So, we put an old Maxtor harddrive in a glass measuring beaker, and 
stood it in one of our fume cupboards.

We poured nitric acid on it. Nothing.

The guy opened a bottle of sulphuric acid, which was smoking slightly. 
Pour some of that in... a tiny amount of fizzing. That's about it.

So we stand at look at it for a moment. And then my college decides to 
add a little hydrochloric acid.

Woah... I'm not sure what the chemistry of this is, but now it's foaming 
like hell, and there's huge clouds of dark brown smoke coming off it. 
Uh, yeah, I think we close the fume hood now...

After a few minutes it eventually stopped fizzing. There's still some 
kind of brown vapour issuing from it though. And the black paint is 
slowly falling off, revealing the dully silver metal beneath.

It will be interesting to see if there's anything left by Monday. My 
college thinks it will have been reduced to sludge by then. I suspect 
it'll still be in once piece, just slightly corroded around the outside.

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On 8/17/2012 7:25, Invisible wrote:
> little hydrochloric acid.

Flashbacks to Breaking Bad.

-- 
Darren New, San Diego CA, USA (PST)
   "Oh no! We're out of code juice!"
   "Don't panic. There's beans and filters
    in the cabinet."

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Le 17/08/2012 16:25, Invisible nous fit lire :
> So, we put an old Maxtor harddrive in a glass measuring beaker, and
> stood it in one of our fume cupboards.
> 
> We poured nitric acid on it. Nothing.
> 
> The guy opened a bottle of sulphuric acid, which was smoking slightly.
> Pour some of that in... a tiny amount of fizzing. That's about it.
> 

Red alert. Mixing Nitric acid with Sulphuric acid is a cocktail to make
nitroglycerin from glycerine. The smallest part of grease might turn
dangerous once dried.


> So we stand at look at it for a moment. And then my college decides to
> add a little hydrochloric acid.

Great, now the cocktail is a mix of Sulphuric acid and Aqua regia, the
solvent for gold & platinum.
(for gold, the proportion are 2/3 Nitric, 1/3 Chloridric; it goes to 7/9
and 2/9 for platinum, IIRC)

All the water generated by Aqua regia attacking the metal will get
captured by the Sulphuric acid.

Notice that Aqua regia is unstable: it will generate chlorine gaz and
nitric oxyd (Cl2 and NO) with water.
Adding water to Sulphuric acid is exothermic. (it generates heat)

> 
> Woah... I'm not sure what the chemistry of this is, but now it's foaming
> like hell, and there's huge clouds of dark brown smoke coming off it.
> Uh, yeah, I think we close the fume hood now...
> 
> After a few minutes it eventually stopped fizzing. There's still some
> kind of brown vapour issuing from it though. And the black paint is
> slowly falling off, revealing the dully silver metal beneath.
> 
> It will be interesting to see if there's anything left by Monday. My
> college thinks it will have been reduced to sludge by then. I suspect
> it'll still be in once piece, just slightly corroded around the outside.

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Le 18/08/2012 10:05, Le_Forgeron nous fit lire :
> (for gold, the proportion are 2/3 Nitric, 1/3 Chloridric; it goes to 7/9
> and 2/9 for platinum, IIRC)

Nah, it's the opposite proportion! More Chlore, less Nitro!

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Am 18.08.2012 10:05, schrieb Le_Forgeron:
> Le 17/08/2012 16:25, Invisible nous fit lire :
>> So, we put an old Maxtor harddrive in a glass measuring beaker, and
>> stood it in one of our fume cupboards.
>>
>> We poured nitric acid on it. Nothing.
>>
>> The guy opened a bottle of sulphuric acid, which was smoking slightly.
>> Pour some of that in... a tiny amount of fizzing. That's about it.
>>
>
> Red alert. Mixing Nitric acid with Sulphuric acid is a cocktail to make
> nitroglycerin from glycerine. The smallest part of grease might turn
> dangerous once dried.

If the aim is to destroy the drive, nitroglycerine would definitely help 
 >_<.


