LookingForAnswers
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PbSO4 to H2SO4
Hello there. All sings on earth and heaven tell me that i fucked electrolysis of CuSO4 and as by product i have lots of white smooth powder easy
solving in hot sulph acid. Propably it is PbSO4. My question is: Can i electrolysis it in diluted h2so4 on both lead electrodes to reduce a lead
cation and get back my acid ?
[Edited on 4-5-2024 by LookingForAnswers]
[Edited on 4-5-2024 by LookingForAnswers]
[Edited on 4-5-2024 by LookingForAnswers]
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bnull
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Well, you can make a miniature (2 V?) lead-acid cell and charge it: products are lead on anode and lead dioxide in cathode. It's easier said than
done, of course. Take a look at Linden's Handbook of Batteries.
Quod scripsi, scripsi.
B. N. Ull
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khlor
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Yes, but you should use graphite on the anode(either that or platinum). For the cathode you can use lead. since it is dilute h2so4 you should be fine
on the electrodes, just know that graphite anodes do tend to exfoliate, but will not react with h2so4, so, you wil remove the lead, but probably will
get a somewhat dirty h2so4, decantation can fix most of it.
"NOOOOOO!!! The mixture is all WROOOOOOONG!"
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Sir_Gawain
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Quote: Originally posted by LookingForAnswers  | | Hello there. All sings on earth and heaven tell me that i fucked electrolysis of CuSO4 and as by product i have lots of white smooth powder easy
solving in hot sulph acid. Propably it is PbSO4. |
How did so much lead get into your electrolysis cell? Were
you using lead electrodes?
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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LookingForAnswers
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| Quote: Originally posted by khlor |
Yes, but you should use graphite on the anode(either that or platinum). For the cathode you can use lead. since it is dilute h2so4 you should be fine
on the electrodes, just know that graphite anodes do tend to exfoliate, but will not react with h2so4, so, you wil remove the lead, but probably will
get a somewhat dirty h2so4, decantation can fix most of it. |
I havent been on forum since I added that post and today i began do it on leads(both) electrodes. fortunetly i stop it when the solution start do a
lot of white foam. unfortunetely it looks worse than before. my plan is: fractional freezing to collect remaining acid, this white pulp flush with
distiled water , than filter under vacum and follow your instructions but the question is: what concentration would you use for electrolysis with
graphite?
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LookingForAnswers
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| Quote: Originally posted by Sir_Gawain | | Quote: Originally posted by LookingForAnswers | | Hello there. All sings on earth and heaven tell me that i fucked electrolysis of CuSO4 and as by product i have lots of white smooth powder easy
solving in hot sulph acid. Propably it is PbSO4. |
How did so much lead get into your electrolysis cell? Were
you using lead electrodes? |
i couldnt get completely colorless solution of my acid, ive begun do a research for a solution this problem. I found somewhere in web the prompt is
possible to rise up conductivity by adding vinegear, propably i added much too much, another thing is too high current I set up and if you combine
these two fails you receive what i received.. :/
[Edited on 7-5-2024 by LookingForAnswers]
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khlor
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| Quote: Originally posted by LookingForAnswers | | Quote: Originally posted by khlor |
Yes, but you should use graphite on the anode(either that or platinum). For the cathode you can use lead. since it is dilute h2so4 you should be fine
on the electrodes, just know that graphite anodes do tend to exfoliate, but will not react with h2so4, so, you wil remove the lead, but probably will
get a somewhat dirty h2so4, decantation can fix most of it. |
I havent been on forum since I added that post and today i began do it on leads(both) electrodes. fortunetly i stop it when the solution start do a
lot of white foam. unfortunetely it looks worse than before. my plan is: fractional freezing to collect remaining acid, this white pulp flush with
distiled water , than filter under vacum and follow your instructions but the question is: what concentration would you use for electrolysis with
graphite? |
Oh no, it seems that much of your acid became lead sulfate (the white foam) lucky you that stuff isn't that much soluble in water, lead chemistry is
hazardous and soluble lead compounds are the worst.
if I were you, I'd try to react the white foam with zinc powder, that would result in metalic lead and zinc sulfate(soluble) then after filtering the
solution, start electrolysis with graphite anode and zinc cathode. it be interesting, but not sure it it is worth the work and zinc used. but at the
end, in theory you'd get metalic lead powder, metalic zinc and a not so pure dilute sulfuric acid solution.
As for your question, I did had success with copper sulfate solutions resulting in up to almost 20% w/v acid, not pure but usable for some non
critical experiments and cleaning.
"NOOOOOO!!! The mixture is all WROOOOOOONG!"
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LookingForAnswers
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i thought about decompose it to PbO and SO3 , then pass sulphur trioxide throught remained acid, the problem is themperature of the decomposing. Wiki
says that PbSO4 need over 1000*C , in theory i can do it but ive read somewhere that so3 decompose to so2 over 600*C, so it dosent have any sense. I
dont have zinc at this moment but i found another possible way with tin which i have a lot. Wiki says:
" Reaction between tin tetrachloride and sulfuric acid in a 1:2 molar mixture at near reflux (114°C):
SnCl4 + 2 H2SO4 → Sn(SO4)2 + 4 HCl
Pyrolysis of anhydrous tin(IV) sulfate at 150°C - 200°C:
Sn(SO4)2 → SnO2 + 2 SO3"
Sulphur trioxide produced this way id pass throught h2so4 but i dont do anything before someone more experienced confirm it.
