Concentrate Nitric Acid ?

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Ammonium nitrate can be used to make nitric acid, but I would advise against it, in my opinion sodium nitrate, then potassium nitrate is the better methods.

Ammonium nitrate can have some dangers involved that is the reason, I would advise against its use, also ammonia is a very volatile gas.


spell check editted
 
If you have ammonium nitrate NH4NO3, you can convert it to sodium nitrate NaNO3, using sodium hydroxide,
NH4NO3 + NaOH --> NaNO3 + NH3 (gas) + H2O
The ammonia gas could be used in other reactions or to concentrate an ammonia solution and so forth.

With KOH you can make potassium nitrate, similar as reaction above.

I prefer sodium nitrate for making nitric acid, although potassium works very well also.

there are several problems I see using ammonium nitrate directly to make nitric acid, ammonium nitrate can decompose and possibly very violently, if heated decomposes at 210 deg C, in making nitric if distilled with H2SO4 sulfuric acid and you carefully watched temperature (not >83 deg C), you will get a low yield of nitric acid (lower than with NaNO3 or KNO3), and then as nitric distill off the (NH4)2SO4 will start to decompose giving off ammonia NH3 gas and a salt of NH4HSO4 and decomposing very heavily at 120 deg C.

now if you are using this for silver you may have some more risk (silver in ammonia dried can have dangers of violent decomposition might blow up in your face), one out here is the nitric would be an acid which may eliminate the chances of this happening) but why risk it leave that for the chemistry major, backyard refiners like me wont play that game.

Here is another formula ammonium nitrate and hydrochloric acid, to give ammonium chloride and nitric acid, both very useful in refining ( the nitric would be distilled off) but her again you would need stiochiometric calculations and then the chances of ammonia in this dilute nitric(??? I am not sure),
NH4NO3 + HCl --> NH4Cl + HNO3:H2O

As a general rule, keep ammonia away from these metals or salts unless you are really sure what the reactions will make and how to make these potentially dangerous mixture's safe
 
Is it possible to obtain HNO3 by dissolving of Calcium ammonium nitrate (CAN fertilizer) in H2SO4 (33%), without distilation or freezing?
Which percentage of HNO3 could be achieved in such a way?
 
Since this reaction is endothermic I wonder it could be favourable in prevention of losing of NOx??
Also, Ca -salts could be desirable because of theirs insolubility and easy extraction!???
 
calcium salts make hard cakes of sheetrock that stick to your reaction vessels, holding bubbles of your nitric solution inside them, very hard to deal with.

There are reasons why most everybody uses certain chemicals and processes on the forum.
we like the wheels that have evolved from years of others trial and error.....
 
i make my own nitric at home.i condense new battery acid till i get white fuming sulfuric acid and use potassium nitrate i buy on Ebay.its not the most cost effective but it does make tech grade nitric.when distilling i dont add water,i put the nitrate powder into the sulfuric acid,nitrogen dioxide wont be produced untill the sulfuric comes to a boil.well,not enough to see or smell.any water will come out in steam first and acid wont be produced till all the water is gone.thats what is diluting other peoples acid.test the liquid that first comes out with a piece of copper and youll see what i mean.its just water.if you add nitrate to water then add acid all the water has to evaporate first.boiling point of water is 100 degrees C and the boiling point of sulfuric is 327-337 degrees C.
 
Geo, adding some water is beneficial, when making nitric acid from fertilizer salts, even if distilling, but you may have more water in your boiled down sulfuric than you think.


I have the impression you think that not having water that you will make a fuming nitric from the salts, while likely it is of much lower composition than you think, and decomposing HNO3 to NOx gas in solution. I agree you are getting a stronger acid but not fuming, and loosing HNO3 unless you bake the potassium sulfate to the bottom of your reaction vessel and ruining your boiling vessel, there is no reason to make much stronger than 70% HNO3 for refining, and if stronger redistill the 70% with dehydrator.

Fuming is usually made from re-distilling 70% with excess H2SO4 as dehydrator.

If nitric is higher than 68% azeotrope and boiled (or distilled) mostly acid boils off (or over) until you reach azeotrope then 68% boils off (or over) till dry.

If your nitric acid is less than 68% then yes mostly water will boil over first and solution will concentrate to 68% then 68% fumes off till dry.

Without some kind of precision refluxing these will be somewhat mixed, example at first distilling weak nitric wont give you pure water, but mostly water with a slight acid content.

A test to see if it is water is touch a drop to your tongue, acid has some bite sour taste. Or use pH test, for stronger solutions density measurements, or titration.
Even the water will have some acid.
 
when i first started distilling nitric acid about ten years ago i had no real guide to go by but text books and all i could garner from them was the fundamentals,reagents and a little on the process so it was alot of trial and error.i dont need anything more potent than tech grade.i do understand that nitrogen dioxide will only make nitric acid in H2O so water is essential to the production of nitric acid but it only needs very little like what remains after condensing your sulfuric.my condenser is two pieces of four foot glass tubing that i "engineered" with pvc sleeves as water jackets so when it starts producing acid i never get loose fumes,i collect all thats made.i know im wasting one reagent or the other but i use 1cup potassium nitrate and 1 cup sulfuric acid and get 1 cup nitric acid.not sure about the percentage but it is very strong acid.
 
