Sciencemadness Discussion Board - PbO

PbO

axehandle - 19-6-2004 at 06:32

"Lead monoxide, or litharge (PbO), a yellow, crystalline powder formed by heating lead in air, <snip>".

No temperature given, no other conditions given. Should it be powdered prior to heating? Would melting it and roast the mass at 1000 degrees C do the trick? Would I have to perform a specific series of dance steps?

This is what I've found. After googling for 30 minutes, only finding references to a mythical substance called litharge, which I've deduced is an archaic name for lead monoxide. Nothing about how it's manufactured.

I need a largeish quantity of lead monoxide as a reagent. It's very illegal here for environmental concerns, so I can't buy it...

So.... Has anyone solved this little problem already and would care to illuminate me..?

Edit: I have a very sophisticated electrochemical process to carry out, and the only thing lacking is the fscking PbO

........

[Edited on 2004-6-19 by axehandle]

Reverend Necroticus Rex - 19-6-2004 at 06:38

I have had SOME success in producing small quantities by heating very thin flakes of lead in air with a blowtorch, but it's very innefficient as you have to heat a pretty small amout bit by bit in thin flakes so it burns rather than melts.

On the other hand, I have got a yellow mass from heating the brown lead peroxide found in car batteries that I THINK is litharge, not 100% sure though.

[Edited on 19-6-2004 by Reverend Necroticus Rex]

axehandle - 19-6-2004 at 06:43

No, no, no!

That would take the entire weekend and probably just end me up with lead poisoning....

BromicAcid - 19-6-2004 at 07:15

Decomposing lead nitrate should yeild lead monoxide.

This PDF has a short interesting section on litharge.

Sounds like heating lead in air is just a surface reaction and atomization of the molten lead is necessary for good yields.

Quote:

On exposure of lead to moist air at ordinary temperatures
the suboxide (Pb2O) is formed ; when melted in contact with
air it is converted to monoxide (PbO), the yellow amorphous
massicot being first formed at a low red heat, while, at a
higher temperature, a bright red heat, this undergoes a
molecular change with conversion to crystalline litharge.
Steady heating at a temperature of from 300 to 500° C. con-
verts litharge (PbO) into red lead (Pb8O4), but this is dis-
sociated at 550° C.

From http://www.dli.gov.in/data0/000/229/TXT/00000027.txt

axehandle - 19-6-2004 at 07:26

Having no access to lead nitrate, this would be difficult.

The PDF is interesting, but "... Today the molten lead is atomized by whirling propellers and allowed to oxidize through contact with the air..." is a bit beyond my abilities, at least without building... Hmm. Interesting project, but...

What I'd really prefer would be a way to convert the hydroxide to the monoxide, chemically. I may be hunting a ghost here though (does not exist).

Edit1: I have an idea.... lead filings in a pure oxygen atmosphere should burn quite vigorously, I think..... hmm.

Edit2: Another one would be bubbling air through molten lead..... I just hope it wouldn't spatter too much... A copper pipe could be bent in an "L" shape, the end of the shorter side crimped and small holes drill along it... this part would then be submerged in molten lead and air be pumped into the upper end of the pipe... probably lots of pressure would be needed though if the holes were clogged...

[Edited on 2004-6-19 by axehandle]

[Edited on 2004-6-19 by axehandle]

I am a fish - 19-6-2004 at 08:07

Step 1: Convert the lead into lead acetate using Chemoleo's method.

(Prepare a saturated solution of copper acetate, and add an excess of lead to it. The lead will displace the copper ions, forming lead acetate. The metallic copper produced on the surface of the lead will periodically flake off, and so even with thick pieces of lead, the reaction will go to completion.)

Step 2: Add sodium carbonate solution. Filter out the precipitated lead carbonate.

Step 3: Thermally decompose the lead carbonate, to yield PbO. Do this in an oxygen-free atmosphere to prevent oxidation into Pb3O4.

axehandle - 19-6-2004 at 08:09

Quote:

Step 1: Convert the lead into lead acetate using Chemoleo's method.

