Alumina all over my glassware!!!!

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bentheimmigrant
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Alumina all over my glassware!!!!

Postby bentheimmigrant » Mon Feb 14, 2011 6:10 pm UTC

So, I've inherited a lab, including the glassware, and it's all covered in alumina - much of the lab included. At least, I'm almost certain it's alumina. Anyway, a solid white powdery looking film that carries a strong resemblance to a metal oxide, like alumina. The point is, does anyone have any advice as to the best way to attack this stuff (specifically on the glassware - I'm willing to put up with the stuff on the worktops). I've tried the obvious and easily available routes, i.e. scrubbing with detergent, and acetone. These do not work. Any ideas?
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Re: Alumina all over my glassware!!!!

Postby meat.paste » Mon Feb 14, 2011 6:25 pm UTC

You can try sonicating the glassware in a good alconox solution, rinsing thoroughly, then sonicating again in clean water. It's what we do to get alumina off of metal parts. I'm assuming the alumina is a powdery coating.

Good luck.
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Re: Alumina all over my glassware!!!!

Postby HungryHobo » Mon Feb 14, 2011 6:41 pm UTC

off the top of my head sitting them in some weak acid for a while should do it and shouldn't damage the glass.
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Re: Alumina all over my glassware!!!!

Postby ++$_ » Mon Feb 14, 2011 7:12 pm UTC

The sonicator idea seems really good, if you have one. (I don't know what kind of lab it is.)

Dilute HCl will work for most metal oxides. I don't actually know how well it works on alumina in particular, because I have never actually tried this, but it sounds quite feasible.

Alumina (and a few other metal oxides, like zinc oxide) will dissolve in concentrated hydroxide solution. Technically, so will glass, but the glass will dissolve much more slowly so you won't notice. This is probably more expensive than HCl and less likely to work (the oxide may not be alumina), so try the acid first. Also, if it turns out you have to leave the glass exposed to the alkali for a long time, don't use it on glass pieces with interesting microstructures, such as frits.

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Re: Alumina all over my glassware!!!!

Postby HungryHobo » Mon Feb 14, 2011 7:38 pm UTC

to try a classic: test a small bit in some cola overnight if you don't have lab grade acid handy.
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Re: Alumina all over my glassware!!!!

Postby bentheimmigrant » Tue Feb 15, 2011 10:13 am UTC

Thanks for the advice! I don't think I have a sonicator around, and I'm in a Chemical Engineering lab, to answer your queries. I've got access to pretty much whatever I need, chemical-wise - as long as it's not a controlled substance. I have a large amount of caustic soda in my lab (because, well, don't we all), so I may try a hydroxide solution first, as I think I'm almost out of acid.
Looking at what's been done in the lab in the past, it's almost certainly alumina - there's nothing else that's been used enough to coat so much of the equipment.
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Re: Alumina all over my glassware!!!!

Postby p1t1o » Tue Feb 15, 2011 10:48 am UTC

Inherited a lab with strange white powder everywhere? *suspicious look*

Just joking :D but you should try and get a positive identification of the substance before you start adding reagents to things.

I doubt someone would leave a lab coated in anything too horrendous, but you never know what it might be, it might not even all be the same stuff.

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Re: Alumina all over my glassware!!!!

Postby bentheimmigrant » Tue Feb 15, 2011 11:02 am UTC

p1t1o wrote:Inherited a lab with strange white powder everywhere? *suspicious look*

Just joking :D but you should try and get a positive identification of the substance before you start adding reagents to things.

I doubt someone would leave a lab coated in anything too horrendous, but you never know what it might be, it might not even all be the same stuff.

Ha! I'm pretty sure it's safe from... that... kind of thing. If it's not alumina, silica is the next possibility, and after that it's down to various metal oxides. I doubt I'll be able to officially identify it, as the people who put it there didn't care about it, and kept reusing the glassware, as they were only putting more alumina in.
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Re: Alumina all over my glassware!!!!

Postby Charlie! » Tue Feb 15, 2011 6:34 pm UTC

bentheimmigrant wrote:silica is the next possibility

Dammit, who put this silica all over my glassware! :D
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Re: Alumina all over my glassware!!!!

Postby bentheimmigrant » Tue Feb 15, 2011 11:31 pm UTC

Charlie! wrote:Dammit, who put this silica all over my glassware! :D
Indeed... I'm kinda hoping it's alumina for that reason... Although I assume that a powdery coating will be more corrodible than the glass itself. At least, I hope it will.
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Re: Alumina all over my glassware!!!!

Postby ikrase » Wed Feb 16, 2011 6:53 am UTC

It could be Ammmonium Chloride.
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Re: Alumina all over my glassware!!!!

Postby ++$_ » Wed Feb 16, 2011 7:51 am UTC

That dissolves in water.

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Re: Alumina all over my glassware!!!!

Postby masher » Wed Feb 16, 2011 8:45 am UTC

Scrape some off and stick it in a diffractometer. That will tell you what it is.

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Re: Alumina all over my glassware!!!!

Postby Cobramaster » Thu Feb 17, 2011 3:59 am UTC

Honestly go buy a bunch of Coca-Cola and let then glassware soak in it a while.
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Re: Alumina all over my glassware!!!!

Postby thoughtfully » Thu Feb 17, 2011 4:04 am UTC

Or vinegar. You've only got one acid instead of two (phosphoric and carbonic), and a lot fewer odd ingredients that could obscure the results or do something unpredictable. Cheaper too, I'll bet. But maybe not cheaper than off brand soda. Oh, and unused portions are probably more useful. Oh wait. You actually drink that stuff? :)

EDIT:
Ok, it's not cheaper. Not for your wallet anyway. But have a care for your souls, damnit :)
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bentheimmigrant
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Re: Alumina all over my glassware!!!!

Postby bentheimmigrant » Thu Feb 17, 2011 10:22 am UTC

I'd rather buy actual chemicals... I have a consumables budget that I don't think would cover soda. In fact, it would be easier for me to buy hydrofluoric acid on my project code than to buy pepsi. Anyway... Thanks for all the help. I used a base bath (alcohol + water + NaOH) and that seems to work. There's one that was a bit stubborn, so I'll probably just put it back in for a longer time. If I'm desperate I've got some 96% H2SO4 coming in for an experiment, and I'll probably have plenty left over.
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Re: Alumina all over my glassware!!!!

Postby p1t1o » Thu Feb 17, 2011 10:34 am UTC

Theres a guy in another topic who has some 98% H2SO4 he wants to get rid of, you guys should talk!

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Re: Alumina all over my glassware!!!!

Postby bentheimmigrant » Thu Feb 17, 2011 4:24 pm UTC

A bit late for that I'm afraid... It's only like £12 for a litre, and it is taxpayers' money.

Wait... I don't think I'm meant to say that.
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Re: Alumina all over my glassware!!!!

Postby p1t1o » Thu Feb 17, 2011 10:47 pm UTC

You're not an MP are you?


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