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Poormans AR with NaNO3

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bswartzwelder

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Posts: 512

Joined: October 24th, 2011, 1:19 am

Post June 5th, 2013, 6:14 pm

Poormans AR with NaNO3

Today I put some HCl (about 384 ml) into a beaker and put it on my stirring hot plate (no heat). Then I added about 68 grams of NaNO3 and turned on the stirrer. After more than an hour, there was still a lot of undissolved NaNO3 left around the inside bottom circumference of the beaker. Does NaNO3 always dissolve this slowly? My NaNo3 was in the form of very small balls or pellets. Shlould I grind them into a powder before using them? I know they will all be dissolved, it's just that it seems to be ssslllooowww.
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MysticColby

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Joined: August 17th, 2011, 12:23 am

Post June 5th, 2013, 6:19 pm

Re: Poormans AR with NaNO3

I was under the impression that poorman's AR was: item in HCl diluted with water, heated, incrementally add sodium nitrate.
this would imply there's no need to fully dissolve it (what dissolves gets used, allowing more to dissolve)
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bswartzwelder

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Posts: 512

Joined: October 24th, 2011, 1:19 am

Post June 6th, 2013, 8:59 am

Re: Poormans AR with NaNO3

I didn't weigh the gold I had left from the HCl/Clorox method, but assumed it to be 50 grams or less. Used enough HCl to dissolve 60 grams just to be sure. Added enough NaNO3 ti make enough poormans to dissolve 60 grams. By now, I assume all the gold has been dissolved. There may still be some NaNO3 left over. At any rate, I plan to run everything through a filter. The solution I will be left with will contain my gold and maybe an excess of nitric. I know I can drive off the nitric by heating. How can you be sure when all the nitric is gone, or do you just leave it on the heat for an extended time?
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butcher

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Joined: January 6th, 2008, 2:09 pm

Location: Pacific NW

Post June 6th, 2013, 4:29 pm

Re: Poormans AR with NaNO3

Evaporation three times as taught in Hokes book, will normally remove the nitric acid.

Adding a bit more gold while concentrating the solution to use up nitric in dissolving the added gold.

Sulfamic acid to convert the excess nitric to sulfuric acid in solution.

(limiting nitric use in the beginning, leaving a little undissolved gold)

I will normally use a combination of the above methods to eliminate the nitric from solution, or to be sure that I have removed all of the nitric, but of course if I limit my nitric use from the beginning it makes it much simpler to remove any remaining traces.

The stannous chloride test will not work if there is free nitric acid in solution. A positive stannous test where the gold is reduced to colloidal gold in solution, is a good indicator that most of the excess nitric acid has been eliminated from solution.

A prill of urea fertilizer to see if it fizzes to check for nitric.

If we had much more Nitrate salt (or nitric acid) compared to the amount of HCl in the reaction we could create a situation where the nitrate or nitric will not be consumed in the reaction, or the nitrate salt is not converted to HNO3 in solution. (I am unsure of how to say this).


If you had Excess or too much NaNO3, and it did not all dissolve, I would tend to wonder if the HCl in the reaction was consumed by the reaction with NaNO3 and gold, if so you may need more HCl to convert remaining NaNO3 to HNO3, (but here then the solution would hold more gold).

Bit late now, maybe next time try dissolving the nitrate prills in a water boil before hand can help to get the sodium nitrate prills dissolved to a thick nitrate salt water solution which could be slowly added in small proportions to the HCl and gold, this may help in not over use of the NaNO3 in solution.
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bswartzwelder

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Posts: 512

Joined: October 24th, 2011, 1:19 am

Post June 6th, 2013, 7:37 pm

Re: Poormans AR with NaNO3

Thanks, Butcher. I had Hokes book out tonight and just starter re reading it from the beginning. Didn't get too far and with the weather system is supposed to hit us tonight and most of the day tomorrow, I'm sure I'll get in some more reading. Uswing the HCl/Clorox method did get me a nice brown mud in the bottom of 1 beaker along with some pretty shiny gold sticking to the beaker sides. Will be putting all mud/powder together for the ifnal cleaning and re dissolving prior to melting. Want some of my sons to witness that. I'm pretty sure they'll be impressed.
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butcher

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Posts: 7212

Joined: January 6th, 2008, 2:09 pm

Location: Pacific NW

Post June 7th, 2013, 2:23 am

Re: Poormans AR with NaNO3

bswartzwelder,
I have been reading with interest this project you have going now, I haven't had anything to add so I haven't made any comments, from what I could tell it looked like you were doing real good, I know your sons will be impressed, especially if they can witness both precipitation and the melt.

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