(Prepare a saturated solution of copper acetate, and add an excess of lead to it. The lead will displace the copper ions, forming lead acetate. The metallic copper produced on the surface of the lead will periodically flake off, and so even with thick pieces of lead, the reaction will go to completion.)

Step 2: Add sodium carbonate solution. Filter out the precipitated lead carbonate.

Step 3: Thermally decompose the lead carbonate, to yield PbO. Do this in an oxygen-free atmosphere to prevent oxidation into Pb3O4.

This sounds workable. Thanks.

BromicAcid - 19-6-2004 at 17:53

Quote:

I have an idea.... lead filings in a pure oxygen atmosphere should burn quite vigorously, I think..... hmm.

Burning in a pure oxygen atmosphere usually brings out the higher oxidation state of an element. Therefore I would think you would get a high percentage of PbO2 as well.

Esplosivo - 20-6-2004 at 01:19

Lead (II) oxide turns to trilead tetraoxide at around 450 deg celcius. Lead (II) carbonate decomposes at 400 deg celcius (at its melting point). Is the inert atmosphere really required - its a drawback since it complicates apparatus etc... . Off topic but what is the max temperature that can be reached by a common bunsen burner? Thanks.

axehandle - 20-6-2004 at 03:22

Depends on the fuel. With propane, the maximum temperature in about 1300 degrees C.

PbO from Pb(OH)2 + H2O2

chemoleo - 23-6-2004 at 18:56

I don't know if you remember, but in the PbO2 thread I subjected Pb(OH)2 to both NaOCl and H2O2.
With the former I clearly got PbO2.
With the latter, I got a bright yellow precipitate, and which is likely to be PbO (what else could it possibly be?).

Maybe try some kind of titratration to find out whehter this is true. If so, it is probably more economical to simply get PbO from Pb(OH)2 with H2O2 rather than decomposition of PbCO3 at high temperatures.

Easy Lead oxide

al93535 - 24-6-2004 at 00:37

I have made lead oxide before a few times with great results. Although it was a by product of what I was making. Heat KNO3 and lead shavings until the KNO3 melts. Keep it molten for about an hour. Works great. I used a old pot and a blowtorch. Of course to make it easier you could fill a steel pipe with it and throw it onto a fire. After it cools, chip out the yellow solid and dissolve it in water. The lead monoxide will not dissolve and thus can be filtered out. I was making Potassium Nitrite which is what dissolves.

Esplosivo - 24-6-2004 at 08:37

I proceeded and used chemoleo's method for the production of PbO. I first added NaOH to a solution of lead acetate until I noticed the ppt starting to 'dissolve' (it was forming soluble sodium plumbate (II)). Then I added an excess of H2O2. It seemed that any amount I was mixing just kept on fizzing. Well at a certain point I stopped adding H2O2. A yellowish-brown ppt was formed. I tried filtering this using a normal coffee-filter, but the ppt came right through the filter! How can this be prevented?

I did a sort of qualitative test. I added 69% nitric acid and the ppt dissolved indicating that the ppt is not PbO2 (which as far as I remeber does not react with nitric acid), and therefore indicating the presence of PbO - although the colour of the ppt was enough as an indication.

Edit 1: I was thinking. What if I first add a largish volume of water to the mixture, then leave the ppt settle at the bottom, decant the top layer and then evaporate off the water by heating? The addition and decanting of the water might be done several times to improve purity. All I must do is take care the PbO is not completely dry so that it would not form higher oxides.

[Edited on 24-6-2004 by Esplosivo]

[Edited on 24-6-2004 by Esplosivo]

chemoleo - 24-6-2004 at 09:33

Well, when I tried it, I used analytical reagents (all of them), and an excess of 30% H2O2.
THe yellow colour change from the clean white Pb(OH)2 occurred immediately, as far as I remember.
On the note of it fizzing - be warned that in the PbO MSDS it states incompatibility with H2O2. I found out why - once I heated it. The mixture heats up to boiling in seconds, and vast quantities of gas are evolved. Any tight necked container might shatter, I was lucky to use a 500 ml beaker. But it's no problem if it isn't heated.