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Rainwater
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Of you want to use the thermal decomposition route may i suggest a single displacement reaction first.
Lead sulfate is more solubility in molten lead than liquid water, but both solvents will work. Water being much much slower
$$ PbSO_4 + Fe \rightarrow FeSO_4 + Pb $$
How I manage lead waste is by converting it into the sulfate and placing it into a bucket with scrap iron, acidified the bucket with sulfuric acid
(any ph below 5-6) to drive off the Cl from any chloride salts. And let it sit at about 23c for a few weeks with a bubbler.
Afterwards, filter the solution(test then discard), melt the sludge down and scrape off the slag amd pour it into a cone mold. This reduces the amount
of lead waste. By isolating the free metal.
The slag and cone plug, are then stored for the next batch.
To fully recover all the lead, the slag and plug are melted with extra lead and more iron. For about 15 minutes at 400c. The liquid is poured into
shot and the soluble iron sulfate allowed to disolve, leaving 95%+ pure lead.
"You can't do that" - challenge accepted
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LookingForAnswers
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| Quote: Originally posted by Rainwater | Of you want to use the thermal decomposition route may i suggest a single displacement reaction first.
Lead sulfate is more solubility in molten lead than liquid water, but both solvents will work. Water being much much slower
$$ PbSO_4 + Fe \rightarrow FeSO_4 + Pb $$
How I manage lead waste is by converting it into the sulfate and placing it into a bucket with scrap iron, acidified the bucket with sulfuric acid
(any ph below 5-6) to drive off the Cl from any chloride salts. And let it sit at about 23c for a few weeks with a bubbler.
Afterwards, filter the solution(test then discard), melt the sludge down and scrape off the slag amd pour it into a cone mold. This reduces the amount
of lead waste. By isolating the free metal.
The slag and cone plug, are then stored for the next batch.
To fully recover all the lead, the slag and plug are melted with extra lead and more iron. For about 15 minutes at 400c. The liquid is poured into
shot and the soluble iron sulfate allowed to disolve, leaving 95%+ pure lead. |
i have 3kg(maybe more) of lead in roller which left after work in roof so i dont care that much on lead. i need sulphuric acid to produce more sulph
acid by contact process. everything is nearly ready , vanadium in the way and... i dont have sulphuric acid.
anyway...
You suggested me something. Ive read somewhere about way with FeSo4 but people say that better is do this decomposition with NaHSO4 because of bigger
yeild. In my case to produce sodium bisulphite i need 1:1 molar ratio? Do i think good?
PbSO4 + NaOH ----> PbO + NaHSO4
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khlor
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I don' know mate, it the Sn and Fe route seems risky, how would you manage to recover the acid this way? I'd do a displacement reaction to get a
soluble sulphate I could later remove the metal easily by electrolysis. Something like zinc or copper, but this talk of thermal decomposition seems to
require specialized equipment a d glassware, are you sure of it? Unless I misunderstood, the goal is to recover sulphuric acid and not the lead.
"NOOOOOO!!! The mixture is all WROOOOOOONG!"
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bnull
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Let me see if I got the situation right: you tried to make sulfuric acid by electrolysis of a copper sulfate solution. You added vinegar to increase
conductivity, but it was way too much vinegar and, using a rather high current, you ended up with a lot of (presumably) lead sulfate. You tried to
remove lead by electrolysis but, again, you used lead on both electrodes and there's even more lead sulfate than before.
Now you want to decompose lead sulfate to make SO3 and PbO so you can make sulfuric acid by the contact process. Unless you have
adequate--proper, really good, not improvised--equipment, far away from other residences, I advise you against doing it. SO3 is nasty, to
say the least. Not as nasty as HF, but nasty anyway.
My suggestion is that you try to remove as much lead sulfate as possible, dry it, store it in a well-labeled flask, and forget the recovery of
sulfuric acid from it. Accept your losses and start with a new solution of copper sulfate (see the threads "Sulfuric acid from copper sulfate" and "Small scale production of H2SO4 in the amateur lab").
Electrolysis with lead electrodes in the presence of acetate ions is not a good idea, since lead is a cumulative poison and lead acetate is soluble.
If your lead electrodes were made from the roofing material, it's possible, if not probable, that they are contaminated with arsenic, and so would be
the solution.
Edit: them bloody typos again...
[Edited on 7-5-2024 by bnull]
Quod scripsi, scripsi.
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Rainwater
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I forgot to state the main purpose of my suggestion, lead compounds are so toxic that thermal decomposition of them is not only dangerous, its so
stupid I dont even do it. ( thats a statement given i neturalized NaK with a water dropper a few weeks ago)
To avoid the danger and contamination hazard, swap out the cation to something easier to work with.
Iron sulfate is a good fertilizer (hint hint) and easy to electrolysis into H2SO4 using a clay pot (8% consentration by weight is my best results).
With a professional membrane id expect higher consentrations. But if its completely unavailable in your are, here is a pathway that will not turn your
lab into Mr. Hahn's backyard.
What ever pathway you take, just be safe. Molten lead produces vapors just like water. It will contaminate your entire work area, guaranteed.
lead test strips that I currently use
"You can't do that" - challenge accepted
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