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#1
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how to dispose of 22k testing solution?
I have a little 22k testing solution in a dish because I was told that
it was a suitable silver etchant. (It actually did not etch my silver, but perhaps I did not leave it in long enough or my image was too thin.) In any case, I need to dispose of it because it can't go back into the little squeeze bottle and I'm moving. It is a pretty small amount...does anyone know of the proper way to dispose of it? thanks in advance, -stacy |
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#2
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how to dispose of 22k testing solution?
On Sat, 01 Aug 2009 03:05:00 -0700, in rec.crafts.jewelry stacy c
wrote: I have a little 22k testing solution in a dish because I was told that it was a suitable silver etchant. (It actually did not etch my silver, but perhaps I did not leave it in long enough or my image was too thin.) In any case, I need to dispose of it because it can't go back into the little squeeze bottle and I'm moving. It is a pretty small amount...does anyone know of the proper way to dispose of it? thanks in advance, -stacy Stacy, The 22k test acid is a mix of nitric acid and hydrochloric acid, a mix also referred to as aqua regia. Nitric acid will etch silver. But hydrochloric acid forms an insoluable surface layer of silver chloride on the surface. Because it won't dissolve in the liquid, it then blocks further etching. So what you were told is incorrect. It WOULD, though, etch gold alloys. Somewhat troublesome as an etchant, since aqua regia is very very aggressive, as well as producing nasty fumes you need to be aware of. It can tend to lift etch resists. Some kinds of resists, at least... What you need for etching silver, is plain nitric acid. Use it diluted, not high concentration. Roughly 20 percent would be suitable. A slower, more even etch will be obtained with using a nitric acid salt, silver nitrate, rather than the straight acid. Advantages of silver nitrate solution are much less problems with fumes, and because it etches less aggressively, you get a more even etch with less undercutting, and less lifting off of your resist. If you want to use one of the small bottles of test acids as an etchant, you need one that's straight nitric, without added HCL. The 10K and 14K acids are probably in that catagory, as would be silver test acid for sure. The 22K acid has to have HCL in it, since gold of that high quality simply doesn't react at all to nitric by itself. Given the small quantity of what you need to dispose of, simply rinse it down the drain with lots of water. The main thing to disposing of such acids is copious dilution with water. That done, it becomes essentially harmless. If you had more than a tiny amount, you might want to dump it down the toilet, not the kitchen drain, since there it's vastly diluted long before it hits any metal plumbing (like sink strainers, etc.) Or, you could if you wished, neutralize the acid first by slowly adding a solution of water and baking soda. But that's really overkill for this. Plain dilution with water is enough. One important note. When diluting concentrated acids, you never want to add a small amount of water to a larger amount of acid. Instead, pour the acid slowly into the water, preferably, a larger volume of water. The other way around, a small volume or narrow stream of water mixing with acid heats up quickly, and small amounts can litterally boil and spatter. Dangerous with acids. (thus the common mnemonic rule of always add acid to water, not water to acid). However, with a small amount of acid, turning on the faucet and simply rinsing the acid down the drain will be safe enough. And your test acid isn't the highest concentration either, so it's also safer to handle. Peter Rowe |
#3
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how to dispose of 22k testing solution?
It is a pretty
small amount...does anyone know of the proper way to dispose of it? thanks in advance, -stacy Stacy, If your local council is nasty about putting heavy metals down the drain,an he amount is small, say not over 100 ccs., get some lime, or washing soda or bicarbonate of sode, mix one of these with a plant-pot full of soil(garden dirt), then tip your acid into it and dispose of it as solid waste. Don't breathe the fumes, do the job outside. Peter's recipe is easier,though! G.H.Ireland. -- _ _________________________________________ / \._._ |_ _ _ /' Orpheus Internet Services \_/| |_)| |(/_|_|_ / 'Internet for Everyone' _______ | ___________./ http://www.orpheusinternet.co.uk |
#4
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how to dispose of 22k testing solution?
On Tue, 04 Aug 2009 22:51:37 -0700, in rec.crafts.jewelry Mr G H Ireland
wrote: If your local council is nasty about putting heavy metals down the drain,an he amount is small, say not over 100 ccs., Last I checked, the type of little bottle of test acid I think she's got is about 10cc or less. Really small amounts. And since she didn't get any significant etching action, then there's no significant metal content either. just the acid. Peter |
#5
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how to dispose of 22k testing solution?