I didnt use filtration, I used centrifugation. Letting it settle is an alternative of course. The yellow PbO has been on air since, and no noticeable colour change occurred - so maybe the formation of higher oxides isn't an issue at RT.

Esplosivo - 24-6-2004 at 10:39

Quote:

THe yellow colour change from the clean white Pb(OH)2 occurred immediately, as far as I remember.

Maybe I didn't express myself well. The colour changed occured immediately on addition of H2O2. Its only that effervesnce continues at any amount of H2O2 added. I think that the PbO formed is acting as a catalyst to decompose H2O2.

On a side note, I used a 250ml beaker - wide enough for small quantities. Anyone knows if this oxidation can be carried out using the carbonate instead of the hydroxide?

Curiosity won and I must ask

For what are you going to use this PbO axe? (perchlorate cell?!)

[Edited on 24-6-2004 by Esplosivo]

Chemtastic - 24-6-2004 at 10:58

I don't suppose there's a thermite-esque reaction, where the element and oxide of one yields the element and oxide of another?

Esplosivo - 24-6-2004 at 11:16

Quote:

Originally posted by axehandle
Edit: I have a very sophisticated electrochemical process to carry out, and the only thing lacking is the fscking PbO

........

You see there is an electrochemical process involved

[Edited on 24-6-2004 by Esplosivo]

axehandle - 24-6-2004 at 12:24

Quote:

[Curiosity won and I must ask For what are you going to use this PbO axe? (perchlorate cell?!)

I not going to use it for anything, now that I've found a cheaper source of copper carbonate. But if I had found an easy + cheap method of making PbO (I was trying to find a method using only what I had at home at the time) I would have dissolved it in acetic acid to form lead acetate. Lead acetate is one of the usable lead salts in the ceramic substrate PbO2 anode construction process that's outlined in the patent I mentioned in the PbO2 thread...

Now, that's not all the reasons I want(ed) PbO... the other is just the fact that possession of it is illegal here! I like to do (harmless) things that are (stupidly) illegal. It makes me feel good.

PbCl making with no success

kazaa81 - 16-8-2004 at 14:39

Hallo to all,
This is procedure for making PbO(2???),
finded in this forum...
----------------------------------------------------
I would say first you have to make you lead into a soluble salt.
Dissolve in HCl, or you can use acetic acid vapors but
the process is slow.
Then take your lead salt and add the hydroxide of
your choosing, like NaOH to precipitate the lead hydroxide.
Take the lead hydroxide and add a hypochlorite
like Ca(OCl)2 or possibly NaOCl and your lead dioxide
will precipitate out.
That is the prep from my chemistry book.
I'm sure you could probably get away with using H2O2
in that last step in place of your hypochlorite though.
---------------------------------------------------
Well, for me seem ok, but, I've tried to
dissolve Pb in HCl, with no success, why?
Later, I've tried with Pb finely divided, but with no success again.....
I am involving a possible procedure (dissolving Pb in HCl) or no?
Any information about simple Pb salts is welcomed!

Thanx for help.

Re: PbO dissolution in HCl

JohnWW - 16-8-2004 at 16:50

I posted a few days ago on this subject on another topic. I noted that the electrochemical potential for Pb to go into solution as Pb++ at the expense of H2 is only -0.13v, and other some sources put Pb below H in the electrochemical series. Also, the PbCl2 that forms is only very slightly soluble, except in boiling water. This means that the dissolution of Pb or PbO in HCl is initially very slow, and is soon arrested due to the PbCl2 layer.

John W.

chemoleo - 16-8-2004 at 17:34

Oh comon, Kazaa, all the questions you have are covered! See the PbO2 thread for details.
And yes, with hypochlorite, you get PbO2.

