Milan
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Production of aluminium hydroxide
So, I've been looking around the forum but haven't been able to find a thread with a similar procedure so I thought about posting it. It might not be
anything important, but who knows someone might find it useful. And just in case anybody was wondering about it, no you can't find it on the market in
my country, only with chemistry supply companies.
Ok, so here are the extracts from the laboratory log I've been keeping:
-First a small amount of table salt is added to the solution of copper sulfate, this will introduce chlorine ions into the solution
which are able to attack the passivating layer on aluminium metal.
-After this a piece of aluminium metal is put into the solution, at first the reaction will start slow until the passivating layer
is consumed after this the reaction will start to get hot enough to sometimes boil water so it should be left over-night in an ice bath.
The reaction goes as follows: 2 Al (s) + 3 CuSO4 (aq) ---> Al2(SO4)3 (aq) + 3 Cu (s)
This reaction will precipitate copper.
-After this is done there will either be an excess of copper sulfate or a colloidal suspension of aluminium which is formed if the aluminium
is left in the solution for too long (half an hour or more), the former can be solved by adding more aluminium, while in the latter case
it can be solved by letting the aluminium settle at the bottom and then filtering it.
-Next step is to filter the solution of aluminium sulfate to separate it from the precipitated copper.
-After this, the solution is reacted with sodium bicarbonate to make aluminium hydroxide.
The reaction goes as follows: Al2(SO4)3 + 6 NaHCO3 ---> 3 Na2SO4 + 2 Al(OH)3 + 6 CO2
This reaction will precipitate aluminium hydroxide.
-At the end the insoluble aluminium hydroxide is separated from the rest of the solution by filtering and washed several times.
Also we got copper powder and NaCl + Na2SO4 solution as by-products. Na2SO4 can be recovered by re-crystallization.
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blogfast25
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For G-d sake man, just dissolve some scrap Al metal in dilutish HCl or H2SO4, filter and treat solution with NH3 solution, Na2CO3 or NaHCO3. Or
dissolve Al scrap with NaOH or KOH and carefully neutralise the aluminate with any acid.
Or treat a solution of potassium alum (crystal growing kits and other OTC sources) with the same.
Why waste CuSO4 on this?
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Milan
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Quote: Originally posted by blogfast25  | For G-d sake man, just dissolve some scrap Al metal in dilutish HCl or H2SO4, filter and treat solution with NH3 solution, Na2CO3 or NaHCO3. Or
dissolve Al scrap with NaOH or KOH and carefully neutralise the aluminate with any acid.
Or treat a solution of potassium alum (crystal growing kits and other OTC sources) with the same.
Why waste CuSO4 on this? |
Ok, first calm down a little.
Second, why are you assuming that the same circumstances are present in your country and in mine. HCl and H2SO4 are not that cheap and NH3, NaOH, KOH
and Alum can only be bought from chemistry supply companies.
While on the other hand CuSO4 and NaHCO3 which I used are quite cheap and can be acquired in larger amounts from a wide variety of sources.
[Edited on 14-6-2015 by Milan]
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Sulaiman
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wow!, I thought UK was getting difficult,
but a couple of days ago I had a look in my local small independent hardware shop and found all sorts of interesting stuff,
e.g. three types of drain un-blocker; 96% H2SO4, 35% HCl, 100% NaOh powder, also some solvents etc.
I did not buy any as I have litres of each of better purity, but nice to know it is there if needed.
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Milan
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| Quote: Originally posted by Sulaiman | wow!, I thought UK was getting difficult,
but a couple of days ago I had a look in my local small independent hardware shop and found all sorts of interesting stuff,
e.g. three types of drain un-blocker; 96% H2SO4, 35% HCl, 100% NaOh powder, also some solvents etc.
I did not buy any as I have litres of each of better purity, but nice to know it is there if needed. |
Well I'm glad for you but not everybody lives in the UK.
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Sulaiman
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what I was attempting to explain is that even though, for example, sulphuric acid is now a reportable substance here in UK,
I can buy it over the counter.
You may find similar 'anomalies' in your country.
Have you tried?
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papaya
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Prepare some NaCl solution, take a piece of Al metal, immerse into the solutiona and connect it with wire to the positive terminal of power supply,
then take another piece of metal(may be also Al) and connect to negative terminal, put into same solution. Wait. Hopefully you'll get hydroxide
precipitation. Don't ask for the references. If you still ask, then explain yourself what else besides Al hydroxide can form.
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Milan
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| Quote: Originally posted by Sulaiman | what I was attempting to explain is that even though, for example, sulphuric acid is now a reportable substance here in UK,
I can buy it over the counter.
You may find similar 'anomalies' in your country.
Have you tried? |
Hmm, I get what you're trying to say, but the problem here aren't the law restrictions since there aren't many of them, the problem here is the lack
of products. If you ask if I was looking for those "anomalies", well for the last year I've been frantically looking over the contents section of
almost any product I could remember. But it doesn't matter I'll usually find one way or another to get the chemical I need.
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Milan
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| Quote: Originally posted by papaya | | Prepare some NaCl solution, take a piece of Al metal, immerse into the solutiona and connect it with wire to the positive terminal of power supply,
then take another piece of metal(may be also Al) and connect to negative terminal, put into same solution. Wait. Hopefully you'll get hydroxide
precipitation. Don't ask for the references. If you still ask, then explain yourself what else besides Al hydroxide can form. |
Thanks for the idea, but my source of Al were cans from drinks, still thank you for mentioning it.
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blogfast25
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| Quote: Originally posted by Milan |
While on the other hand CuSO4 and NaHCO3 which I used are quite cheap and can be acquired in larger amounts from a wide variety of sources.
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Fine. So you end doing boring stuff that's been done a thousand times before. I mean, Al hydroxide, REAL exciting, man!
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j_sum1
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Hey. I've never made Al(OH)3. I've never had a need to, admittedly. But I doubt I would find it boring.
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battoussai114
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Of course not! You can make Sapphires out of it.... sorta of.....
Yes yes.... I know the thread is 7 days old, it's just that I'm really bored around here after bashin my head against some problematic software.....
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violet sin
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I currently have a batch of aluminum scrap( half oxidized pulleys from a spring assisted garage door) in lye water. Some that has already been ppt.
from sol. with HCl and heated, is being leached for salt now. I had a couple ceramic pieces that are needed, no alumina, and can't justify eBay
prices for the amount I need. Nor more money/shelf space, to bulk buy for good prices. Would really like to hit up a pottery store one of these
days, though project time and money are in short supply as usual.
It's not as boring as one would think, still deff not exciting. A bit peaceful and tedious, with parts that make you think about proper time
management. One bonus is that it can sit quietly waiting for my spare time, unlike many projects.
Projects, to make pieces for other projects, that are in and of them selves partial solutions to a bigger picture project... Gotta love that.
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