Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  2  
Author: Subject: PbO
10fingers
Harmless
*




Posts: 7
Registered: 16-11-2002
Location: USA
Member Is Offline

Mood: No Mood

[*] posted on 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.
View user's profile View All Posts By User
Smoer
Harmless
*




Posts: 16
Registered: 24-5-2004
Location: Belgium
Member Is Offline

Mood: Relaxed

[*] posted on 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]




www.freewebs.com/smoer333 <===check my site!
View user's profile Visit user's homepage View All Posts By User
tom haggen
National Hazard
****




Posts: 488
Registered: 29-11-2003
Location: PNW
Member Is Offline

Mood: a better mood

[*] posted on 5-2-2005 at 12:50


Just exactly at what temperature does lead nitrate decompose?



N/A
View user's profile View All Posts By User This user has MSN Messenger
Mumbles
National Hazard
****




Posts: 436
Registered: 12-3-2003
Location: US
Member Is Offline

Mood: Procrastinating

[*] posted on 5-2-2005 at 15:41


470 C
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
Theoretic
International Hazard
*****




Posts: 770
Registered: 17-6-2003
Location: London, the Land of Sun, Summer and Snow
Member Is Offline

Mood: eating the souls of dust mites

[*] posted on 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.



View user's profile View All Posts By User
chloric1
International Hazard
*****




Posts: 1039
Registered: 8-10-2003
Location: closer to the anode
Member Is Offline

Mood: Strongly alkaline

[*] posted on 6-2-2005 at 14:10
Simpler method


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




In the theater of life its nice to know where the exit doors are located.
View user's profile Visit user's homepage View All Posts By User
BromicAcid
International Hazard
*****




Posts: 3071
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline

Mood: Legitimate

[*] posted on 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.



Shamelessly plugging my attempts at writing fiction: http://www.robvincent.org
View user's profile Visit user's homepage View All Posts By User
chloric1
International Hazard
*****




Posts: 1039
Registered: 8-10-2003
Location: closer to the anode
Member Is Offline

Mood: Strongly alkaline

[*] posted on 6-2-2005 at 14:53
Thier you go again..


Lead Nitrate fetish?:P:P:D 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:



In the theater of life its nice to know where the exit doors are located.
View user's profile Visit user's homepage View All Posts By User
Smoer
Harmless
*




Posts: 16
Registered: 24-5-2004
Location: Belgium
Member Is Offline

Mood: Relaxed

[*] posted on 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...




www.freewebs.com/smoer333 <===check my site!
View user's profile Visit user's homepage View All Posts By User
Jome
Hazard to Others
***




Posts: 126
Registered: 10-6-2004
Location: Soutwest sweden
Member Is Offline

Mood: desiccated

[*] posted on 7-2-2005 at 09:27


lye is NaOH-solution.



View user's profile View All Posts By User This user has MSN Messenger
CycloKnight
Hazard to Others
***




Posts: 128
Registered: 4-8-2003
Member Is Offline

Mood: Still waiting for the emulsion to settle.

[*] posted on 9-2-2005 at 10:15
PbO


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.
View user's profile View All Posts By User
Esplosivo
National Hazard
****




Posts: 491
Registered: 7-2-2004
Location: Mediterranean
Member Is Offline

Mood: Quantized

[*] posted on 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...;)



Theory guides, experiment decides.
View user's profile Visit user's homepage View All Posts By User
Mumbles
National Hazard
****




Posts: 436
Registered: 12-3-2003
Location: US
Member Is Offline

Mood: Procrastinating

[*] posted on 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.
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
The_Davster
A pnictogen
*******




Posts: 2861
Registered: 18-11-2003
Member Is Offline

Mood: No Mood

[*] posted on 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.



View user's profile View All Posts By User
Mumbles
National Hazard
****




Posts: 436
Registered: 12-3-2003
Location: US
Member Is Offline

Mood: Procrastinating

[*] posted on 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.
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
chemoleo
Biochemicus Energeticus
*******




Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline

Mood: crystalline

[*] posted on 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.




Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
View user's profile View All Posts By User
CycloKnight
Hazard to Others
***




Posts: 128
Registered: 4-8-2003
Member Is Offline

Mood: Still waiting for the emulsion to settle.

[*] posted on 11-2-2005 at 04:52
Lead powder


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.
View user's profile View All Posts By User
Esplosivo
National Hazard
****




Posts: 491
Registered: 7-2-2004
Location: Mediterranean
Member Is Offline

Mood: Quantized

[*] posted on 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.:)



Theory guides, experiment decides.
View user's profile Visit user's homepage View All Posts By User
Theoretic
International Hazard
*****




Posts: 770
Registered: 17-6-2003
Location: London, the Land of Sun, Summer and Snow
Member Is Offline

Mood: eating the souls of dust mites

[*] posted on 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? :o




View user's profile View All Posts By User
neutrino
International Hazard
*****




Posts: 1583
Registered: 20-8-2004
Location: USA
Member Is Offline

Mood: oscillating

[*] posted on 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.:o
View user's profile View All Posts By User
Theoretic
International Hazard
*****




Posts: 770
Registered: 17-6-2003
Location: London, the Land of Sun, Summer and Snow
Member Is Offline

Mood: eating the souls of dust mites

[*] posted on 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.




View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 10-3-2005 at 03:53
Making PbO


This is probably in another thread but I'm an attention whore :D :P 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:
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
chemoleo
Biochemicus Energeticus
*******




Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline

Mood: crystalline

[*] posted on 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]




Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 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 :P

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
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 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
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
 Pages:  1  2  

  Go To Top