As to the dissolution of lead salts - again, its been covered in depth!
Either it's
Pb + HCl + H2O2 (slow)
Pb + HAc + O2 (air bubbled through for weeks --> slow)
Pb + HNO3
Pb + Cu (Ac)2

All of these work, to a lesser or greater extent. The choice is yours.

Just read up, and then you won't need to write questions that have been covered many times before !

BromicAcid - 16-8-2004 at 18:22

A chunk of lead boiled in HCl for about an hour will yield some crystals in the beaker when it cools back down, dissolving Pb in HCl is a pain in the butt, I just use my good nitric although that is a waste, I suggest Chemoleo's method any day.

halogen - 17-8-2004 at 07:05

litharge... hmm, interesting.
If im not mistaken, can't it be mined?

Theoretic - 20-10-2004 at 01:20

Yes, but we want to make it chemically.

Maybe PbAc2 can be straight roasted on air to give PbO? Reduction of Pb++ with the decomposition products of CH3COO- (CO, H2, CH4, C are the main ones) can be prevented by stirring the powder (careful: don't agitate too hard to create dust) on air while heating so oxidation is the main mode of decomposition.
Or heat at low temperature to make PbO and acetic anhydride.

Esplosivo - 20-10-2004 at 02:21

The temp. must be controlled since PbO forms Pb3O4 when heated to above >200deg celcius if I remeber correctly. Anyway, I find the rxn of Pb ethanoate and H2O2 to give a very good (and pure) source of PbO. The main problem is the seperation of the product - centrifugation is the way to go I suppose.

10fingers - 30-10-2004 at 17:05

As someone already mentioned, the method of adding sodium or potassium nitrate to molten lead works quite well. You get lead monoxide and a nitrite, which can be easily removed with water. This is a very common method of obtaining nitrites. The monoxide which floats on top of the lead can be easily removed after it cools.
You can also use a small air pump to pump air into the molten lead but it takes longer.
Lead melts so easily that you can just put it in a pan and do it on the stove.

Smoer - 4-2-2005 at 13:09

I just added some Pb to 30% H2O2 and it reacted violently,even boiling.A white salt/oxide was produced.

Is this PbO??

I thought this would happen:
Pb + H2O2 ==> PbO + H2O

cheerz

[Edited on 4-2-2005 by Smoer]

tom haggen - 5-2-2005 at 12:50

Just exactly at what temperature does lead nitrate decompose?

Mumbles - 5-2-2005 at 15:41

470 C

Theoretic - 6-2-2005 at 09:50

I've heard stories that lead nitrate decomposition is NOT GOOD for the glass vessel (maybe because the lead oxide formed reacts with the glass, this is probable as lead oxide is a major comomnent of crystal glass and so must hyave high solubility in glass), this apparently can be alleviated by mixing the nitrate with sand, which presumably forms lead silicate.

Simpler method

chloric1 - 6-2-2005 at 14:10

acetic acid with 30% H2O2 does dissolve metalic lead to the acetate. Turning this into the hydroxide with lye to form Pb(OH)2. This can be warmed on a charcoal fire and the CO fumes should protect it somewhat.

Alternatively, you can use lead rods hooked up to a power supply and electrolyze a sodium chlorate solution with a little lye and also get lead hydroxide

BromicAcid - 6-2-2005 at 14:18

Quote:

I've heard stories that lead nitrate decomposition is NOT GOOD for the glass vessel

In the Preparative inorganic chemistry series they use the thermal decomposition of lead nitrate to yield NO2, the recomendation in the method is that you take aluminum foil and place it into the flask to line the bottom, the lead monoxide thus formed doesn't penetrate it I guess and it prevents the attack on the glassware. Afterward it is pulled out and the lead monoxide breaks off the foil. Of course you need to use your praised lead nitrate for that.

Thier you go again..

chloric1 - 6-2-2005 at 14:53

Lead Nitrate fetish?

