# sodium nitrate and sulphuric acid to separate gold & silver



## chrisjames (May 12, 2015)

Hi there,

I am new to this site and I have trawled through to find the answer however couldn't so I'm sorry if I have started a new thread unnecessarily.

I am fairly au fait on the processes surrounding parting and refining gold (inquarting, nitric acid & H20 and aqua regia etc). However I live in the UK where nitric acid has recently become a controlled substance which needs a licence with a lengthy application process, not to mention the price. I have therefore looked into sodium nitrate as a substitute as it is still available without licence.
I have read up on lazersteves nitric acid production using sulphuric acid and sodium nitrate etc however am unsure if it will work for me so I guess my question is;
I have about 2.5 ounces of different carat gold. I would like to refine it to re-alloy it into rose gold to produce my own jewellery (18K) so it needs to be fairly pure but not 99.99%. could anyone tell me if I need to go through the normal procedure as if I were using nitric acid when it comes to the parting phase?
I assume I have to;

-inquart the gold to 6K
-mix up lazersteves nitric acid (sodium nitrate and sulphuric acid...)
-use mix to extract the silver/copper etc to produce gold sponge.
-boiling water washes
-dissolve gold with poor mans aqua regia (hydrochloric acid and sodium nitrate)
-acid washes etc etc etc.

I'm not too worried about the silver in the silver nitrate solution, just the purity of the gold. Will using sodium nitrate & sulphuric acid in the parting phase affect this.

Any help and advice would be much appreciated.
Thanks in advance,
Regards,

Chris


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## rickbb (May 12, 2015)

1st. Don't be surprised if/when this post gets moved from General to Help Wanted.

2nd. If you goal is to dissolve karat scrap to refine it, you don't need to make nitric first. Search for 'poor mans AR", you can use potassium nitrate directly to make the nitric portion of AR on the fly so to speak.

3rd. Please download and read Hoke's book, several members have links to download it. You will learn a great deal about what you want to do from it.


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## Anonymous (May 12, 2015)

Dear Chris

The "nitrates" are still reportable substances under the act brought in in Sept 2014. How have you found peoples' response to enquiries to buy it - have they asked for any further information? 

Regards

Jon


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## g_axelsson (May 12, 2015)

Silver nitrate and sulfate forms weakly soluble silver sulfate (0.8g/100 ml @ 20 C) so the process would slow down and stop after a short while when the holes between the gold is filled up with solid silver sulfate.

Home made nitric that is used for silver needs distillation to get rid of the sulfates if you plan on using it on silver.

Göran


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## chrisjames (May 12, 2015)

Thank you Rick I'll have a look for hoke's book and have a read. I'm new to forums in general so still finding my feet with it. I'll get the hang of it.

Hi Jon, I spoke to a friends father who sells fertiliser etc however I'm massive quantities to large companies. He advised that it shouldn't be a problem. I looked on the GOV site and I imagine it could be reported however haven't enquires yet as I'm still trying to put my notes together and figure out how I'm going to do things. I'd be buying it as a sole ingredient so I'd imagine they would report it however I'm not using it for anything I shouldn't be so I can't foresee a problem. Or I may have the police bang my door down at 3 in the morning


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## chrisjames (May 13, 2015)

g_axelsson said:


> Silver nitrate and sulfate forms weakly soluble silver sulfate (0.8g/100 ml @ 20 C) so the process would slow down and stop after a short while when the holes between the gold is filled up with solid silver sulfate.
> 
> Home made nitric that is used for silver needs distillation to get rid of the sulfates if you plan on using it on silver.
> 
> Göran



Thabks Goran, have you seen lazersteves cold nitric acid process? I wondered if I used that, did a thorough wash and incineration followed by another nitric leech if that would be enough to remove the silver sulfate that built up (hopefully less with this process??). This is based on my rudimentary understanding of the processes so may be no better than guess work. I spent last night digesting Hoke so understand a bit more today... Just!

I didn't want to start distilling acids etc as I have limited equipment. If all else fails I may have to just bite the bullet and get a licence. It may prove cheaper and easier in the long run to just use 70% nitric from a supplier.

Many thanks,

Chris


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## g_axelsson (May 13, 2015)

I always use bought nitric acid for my silver so I don't know if a certain way to wash would help. My guess is that it will be many wash cycles to get it to work.
Maybe if you tried to inquart with copper instead of silver it would lower the silver content enough to let the process work with homemade nitric.

Göran


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## chrisjames (May 13, 2015)

Thanks again Goran.

I hadn't thought about that. Maybe that could work. It would take more acid I'd imagine but should work (in my head anyway)

If anyone else knows if that's feasible could they let me know. That might make the process a bit easier.

Kind regards,

Chris.


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## rickbb (May 13, 2015)

If you break, chop up, or melt and make flakes of your karat scrap you will start with small enough pieces that poor mans AR will do a decent job of digesting it all. A little heat and some occasional stirring help keep it going to completion. Especially with the small amount that you're starting with.

When at the end of the digestion and start of the recovery phase the silver will fall out as silver chloride while the gold will still be in solution with copper. You can decant the liquid off and wash the silver for conversion back to metal later.

Then proceed to drop the gold to begin washing, etc. 

In the end you will have decently pure, (99.7% or so), and separate gold and silver to re-alloy to 18k for your use. All without any need to make or buy nitric acid. 

If you need the gold more pure than that you can simply re-dissolve it and drop it again. With good attention to washing you can get to .9997. To get the silver more pure will require a electrolytic cell and nitric acid.

The details for all of this is in Hoke's book and here on the forum. I can only offer this advise because I learned it all here and from Hoke. 2 years ago I was as green as a spring turnip at this.