Peter W. Rowe wrote:
On Tue, 04 Aug 2009 22:51:37 -0700, in rec.crafts.jewelry Mr G H Ireland wrote: If your local council is nasty about putting heavy metals down the drain,an he amount is small, say not over 100 ccs., Last I checked, the type of little bottle of test acid I think she's got is about 10cc or less. Really small amounts. And since she didn't get any significant etching action, then there's no significant metal content either. just the acid. If you're in the UK your supplier must supply you with the appropriate 'control of substances harmful to health' or COSHH form which will detail the disposal method you MUST follow. Just ring them up and ask for it... -- William Black The secret of life is honesty and fair dealing. If you can fake that, you've got it made. |
#6
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how to dispose of 22k testing solution?
Mr G H Ireland wrote:
It is a pretty small amount...does anyone know of the proper way to dispose of it? thanks in advance, -stacy Stacy, If your local council is nasty about putting heavy metals down the drain,an he amount is small, say not over 100 ccs., get some lime, or washing soda or bicarbonate of sode, mix one of these with a plant-pot full of soil(garden dirt), then tip your acid into it and dispose of it as solid waste. Don't breathe the fumes, do the job outside. Peter's recipe is easier,though! G.H.Ireland. Peter's recipe is wrong, albeit easier. Yours is right, and the only way this should be done, no matter what the amount is. -- Abrasha http://www.abrasha.com |
#7
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how to dispose of 22k testing solution?
Peter W. Rowe wrote:
Given the small quantity of what you need to dispose of, simply rinse it down the drain with lots of water. NO! NEVER ADD WATER TO SUCH A POTENT ACID SOLUTION, UNLESS YOU WANT TO WITNESS A VIOLENT ACID EXPLOSION! I HAVE SEEN THE RESULT OF THAT. A PERMANENTLY DISFIGURED FACE OF MY BLIND CHEMISTRY PROFESSORS AT THE UNIVERSITY OF AMSTERDAM. The main thing to disposing of such acids is copious dilution with water. NO, NO, NO. NEVER EVER ADD WATER TO ACID. In Germany we had a standard Goldsmith's rhyme to rtemember what to do: "Erst das Wasser, dann die Saure. Sonst passiert das Ungeheure." (First water, then Acid, otherwise the gruesome will happen) In the US we are taught to remember AAA (Always Add Acid) That done, it becomes essentially harmless. If you had more than a tiny amount, you might want to dump it down the toilet, not the kitchen drain, since there it's vastly diluted long before it hits any metal plumbing (like sink strainers, etc.) Are you out of your ****ing mind Peter?!? Or, you could if you wished, neutralize the acid first by slowly adding a solution of water and baking soda. If you wished? This is the only way to do it. And no water of course! But that's really overkill for this. Plain dilution with water is enough. Are you nuts giving this kind of advice to a novice, who knows nothing about these matters! No matter what amount, ALWAYS do it the right way. Dilute first with baking soda, then dilute further with water. -- Abrasha http://www.abrasha.com |
#8
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how to dispose of 22k testing solution?
stacy c wrote:
I have a little 22k testing solution in a dish because I was told that it was a suitable silver etchant. (It actually did not etch my silver, but perhaps I did not leave it in long enough or my image was too thin.) In any case, I need to dispose of it because it can't go back into the little squeeze bottle and I'm moving. It is a pretty small amount...does anyone know of the proper way to dispose of it? thanks in advance, -stacy Put the solution in a larger container and add liberal amounts of baking soda, a small amount at a time, until the solution no longer "bubbles up". Be very careful doing this so nothing splashes out. Wear safety goggles and rubber gloves to adequately protect yourself. Then dilute everything with water. Add more baking soda. The acid should now be sufficiently neutralized to be disposed of safely down a drain or in a toilet. -- Abrasha http://www.abrasha.com |
#9
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how to dispose of 22k testing solution?