I tried making PbO this way to make lead acetate with glacial acetic acid. What I had not realized was that I really only had basic nitrate and when I heated this with 100% acetic acid after about 20 minutes the whole mess ignited like gun powder and grey acetic smelling smoke with a little NO2 was billowing off!! Caugh Caugh! Ever since I always made lead hydroxide. Its funny how our experiences influence our methodologies. :cool:

Smoer - 7-2-2005 at 02:30

Quote:

acetic acid with 30% H2O2 does dissolve metalic lead to the acetate. Turning this into the hydroxide with lye to form Pb(OH)2. This can be warmed on a charcoal fire and the CO fumes should protect it somewhat.

How concentrated must this acetic acid be???

What does 'with lye' mean??

Sorry somethimes my english is very bad...

Jome - 7-2-2005 at 09:27

lye is NaOH-solution.

PbO

CycloKnight - 9-2-2005 at 10:15

I know an easy way to make quite a fair amount of lead oxide, provided you have decent ventillation.
This is a little story you might find interesting:
Recently, I was in a model airplane shop buying high concentration nitromethane fuel for my model airplane....Sure. Well, I saw a little bottle of powdered lead (tiny little pellets), it's used as ballast for little powered models. I assume they sell it in most model stores. I bought the bottle of lead.
Not that long ago I needed these lead electrodes for another experiment, so I decided to use that pound or so of tiny lead pellets. I poured the lead pellets into my crucible, fired up the blow lamp and even after 30 minutes of intense heating I still had almost no melted lead. But I did have an entire crucible full of a very heavy white powder, the more stirring, the more powder that was formed., until it stopped forming. Keep heating/stirring until the powder is more like powder and less like sticky wet sand. Eventually it will be a white dust.
End of story.

Esplosivo - 9-2-2005 at 11:55

The purest PbO is not white, it's yellowish orange (contaminated it might look more light orange). On heating it turns to red. It must be some impurities which have formed the white powder. Don't take it the wrong way, it is worth some analysis...

Mumbles - 9-2-2005 at 17:50

I find it really weird that it did not melt, expecially in a blow furnace. I always get a little lead oxide on the surface melt, but it melts with ease. Maybe it has something to do with the fact that you used a blow furnance and I usually use a blow torch or heat gun.

The_Davster - 9-2-2005 at 18:32

It did say it was lead on the container right?(It should have some sort of warning label on it if it is real lead). It could be that a more "environmentally friendly" metal was used instead, or even an alloy of some sort.

Mumbles - 10-2-2005 at 15:13

The only other compound I can think of it being is Titanium. This accounts for the white oxide, and no melting. I really don't think this would be sold as a weight though. It almost has to be lead. Aluminum is too light.

chemoleo - 10-2-2005 at 15:42

Well, it should be easy to test whether it is PbO.
Dissolve it in HCl for instance. One should get sparkingly white crystals when dilute, as it is quite insoluble. If this doesn't work (i.e. it clumps up), try HNO3 instead, or even strong HAc. Complete dissolution should occur. Then, add NaOH. A white precipitate should appear, that redissolves once more NaOH is added forming the plumbate.
Adding H2SO4 to the clear solution should eventually give the totally insoluble PbSO4.
These few experiments already narrow the identity down to just a few elements, and realistically speaking it should be unequivocally clear. Aside from this, that may be a good way of removing impurities.

Lead powder

CycloKnight - 11-2-2005 at 04:52

Hi,
I will try the PbO test, to be sure of its composition.
I think the lead may have contained an alloying agent. Perhaps the lead is a by product from some metal processing plant and is quite impure, hence it's being sold as "ballast" material.
This lead feels extrememly heavy. I could use the tiny plastic bottle (~100ml) to knock someone unconcious if I wanted to - it's that heavy. That should rule out titanium, but it may contain zinc. Zinc can from a white oxide when heated.
I am curious now, because I've seen this white oxide many times. In fact, everytime I've melted lead I've seen this whitish powder forming. If the liquid lead is stirred long enough, a large fraction will get converted to the powder - which is why I try not to stir it any more than I have to.

