# Any use for Kleen Strip's "safer" muriatic acid?



## chlaurite (Mar 17, 2013)

Hi guys... First post, and I wanted to ask a few questions *before* I start making mistakes.

I read Hoke, watched every video on LaserSteve's site (couldn't get enough of those, loved 'em!), and have a pretty decent general background in chemistry (though more on the organic side, not so much with metals). I think I've reached the point that I understand the AP/CuCl2 process well enough to try a small test batch with some simple clean gold pins.

So... I headed out to Home Depot to pick up my reagents, and already made a really dumb mistake - Somehow I ended up with Kleen-Strip's crap-buffered-with-who-knows-what green/safer/low-fume muriatic acid. *Fortunately* I noticed my mistake _before_ I added it to anything, but not until after I opened it (so I can't really take it back to the store).

Now to my first question - Can I do _anything_ useful with it (I don't have any concrete that needs washing :roll: ), or should I just neutralize it with NaOH and write it off? I was thinking that perhaps I could use it straight as a pre-treatment to leach out the ferrous metals (and then remove it before starting with "real" HCl), but with unknown additives in it, am I risking even _that_ leaving me an awful mess to deal with?

Second, I notice everyone uses 3% H2O2; given the ready availability of concentrations up to 30% (100 volume), is it not better to keep the acid concentration higher by having less water diluting the solution (which would also leave less liquid to deal with at the end)? 

I also had a (not entirely unrelated) question about how to deal with all the "base" (and even "heavy") metal salts I'll end up with - I understand moving down the reactivity series to selectively precipitate out specific metals, but what to people do with, for example, lead, cobalt, and chromium? Do any legit chemical waste disposal companies accept low quantities from individuals?


Thanks!


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## Jhuff8181 (Mar 17, 2013)

I have the same question. FYI the concentration is <25%.


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## philddreamer (Mar 17, 2013)

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=12690&p=126822&hilit=green+label+HCl#p126534


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## kkmonte (Mar 17, 2013)

chlaurite said:


> Second, I notice everyone uses 3% H2O2; given the ready availability of concentrations up to 30% (100 volume), is it not better to keep the acid concentration higher by having less water diluting the solution (which would also leave less liquid to deal with at the end)?
> 
> Thanks!



If you use too high of a percentage (or too much of it) of H2O2, it will dissolve the gold as well. So the goal is to dissolve the copper only (in the case with fingers) and not dissolve the gold.


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## chlaurite (Mar 17, 2013)

philddreamer said:


> http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=12690&p=126822&hilit=green+label+HCl#p126534



Thanks, my original search somehow missed that thread. Though sadly, I notice it doesn't really have all that conclusive of an ending to it - Which I guess at least partially _does_ answer my question "Use it at my own risk".  

I picked up some straight HCl today, perhaps I'll try an AP batch with each and document the differences between the batches (though not having much experience with this yet, my observations probably aren't all that valuable yet).


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## butcher (Mar 18, 2013)

I would save that jug of muriatic acid with buffering agents for things like cleaning up the stockpot, or acidifying a waste material when needed...

With dilute 3% hydrogen peroxide we generate oxygen gas in the HCl acid (to oxidize copper), where if we added 30% hydrogen peroxide to that acid we would oxidize the HCl to form Chlorine in solution (that not only would oxidize the copper, but would also oxidize gold putting both metals into solution at the same time, something we really want to avoid).

HCl alone cannot oxidize copper and dissolve it, but in the HCl acid the 3% hydrogen peroxide can supply oxygen to help to oxidize the copper (Cu) and make a copper oxide (CuO), then this copper oxide can be oxidized to a higher state with the HCl. to make copper (II) chloride (CuCl2). Now copper (II) chloride can oxidize more copper. Forming copper (I) Chloride (CuCl), we can rejuvenate the copper (I) chloride back to copper (II) chloride with adding a little more HCl, ready to dissolve more copper. 

Laser Steve's web site has a document that explains the process and how it works.

For treating your waste, I would begin my with studying the thread dealing with waste in the safety section, also the less of these metals you but in solution the less of them you will be dealing with, you should remove as much as possible by mechanical methods as possible.

Also take lead for example when I do put it into solution I know how it reacts in solution, this gives me a way to separate it, from the majority of other metals, or salts, and I can store it for other uses, like if I wish to make litharge, learning how the metals react can also help you learn to separate them, and convert them to another salt or sometimes back to the metal so that I may also not have to dispose of it.

We Have amnesty day here were they take the hazardous waste in small volumes from you home.


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