>> So we stand at look at it for a moment. And then my college decides to
>> add a little hydrochloric acid.
>
> Great, now the cocktail is a mix of Sulphuric acid and Aqua regia, the
> solvent for gold & platinum.
> (for gold, the proportion are 2/3 Nitric, 1/3 Chloridric; it goes to 7/9
> and 2/9 for platinum, IIRC)

Fine, so gold parts won't escape either :-P

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On 18/08/2012 09:19 AM, Le_Forgeron wrote:
> Le 18/08/2012 10:05, Le_Forgeron nous fit lire :
>> (for gold, the proportion are 2/3 Nitric, 1/3 Chloridric; it goes to 7/9
>> and 2/9 for platinum, IIRC)
>
> Nah, it's the opposite proportion! More Chlore, less Nitro!

Interesting. I thought aqua regia was sulfuric and nitric... oh well!

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On 18/08/2012 09:05 AM, Le_Forgeron wrote:
> Red alert. Mixing Nitric acid with Sulphuric acid is a cocktail to make
> nitroglycerin from glycerine. The smallest part of grease might turn
> dangerous once dried.

How about all the metal irons now floating around? Will that affect 
anything?

>> So we stand at look at it for a moment. And then my college decides to
>> add a little hydrochloric acid.
>
> Great, now the cocktail is a mix of Sulphuric acid and Aqua regia, the
> solvent for gold&  platinum.

Well, yeah, we /are/ trying to dissolve metal...

> All the water generated by Aqua regia attacking the metal will get
> captured by the Sulphuric acid.
>
> Notice that Aqua regia is unstable: it will generate chlorine gaz and
> nitric oxyd (Cl2 and NO) with water.

Apparently it also evolves NOCl, which might explain the dark brown fumes.

> Adding water to Sulphuric acid is exothermic. (it generates heat)

Yeah, I gathered at least one of them is. Good thing we didn't add any 
water, eh? (Might explain the fizzing though... it certainly didn't seem 
to remove any metal!)

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On 17/08/2012 03:25 PM, Invisible wrote:
> It will be interesting to see if there's anything left by Monday. My
> college thinks it will have been reduced to sludge by then. I suspect
> it'll still be in once piece, just slightly corroded around the outside.

Well, the results are in:

The drive is now somewhat corroded, and most of the paint is missing. 
The circuit board probably won't work again. But other than that, the 
drive is more or less completely unharmed. Apparently soaking it in a 
vat of acid for 4 days is /not/ sufficient to dissolve the entire thing 
down to the platters. :-P

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Le 21/08/2012 11:02, Invisible a écrit :
> On 17/08/2012 03:25 PM, Invisible wrote:
>> It will be interesting to see if there's anything left by Monday. My
>> college thinks it will have been reduced to sludge by then. I suspect
>> it'll still be in once piece, just slightly corroded around the outside.
> 
> Well, the results are in:
> 
> The drive is now somewhat corroded, and most of the paint is missing.
> The circuit board probably won't work again. But other than that, the
> drive is more or less completely unharmed. Apparently soaking it in a
> vat of acid for 4 days is /not/ sufficient to dissolve the entire thing
> down to the platters. :-P

I told you: boiling hydrochloric acid. No fancy mix, just plain Hcl,
enough HCl.

Now, rinse it, dry it and to the boiler...

Or if you have some liquid nitrogen and a hammer... it can be fun too.

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>> Well, the results are in:
>>
>> The drive is now somewhat corroded, and most of the paint is missing.
>> The circuit board probably won't work again. But other than that, the
>> drive is more or less completely unharmed. Apparently soaking it in a
>> vat of acid for 4 days is /not/ sufficient to dissolve the entire thing
>> down to the platters. :-P
>
> I told you: boiling hydrochloric acid. No fancy mix, just plain Hcl,
> enough HCl.
>
> Now, rinse it, dry it and to the boiler...

I don't have any way of heating the acid. Also, we have now run out of acid.

> Or if you have some liquid nitrogen and a hammer... it can be fun too.

We have a 2 tonne liquid nitrogen tank. However, the nitrogen can only 
be withdrawn in gaseous form.

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