Questions about lazersteve's cold nitric acid recipe

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KU4TP

New member
Joined
Jul 26, 2009
Messages
4
Hello all,

First, the usual thanks to all that have worked to answer questions here. As a noob to this, you all have been most helpful.

I have been trying to make nitric acid using lazersteve's cold recipe and the one hurtle I am having trouble overcoming is the dissolving of the 170g of sodium nitrate into the 100ml of water. I've found other posts that mention this so I know I'm not alone but no discussion of what might be wrong. If the post is there and I simply have not searched long enough, I apologize.

Per the instructions I am using 100ml (on some attempts a few ml more) to dissolve 170g - (2M) of sodium nitrate (or slightly less). I have checked temperature each time to verify 100 degrees C except the last time. In that case I used a microwave to heat the distiled water and had violent boiling before pouring off 100ml to use. I am stirring for up to an hour with only short pauses to switch hands or shift my position - no pause was over a minute. in each case (5 now) I have had about the same amount of sodium nitrate left undissolved in the bottom of the container. I am using Nitrate of soda - 16-0-0.
As an experiment on one batch I continued the procedure despite the left over material. Other than the sediment I started out with everything went as described. The resulting sediment I am assuming to be undissolved sodium nitrate with a covering of sodium sulphate. I tested the pour-off in a test tube with a scrap of copper pipe and got the expected green tint and could see a few bubbles from the reaction at first. I also noted a slight dark vapor rising from the tube - also what I would expect. Leaving it standing for a few days I saw only a bit of copper left but had a while sediment in the bottom of the tube. At the end of 5 days the sediment was thicker and the copper was either gone or buried in the sediment and the color was more of a light blue than green.
From what I have observed I am guessing: 1 - I got some form of nitric acid from my test. 2. It is either weaker than the 50% lazersteve describes or is contaminated with other stuff or both.

So the questions are 1. - is there something I am missing when it comes to dissolving the sodium nitrate? 2. - if one were to double the water could one reasonably expect to get something near a 25% solution out of it. From what I have read here that would be sufficient for the first acid steps described on this forum and in Hoke even if one had to wait a bit longer for the reaction to eliminate the base metals you need eliminated. (is that last statement correct?) 3. Any thoughts as to the composition of the sediment in the test tube?

Other questions / thoughts - The only reason I am concerned about getting nitric is the reclaiming of pins and crushed CPUs (at least for now). I saw a post where lazersteve used his AP for the pins at least but the time was a bit prohibitive. Time for me is not a big issue, so should I give up on the nitric in any case? Time is not such a big deal for me at this point, but the conversation seemed to stop shortly after so I never did get a good feeling for how effective it might be. (as an aside - lazersteve -- you rock! Can't thank you enough for the help and materials you make available.) And IF I could find a source of nitric that did not cost an arm, leg, and other body parts I am fond of I would certainly not bother making it.

Thanks again to everyone that makes this forum and their knowledge available.

Virgil
 
Virgil,

Welcome to the forum! It's good to see that you have searched for an answer before posting your question. My experience making nitric by Lazer Steve's method is limited - I've done it twice. I bought a combination hotplate/stirrer off eBay that was non working, repaired it (broken wire) and used it to dissolve the nitre. I had no problem getting it to dissolve either time. I removed the stir bar before adding the acid so it wouldn't get buried in the white cake.

My best guess is that you simply need more stirring. I know you said that you only took a short break from stirring, but a stirrer will really get the job done with much less effort on your part.

It does sound as though you have successfully made nitric acid, and I agree with your assumption that it may be a bit weaker than intended, but still capable of doing what you need it to do.

You didn't mention the length of time you cooled the mixture before pouring off the nitric, or how cold you got it. I use an ice & rock salt mixture to bring it below 0* Celsius (in a cooler) and let it chill for 5 hours or so to make sure all the precipitant has come down before pouring off the nitric.

With that method I haven't had any problem with it continuing to drop the white material while in use.
 
Thanks for the reply.

In answer to your question - I used the ice and rock salt as well for about 2-1/5 hours. Temp never got above -5 C the whole time. I think I'll try putting the mix in a jar with a lid and spend time agitating it that way. And leaving it in the cold bath longer. I'm still curious as to the effect of adding more water.

I have only done one small batch of fingers using AP - 63g to start with which yielded - at least enough gold to see *S*. The point was to learn how everything reacts and in that aspect I consider it a complete success. Not that I did not make mistakes, mind you but the answers were all here! So now I'm in a harvesting mode and want to do some pins next. Hopefully enough to get a small button out.
 
