Nitric acid recovery from sodium nitrate waste solution with excessive sodium chloride (salt)?

[FrugalRefiner]

Next time you don't need to calculate, just take 100ml of the solution and add sulfuric, slowly and keep track of how much you added until a test drop turns white.
Multiply it by 10 times the total amount of liters of solution to convert and add a bit less at once. Then add small bits until the test drop turns white again.

Be careful adding a lot of sulfuric acid to any solution all at once. It can create a lot of heat. Add it slowly with a lot of stirring.

Dave

 

[icejj]

Next time you don't need to calculate, just take 100ml of the solution and add sulfuric, slowly and keep track of how much you added until a test drop turns white.
Multiply it by 10 times the total amount of liters of solution to convert and add a bit less at once. Then add small bits until the test drop turns white again.

That is the method I used to determine the amount of sulfuric. It took about 15ml of sulfuric added to 100ml of the solution to turn the test drops white, which amounts to 15% sulfuric of the total amount of solution needed. I calculated 15% of the total amount of solution that I had, and used that to determine the amount of sulfuric needed for the total amount of solution.

 

[icejj]

Be careful adding a lot of sulfuric acid to any solution all at once. It can create a lot of heat. Add it slowly with a lot of stirring.

Dave

Thanks, I thought that I added it slowly enough the first time around, but noticed that the beaker was a little warm to the touch. I will add it slower next time around.

 

[orvi]

Nurdrage on YouTube has a video on how to make nitric acid from Sodium Bisulfate and a nitrate salt. It will still require a distillation.

I've never had the need to try it........yet.

I did this in the past (when sulfuric wasn´t banned yet, but nitric was since our country is in EU), it works. I got a yield of roughly 70-80%, used a ground glass apparatus for it. If you need like half liter, you can make it yourself, it would be quite an experience if you didn´t ever distilled anything... But be very careful as hot nitrosulfuric mix is "flesh eater" literally. In 2L boiling flask (from quality silica glass, not chinese junk), you can reliably do this and survive. Little bit of water helps to lower the decomposition (aim for 68-70% stuff to come over, azeotrope) to NOx-es.

Then, I spent more time on looking for viable sources of nitric acid, rather than making it myself Too much problems regarding larger scale prep. As I needed liters at the time, and I was too afraid to heat 4L sulfonylation flask with sulfuric acid/bisulfate in the mantle to 300 °C.

Bisulfate method is nice, I need to say that if I was about to make some nitric, I would definitely go with bisulfate.
As unfortunately, our beloved EU government decided that sulfuric acid of any concentration is just too harmful for the public and banned it altogether. No comment. I just wait when they ban hydrochloric too...

 

[eaglekeeper]

Then, I spent more time on looking for viable sources of nitric acid, rather than making it myself Too much problems regarding larger scale prep. As I needed liters at the time, and I was too afraid to heat 4L sulfonylation flask with sulfuric acid/bisulfate in the mantle to 300 °C.

I do have a distillation set up, I just don't need clean nitric very often. And yes, I'm always a bit worried that something will go wrong during a distillation.

I once made the mistake of using a Graham condenser and the reaction foamed up so bad that it made it up to the condenser. The salts immediately solidified in the condenser and within seconds the pressure built up enough to blow the thermometer well out. Fortunately I have always made it a habit to never keck clip that thermometer well.

Needless to say, all of my condensers are now Liebig condensers...a little less likely for that to happen next time.

 

[orvi]

I do have a distillation set up, I just don't need clean nitric very often. And yes, I'm always a bit worried that something will go wrong during a distillation.

I once made the mistake of using a Graham condenser and the reaction foamed up so bad that it made it up to the condenser. The salts immediately solidified in the condenser and within seconds the pressure built up enough to blow the thermometer well out. Fortunately I have always made it a habit to never keck clip that thermometer well.

Needless to say, all of my condensers are now Liebig condensers...a little less likely for that to happen next time.

In amateur setup, reliable and controlled heating is sometimes big issue. I know it first hand I also encountered several boil-overs or runaway reactions, popped flasks during distillations etc.
That "spiral" condenser thing is very dangerous, that is for sure - thin glass spiral inside. We usually use Liebig-like types, or Dimroth-like condensers as organic chemists. Dimroth type condensers are also the most efficient from the common ones.