On Tue, 25 Aug 2009 00:43:26 -0700, in rec.crafts.jewelry Abrasha
wrote: Peter W. Rowe wrote: Given the small quantity of what you need to dispose of, simply rinse it down the drain with lots of water. NO! NEVER ADD WATER TO SUCH A POTENT ACID SOLUTION, UNLESS YOU WANT TO WITNESS A VIOLENT ACID EXPLOSION! The whole situation relates to the fact that strong acids, when being diluted or mixed with water, generate heat. A fair amount of it. A small quantity of water mixing with a large quantity of acid can be heated to boiling, which then spatters, a dangerous situation indeed. But Abrasha, please re-read the situation. The amount of acid involved is perhaps at most a teaspoon. If you run the tap water in the sink and dump that tiny quantity of acid into it, even though this violates your normally correct rule, the small amount of acid simply cannot heat the water (a larger quantity) enough to cause a problem. The rule, after all, is to add acid to water, not water to acid, right? And running the tap and dumping the acid down the sink is doing exactly that. Even if you did the reverse, dumping the acid in, then turning on the tap, the added water is an instant and very large amount. With such a tiny amount of acid, there will simply be no reaction. It's certainly true that the rule, acid to water, not water to acid, is something people need to know, and if it's more than a tiny amount of acid, is important. The dangerous situation, though, usually involves something like someone having a volume of acid and slowly pouring a thin stream of water into it. THAT is a recipe for disaster. But a rapid addition of an overwhelmingly larger amount of water to a small amount of acid will not be. The key, here is the definition of "small amount". The OP in this case had one of those tiny plastic squeeze bottles of test acid. They contain perhaps 2 ml of acid, if that. It would be difficult to add water to it slowly enough from a kitchen tap to cause a problem even if the acid remained in a container for the addition. But poured down the drain at the same time as turning on the water simply won't. I've done it many times. I HAVE SEEN THE RESULT OF THAT. A PERMANENTLY DISFIGURED FACE OF MY BLIND CHEMISTRY PROFESSORS AT THE UNIVERSITY OF AMSTERDAM. The main thing to disposing of such acids is copious dilution with water. NO, NO, NO. NEVER EVER ADD WATER TO ACID. Right. My sentance did not mean to indicate an order. Only the relative amount of water to acid. Perhaps I should have been clearer. But remember, I was commenting in the context of the OP's tiny amount of acid. In Germany we had a standard Goldsmith's rhyme to rtemember what to do: "Erst das Wasser, dann die Saure. Sonst passiert das Ungeheure." (First water, then Acid, otherwise the gruesome will happen) In the US we are taught to remember AAA (Always Add Acid) That done, it becomes essentially harmless. If you had more than a tiny amount, you might want to dump it down the toilet, not the kitchen drain, since there it's vastly diluted long before it hits any metal plumbing (like sink strainers, etc.) Are you out of your ****ing mind Peter?!? No. My mind is clear. Think about it. Pouring acid into the toilet is adding acid to water, which is correct. And again, the context of the discussion is small amounts. I state elsewhere in the thread that the question of whether acid should be diluted depends on the quantity. This thread discussed a very small insignificant amount. Anything more substantial is a whole different subject, where you'd need to consider more active neutralization of the acid in order to prevent problems or violate pollution standards or the like. Or, you could if you wished, neutralize the acid first by slowly adding a solution of water and baking soda. If you wished? This is the only way to do it. And no water of course! It's certainly not the only way. Baking soda dissolved in water works with much less mess. Of course, you add the acid to the baking soda solution, not the reverse for the same reason you add acid to water, not the reverse. But there are many other bases which would effectively neutralize an acid solution. My preferred method the last time I needed to get rid of more than a few ml of strong acid was a plastic bucket of crushed limestone with a bit of water in the bottom under the crushed rock. The acid reacts to the limestone as well as with baking soda, but without foaming up all over the place, which can make a bloody mess. In some lab work (or acid refining, for that matter) urea (dry powder or granules) added to HCL neutralize it effectively without any foaming or annoying reaction, for example. (used in refining because it neutralizes excess Hydrochloric acid without neutralizing the nitric acid componant.) But that's really overkill for this. Plain dilution with water is enough. Are you nuts giving this kind of advice to a novice, who knows nothing about these matters! There were more complete instructions also sent in email to the OP, which included cautions regarding amount, as well as against adding water to acid, especially slowly. No matter what amount, ALWAYS do it the right way. Dilute first with baking soda, then dilute further with water. As I said, and I know you'll argue, right depends on the situation. Keep in mind that I've got a good deal of chem lab experience, and a family history of professional chemists (my father). There are times when the rules need to be blindly and mindlessly followed for safety, and beginners are often one of those times. You are correct in this. But nothing is absolute. For example, when I do an acid test with a drop of acid on a touchstone, I simply rinse it off when done. That's "acid to water", against the rules. But it's not been a problem, or produced any noticable negative effects in 30 years of doing it that way, either for me, or anyone else I know. Would I slowly pour a bit of water into a beaker of acid? No, of course not. That's dangerous as hell outside of an entirely closed reaction vessel. But dumping a teaspoon of acid into the sink with the faucet running to dilute it simply isn't the same situation, and that situation is what we've been discussing. You can use baking soda if you wish too. But I don't consider it necessary, and neither would the various chemists I've known or worked with over the years, I promise you. Peter |
#10
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how to dispose of 22k testing solution?
Here, here, Peter!
[[moderator's note: This is a response to a thread active last summer...]] |
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