Yeah, it takes about 500 grams (1 pound) of fingers to get a 2gram or so gold button.
I say "or so" because some of the older fingers yield more because they were plated
more thickly than the newer fingers. Some of the old mil spec fingers are nice!!!!
 
KU4TP said:
I'm still curious as to the effect of adding more water.

A little extra water won't hurt.

Here's a few more tip's on a new improved cold nitric acid method:

1. You can substitute dry powdered swimming pool pH decreaser for the sulfuric acid. It's sold in all types of stores (Walmart, Lowes, Home Depot, etc) and on eBay for around $2 per pound. It's about 95-98% NaHSO4 depending on the brand. Bonide sells a slightly brown Nitrate of Soda that works great in this recipe.
  • Use 1.4 parts NaHSO4 to 1 part sodium nitrate (ie: 140 grams of NaHSO4 + 100 grams of NaNO3).
  • Dissolve the ph decreaser in 167 mL of 95-100C distilled water for every 120 grams of NaHSO4.
  • When all of the ph down has dissolved, add in the dry sodium nitrate while heating until it also all dissolves. Boiling is not required.
  • Filter the hot liquid to remove any debris from the solution.
  • Cool to -5C for 2-5 hours. You will see some long, clear, ice like crystals form quickly once the solution reaches the correct temperature. Continue cooling for at least 1 hour after you see these crystals form. If a gel or slush like substance forms follow the directions given here:

    Cold Nitric Fix

  • Pour off the liquid from the crystals. Expect a volume of liquid slightly greater than the amount of water used. The density of the liquid should be around 1.3 - 1.4 and be 25-30% nitric acid.

The cold method acid is further purified by stirring in 0.1 grams of clean powdered refined silver for every 100 mL of liquid produced. The silver will dissolve and form silver sulfate with any sulfate and chlorides* remaining in the solution. Silver nitrate can also be used. After the silver sulfate/chloride* forms let it settle then pour off the acid again.

I've been working on more improvements to the method and will post more as I confirm them experimentally.

* Edits

Steve
 
Am i missing something, wheres the Sulfuric Acid? This is great news for me because Sulfuric Acid is hard to get here in Australia.

Steve, can i substitute Sodium Nitrate for Potassium Nitrate instead?

And can i pickle my silver in the Sodium Bisulfate also?
 
stihl88 said:
Am i missing something, wheres the Sulfuric Acid? This is great news for me because Sulfuric Acid is hard to get here in Australia.

Steve, can i substitute Sodium Nitrate for Potassium Nitrate instead?

And can i pickle my silver in the Sodium Bisulfate also?

The sodium bisulfate is used in place of sulfuric acid.

Bisulfate in water can be used as a substitute for dilute sulfuric acid in many instances and should work for pickling gold.

The bisulfate provides the acidic hydrogen needed to convert the sodium nitrate into nitric acid.

I have not tried this reaction with potassium nitrate. Give it a try and let us know what you find.

I'm working on more substitutions in the reaction. All we really need is a source of acidic hydrogen and a source of nitrate. The other key factor is the solubility of the reactants and products.

Enjoy!

Steve
 
Steve you are the Bom+, I never thaught of adding silver to remove the excess sulfate, and if silver nitrate you will not reduce the amount of nitrate in solution, thats great.

I have some calcium nitrate, I think it is problamatic as it does not settle well, but if only a small quantity is used it would clean it also.

Jim
 
Jim,

You'll also notice this method produces zero fumes during the mixing stages.

Once your water is hot the solids dissolve in a matter of minutes.

Steve
 
Jim, the reason Steve mentions using a bit of silver or silver nitrate to clean up your nitric is
to remove any chlorides you may have from your nitrate source, by forming silver cloride.

Are you saying calcium will form a calcium chloride, that would be easy to separate?
 
I think he covers two bases with the silver, chlorides, and sulfates. My concern is sulfates, they get in the way, chlorides mostly dont.
Now you have to understand, I have very little interest in refining to bullion grade, I can not get paid for it and it takes more time and chemicals. I just want high purity so when I sell I know the amount of metal I am selling.

So for me, I think just putting a little calcium nitrate will cause calcium sulfate to precip, this will keep the sulfate from causing problems with silver, and lead.

thats my thaughts anyways, and no need to put silver in to try and get it back later.

As, I said earlier, Steve is tops and I appreciate the fact he shares this information with us, I preformed the cold process a few times but the excess sulfate got im my way, so I got a distillation set. I do not like distilling, always waiting for something to go wrong if you know what I mean. I am going to give his new and to me improved process a go.

