Non-Chemical Some type of Acid reaction vessel verses the scrubber

[Lonnie]

Being new I have all sorts of ideas but quite frankly have no real idea or knowledge of just how any of them would actually work . I know for me a good place to work and a fume hood is a must I simply will not try this without them . Well of course maybe besides some small test tube experiment or a simple cell of some kind . But i will not be digesting in AR or nitric without a hood in place .

I've also been milling over the idea of some type of fume scrubber to at least try and clean the fumes up . No more than I'd be doing I probably could get by without one but would like to do all I can to reduce fumes reliesed into the atmosphere .

Has anyone ever tried or considered condensing the fumes and re-capturing the acids ?? Wouldn't the fumes condense to make the acid you started with or would they be changed into some other acid ? Reading up on reaction vessels I see that most will drip the acid back into the reaction vessel .

I guess what I'm thinking is why couldn't these be dripped back into another vessel so your still depleting the nitric but not loosing the acid or pumping them into the air ? Has anyone ever done this ? It seems the set up cost couldn't be that much more than trying to build and maintain a scrubber and if you could use the nitric again it seems it might pay for itself in time if you done enough refining .

Any comments by those with the knowledge would be greatly appreachated .

Thanks Lonnie

 

[lazersteve]

There are many posts on recycling the nitric acid vapors.

The cheapest and easiest way to reclaim the fumes is to use a watch glass or a condenser on the reaction vessel. This simple method provides an instant reclaiming effect by reducing the NOx losses and extending the amount of metal your nitric will dissolve.

Search for the forum for keywords like NOx, ice, condenser, and marbles for ideas on catching NOx fumes.

The reason this works can be seen in the chemical equation of nitric acid dissolving copper:

1) 3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O

and the subsequent reaction of NO with O2 (from air) and water:

2) 2NO + O2 → 2 NO2

3) 3NO2 + H2O → 2HNO3 + NO

Extends your nitric by 1/4 more if your capture all of the off gases.

I found all of the above information by searching the forum for Cu(NO3)2 posts by lazersteve.

If you are seeing red-brown (NOx) fumes getting out of the reaction vessel or condenser then the reaction life of your nitric will be shorter. You want a steady fizzing reaction that is not billowing red-brown off gases out of the reaction vessel, but instead returns these vapors to the reaction with some form of vapor trap or condenser to be used to their fullest extent.

Steve

 

[Lonnie]

Steve

Thanks man thats very incouraging to hear from someone like you that knows what he is doing . So if I understand correctly this can be done quite simple provided I control the reaction and keep it working slow .

To control the reaction and keep it slow I'm assuming adding small amounts of digestable material and keeping it from getting to warm would be the way to proceed . Possably no heat in the beginning and warming up slowly during the process to keep things working .

One question about this

" Extends your nitric by 1/4 more if your capture all of the off gases."

I think I understand that your saying X ML of nitric will dissolve X grams of silver and if by reclaiming the fumes this way I can dissolve X plus 25% more silver . My question is will doing things this way also use up all the nitric in the solution so no or very little urea is needed ?

Thanks for the information I'm deffently leaning towards a set up like this .

Thanks again
Lonnie

 

[lazersteve]

Lonnie,

Don't add material, add nitric in small increments. Choose a reaction vessel sized appropriate to your scrap that you are digesting. If you have to split the lot into several runs to fit in your reaction vessel. Add the nitric in small doses.

I rarely run reactions cold, especially poor man's AR .Typically I run on setting 3-5 out of 10 on the hot plate dial. I judge the temperature setting by how much off gassing I'm getting and how vigorous the reaction is. I want the most vigorous reaction with the least off gassing.

The savings in nitric can be interpreted from either perspective, more silver dissolved, or less nitric used. Regardless of which way you think of it, the key is to follow the observations of how to identify when the nitric is used up and work so that the reaction completes when the nitric is all consumed.

Steve

 

[Lonnie]

Steve

Thanks for putting up with all the questions . Especially when it will be awhile yet before I do attempt this . Thing is I feel better trying to figure out the process , gather needed supplies and get things I'm in doubt answered before I try . That just seems to me a more logical approach than diving in head first then hollering HELP !! LOL

It seems to me it will just be a do and learn process untill I've done it a few times . These contacts weigh like 1.15 troy ounce each so I'm thinking just 2 or 3 of them for the first time or two . Then the smallest beaker they would lay flat in for the reaction . Slowley add heat and small amounts of nitric and watch the reaction . If it stops reacting while material is still un-digested slowly add more nitric .

Near the end of the reaction and I'm trying to use up any remaining nitric I assume it might be approprate to turn the heat up just a bit more once the reaction slows down trying to drive off the last of the nitric ?? My way of thinking is that I'd be better off to have a chunk of material left to process later than have everything digested with extra nitric left .

Anyhow I think that answers my questions and I'm to a point I'll just have to dive in and do this to get a feel for whats involved in the process .

Thanks a lot Steve your help has been very much appreachated .

Lonnie