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Jome
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Are you saying Lead nitrate be isolated in the same way as KNO<sub>3</sub>, by addition of ice cold ethanol? Is this method as efficent
with lead nitrate?
I've had a solution of it sitting for months in a huge jar, being to scared of droplets and such to appempt boiling it down.
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chemoleo
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Well I don't know, but I suspect that lead nitrate being an ionic salt it won't be well soluble in ethanol, thus it should precipitate. I
haven't tried that though, I used crystallisation and evaporation.
Try it and see if it works. I should think it will.
Else, try acetone, which is slightly better for precipitation (albeit more expensive).
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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neutrino
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I was going by personal experience and others’ posts. I had never come across any testimony to its actually working. Thanks for enlightening me.
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chemoleo
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| Quote: | | The CaSO4 precipitate is extremely difficult to filter out, if not impossible. More than one person on this board has tried something like this and
utterly failed. |
I wonder who those people are. I remember marvin commenting elsewhere this being difficult, I think over at the E&W where I first described it,
and I remember telling him it is absolutely doable. And I made 10 litres (!) of Cu acetate solution that way!
I presume the problem was that when people attempted it that they used too little water vs Caacetate/nitrate and thus got those problems.
And for this reaction, concentration doesn't really matter that much as the equilibrium of Pb dissolution lies very far to the right.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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neutrino
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Ah, that might have been my problem: not enough water. I can't remember exactly who the other person was...
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Jettin4u
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I have made lead nitrate by using lead oxide and nitric acid, you could also use lead carbonate and nitric acid. just filter, boil down and
recrystalize
But im not sure what you guys can get your hands on though. This is the easiest way.
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chloric1
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I guess in the past I must have had antimonial lead as I could not get it to dissolve in nitric acid too well. The lead sheet I have from Mcmaster
Carr that I bought for aluminum anodizing is quite pure. In a 1:1 ratio of nitric acid to water by volume you can get a decent sized 35 gram strip to
dissolve in 2.5 hours. I applied moderate heat. Chemical action was seen at about 42 to 44 degrees C but was lethargically slow. Above 60 it was
more steady by the time the solution reached the high 80's most of the lead is almost gone. Lead nitrate not being soluble in nitric acid is a
strong plus indeed. I simply decant the liquid and reuse with more lead and add nitric acid an water as needed. That way I am never losing nitric
acid except towards evaporation.
[Edited on 11/17/2005 by chloric1]
Fellow molecular manipulator
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ADP
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Lead Monoxide
Is there an easy route to produce lead monoxide? I didn't think this question warranted a new thread.
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stygian
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I don't think it even warrants a post. Try searching.
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SAM4CH
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Pure Lead nitrate!
I have technical lead alloy "about 90% Lead" and I want to make pure lead nitrate "I have very good method for that" but I like to purify lead alloy
to be around 98-99% and I do not know the composition of the other material in this alloy.
I tryed to recrystalize my lead nitrate but it was not good idea.!!
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12AX7
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Hum, electroplate it?
Tim
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unionised
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Disolve it in nitric acid, ppt the Pb as PbCl2 with HCl, filter, wash, boil with Na2CO3 to get PbCO3. Filter + wash. Disolve in HNO3.
Since almost all chlorides are soluble this should get rid of everything apart from Ag and Hg (And Tl perhaps- probably not important).
Since Ag and Hg are expensive they probably are not present in the alloy in the first place.
If they are then you could remove them by only disolving 90% of the metal, shredding the rest of it to give lots of surface area and adding this to
the solution of Pb(NO3)2. Then Ag and Hg would ppt out as the metals.
Of course, if you actually do this be careful with the NOx fumes when you disolve the metal.
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SAM4CH
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I like to make purification of lead alloy by electrolysis at high current density "I do not like fine electroplate", What the the best electrolyte
solution for this?
[Edited on 8-6-2006 by SAM4CH]
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SAM4CH
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[Edited on 9-6-2006 by SAM4CH]
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alancj
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What is the white stuff?
| Quote: | Originally posted by TheBear
Another cheap way of making it would be by making an separated cell (saltbridge) and electrolyse with
KNO<sub>3</sub>/NaNO<sub>3</sub>. Use Pb as anode, cathode can be made of any resistant material. The same works for making
AgNO3. Think I read this in another thread.
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I'm trying this procedure right now; using a lead anode and stainless cathode with potassium nitrate in the solution. I forgot about the salt bridge,
and just put the whole of it in a glass jar. It is still running but it appears that I'm getting lead plated on the cathode and I'm getting LOTS of
white precipitate forming on the lead anode. It has already settled at the bottom and is about a half inch thick, and it has only been going for an
hour. Anyone know what this per. is? I don't have a salt bridge so it could be some other compound. Please enlighten me...