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## chrisjames (May 13, 2015)

rickbb said:


> If you break, chop up, or melt and make flakes of your karat scrap you will start with small enough pieces that poor mans AR will do a decent job of digesting it all. A little heat and some occasional stirring help keep it going to completion. Especially with the small amount that you're starting with.
> 
> When at the end of the digestion and start of the recovery phase the silver will fall out as silver chloride while the gold will still be in solution with copper. You can decant the liquid off and wash the silver for conversion back to metal later.
> 
> ...



Thanks Rick,

I take it you've done it yourself then and not just regurgitating the info 
I saw this on the forum and have been thinking about it but have also seen people panic that the reaction has frozen and they now have to add more steps. The comment below their panicked one starts with "you should have inquarted... This is what happens when you miss steps" :lol:

I just didn't want to be that person! Also I don't know if it matters but some of the gold is fairly old and from what I've read may contain more silver than modern gold alloys.
I had thought that if the reaction freezes then I could clean and incinerate then try the poor mans AR again (in the original AR obviously).
I'd say just the once for dissolving and precipitating would be easily good enough for my needs.

I'll take a closer look and probably give it a go in the next week so you may see me on here panicking soon!

Thanks for your help guys.


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## Anonymous (May 14, 2015)

I did some homework today and can confirm that suppliers in the UK seem happy to supply Sodium Nitrate without any problem as Chris alluded to above.

Chris check your PMs mate.

Jon


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## chrisjames (May 14, 2015)

Hi Jon,

I too have been researching and it's as easy as buying on Ebay or Amazon. I have priced it all up and it's all really reasonable. Especially for what I want it for.
I have worked out the carat of my gold in all to be just under 18K (I want 18K rose in the finished product otherwise I wouldn't have to go through this  Although I must admit I'm loving learning about this!). I'm hoping that will be ok to just cornflake and poor man's AR twice. From what I've read the gold content should be enough that any silver shouldn't impede the reaction too much, but we shall see. I'll do it next week with any luck.

I had a look at my PMs and there isn't anything there mate.

Regards,

Chris.


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## nickvc (May 14, 2015)

Chris if you add copper or silver to inquart your material and simply dissolve the base metals off with heat applied and do it twice you should get to around 98-99% fine. It you need to drive the reactions.
Making 18 carat red is a challenge, you might get pink but red very hard, the colour comes from the copper part of the alloy. Depending on what you want to make from your 18k red will determine the alloy needed give us more details and I'll see if if I can suggest a decent alloy for the job.


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## chrisjames (May 14, 2015)

Hi Nick,

I think I'm confused now! Are you saying just I quart and drive off with heat, without using any acid?? I think you may have lost me.
I do want to get it as close to pure as I can without going overboard as I will be getting it assayed when the final piece is finished. 

I'm looking to make more of a rose rather than pink hopefully bit we shall see! It may take a few attempts. With some trial and error.

I'm going to attempt to cast a watch case. I've had some experience casting so thought I'd try my hand at this.
I designed (CAD)and 3d printed the watch case. I'm going to investment cast it from wax models of the original.
I shall then clean up and figure out the rest from there. I bought an automatic watch mechanism that I intend to use... I haven't even figured out the first stage get so it's going to be a long process I think!!!

Regards,

Chris


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## nickvc (May 15, 2015)

Chris to inquart the material you want it to be as close to 6k as possible then melt and pour it into shot put it in a beaker add your water, heat and slowly add your nitrate. With this process you need to drive it with heat. Allow the solution to cool decant it then repeat but add in good vigourous stirring to try to expose all the base metals to the hot acid. If done at high heat, boiling at the end it should remove virtually all the base metals, this is the method many Asian jewellers use but be aware of the fumes they are not good!
If you then want to actually refine it use the HCl bleach process.
With your alloy add a little silver, 5%, it helps with the casting of the metal.
Don't try and cast the back use a stainless one, the metal will be too thin to get a decent cast.

Edited for clarity.


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## chrisjames (May 15, 2015)

nickvc said:


> Chris to inquart the material you want it to be as close to 6k as possible then melt and pour it into shot put it in a beaker add your water, heat and slowly add your nitrate. With this process you need to drive it with heat. Allow the solution to cool decant it then repeat but add in good vigourous stirring to try to expose all the base metals to the hot acid. If done at high heat, boiling at the end it should remove virtually all the base metals, this is the method many Asian jewellers use but be aware of the fumes they are not good!
> If you then want to actually refine it use the HCl bleach process.
> With your alloy add a little silver, 5%, it helps with the casting of the metal.
> Don't try and cast the back use a stainless one, the metal will be too thin to get a decent cast.
> ...



Thanks for the clarification Nick,

From the research I have done sodium nitrate would have to be mixed with sulphuric acid however the formation of silver sulphates would stop the reaction. This is my understanding anyway. So I'd have to distill the nitric acid from the solution prior to adding the inquarted gold otherwise the reaction will probably freeze. I have also read that because the gold I am using is near to 18K I should be able to go straight for poor man's AR instead of inquarting.
The issue I've had the whole time is that I don't have a licence for the nitric acid and so trying to find a work around. of course I may be wrong and this could go horribly :shock: 

Actually the back is only really a loop as I'm going to have a crystal to view the mechanism (I thought it appropriate seeing as they're so beautiful to look at)

The 5% silver sounds just about right from what I've read I had it at: gold 75%, copper 17% and silver 8% for the alloy I'm looking for. That also makes it easier if it isn't right and I need to re-process it with the low silver content!

regards

Chris


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