possible poorer man's AR

[solar seeker]

I recently came up with the idea that ammonium chloride could be oxidized by mixing it with hydrogen peroxide potentally producing nitric acid and either hydrochloric or hypochlorious acid which would essentially be aqua regia at least hypothetically. Upon testing this I found that this combination does dissolve copper when mildly heated where an ammonium chloride solution alone does not. The over all process is quite slow and needs to be further researched and or experimented with in order to make this into a usefull method for recovering metals but the ingredients can be bought at your local walmart in the form of instant cold packs (the ammonium nitrate free varriety) and common 3% hydrogen peroxide. I suspect that using a stronger form of hydrogen peroxide, a catalyst ,and some chemical to stablize the hydrogen peroxide in order to slow the loss of oxygen gas will enhance the usefullness of this as a metal etching solution. One interisting thing I should note is that this mixture turns a pale blue color like that of copper nitrate.

 

[Oz]

I am at a loss here. It seems you are going out of your way to have chlorides and no nitrates. I fail to see how you can get nitric without nitrates. You can digest gold with a chloride and H2O2, but I sure would not do it with ammonium present as it could easily go BOOM.

 

[solar seeker]

As I understand it nitric acid is commercially produced by catalytic oxidization of ammonia.
The idea is to use hydrogen peroxide as an alternitive method of oxidizing ammonia into nitrogen oxides which are combined with water to make nitric acid. If one oxidizes the ammonia in an ammonium chloride solution to form nitric acid then the remaining chloride ions will be in the form of hydrochloric acid. Nitric and hydrochloric acid combined make the lovely brown fuming mixture known as aqua regia which laser steve has shown to work better in the presence of hydrogen peroxide. The problem is encourraging the ammonia to combine with the excess of oxygen that hydrogen peroxide provides hence the need for a catalyst to drive the reaction in the right direction.

 

[butcher]

they are using a strong ammonium gas and a catalyst and high temperature's, making this very hard to do, and even if you can form some of the gas converting them back to Hno3 would be another challenge, this would not be a simple task, much better ways to make nitric or HCl on a small scale.
yes you can electroyize air and make nitric acid, but here also is not practical on small scale. some things they do on large scale industrially are very hard to make at home, especilly on limited budgets.

most any cloride salt will dissolve some copper if it is oxidized first.
ammonia naturally breaks down to nitrogen (a bacteria in soil helps with this)but you would have to wait for some time.

good luck with these expieriments, and be careful, as of yet I am just skeptical. maybe you will change my mind?

 

[solar seeker]

According to this link http://www.blurtit.com/q393093.html when you mix ammonia and hydrogen peroxide you get nitrogen,water,nitric oxide,hydrogen,oxygen,and heat. Although it's incomplete and unbalanced here is the equasion from that website.

NH4 + H2O2 -----------> N2 + H2O + NO

I can't find any information on weather or not this happens in the pressence of chlorine but the innitial test showed good results. I had also considered using common household ammonia or ammonium nitrate as possible substitutes for ammonium chloride.

Btw Oz I did take into consideration that something could go very wrong so I tried my first batch on a very small scale.

In response to butcher's post: The heat is a by prouduct of the catalytic convirsion from ammonia to nitric oxide and while platinum is a potential catalyst so is copper. The high pressures are optional on a small scale.

In this case however ammonia is converted to NOx gasses without a catalyst meaning other than heat control all one needs to do is react the NOx with water or better yet hydrogen peroxide in an optional ice bath.

 

[SilverNitrate]

Ammonium (NH4OH) is loudly irritating and can only come in strengths of 26% ammonia. Ammonium nitrate is commonly used as an explosive and one may need demolition license. nitric acid isn't that impossible to get a hold of. A simple search online can find you a list of suppliers, however usually they have minimum usually 15 gal and have to leave a rather high deposit on the drum.

 

[butcher]

I am not disagreeing that it can be done, and you may produce a small bit of nitric, but it is not practical from all I have read, and I have studied nitric acid an awful lot, reading many expieriments were people have succesfully made some (small amounts) using processes we have been talking about and read about many failed expieriment to to this. I like making nitric acid with sodium nitrate, potassium nitrate, or calcium nitrate, or ammonium nitrate and sulfuric acid, is much more practical and easy to do, (here I can still buy ammonium nitrate as fertilizer locally), I prefer sodium nitrate. sorry I try to spend my time using what I know works, or at least has a good chance of working , than trying to find something that just might work.

 

[Harold_V]

sorry I try to spend my time using what I know works, or at least has a good chance of working , than trying to find something that just might work.

