20 replies to this topic

[nlazenby]

I was wondering what would be a good way to obtain aluminum powder from soda cans
I have a ball mill
and why buy on ebay when cans are free
any ideas? ive already tried cutting it in to small strips and blending it but that doesn't work

[alany]

You may prefer to buy it, vastly easier!

A cross-cut shredder fed kitchen foil, then ball milled with a little sterine for a month should do the trick. Even starting with swarf or filings it will take a long, long time. Aluminium cans aren't the best alloy, they are fairly high in silicon, when I melt them down I get a lot of slag, probably similar levels of contaminates if you managed to mill them.

I was crazy enough to ball mill magnesium once, I would not attempt that again. I feel lucky i got away with it. I feel a lot more comfortable about magnalium and aluminum, but still rather cautious, especially as it gets really fine.

[nlazenby]

well i was able to cut off the ends of the can leaving me with a coil, then i cut the coil leaving me with a ribbon which i then fed into a paper shredder and that left me with diamond shape pieces (about 2-3cm) then i put them into the Magic Bullet(blender) that I received as a Christmas present last year and that left me with some particles a little bigger than sand

My question is if I were to then mill the Al particles with lead media would that do the trick or would the aluminum be to dense or what would be a more effective media
as for just buying it:I'm really on a tight budget and cans are pretty plentiful plus i like a little challenge

Edited by nlazenby, 25 July 2010 - 06:21 PM.

[alany]

I'd use steel media, but if you've got more time than money, why not give it a try?

[vaslop2005]

I have managed to make Al powder by ballmilling and it is relatively easy, and will only take a week to obtain a very fine powder in even my tiny mill. But you'll soon find, as I did, that bright flake Al is very cheap, and can be used for almost everything (even flash)

If you want a good yeild of Al powder you will need a large diameter ballmill (which is expensive) and a 250 mesh screen so that you can open up your mill every few days and extract the usefull size powder.

I know it seems a shame to buy something that you can make, but sometimes it's realy the only way...

[Arthur Brown]

I've seen a paper discussing milling drinks cans to produce fine powder Al. They said it was successful HOWEVER;

They used a steel jar and steel balls
they used stearic acid as a process modifier,
They used a purge gas mix of argon,
They ran the mill for a week.

The trade value of the Al dust was less than the cost of the electricity to the motor, then the argon gas cost money.

Yes it's possible to make Al powder, but usually it's cheaper to buy it.

Now! Getting all the grades of flake and flitter from foil or cans with a shredded/blender/mill does mean that you can have lots of grades to get different burn times. Which may well be interesting

However (again!) getting a repeatable effect means getting the same sort of particle every time you need to mill, which means careful process control.

[cooperman435]

I too can confirm that milling Al is possible but if your doing it to save money your wasting time and money.

Large diameter mill jar and steel media results in high setup fee then electrical energy resulting in expensive ali flake.

[nlazenby]

I have a 6lbs ball mill form united nuclear
Ill try it with steel balls(can i mix 1/2in lead with 1/4in steel balls) , as far as time is concerned it only takes me about 20min to shred 100-150g then 5min of blending
my utility are paid for by the university I attend, energy cost wont be an issue. One of the above posters mentioned using stearic acid as a process modifier? Whats a process modifier and would the inclusion of just the stearic acid help at all?


oh and buying it.....not as much fun.

[Arthur Brown]

As the milling procedes the particles cam impact fuse as well as abrade. A small amount of stearic acid (say 2 - 5% ) should permit the abrasion without the impact fusion getting finer particles.

Still I think you are mad! Buy some of whatever mesh you want. If you are very lucky you will mill 500g in a week to a range of sizes giving you some 600mesh and some 10 mesh and no useful amount of any mesh cut.

NO don't mix media, the hard media abrades the soft media.

[cooperman435]

6lb means nothing to me sorry but mixing media is a bad idea as I found long ago it can damage your softest ones quickly (Ie the lead)

Honestly buy it.

[dr thrust]

just noticed the size of your steel media 1/4inch?, surely the min size is 1/2? what size is your milling jar 8 inch?

[digger]

By the way just for your information.

The stearic acid is there to provide a coating for the aluminium to help prevent it reacting with atmospheric oxygen (all pyro aluminum is coated, well every drum I have seen is).

The other thing to consider is that many industrial processes use a wet method for milling aluminium. As a rule of thumb wet milling will allow particles 1/3 of the size of dry milling to be produced. So you may find that the stearin is often actually dissolved in a non polar solvent.

The wet method helps to keep the powder in contact with the media rather than it just floating about.

One other myth is that carbon is added in the milling process. This is certainly not true for german, Indian and Brazilian pyro grade aluminium powders.

[Mumbles]

The carbon comes afterwards. One method for VERY fine aluminum flake is to glue it to a sheet of paper, and then mill it. Afterwards it can be burned off. I don't know if the paper helps to get the foil thinner in the first place, or makes it heavier/denser, or prevents fusion, or what exactly. I've seen it listed on barrels and COA for a few grades from Eckart. 10890 and 5413 to be specific.

Edited by Mumbles, 26 July 2010 - 03:16 AM.

[digger]

One method for VERY fine aluminum flake is to glue it to a sheet of paper, and then mill it.

I have heard of this mentioned in past. However I have not come across any actual proof of this process (or that it ever exisited). Can you point me towards some patents/equipment/literature?

Edited by digger, 26 July 2010 - 11:54 AM.

[digger]

I've seen it listed on barrels and COA for a few grades from Eckart. 10890 and 5413 to be specific.

Interesting, I have not. I will go and have a closer look. Do you have a copy of the COA as I would be interested to see that.

The data sheets do not list it.