Nitric acid not condensing.

[Mmbullion1776]

I’m running a simple distillation apparatus 1000ml round bottom flask, with Liebig condenser. I have 400grams of 98% potassium nitrate and 400 grams of 98% sulfuric acid in the flask reacting over heat. My thermometer says about 170f. I know that’s not exactly as hot as it should be. The problem is the reaction seems to be going fine but the cloud of nitric gas is just hovering around the condenser not going down it turning into liquid. The water running through it is ice cold I don’t know what the problem is.

 

[Lino1406]

To me it looks not "nitric gas" but NO2

 

[Mmbullion1776]

I’m sorry I didn’t use the correct term I’m pretty sure that’s what I meant. I’m really bummed out about this, I have watched the process over and over and I thought I did everything right. I called my friend who has taught me the most and he believes my temps aren’t high enough or the condenser is to warm.

 

[Mmbullion1776]

Not condensing.. Going to pack ice around it.

 

[butcher]

with that ratio of nitrate to sulfuric acid you will be fuming off NOx gases at about half that temperature, the fume will continue until you vapor off all of the solution...

The ratio is too concentrated you would need more dilute acid.
Too concentrated for refining, with this I am hesitant to help, why so concentrated? it has no use in recovery or refining,...
You have plenty of gas and not enough water in the solution, the gas would dissolve in water, a little hydrogen peroxide will help, bubble the gas, the smaller the bubbles, the longer the contact with water the more the gas will go into solution as nitric acid.

NO + air = NO2
NO2 + water = HNO3
even the water in your lungs nitric acid will form with this gas...

 

[Lino1406]

Sorry, N2O5 + water ,= HNO3

 

[Mmbullion1776]

with that ratio of nitrate to sulfuric acid you will be fuming off NOx gases at about half that temperature, the fume will continue until you vapor off all of the solution...

The ratio is too concentrated you would need more dilute acid.
Too concentrated for refining, with this I am hesitant to help, why so concentrated? it has no use in recovery or refining,...
You have plenty of gas and not enough water in the solution, the gas would dissolve in water, a little hydrogen peroxide will help, bubble the gas, the smaller the bubbles, the longer the contact with water the more the gas will go into solution as nitric acid.

NO + air = NO2
NO2 + water = HNO3
even the water in your lungs nitric acid will form with this gas...

First off butcher let me say I APPRECIATE you coming on my posts, and trying to help me learn. Not just correcting me and my terminology then not telling me why it is you are correcting me.
I was hoping to dilute later to 68% I’m going to show you 2 links on where I have gotten my process from. If you have time to look at them.
https://m.youtube.com/watch?v=DJ7D4FOUMQw
And the end of this one.
https://m.youtube.com/watch?v=2yE7v4wkuZU
I’m also using some information I’ve learned from other places and people. Including Cody’s lab. I know I am such a noob I try to read as much as possible and educate myself. I practiced for almost 8 months before I tried this today. It was really overwhelming and sad it didn’t work the way I thought it would. Again I REALLY appreciate the time you take to reply to me and guide me in the right direction. I can only read so much on my own, it doesn’t help when I don’t have an outlet for my questions. I felt really intimidated asking this today as a lot of you guys have knowledge I hope to one day come close to.

EDIT~
I have done some reading and I understood what you are saying the ingredients being so dry is definitely a problem. I got a few things wrong that’s for sure. I will try again tomorrow with some distilled water.

 

[butcher]

There is no need to make fuming nitric acid it has no use at all in refining.

When water or a less concentrated sulfuric acid is used you will have water involved in the boiling reaction, this water will vaporize along with the decomposing nitrates which form the NOx gases and they will then combine and condense back into nitric acid when cooled in the condenser.

Water can be in a receiver vessel and then the NOx gases can be bubbled through this water, hydrogen peroxide would provide oxygen to help convert NO gas into NO2 gas, then NO2 gas and water will combine to form nitric acid.

Note methods above are slightly different but produce the same reaction and results.
The first one is using the condenser with the water vapors and Nitric oxides condensing together in a water-cooled condenser, the second setup we are bubbling the gases from the boiler through a cold water solution in a receiver vessel.

 

[rickbb]

I was hoping to dilute later to 68% I’m going to show you 2 links on where I have gotten my process from.

You can't dilute it down to 68%, 68% is the highest you will ever get outside of a very highly specialized lab.

I think you need to slow down a learn a bit more, you have enough brown fumes there to, well, just stop. Please.

edit to fix errors.

 

[Mmbullion1776]

I was hoping to dilute later to 68% I’m going to show you 2 links on where I have gotten my process from.

You can't dilute it down to 68%, 68% is the highest you will ever get outside of a very highly specialized lab.