You know, I had that attitude when I refined. I simply was not interested in re-inventing the wheel, which I found to be round to my satisfaction. Instead of worrying about such things, I spent my time refining, using well known and accepted processes, and commercial acids. Only under extreme circumstances would I consider dedicating my time to making my own. Too much time is lost otherwise, often with little success. After all, my purpose was to accumulate precious metals---not to become an inventing scientist. One must keep site of their objective in matters such as this.

In today's market, where buying nitric has been made difficult (and expensive), I may see things differently were I still involved in refining.

Harold

 

[nickvc]

sorry I try to spend my time using what I know works, or at least has a good chance of working , than trying to find something that just might work.

You know, I had that attitude when I refined. I simply was not interested in re-inventing the wheel, which I found to be round to my satisfaction. Instead of worrying about such things, I spent my time refining, using well known and accepted processes, and commercial acids. Only under extreme circumstances would I consider dedicating my time to making my own. Too much time is lost otherwise, often with little success. After all, my purpose was to accumulate precious metals---not to become an inventing scientist. One must keep site of their objective in matters such as this.

In today's market, where buying nitric has been made difficult (and expensive), I may see things differently were I still involved in refining.

Harold

Even at today's prices Harold I think you would still buy it in , commercial volumes are still relatively cheap compared to the value of the metals to be recovered. I can fully understand members trying to look for ways of producing small volumes of nitric with the prices I see people paying but when your in a commercial refining operation as you were ,time is money.

 

[solar seeker]

It seems that I gave the impression that I don't have an easier method of obtaining nitric acid. In my case it is far cheeper to make poor man's aqua regia and recycle the NO2 fumes or distill nitrates with sulfuric acid than to buy nitric at the high price of $100 per gallon.
What I'm trying to do is find a way to completely recycle nitric acid if not produce more than I had to start out with. By doing this I can have a more efficiant and perhaps a closed looped system that I never have to buy nitric for again. 8) It's an ambitious goal I know but It's really more of a hobby to satisfy my invintive nature than a business in which to make money.

 

[Harold_V]

It's an ambitious goal I know but It's really more of a hobby to satisfy my invintive nature than a business in which to make money.

That's what I meant when I suggested one must keep site of their objective. Mine was to own precious metals, so buying and using supplies was a means to an end.

I think what you're trying to do is admirable, and while my goal was very different, yours is equally important, and that's what matters.

Good luck with your venture. Be certain to share what you learn with others, for that's what the board is all about.

Harold

 

[solar seeker]

Thank you for such high prase. On that last note about shairing what I learn, I've found that chlorine bonds to ammonia far stronger than oxygen does which means that it doesn't react with hydrogen peroxide very well untill metal is added to the solution. When metal is added to the solution it releases oxygen gas at an increasing rate. As far as I can tell the copper forms compounds of both ammonia and chlorine because niether of them bubble out. :|
At any rate it does dissolve copper at a better rate than copper chloride but slower than acid peroxide. I have yet to test other metals but it seems that ammonium nitrate and peroxide may work better.

Btw I had to type this whole thing with a non functional backspace key. :lol:

 

[butcher]

Ammonia solutions and H202 is a well known copper etch. as far as making nitric this way I have doubts, as to the ease of doing so or the safety of doing this on the home scale. and to make nitric acid even with metal catalyst I believe this would need to be done with ammonia gas (NH3), as soon as we have water in solution we no longer have ammonia but now ammonium NH4, NH3+H20-->NH4OH. This salt of ammonia, ammonium hydroxide is a basic salt. Take caution with ammonia and metals, they can form very dangerous metal salts they can detonate just by drying, or barely moving them. Ammonium compounds also form amines very easily.

As far as recycling nitric acid this can be done easily but you will not get back as much as you put in, or more than you put in, as some of the gasses of NOx may be hard to get back into solution, so some loss there, and in a home unit the contact time bubbling the gases into water some gas pass through as unreacted NOx gas bubble, not reacting with the water. Some loss the metal as a nitrate salt, which can still be soluble you can retrieve some of this nitric back; some nitrate may take fairly high temperatures of the dry salts.