Jim
 
lazersteve said:
stihl88 said:
Am i missing something, wheres the Sulfuric Acid? This is great news for me because Sulfuric Acid is hard to get here in Australia.

Steve, can i substitute Sodium Nitrate for Potassium Nitrate instead?

And can i pickle my silver in the Sodium Bisulfate also?

The sodium bisulfate is used in place of sulfuric acid.

Bisulfate in water can be used as a substitute for dilute sulfuric acid in many instances and should work for pickling gold.

The bisulfate provides the acidic hydrogen needed to convert the sodium nitrate into nitric acid.

I have not tried this reaction with potassium nitrate. Give it a try and let us know what you find.

I'm working on more substitutions in the reaction. All we really need is a source of acidic hydrogen and a source of nitrate. The other key factor is the solubility of the reactants and products.

Enjoy!

Steve


Thanks Steve :mrgreen:

I'm going to give it a go when i run out of sulfuric acid.

Do you think the Sodium Bisulfate and Water solution could be boiled down to produce concentrate Sulfuric Acid, or up in the 80-90% concentrate? To be used in an electro cell!

Regards

Will
 
Will,

I don't think boiling it down will make sulfuric acid as the sodium sulfate will still be in there and the parent compound will form again upon evaporation.

I believe you can, however; regenerate some sulfuric acid from the mix using other techniques. First you may find that you can form some sulfuric acid by freezing the solution and pouring off the sulfuric acid from the crystallized sodium sulfate very much like the cold nitric method without the nitrate. You may also be able to get sulfuric acid out using ethanol* according to wiki.

Sodium bisulfate can be used to form just about any volatile acid when distilled with the appropriate sodium salt (sodium nitrate = nitric acid, sodium chloride = hydrochloric acid, sodium acetate = acetic acid, sodium formate = formic acid, etc) in the proper ratio. You'll end up with the acid in the collection flask and sodium sulfate in the reaction flask. Of course, some of these combinations can also be made using the cold technique also, while others can not due to the freezing point of the resulting acid.

As you can see from the above information, sodium bisulfate is a very useful ingredient for many reasons. It can also be used in Rhodium fusion reaction. At $2 a pound I recommend everyone on the forum has some in their chemical cabinet.

Steve

* Merck Index of Chemicals and Drugs, 9th ed. monograph 8330
 
Ku4TP, Virgil,
sometime's prill's (fertilizer) balls, are coated, My guess is so they cannot be used easily to make dangerous mixtures, or to dissolve slowly in the garden, or both.

Try crushing the prills (rince may help also) before disolving in hot water.

Steves recipee's are calculated out and give good results, and if you were using pure sodium nitrate not fertilizer prills disolving in water should be a none issue, mainly the hot water is to get the most nitrate to disolve with the least water, so the end product is stronger.

weak nitric can be heated and concentrated up to 68%(azeotropic), driving off water which will evaporate before the NOx does, as long as temperature is not to high, pure water boils 100 deg C = 212 deg F, and 68% nitric boils @ 120.5deg C = 249 deg F, so if temperature kept below this you will loose very little nitric untill you reach 68 percent concentration, then you will stat to boil or vaporate your 68% nitric into the air.
the boiling points change with concentration of the water to acid,for solutions,

sulfuric acid can help to dehydrate (dry) the nitric.
H2O2 peroxide can also be used to keep NOx from excaping a nitric solution.
 
Sodium bisulfate is very useful as Steve pointed out and a must to keep on hand for the backyard chemist. I use it a lot as a pickle leach for silver. It cleans it up rather nicely.
 
Thanks again to all for the assist. Sorry for the late reply but my day job calls. Butcher, the last attempt was with the Sodium Nitrate powdered by crushing in a mortar. Almost a fine powder before adding the water. Still no joy. I think I'll try to find another source for the sodium nitrate. Also, lazersteve, I think I'll try your alternate method. I like the idea of reducing my exposure to noxious fumes *S*. If I find out what is causing the problem I'll post to this thread and let everyone know.
 
I did all of this except I never seen the crystals form did I miss them? The mixture is a cold gel. To clairify exactly what I did: 170 ml of H2O heated and disolved 121.1 grams of Sodium bisulfate stir till completely disolved, then add 86 grams of Sodium Nitrate. Put in freezer. 3 hours later gelled. Anybody?
 
Platdigger said:
I see you put an "mta" in front of your bisulfate.
Are you sure you did not use metabisulfite?

If so, this would be the problem.


Nope I got both chemicals from Lazersteve himself. I don't know what I did but it can't be right.
 
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