I think you need to slow down a learn a bit more, you have enough brown fumes there to, well, just stop. Please.

edit to fix errors.

I’m curious isn’t what I am doing learning? How does one learn without practicing the procedures. I am doing the best I can I am reading as much as I can. I understand that i need 68% nitric acid. I understand that it is an azeotrope, and I shouldn’t worry about getting anything stronger. You know I come on here to learn, I want to be safe I want to be successful and I know this is a good place to start. It’s really hard when someone tells you “you need to learn more” then not even attempt to point a finger in the right direction. At least butcher tried to help me. I think I am about done here, I have come to learn but it seems like there are few willing to teach or point in the right direction. I thought this was the right place a forum where I could grow and learn, but I’m starting to wonder and it makes me really sad cause I have put a lot of heart into this. Thanks.

 

[butcher]

Take a breath, but do not breath those RED fumes, Re-LAx.

You can make fuming nitric acid, and distill 98% nitric.
We are not making explosives and have no need to discuss it further on the forum.

It would be a waste of chemicals to attempt to make your nitric acid stronger than 68%.
Actually, it is better to make it a bit more diluted and use heat in your processes.

I suggest using the cold nitric acid recipe so popular on the forum, removing the salts, then distilling the acids...

You do need to study, I can answer a question, or even a few thousand, but it would be very hard to even cover a tiny bit of the information that I have studied or experienced with concerning nitric acid, a thousand answer would not get you far in your research on this subject.

Take another breath,
Ok, let us get back to making nitric acid, learning from each other, and sharing what we work so passionately to find the answers too.

 

[Mmbullion1776]

Take a breath, but do not breath those RED fumes, Re-LAx.

You can make fuming nitric acid, and distill 98% nitric.
We are not making explosives and have no need to discuss it further on the forum.

It would be a waste of chemicals to attempt to make your nitric acid stronger than 68%.
Actually, it is better to make it a bit more diluted and use heat in your processes.

I suggest using the cold nitric acid recipe so popular on the forum, removing the salts, then distilling the acids...

You do need to study, I can answer a question, or even a few thousand, but it would be very hard to even cover a tiny bit of the information that I have studied or experienced with concerning nitric acid, a thousand answer would not get you far in your research on this subject.

Take another breath,
Ok, let us get back to making nitric acid, learning from each other, and sharing what we work so passionately to find the answers too.

Thanks so much I’m going to do some more research, and try to get a better understanding of the processes that are popular on here. Just so everyone knows I am using a full facemask by 3M rated for nitric acid.

 

[g_axelsson]

Butcher is spot on. Too concentrated starting products. You need more water in your boiling flask.

Without water you are trying to condense NOx gases, there is no water to form the acid. Even stronger acid than 68% still needs some water and 98% sulfuric isn't going to let any of those 2% water it got get away. That strength of sulfuric is used to DRY other chemicals.

With a look at the chemical formulas of nitrate + sulfuric acid => sulfates + nitric acid you could find the perfect mix, but I'm very confident that it will be close to the amounts used in the cold nitric acid method found here at the forum. I would start with those proportions and take it from there.
Even better if you make the cold nitric first, then you don't have the problem with a solid chunk of sulfate salt in your boiling flask.

Fuming nitric acid has no use in refining and recovery, it was used as an oxidizer for rocket fuel and would self-ignite if it gets into contact with anything combustible. I've seen some instruction films from NASA where they were handling red fuming nitric acid and it was a bit scary how aggressive that chemical is.

Play it safe, dilute the starting product. If there is a lot of red fumes getting past the condenser then dilute it some more. Sunlight will break down the acid too and release some fumes so you might want to put some foils to block direct sunlight.

And don't get mad if some poster writes something you don't find helpful. It is often written in good faith, trying to warn you about dangers. We don't want people to get hurt. We have a number of members that have hurt themselves pretty bad, spending months hospitalized from doing what we do.

So thread carefully and don't be too offended when someone tries to help. Good luck with your studies. And when you got the distillation working, come back and share. We all love reading success stories.

Göran

 

[rickzeien]

This is a great thread. Someone willing to ask for advise and more experienced members willing to share their experience. The learning experience doesn't get any better than.

Questions I never thought to ask and answers that I never knew I could find.

Thanks to all who have contributed.

Sent from my SM-G950U using Tapatalk

 

[Williamjf77]

Dougs lab has a good video about this method, in my opinion the best and he explains all the reasons to start with nitrate, sulphuric and water.

I’ve done it several times, takes a while. Watch out for suck back from your fume scrubber at the end, that will end up in your product if you don’t take care.

It happens very fast. You need a suck back trap or another way to vent the apparatus.