Thanks,
Alan
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TheBear
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At the cathode the following reduction is taking place:
K+ + e- ---> K
Potassium / sodium instantly reacts with water to give off hydrogen gas and hydroxide ions:
4K + 2H2O ---> H2 + 2K+ + 2OH-
And at the anode lead is being oxidised:
Pb ---> Pb2+ + 2e-
Since the cell isn't separated lead will plated on the cathode, and mix with the hydroxide ions resulting in a precipitate consisting of Pb(OH)2.
Pb2+ (aq) + OH- (aq) -----> Pb(OH)2 (s)
So if a soluble lead salt is all you're after just let i run until the lead anode is dissolved (add more electrolyte if needed) and then filter your
white precipitate. Then add this to acetic acid and recrystallize the formed lead acetate, Pb(CH3COO)2. (Even though this topic is about making the
nitrate, I assume you're not in possession of nitric acid, or if you are, use it instead to form the nitrate).
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alancj
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| Quote: | Originally posted by TheBear
At the cathode the following reduction is taking place:
K+ + e- ---> K
Potassium / sodium instantly reacts with water to give off hydrogen gas and hydroxide ions:
4K + 2H2O ---> H2 + 2K+ + 2OH-
And at the anode lead is being oxidised:
Pb ---> Pb2+ + 2e-
Since the cell isn't separated lead will plated on the cathode, and mix with the hydroxide ions resulting in a precipitate consisting of Pb(OH)2.
Pb2+ (aq) + OH- (aq) -----> Pb(OH)2 (s)
So if a soluble lead salt is all you're after just let i run until the lead anode is dissolved (add more electrolyte if needed) and then filter your
white precipitate. Then add this to acetic acid and recrystallize the formed lead acetate, Pb(CH3COO)2. (Even though this topic is about making the
nitrate, I assume you're not in possession of nitric acid, or if you are, use it instead to form the nitrate). |
I thought maybe i would get hydroxide. Wasn't sure. What happens to the NO3 and K ions? Do they just float about? Would I be able to make the Pb(OH)2
with a different salt, like NaCl? Also, my solution smells strongly like a ammonia, why is that? I guess ammonia is NH3 so maybe some of the hydrogen
is combining with the N in the NO3 and relasing the O3, which would be ozone... I'm just guessing though, I don't know much chemistry, I only took
half a year of high school chem  .
-Alan
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12AX7
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Nah, the O breaks off with hydrogen at the cathode, producing water.
Eh, was afraid of that... I noticed, with a strong chlorate solution (around 50g/100ml NaClO3, I think), weird smells and behavior being produced, my
guess is the chlorate ion was being reduced.
Nitrate and chlorate are about on par... they decompose about the same temperature for instance.
Maybe perchlorate is stable enough to provide gobs of easy lead hydroxide?
Any thoughts on preventing the lead sponge deposit at the cathode? I *always* get one. I also get, when the Pb(OH)2 isn't scraped off hourly, a
transformation to PbO2, which cakes on and ends up making a mess of things (a hodge-podge of chemistry then going on).
(Hmm this should be moved to the PbO thread...)
Tim
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hodges
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| Quote: | Originally posted by alancj
Also, my solution smells strongly like a ammonia, why is that? I guess ammonia is NH3 so maybe some of the hydrogen is combining with the N in the NO3
and relasing the O3, which would be ozone... I'm just guessing though, I don't know much chemistry, I only took half a year of high school chem .
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At the cathode (negative terminal), some of the nitrate ion from the KNO3 is getting reduced to ammonium ion. Since the solution is basic at the
cathode, the ammonium ion is forming ammonium hydroxide which you smell.
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alancj
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| Quote: | Originally posted by 12AX7
Nah, the O breaks off with hydrogen at the cathode, producing water.
Eh, was afraid of that... I noticed, with a strong chlorate solution (around 50g/100ml NaClO3, I think), weird smells and behavior being produced, my
guess is the chlorate ion was being reduced.
Nitrate and chlorate are about on par... they decompose about the same temperature for instance.
Maybe perchlorate is stable enough to provide gobs of easy lead hydroxide?
Any thoughts on preventing the lead sponge deposit at the cathode? I *always* get one. I also get, when the Pb(OH)2 isn't scraped off hourly, a
transformation to PbO2, which cakes on and ends up making a mess of things (a hodge-podge of chemistry then going on).
(Hmm this should be moved to the PbO thread...)
Tim |
I didn’t measure the amounts put into the cell, but I estimate I had 500 ml of tape water and I added 4 spoonfuls of KNO3… So maybe 50 grams. It
all dissolved in the water cold.