Even with losses recycling your nitric as much as possible makes sense, I try to recycle as much of the chemicals I can, for me it is also a disposal issue that makes me want to do so.
Closed cycles work fairly well, this can not only save on chemicals and cost but also on disposal issues.

as far as generating nitric acid from ammonia, I believe you would have better luck generating nitric acid from dirt, which can be done easily but is very time consuming, buying the nitrate salts is so much easier, and buying the nitric acid is also fairly easy for me but the price and how far I have to drive it gets expensive, so I find myself making alot of my own nitric acid and saving the store-bought for special processes

 

[solar seeker]

The biggest losses I find when trying to recycle nitric is in reacting water with NO2 gasses.
In my set up I have my reaction mixture in a wine bottle and a chemically resistant cork that has a fish tank style tube through it. On the other side of the tube I have a small ammount of water in a gallon size glass jug so that I can capture as much NO2 gas as I can. When the jug gets full I transfer the tube to annother simliar container while I shake the previous container to aid in the absorbsion process. In spite of my best efforts I still lose more NO2 than I would like. Given how labor intensive this is I use poor man's aqua regia for all my larger scale processes and I save the small ammount of nitric I have for testing metals or when I don't want sodium in my reactions.

 

[solar seeker]

Annother step in the right dirrection . According to this wikipedia article ammonium nitrite can be made by reacting aqueous ammonia with ozone or hydrogen peroxide http://en.wikipedia.org/wiki/Ammonium_nitrite
I have also found that both hydrogen peroxide and household ammonia have a freezing point well below that of water meaning it is possible to concentrate them by freezing the water out.
Unfortunately where I live it's far cheeper to simply buy ammonium nitrATE :roll: .

 

[solar seeker]

I found this article recently. http://www.scienceforums.net/topic/20938-sodium-nitrite-dissolving-in-concentrated-h2so4/ It says that No2 gas can be produced by mixing sodium nitrITE with a dilute acid. Another article says sodium nitrITE produces no2 when heated. After a visit to a tutoring website i got the final part for my process. NH4 (ammonia) + H202 (hydrogen peroxide) = NH4NO2 (ammonium nitrite) +H4 +H2O. Next NH4NO2(ammonium nitrite) + NaCl (table salt) = NH4Cl (ammonium chloride) + NaNO2 (sodium nitrite). When sodium nitrite is heated it produces NO gas which oxidizes to NO2 leaving behind sodium oxide which can be combined with water to make hydroxide. The sodium hydroxide can be mixed with ammonium chloride to release the remaining ammonia and produce table salt which can be re used. In the end the products consumed are ammonia and hydrogen peroxide. The NO2 gas is used to make nitric acid. In the end it is significantly less work than the arc process or the catalytic process and is producible on a small scale provided you have a good absorption method to capture the NO2 gas.

 

[goldenchild]

...provided you have a good absorption method to capture the NO2 gas.

That's the hard part.

 

[AuMINIMayhem]

In today's market, where buying nitric has been made difficult (and expensive), I may see things differently were I still involved in refining.

Harold

Even at today's prices Harold I think you would still buy it in , commercial volumes are still relatively cheap compared to the value of the metals to be recovered. I can fully understand members trying to look for ways of producing small volumes of nitric with the prices I see people paying but when your in a commercial refining operation as you were ,time is money.

Speaking strictly for myself, money's not so much an issue.. I can't get it locally without a business license and good reason for buying it... ie: just because I have a business license to own a restaraunt, doesn't show a "need" for Nitric to the sellers up here. I'm not sure if this is law or safe operating practices companies are moving towards. Not many companies out there (probably for good reason) that are willing to sell potentially dangerous chemicals to the general public.. It's to the point, I've actually thought about getting a license for small-scale refining, if such a monster exists. :roll:

I just go with the tried and true: Muriatic + (Sodium Nitrate + H20) = poor man's AR..

on a side note... I can never seem to eliminate the Nitrates using the Urea method.. I always seem to have to go the "evaporate, add more HCL, evaporate, add yet more HCL and evaporate again" route.. is Urea worth even trying?

 

[goldenchild]

Speaking strictly for myself, money's not so much an issue.. I can't get it locally without a business license and good reason for buying it... ie: just because I have a business license to own a restaraunt, doesn't show a "need" for Nitric to the sellers up here. I'm not sure if this is law or safe operating practices companies are moving towards. Not many companies out there (probably for good reason) that are willing to sell potentially dangerous chemicals to the general public.. It's to the point, I've actually thought about getting a license for small-scale refining, if such a monster exists. :roll:

I just go with the tried and true: Muriatic + (Sodium Nitrate + H20) = poor man's AR..

on a side note... I can never seem to eliminate the Nitrates using the Urea method.. I always seem to have to go the "evaporate, add more HCL, evaporate, add yet more HCL and evaporate again" route.. is Urea worth even trying?

Ever think of getting a distillation set up and making the HN03? I use the cold method to make 50/50 nitric but have to buy technical grade. As you said it can be a pain getting technical grade without a business license and good reason. I'm thinking about getting a distillation rig to make my own technical grade for when I need it.

The problem you're having with the Urea sounds like it stems from adding too much nitrate to the HCL in the first place. Just a guess though.