Esplosivo - 11-2-2005 at 06:43

If it is Zinc Oxide then on heating the white powder strongly the colour should change from white to yellow. On cooling the colour returns back to white. Check this out if you have any doubts of it being zinc oxide, although the melting point of zinc is about 100 deg celcius higher than that for lead and therefore it would be a little harder to melt. Could be an alloy with a lower boiling point though, just check it up. The procedures mentioned by chemoleo are excellent. There are other tests which can be carried out to pin point lead, if you want any help just ask for it.

Theoretic - 12-2-2005 at 13:41

"In the Preparative inorganic chemistry series they use the thermal decomposition of lead nitrate to yield NO2, the recomendation in the method is that you take aluminum foil and place it into the flask to line the bottom, the lead monoxide thus formed doesn't penetrate it I guess and it prevents the attack on the glassware. Afterward it is pulled out and the lead monoxide breaks off the foil. Of course you need to use your praised lead nitrate for that."

Aluminium foil + molten nitrate? Aluminium foil + hot lead oxide? Aluminium foil + hot nitrogen oxide + oxygen? What will happen if this is ever followed?

neutrino - 12-2-2005 at 16:42

I doubt there’d be a problem as long as the temperature didn’t get too high. Remember that aluminum is impervious to nitric acid (mostly likely nitric oxides, too) because the strong oxidizing properties of the acid form a layer of oxide on the metal, thereby passivating it. You might, however, have a problem if the temperature got too high and it started to burn.

Theoretic - 15-2-2005 at 07:42

I have once seen a picture of lead nitrate decomposing in a straight glass vessel, while molten, and the vessel didn't appear damagesd or anything, no damage was reported either. Maybe that's the key - keeping it molten so the lead oxide stays suspended in the molten nitrate untill the last of the nitrate has been decomposed?
The Pb++ ions may be able to penetrate the oxide layer and then when aluminium is substituted for lead more of the oxide layer sloughs off as the lead can't adhere to the oxide layer, and melts too. From the look of it it doesn't usually happen if the procedure is recommended in a textbook, but it's a real danger.

Making PbO

12AX7 - 10-3-2005 at 03:53

This is probably in another thread but I'm an attention whore

and this might be a little diferent anyway.

The other day I cooked up a pounds of lead in a steel can while stirring with a steel tube (to blow air in), when it got around red hot the oxide melted and disappeared - it entered solution with the metal, interestingly enough (yum, self fluxing). This makes some sense from the phase diagram. I shut it off because the heat and oxide was chewing up my steel, turns out it thickened it (layer of PbO and etc.) and oxidized the iron (makes sense, iron is above lead).

On cooling, the oxide came out of solution as a metallic and green mush. Any idea what the green would be? It's not yellow or orange or brown like lead oxides are supposed to be...

On another note, I have some lead dissolving in HCl/H2O2....very slowly. I need to check Ace for some wood bleaching solution... One thing I noticed, it's getting green. I didn't notice green in anyone's pictures of this reaction.

And yes, I'm curious just how fast lead thermite burns. :cool:

chemoleo - 10-3-2005 at 16:52

I don't quite understand, first you say you 'cooked up a pounds of lead', and then 'the oxide disappeared'.
So what did you 'cook', oxide or lead, or both?

As to the metallic 'green mush', you realise you have iron oxides and other things in there? I know, iron oxide has a different colour. Nonetheless, if you want to follow this up... there are analytical routes to this. You could for instance dissolve the 'oxide mush' in HCl, and see what you get with various acids, salts, bases etc.
It's hard to say what it is becuase you are using reagents of unknown purity.

Re. H2o2/HCl - axehandle tried this, see above (or in the PbO2 thread.. there's a big pic of it). Dissolved chlorine is green/yellowish. Alternatively, your Pb contains Cu traces. H2O2/HCl is not good anyway as the resulting PbCl2 is insoluble and thus forms a film over the unreacted lead, increasing reaction times.

