# Nitric Acid Distilation



## chefjosh77 (Feb 13, 2010)

Can someone point me to the the methods for distilling Nitric. I have an all galss rig and I have distilled several batches, but I do not know how to calculate the ratio of concentrated sulfuric acid to sodium nitrate and potassium nitrate. So how many grams of Sodium nitrate per Ml of sulfuric. I do have vaccume dist ability also. Thanks folks. And for you chemists, if you have a sec can you show me how to calculate the stochimetric numbers?


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## aflacglobal (Feb 13, 2010)

Try this method. http://goldrefiningforum.com/phpBB3/viewtopic.php?p=2572#2572

Here's a vid http://www.youtube.com/watch?v=G8U7t_UDy8s


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## chefjosh77 (Feb 13, 2010)

Ive done this method too. Works great, but the output is Dilute Nitric. Great stuff but I would rather start as concentrated as possible, then Dilute later. Nurd rage has a Vid on youtube, and This is the Kind of setup I have(the third type), but he doesnt explain the ratio of sulfuric to sodium Nitrate or potassium nitrate.


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## chefjosh77 (Feb 13, 2010)

PS Great Books aflac! Big fan of your posts.


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## butcher (Feb 14, 2010)

68% nitric is all we need to refine with, a dilute nitric acid can be concentrated to 68% easily, this is the approximate azeotrope of nitric acid, you cannot concentrate further than this without special proceedures, as further evaporation will just vapor off 68%.

higher concentrations can be made but have no use in refining.


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## chefjosh77 (Feb 14, 2010)

butcher said:


> 68% nitric is all we need to refine with, a dilute nitric acid can be concentrated to 68% easily, this is the approximate azeotrope of nitric acid, you cannot concentrate further than this without special proceedures, as further evaporation will just vapor off 68%.
> 
> higher concentrations can be made but have no use in refining.


Good info, so what process and ratios of sulfuric to sodium nitrate are used to get to your 68 percent mark. I really am just interested in not wasting ingredients and time. 

I have tried the Cold methods, and I can get great results with LazerSteves cold methods. Dissolving salts Waiting to cool, then adding acid to the saturated salt then freezing takes several hours. I can vaccume distill the same amount in about an hour with very similar results. But again, I just guess at the amounts of each ingrediant to use. Right now I am doing a 2 to 1 ratio of satls to acid by weight, It seems to make some pretty nasty stuff, and Under vaccume it turns out very clear.


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## ander (Feb 14, 2010)

85g of sodium nitrate (or 101g potassium nitrate )and 98g of concentrated sulfuric acid, theoretical yield is 62g or 40ml. Distillation gives 98% acid so it needs to be diluted. To get 65% acid for 1 liter (1,5kg) of acid about 0,8l water is needed.


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## lazersteve (Feb 14, 2010)

ander said:


> 85g of sodium nitrate (or 101g potassium nitrate )and 98g of concentrated sulfuric acid, theoretical yield is 62g or 40ml. Distillation gives 98% acid so it needs to be diluted. To get 65% acid for 1 liter (1,5kg) of acid about 0,8l water is needed.



Ander,

I come up with 100.1 grams of 98% H2SO4  and 170 grams of sodium nitrate.

Here's the formula:

H2SO4 + 2 NaNO3 = 2HNO3 + Na2SO4


for Potassium Nitrate use 202 g of the salt.

Steve


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## chefjosh77 (Feb 14, 2010)

Awesome guys, thanks for the numbers. Its been forever since Chemestry class, and Im not all the way through the chapter on Molarity yet. Gotta get back to the books and the basics. Thanks again!


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## ander (Feb 14, 2010)

Of course Steve, you are right. I got the data from inogranic preparation book. Reaction goes through two stages, first saltpeter reacts with sulfuric acid to give hydrosulfate, so the molar ratio is 1:1. And if you don't use heating you can simply mix the salt with acid, leave it for couple of days and decant obtained nitric acid, but it contains some sulfuric, thats from another book. If you distill mixture molar ratio for saltpeter:sulfuric acid is 2:1. Using more acid is for safety reason- salt drops out onthe bottom and it leads to local overheating and glass breakage. So to avoid precipitation more acid is used, for more diluted acid which is actually used for metals water can be added instead of acid. My friend had major accident with this method of acid distillation, his employee did not make any calculations due to lazyness- Glass reactor with couple of kgs of cyanide broke. Nobody was poisoned or injuired but reactor worth couple of grands went to garbage. Of course reagents also wasted. If you use oil bath overheating is less possible.


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