Sciencemadness Discussion Board - Purifying Zn powder from alkaline batteries' Zn paste

Purifying Zn powder from alkaline batteries' Zn paste

Demonblack - 23-11-2011 at 12:54

Hi everyone, i've got some zinc paste from alkaline batteries (it should be zinc powder, but i'm not sure. That's basically the problem) and i was looking for a way to purify it.

It still has all of the electrolytes in it (some of which also exothermically reacted when they came in contact, probably i shouldn't have mixed different batteries) and also a bit of water that accidentally got inside while i was cooling down the container from said reaction.

One of the biggest problems is that i don't even know for sure wether it's zinc powder or some sort of salt, because it looks way too white-ish to me to be zinc powder, but that maybe from the electrolytes, i don't know.

I made a video of the paste but, ironically, speaking of batteries i can't find my camera's battery and i had to record it with the phone...

Sorry for the crappy quality and also for my horrible accent, lol.

The vid is here: http://www.youtube.com/watch?v=crEN0-uT-TQ

Endimion17 - 23-11-2011 at 13:21

Just wash it quickly to avoid it being consumed by the dissolved base, and then heat a small amount until it oxidizes. It burns with bluish flame, evolving lots of zinc oxide smoke.
Its oxide is yellow when it's hot, and white when it's cold.

If the batteries were old, not much zinc will remain...

You sound like a Enrico Fermi crossed with Super Mario. That's cool.

blogfast25 - 23-11-2011 at 14:24

Any zinc in there will have been used up: i.e. irrecoverably oxidised.

If Zn metal is what you're looking for then look to the zinc sheet casings of these batteries.

BTW, it takes more than 'washing' to get to the MnO2 in battery crud. The manganese oxides in there are mixed with graphite and other stuff. Search the forum for a multitude of threads on extracting manganese from battery crud.

Demonblack - 23-11-2011 at 14:35

Lol Fermi mixed with Super Mario, who knew that

Ok so i washed the solution and it's now filtering (it will take at least 1 hour i think, i used a regular paper sheet and not filter paper which i don't have).

After it finishes i'll wash it again and do the rest tomorrow.

For the heating, should i do it with free flame or on a plate?

Demonblack - 23-11-2011 at 16:00

Sorry, you replied while i was replying too and i didn't see it.

Yeah, seems to turn out you're right - although it's not dried up yet (i rewashed it and it's now re-filtering) the powder appears to be white oxide.

I was looking for the powder, i know i can get zinc from the casings (but only carbon-zinc casings, alkaline cases are actually made of cheaper steel).

For the MnO2, i found out that graphite usually floats on water, and slowly overflowing the beaker with water makes it drip out of it while leaving the MnO2 on the bottom.

As a further test, i tried igniting the powder with an oxidizing flame and nothing happened, so i'm quite sure it is only MnO2.

simba - 23-11-2011 at 16:21

Quote: Originally posted by Demonblack

Ok so i washed the solution and it's now filtering (it will take at least 1 hour i think, i used a regular paper sheet and not filter paper which i don't have).

Is it so hard to get at least a coffee filter? With the time you used to wait it to filter, you could have used to go buy some instead.

Demonblack - 23-11-2011 at 16:58

It was 23:30 here when i started the filtering...

[Edited on 24-11-2011 by Demonblack]

simba - 23-11-2011 at 17:24

Quote: Originally posted by Demonblack

It was 23:30 here when i started the filtering...

[Edited on 24-11-2011 by Demonblack]

Oh well...I guess not everyone is a coffee addict like me, I think I have more filter paper then sulfite in my house.

Sedit - 23-11-2011 at 19:45

If you need Zinc and can't think of any other source then take as many US pennies as you can and put them in a pan on the stove. Before you know it the Zinc will melt out and you will be able to pour off, with ease, a mess load of relatively pure Zinc.

Pennies are cheep and the newer the US penny, the more Zinc they contain. What a wonderful economy we live in when our coins are worth only a small fraction of there real value.

Demonblack - 24-11-2011 at 13:36

I don't live in the US, so pennies aren't an option...
What about euro cents?
I also saw on youtube a video in which the maker used some roof thing made of zinc, they sell it in stripes to prevent corrosion or something. Might be a good source.

By the way having the Zinc and having it in powder is not the same lol.

Is there any simple way to reduce the oxide i got and still get a powder (-> no thermite)?

Endimion17 - 24-11-2011 at 15:34

If you live by the sea and there's a shipyard nearby (or any place where people repair their boats), go there and ask them to give you their waste zinc anodes. Those things are fairly large, porous and covered with zinc oxide, sodium chloride and small marine life so you'll have a hard time getting the pure metal, but it's worth it.
Be sure to ask for zinc, because they might give you aluminium.
I'm not sure that roof thing is zinc. It's probably zinc plated steel, common and usually worthless junk to home chemists.

Otherwise just buy the anodes. Zinc is not expensive.

blogfast25 - 25-11-2011 at 10:42

Quote: Originally posted by Endimion17

I'm not sure that roof thing is zinc. It's probably zinc plated steel, common and usually worthless junk to home chemists.

You can buy zinc cladding here, for roofing jobs etc. This is soft anf malleable and mainly zinc, a little alloyed probably.

But what's wrong with the zinc casings from Zn/MnO2 batteries? Granted, it's not powder...

Quote: Originally posted by Demonblack

For the MnO2, i found out that graphite usually floats on water, and slowly overflowing the beaker with water makes it drip out of it while leaving the MnO2 on the bottom.

As a further test, i tried igniting the powder with an oxidizing flame and nothing happened, so i'm quite sure it is only MnO2.