I suggest you read this thread, and related ones ...!

[Edited on 11-3-2005 by chemoleo]

12AX7 - 10-3-2005 at 17:48

I don't think iron has much if any solubility in lead. Dunno about the oxide. I know lead and lead oxide are soluble, that's what I mean about it disappearing - it was dissolved into the metal. The lead itself is pretty pure, it's very soft.

I heated some of the junk earlier today and it turned orange, so it must be a suboxide or very thin combination of metal and oxide or something...(the oxide forms a thin skin on the metal, so that makes sense).

I read this thread a few days ago, but didn't notice anything about green solutions. I should read closer eh

So...uh...yeah. Not really sure where I want to go with this post, but I would like to try lead thermite... oh and speaking of which I found some MnO2, mixed with aluminum filings and lit it, burns nice and slowly.

Tim

12AX7 - 13-3-2005 at 12:27

Well yesterday I neutralized the lead/HCl solution, the chlorine smell was getting annoying and the lead wasn't corroding anyway (seems to have a solid layer of white on it, bah). Since I didn't have any baking soda on hand, I used some local dolomite (both calcined and raw material). The odd thing is when I came back to it this morning, it was gelled! (Yellow/green color now, with a little foam still sitting on top.) After some stirring it seems to be fluid again. What happened?

FYI, the dolomite is (Ca,Mg)CO3 + unknown FeS, SO4, etc. impurities. Before I let it suck on a chunk I was neutralizing with calcined material (Ca/Mg(OH)2), which bubbled on addition so might not've been fully calcined.

Tim

12AX7 - 14-3-2005 at 21:33

Picture.

LeadAcidGlop.jpg - 29kB

12AX7 - 6-4-2005 at 22:23

...On another note, I've been soaking lead bits in strong HCl for the last week or two, occasionally stirring up the gray/white crud, decanting and drying it. Well here's an odd one, I seem to have a yellow/green coloration to the solution. PbCl2 doesn't dissolve much, and is white anyway, doubtful that's the culprit. Besides, after letting the acid sit a while, I get a layer on top of clear white acid! There are also a few drops of the stuff left in the bucket with the lead, it's almost oily in that it seems to be at least partially seperated and floating.

It could be iron or copper ions (though the latter is unlikely with lead metal in solution, though at this pH that would be an equilibrium of Cu in solution depsite the Pb, no?), but that wouldn't explain the seperation.

I'll take a photo tomorrow...

Tim

Alternate PbO method?

12AX7 - 23-7-2005 at 19:29

KClO3 has low solubility (and as I recall, tends to plate Pb alone), and as I don't have any NaClO3 or KNO3 on hand, I can't really do much for electrolytic corrosion of lead. So I was thinking, I have a pretty good amount of CuO on hand, let's react that. Thermite won't have enough energy from Cu > Pb to sustain, so it'll need cooking, but how much? Enough to melt Pb, okay, but what of the CuO, and PbO and Cu products?

I'm guessing I should melt the PbO, which unfortunately is a powerful flux (see: lead crystal), and being below iron will oxidize it as well. So that leaves what, tough alumina-glazed crucibles to try?
Also the problem of getting solid PbO as a result, that might be hard to grind...

Oh, and hrm, I suppose I could try sodium acetate. I guess I'll neutralize some and give it a try...

Tim

P.S. ssssss...GRR! This is the only forum that doesn't have ALT+S = send!

jpsmith123 - 23-7-2005 at 19:55

Hello Tim,

I'm not sure I understand what you ultimately want to do. Do you want to make PbO2 powder and do something with that, or are you trying to "anodize" lead or plate another substrate with PbO2?