Kraguj, this posting at the bottom of this page made by James may help:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=3345&hilit=Calcium+ammonium+nitrate&start=20
Of course his starting material was calcium nitrate, not ammonium calcium nitrate
but, I am sure there are ways to deal with the ammonia as some have already been
mentioned in this thread.
Not sure about the other salts in the fertilizer grade, and how they would, could be dealt with.
 
lazersteve said:
All,

I put my thinking cap on at lunch today and fine tuned my original nitric acid recipie from yesterday's post. I'm running the numbers one more time and will be posting a new and improved, never before seen, version of the experiment. The chemicals are readily available, safe, and the reaction produces a product that is more concentrated than the previous version of the experiment. Stay tuned gold diggers!

Catfish,

Thank you for the kind words, they make my efforts all that much more rewarding!


Steve


Steve,

Did you ever complete this? Just curious if you improved on your first recipe, or came to the realization that your new idea wasn't going to work. I didn't see a follow-up to the above statement.

I have a batch from your first recipe in the freezer right now. It's a milky light green color a little lighter green than key lime pie. When I checked it this morning, most of the salts had precipitated, but it looks like I still have a bunch in suspension. I'll check it again after work. I will say, after trying the method on Youtube (sodium-nitrate+HCl+copper outgassing through a tube and pipette through H2O2), your method was much easier to do. Especially since I mistakenly used Muratic when their recipe called for concentrated HCl. I think it was way too dilute, so my small brain thought adding heat would help the process. I ended up pumping too much of the orange gas into the hydrogen peroxide and made a real dirty, real weak nitric.
 
zuberb said:
Steve,Did you ever complete this? Just curious if you improved on your first recipe, or came to the realization that your new idea wasn't going to work. I didn't see a follow-up to the above statement.
I have a batch from your first recipe in the freezer right now. It's a milky light green color a little lighter green than key lime pie. When I checked it this morning, most of the salts had precipitated, but it looks like I still have a bunch in suspension. I'll check it again after work. I will say, after trying the method on Youtube (sodium-nitrate+HCl+copper outgassing through a tube and pipette through H2O2), your method was much easier to do. Especially since I mistakenly used Muratic when their recipe called for concentrated HCl. I think it was way too dilute, so my small brain thought adding heat would help the process. I ended up pumping too much of the orange gas into the hydrogen peroxide and made a real dirty, real weak nitric.

there are different brand names and different grades of muriatic acid, but the typical concentration of hcl in muriatic acid is 32% so it is considered concentrated hcl. check the label on what you used, if it is 32% then its not diluted by much and should work for this purpose with no problem.
 
It is the Crown (31.45%, 20 deg BAUME) from Lowes. I found a video about a process to concentrate it up to 35% by placing equal volumes of Muriatic and hydrogen peroxide side by side in separate containers, both inside a larger sealed container. The peroxide absorbs the HCl fumes and becomes 35% reagent grade HCl. The dude says it takes up to two weeks. Does that sound feasible?

The reason I suspected it was too dilute was that I did not get the immediate reaction they did in the video. That's why I added heat. The copper I used was 40g of copper wire I took from transformers in the computers I've recycled. I would say at least 90% of that copper didn't dissolve at all, even under heat. I think I've read somewhere now that I think of it that copper wire is not pure copper. Assuming 31.45% HCL and the sodium nitrate I got from Amazon are sufficient, the wire may have been the problem. Anyway, I like Steve's method better. I think I'll be saving up for a distillation rig though so I can make something stronger than 50% nitric. Sounds like that won't cut it for the silver reactions.
 
did you incinerate the wire first? wire in transformers is coated with a shellac to insulate the wire from contact with other winding's. even though it looks bare, it is still coated.
 
I did not incinerate first. That's probably it because they seemed to react more at the tips. Lesson learned on that one I guess.
 
I used a "How to" site for Nurds. (NERDRAGE) This site provides a way to make three strength's of Nitric acid. Weak to pure. The last of the video will show you how to make the stronger solution.

http://www.wonderhowto.com/how-to-make-nitric-acid-278165/.

I never made the weak acid, for I did not find the need to yet. If this site is okay to use, I thought the video was produced in a simple format.

Gene
 
wywiwyg2000 said:
I used a "How to" site for Nurds. (NERDRAGE) This site provides a way to make three strength's of Nitric acid. Weak to pure. The last of the video will show you how to make the stronger solution.

http://www.wonderhowto.com/how-to-make-nitric-acid-278165/.

I never made the weak acid, for I did not find the need to yet. If this site is okay to use, I thought the video was produced in a simple format.

Gene

That was the exact video I was talking about. I tried the second method. I don't have a distillation kit to do the third one.
 
Ok, first attempt at the cold nitric acid recipe was an epic fail (I think). I came home from work and poured off the clear solution being careful not to pour off any salts. The resulting liquid still looked a little cloudy, so I ran it through two filters in my Buchner. That caught some salts, but the solution is still a little cloudy. The beaker I froze it in contained 92g of salts, and the liquid I poured off and filtered is exactly 250ml. The solution sat undisturbed in a freezer for about 18 hours. Is it possible a bunch of the salts are still suspended?

I'm guessing that is the case, so I've put the filtered solution back in the freezer to see if it will precipitate more over a second night. I'll filter it again tomorrow. I know the instructions said this should make 160ml of nitric, so I'm not sure where I got an extra 90ml of liquid.

**Edited for accuracy
 
Follow up:

No significant precipitate on the bottom of the vessel yesterday, so I took it out of the freezer. I'll test it at room temp on a piece of copper and see if it even acts like nitric.
 
Because of the ammonium, and its dangers and problems in refining, I feel it woud be best to convert the ammonium nitrate to sodium or potassium nitrate, and then use these to make nitric acid with.
 
Back
Top