To remove all the graphite by floatation only is nigh impossible IMHO: the two materials are far too much interwined for that, it's a real paste, not just a dry blend of two powders. Just trying to ignite your powder is a poor test. Dissolve some in HCl: you’ll be left with at least some black residue of graphite (the liquid phase contains the Mn as MnCl2). The subject of extracting the manganese oxides from battery crud has been exhausted to destruction here on this forum in various often lengthy threads.

[Edited on 25-11-2011 by blogfast25]

S.C. Wack - 25-11-2011 at 11:11

It is not challenging to get a nice shiny powder from alkalines. It may be impossible from some brands, but is very easy from others (once you've got the case open).

Demonblack - 3-12-2011 at 16:50

Sorry for the absence.

Quote: Originally posted by blogfast25

But what's wrong with the zinc casings from Zn/MnO2 batteries? Granted, it's not powder...

What's wrong with them? That i don't have tons of carbon-zinc batteries, lol

Quote: Originally posted by S.C. Wack

It is not challenging to get a nice shiny powder from alkalines. It may be impossible from some brands, but is very easy from others (once you've got the case open).

I suspect i didn't get any zinc because i used depleted batteries (the best-performing one putting out 0.23 amps shorted).

I should try with a new battery, but even if that works it's kind of wasteful.

By the way, i think i got ZnO.
It's a very fine powder (there are some bigger clumps but just because i didn't break them well enough), light gray, somewhat tending to blueish.

Endimion17 - 3-12-2011 at 19:12

Quote: Originally posted by blogfast25

But what's wrong with the zinc casings from Zn/MnO2 batteries? Granted, it's not powder...

Nothing is wrong. It's just very expensive, compared to waste anodes. I've managed to get mine for free. It's essentially waste.
It was big as a 1 liter bottle, meaning several kilograms in mass, and all it took was a few nice words with the kind worker at the shipyard.

Purifying it was a nightmare. It took me a whole afternoon of messing with refractory bricks, tongs and propane-butane fire to deliver enough heat to the huge anode. The temperature is not a problem, but the heat... holy cow.

I don't have large enough crucibles, nor a furnace, so I had to heat the whole anode several times, filling my steel crucible beneath.
I was outside the ventilated room most of the time, but even with that precautions, I've even managed to get slight "zinc shakes" simply because it took so long. 24h later I was OK.
Ah, good times.

[Edited on 4-12-2011 by Endimion17]

blogfast25 - 4-12-2011 at 09:11

Quote: Originally posted by Endimion17

How can something that's free be expensive? And who needs about 7 kg of zinc? From where I stand waste anodes are a lot harder to get than spent battery casings.

Arthur Dent - 5-12-2011 at 04:30

I understand the reflex of using the least expensive sources for chemicals, but depleted alkaline and C/Zn batteries is more wasteful of your time and energy than anything. As the members above have posted, there are far better sources for these components.

1st thing is real carbon zinc batteries, I suggest that you go to a dollar store (do you have those in Italy?) and buy some fresh C/Zn D-cells, two packs of two at a dollar a piece isn't bad. You'll get some Manganese dioxide that you can clean-up and purify (several threads here on that). The casings are made of relatively pure zinc, and can be cleaned and cut in little bits. Finally, you have the rods that are made out of carbon and can be used for electrolysis and stuff.

If you don't have such a store in your area, it's worth it to do a little trekking around town to find one. For example, just at my store near me, I can get pure paraffin oil for lamps, pure sodium acetate in hand warmers, hydrogen peroxide, naphta, baking soda in bulk, ammonia, denatured alcohol, zeolite, coffee filters, wire brushes, reagent jars and a ton of useful stuff... all for a dollar or two!

Robert

Demonblack - 5-12-2011 at 05:56

Quote: Originally posted by Arthur Dent

1st thing is real carbon zinc batteries, I suggest that you go to a dollar store (do you have those in Italy?) and buy some fresh C/Zn D-cells, two packs of two at a dollar a piece isn't bad. You'll get some Manganese dioxide that you can clean-up and purify (several threads here on that). The casings are made of relatively pure zinc, and can be cleaned and cut in little bits. Finally, you have the rods that are made out of carbon and can be used for electrolysis and stuff.

It's pointless and wasteful...
If i wanted to buy it, i'd go at the chemical shop (there's a relatively big one in Turin).
The thing about using depleted batteries is that they're not useful anymore, and their processing as special waste also costs money and energy. Opening them with a pair of pliers doesn't

Oh, btw we do have the "1€" stores

Quote:

If you don't have such a store in your area, it's worth it to do a little trekking around town to find one. For example, just at my store near me, I can get pure paraffin oil for lamps

Also sold as baby oil (get the cheapest one so that it doesn't have any parfumes)

Quote:

pure sodium acetate in hand warmers

Never even heard of these, more info?

Quote:

, hydrogen peroxide,baking soda in bulk, ammonia, denatured alcohol

Pretty much everywhere lol

Quote:

naphta,

Lamp fuel, pretty hard to find these days

Quote:

zeolite, coffee filters, wire brushes, reagent jars and a ton of useful stuff... all for a dollar or two!

I got some coffee filters for 0.7€, but they're crap. They tend to self-destruct much more easily than regular paper and also allow the finer powders to pass trough. Avoid the "Aromata" brand...

Never saw zeolite around, but a lot of regular supermarkets sell sodium hydroxide in 500g packs for like 3€ or so.

However i have trouble finding KCl, they sell it as salt subtitute but all the brands i saw are around the 7/3 KCl/NaCl ratio, no pure KCl...