Regards,
Joe

MANUFACTURING OF LEAD DIOXIDE COATINGS

Lambda - 23-7-2005 at 21:50

Please check this out:

MANUFACTURING OF LEAD DIOXIDE COATINGS:
http://mitglied.lycos.de/echem03/

12AX7 - 23-7-2005 at 22:30

Not PbO2, just PbO. Besides then having fixed lead, I'll have oxide for ceramics projects (why of course I'm going to be trying lead glazes some day). If I want PbO2 I can always dissolve in vinegar and precipitate with bleach (I believe that's the standard method, no?). So I'm not too concerned about quality (though in the preceeding method, CuO would be a major impurity and would surely color everything I put it in).

Of course I can also cementate, but how much boiling would be needed to complete CuCl2 > PbCl2? But that also wastes even more chemicals, if cheap ones (HCl, then NaCO3 to ppt).

Tim

jpsmith123 - 24-7-2005 at 01:38

You mean there is some use for lead compounds besides electrodes for chlorate/perchlorate cells?!!!

What happens when you decompose (heat) lead acetate? I think I read somewhere that you get PbO... but I could be mistaken.

Regards,
Joe

12AX7 - 24-7-2005 at 09:41

Most likely (hm... Pb(OOCCH3)2 = Pb + 4CO + 3H2?), but that would be a bad waste of good lead acetate which needs PbO (or CuO) to start with in the first place anyway.

Anyone know exactly how they made red lead? Yeah, heating in a furnace. How *exactly*?
I've only ever made the green suboxide, stirring around a Pb melt.

Tim

jpsmith123 - 24-7-2005 at 17:10

Unfortunately I can't find the information, but supposedly the products are PbO, CO2, and H2O (don't forget, you're heating to >300 degrees C in *air*).

Maybe Pb(CH3COO)2 + 4O2 = PbO + 4CO2 + 3H2O

In any case, I haven't tried it, but supposedly you can make Pb(CH3COO)2 from lead and vinegar; you don't have to use PbO, but I've heard that adding some H2O2 speeds it up.

I don't know how red lead is made, but supposedly to make litharge from lead you have to melt the lead and spray it into the air through a nozzle.

Here's a link to an article about making lead acetate from vinegar:

http://www.sas.org/tcs/weeklyIssues_2005/2005-06-17/feature4...

[Edited on 25-7-2005 by jpsmith123]

tumadre - 7-8-2005 at 22:22

I melted about a pound of lead in a clay pot and just let it get red for about two hours, after it cooled I had about an ounce of blue, brown and red material. however the lead was contaminated with antimony and a small amount of zinc/tin from my good supply of car batterys. I am interested knowing if any specific antimony oxides are blue. also will acetic acid react with pb02? I know it wont with pbso4

12AX7 - 8-8-2005 at 00:33

Was it powdery, flakes or an adherent layer on the metal? Blue sounds like interference to me (that is, the oxide layer is on the order of a half wavelength of red or so).

I tried burning an antimony alloy as well, it made some yellow oxide, which is perhaps better. The leftover metal is soft and reasonably pure (large crystals), but also hot short (it broke in two on removing it from the mold just after it solidified). I was going to try dissolving this in HCl to see if I can get SbCl3 out...

Tim

12AX7 - 23-5-2006 at 18:30

Ah, that reminds me, now that I have some NaClO3 on hand I thought I'd take a stab at electrolytic corrosion again.

200g NaClO3 (finally mostly anhydrous as near as I can tell, stuff loves to cake up!) was added to 500g (..500ml..) H2O. Electrolysis was performed with a 99%+ pure lead anode and some copper wire cathode. About 4V was applied, giving an estimated current of perhaps 5A. Initially, much Pb(OH)2 was produced, but over time, spongy lead formed on the cathode and the anode was oxidized to PbO2. Oxygen bubbles were noted from the anode.

(Chemical standard of past tense, but it's still running as I type...)

So, um, I've got some voltage here, the anode seems to be turning to PbO2 and not gaining gross [electrical] resistance, and the chlorate solution is getting oxygen bubbled through it. Surely I am making perchlorate to some extent here!?

Tim