Perchlorate… that’s funny, you need perchlorate to make lead salts to make lead dioxide anode to make perchlorate.
Well, since some lead is plated and some turns into hydroxide…maybe having both electrodes being lead and then reversing the current every few
seconds would cause all the lead to eventually turn into hydroxide. It could be done with some pretty simple electronics, probably just some relays
and 555 timer.
| Quote: | Originally posted by hodges
| Quote: | Originally posted by alancj
Also, my solution smells strongly like a ammonia, why is that? I guess ammonia is NH3 so maybe some of the hydrogen is combining with the N in the NO3
and relasing the O3, which would be ozone... I'm just guessing though, I don't know much chemistry, I only took half a year of high school chem .
|
At the cathode (negative terminal), some of the nitrate ion from the KNO3 is getting reduced to ammonium ion. Since the solution is basic at the
cathode, the ammonium ion is forming ammonium hydroxide which you smell. |
I read that ammonium hydroxide is just aqueous ammonia, And according to the lead salts table I got from another thread on this board Pb(OH)2 seems to
be insoluble. Just 0.00012 g/100 ml at 20 deg Celsius. The next column is “Qualitative Solubility” and it says “s acid” which means it is
soluble in acid. So washing the perc. would probably remove the ammonia and then I can dissolve the Pb(OH)2 in vinegar. I only have 5% stuff, but I
suppose it would work.
I’m distilling nitric acid right now as well as precipitating my lead chloride that I’ve been making in boiling HCl for the past 2 days. Getting
lots of needlely crystals! I wonder what would happen when one does electrolysis with a lead anode in a solution of PbCl2? Not real soluble so it
might not be very conductive.
-Alan
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12AX7
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| Quote: | Originally posted by alancj
...as well as precipitating my lead chloride that I’ve been making in boiling HCl for the past 2 days. Getting lots of needlely crystals!
|
Yep, I've got a jug of impure PbCl2 (among probably clay, rust, etc.) with hot water on top, hotter on the side piled up with PbCl2. Not much has
crystallized on the cooler side yet, but it's getting there. More seems to come out due to evaporation loss (which is condensed, but drips back in
and doesn't dissolve the crystal mat). *shrug*
| Quote: | I wonder what would happen when one does electrolysis with a lead anode in a solution of PbCl2? Not real soluble so it might not be very conductive.
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I tried something like that before and posted in the PbO(2?) thread. When warm, in NaCl solution, Pb(OH)2 is produced, because the PbCl2 intermediate
is soluble -- same process as you tried, with Na and Cl spectator ions. When cold, PbCl2 precipitates at the anode (along with Pb(OH)2), which is
slowly oxidized to a porous, resistive layer of PbO2.
In case you're wondering, sulfuric acid produces a much better PbO2 deposit, which isn't saying much.
Tim
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alancj
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Some experiments with a diaphragm
I made a diaphragm to isolate my SS cathode from the rest of the cell. It sits in an acrylic pocket with six 1/2" holes drilled in one side and uses
two layers of filter paper to form a diaphragm. Water and electricity must pass through the paper before it reaches the cathode. It completely stopped
the plating of lead onto the SS and instead the spongy lead would build up around the holes in the acrylic where the paper blocks further progress.
The lead falls off or is easily scraped off.
Unfortunately I still smelled a strong ammonia odor coming from the cell. And I still get a white insoluble precipitate forming in the cell which I
assume is lead hydroxide. The water will also make your fingers very slippery, much like sodium hydroxide does. Lead nitrate, which I'm aiming for,
would be soluble and wouldn't precipitate right away.
I thought that a diaphragm would be equivalent to a separated cell with a salt bridge in that they both would stop the transfer of ions. Assuming that
two separate containers with a salt bridge would actually work for making lead nitrate, then maybe my diaphragm is not working the way it should. The
paper is very close to the cathode, and the hydrogen bubbles certainly come into contact with the paper. I think that that could be the problem. But I
don't really know. I could make it a lot more rummy with some modifications if need be.
So, how exactly does a separated salt bridge work for making AgNO3? How is the bridge constructed? What salt is used in the bridge, what is the
catholyte and anolyte? All the same? Would a diaphragm work to separate the anode and cathode, and if so what's wrong with mine?
Thanks,
Alan
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12AX7
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Might just need to run it for longer. As long as there are potassium ions in the anolyte, it's probably going to make hydroxide. Wait, that doesn't
make much sense, cations spectate at the anode.
Tim
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MadHatter
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Lead Nitrate
The CuSO4/Ca(NO3)2 method works very nicely. Just use some lead filings or #9 lead bird
shot to increase the surface area.
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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