 

[Williamjf77]

Also I should add that thermometer still head is a bad idea for nitric acid, I had one blow out on me the first time I distilled nitric. Luckily it was mostly water vapors. I’m not a pro here but I can share my mistakes. Get thermocouples a thermocouple display and a thermocouple well that doesn’t put the probe in contact with the chemicals and a regular still head with ground joints. They are all so cheap now a days anyway and you get a digital read out. Probably <20$ shipped and you don’t have to worry about a thread on connection and that flimsy gasket for the thermometer. If you have to use that style wrap Teflon tape around the thermometer to get a good seal where you need it.

Also as everyone said red fuming nitric is nasty stuff, will set gloves on fire on contact and you have to store it completely different. I haven’t tried the cold nitric yet but that’s what I will do next, you can make way more for the amount of set up and clean up involved and then just distill the liquid if you find it necessary.

 

[Beerocker1]

I’m running a simple distillation apparatus 1000ml round bottom flask, with Liebig condenser. I have 400grams of 98% potassium nitrate and 400 grams of 98% sulfuric acid in the flask reacting over heat. My thermometer says about 170f. I know that’s not exactly as hot as it should be. The problem is the reaction seems to be going fine but the cloud of nitric gas is just hovering around the condenser not going down it turning into liquid. The water running through it is ice cold I don’t know what the problem is.

I use sodium nitrate and distill as you suggest. My distillation works best at about 100°C. At that temp I still wrath my upper apparatus with aluminum foil and at that temp I get a nice steady drip. Nothing too fast, but a steady drip every 2 seconds or so

 

[Beerocker1]

I use sodium nitrate and distill as you suggest. My distillation works best at about 100°C. At that temp I still wrath my upper apparatus with aluminum foil and at that temp I get a nice steady drip. Nothing too fast, but a steady drip every 2 seconds or so

 

[Jimbriese]

There is no need to make fuming nitric acid it has no use at all in refining.

When water or a less concentrated sulfuric acid is used you will have water involved in the boiling reaction, this water will vaporize along with the decomposing nitrates which form the NOx gases and they will then combine and condense back into nitric acid when cooled in the condenser.

Water can be in a receiver vessel and then the NOx gases can be bubbled through this water, hydrogen peroxide would provide oxygen to help convert NO gas into NO2 gas, then NO2 gas and water will combine to form nitric acid.

Note methods above are slightly different but produce the same reaction and results.
The first one is using the condenser with the water vapors and Nitric oxides condensing together in a water-cooled condenser, the second setup we are bubbling the gases from the boiler through a cold water solution in a receiver vessel.

You said it has no use in refining is that because it will cause issues with the processes or just because it has a more Violent reaction?
I make my own nitric acid due to cost my first batch I made was with lab grade like he was use if here but those chems are sitting now I buy what I need at lowes. I get the Spectracide stump remover that is potassium nitrate and Zep sulfuric acid drain opener which I don’t know the Concentration of and it still makes a fuming nitric.
Now my first time making nitric with the 98% sulfuric acid there was a lot more of the red fumes but as the temp got above 80c the fumes slowed down and it started to condensate into the receiver. Using the drain opener I get a lot less fumes but still end up with a fuming nitric acid.
The only issue I have seen using this is it is very easy to add too much and get a boil over but I now cover whatever I’m processing with water then add nitric. Which slows down the reaction.

Thanks in advance as yes I’m still new to this been researching this for few years just recently found this forum and it has been a life saver as trying to find info else where there is so much conflicting info out there it’s hard to distinguish between good and bad info.
Been doing some small recovery and refining of gold and silver for a few months now trying to learn.
I have about 2g of gold powder and a 2g bead of silver and hoping to add to them soon

 

[butcher]

There are many reasons, too many to list here why fuming nitric acid is not needed and would be detrimental to good success in the processes of recovery or refining of metals

Many of the metals you are trying to dissolve with nitric will passivate (build an oxide coating that protects the metal from the acid) so the metal will not dissolve in a concentrated nitric but would dissolve more easily in a more dilute nitric solution.

Most metals that are dissolved in nitric, form nitrate salts which are soluble in water, in a diluted nitric solution you can hold more of these salts dissolved, so you can dissolve more metal in a dilute nitric than you can in a concentrated nitric without water which has no place for salts to remain in the solution.

The dangers of fires such as spills on wood tables, cotton, or organics materials become more of a concern, the loss of nitric due to fuming of copious amounts of NOx gassing which does no work in the reaction, no water to dissolve nitrates basically wasting the availability of the nitric to do the most work with less waste.

68% HNO3 azeotropic solution of nitric is the strongest we need to make aqua regia to dissolve gold or many of the platinum group metals, for silver we need much more water so we normally dilute the 68% nitric with equal volumes of water or more, to get the best reaction with silver and be able to keep the silver salts in solution...