboratory
Basis for the Study of General Inorganic Chemistry" by W. C. Morgan, which
is freely availlable online, gives a neat little procedure for determining
which anions are present in an aqueous solution by adding Ba++ and Ag++ and
noticing what does or does not precipitate as one oxidizes, reduces,
acidifies, and basifies the mixture.

Secondly, a quite different use stems from the fact that, as its name
Barium has quite a high atomic weight (the heaviest stable alkaline earth)
and hence is good at blocking x-rays. If my memory serves me correctly,
radiologists often have their patients drink some barium salts to make their
internal organs stand out more prominently.

As for your lithium carbonate, the above mentioned book on ceramic
science talks about how lithium ceramics have abnormally small
coefficients of expansion and hence are extremely resistant to
thermal shock --- the ceramic version of invar, I suppose. That might
make them a useful material for making labware and apparatus. In fact,
some of them even have negative coefficients of thermal expansion!
So, if you are into doing your chemistry at extreme temperatures, you
might want to synthesize a batch of this stuff and play around with it.

[Edited on 4-1-2008 by microcosmicus]

[Edited on 4-1-2008 by microcosmicus]

microcosmicus - 4-1-2008 at 00:28

@not_important

Whilst I didn't see any lead on my shopping sprees at the pottery place,
I did see plenty of cadmium, which is just as nasty.

@MagicJigPipe (most recent post)

I would guess that the tin compound is SnO, which is used to make
glazes opaque.

[Edited on 4-1-2008 by microcosmicus]

woelen - 4-1-2008 at 11:24

The tin compound is not SnO, but SnO2. The latter is a very inert off-white powder, which is not easy at all to dissolve in any acid or base. It can be dissolved in molten alkalies. SnO, on the other hand, is a fairly reactive oxide with a dark color, which easily dissolves in concentrated HCl to make solutions of SnCl2.

MagicJigPipe - 4-1-2008 at 11:28

Update:

The cobalt oxide that I obtained dissolved in 35% HCl at room temperature in a couple of hours. I wonder why mine was so easy to dissolve and woelen had to use hot HCl and it still didn't dissolve fully. Interesting....

microcosmicus - 4-1-2008 at 12:18

@woelen I was quoting my ceramic supplier's catalog,
where they list the compound as SnO. Of course, they
might be mistaken or perhaps both oxides are used
because they will turn into the same product upon
firing anyway.

@MagicJigPipe Particle size?

woelen - 4-1-2008 at 12:40

Does the catalog show pictures? If the material is white, then it is SnO2, if it is almost black, then it is SnO.

I know this, because I have had a little dispute with an eBay seller, who sells all kinds of materials. One of the chems he sells is tin oxide, 88.1% tin.

http://cgi.ebay.co.uk/TIN-OXIDE-Sn-88-1-500g_W0QQitemZ320082...

This corresponds to SnO, which I really wanted because of its reactiveness and allowing one to make tin(II) salts. I ordered the material, and I received a bag with 500 grams of white powder, which is extremely inert. The MSDS for SnO tells its dark brown or dark blue. The MSDS for SnO2 tells it is white.

I complained about this. The seller told me I am the first one, who complained, but his other customers usually are not home chemists but ceramists

, and the latter kind of people is less picky

. Things were arranged in a satisfactory manner (the seller has offered me other materials at reduced price, such that I had the SnO2 for free) , but he did not want to change the stated percentage of Sn in the oxide.

microcosmicus - 4-1-2008 at 13:02

Unfortunately, the catalog is pretty much text-only

Since the material is rather expensive ($41.60 per
pound, i.e. $91.63 for a kilogram) I doubt I will buy
some in the near future. However, I did notice that
the catalog lists Chemical Abstracts Number
18282-10-5 so you might be able to look that up
to see what oxidation state of tin it refers to.

-jeffB - 4-1-2008 at 21:25

Quote:

Originally posted by microcosmicus
Unfortunately, the catalog is pretty much text-only

Google makes it SnO2. I just stopped into my local (central North Carolina, USA) pottery-supply store, and they have it in half-pound bags for $30/lb, but it's sounding like it's not an especially good buy. They also had V2O5 for $28/lb, along with the of the usual suspects at what appear to be reasonable prices. Now, if only they carried aluminum dust...

12AX7 - 4-1-2008 at 23:52

Quote:

Originally posted by -jeffB
Now, if only they carried aluminum dust...

They do, and it's even already combined with oxygen, ready for pottery purposes.

Tim

microcosmicus - 5-1-2008 at 00:37

@jeffB
For comparison, tin metal retails at $16/lb, so you can
save a lot by rolling your own Sn compounds.

@12AX7 My pottery shop also carries cryolite, grinding
balls, and sieves so you could reduce your Al2O3 and
grind it to dust if you felt so inclined

[Edited on 5-1-2008 by microcosmicus]

-jeffB - 5-1-2008 at 10:44

Quote:

Originally posted by 12AX7

Quote:

Originally posted by -jeffB
Now, if only they carried aluminum dust...

They do, and it's even already combined with oxygen, ready for pottery purposes.

Tim

If only there were some way that I could reduce it, perhaps by igniting it with another metal... no, wait.

MagicJigPipe - 24-5-2008 at 18:54

I still can't determine whether I have cobalt (II) or (III) oxide. Perhaps it's a mixture of both?

It dissolves in concentrated HCl solution forming a dark blue solution. It very slowly dissolves in water forming a very lightly blue solution. I might go so far as to say that it's "sparingly soluble" in water.

It's supposedly "cobalt blue" for use in pottery. Sources claim that this is CoO but, if so, shouldn't it form a pink solution with HCl because of it forming hydrated CoCl2?

This is really bugging me. What other experiments could I perform to determine what this crap is?

Also, Wikipedia claims that CoO can be had from Co2O3 by heating it above ~975*C. That makes sense but that is VERY hot and I don't think I have a suitable container that can reach temperatures that high at the moment.

[Edited on 5-24-2008 by MagicJigPipe]

not_important - 24-5-2008 at 19:50

Try diluting the concentrated solution, the pink hydrated Co(II) dehydrates in strong acid and will complex with Cl ion in high concentration.

From my experience it is often a mixed oxide, mostly Co(II) but also a little Co(III). Dissolving it in hot hydrochloric acid releases some chlorine, but less than Co2O3 or even Co3O4 should.