making nitric acid

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Geo

Geo

Well-known member
Joined
Mar 1, 2011
Messages
7,069
Location
Decatur,Ala.
this process should be done out doors and away from people and pets and always wear protective gear.my process for making nitric is simple enough but should never be done by anyone that doesn't understand the dangers involved.I've made my nitric like this for about 15 years now.first i make a condenser with a piece of 3/8 inch glass tubing that i purchase from the local neon sign company for about $2 apiece,its easy to melt and bend to 90 degrees,make a 90 at one end about 2-3 inches long.make a sleeve with 1/2 inch pvc pipe with a "T" at each end threaded to affix water inlet and outlet and silicone the ends to make water tight,and low yield water pump or just a garden hose will do for water source.be creative and elevate the condenser to the height of your reaction chamber mouth.you will need a sturdy plastic catch pan big enough to fit hot plate.the reaction chamber can be any glass bottle but big enough to contain the reaction and not boil over,the thicker the glass the better.use cast iron hot plate or sand bath (though the sand bath is slower).i prepare the condenser by wrapping Teflon tape around the bottom of the 90 to make a seal(takes about a half of a roll).prepare the reaction chamber,add 1standard cup potassium nitrate and 1 standard cup of concentrated sulfuric acid(reaction will not take place till heated) do not add water.place hot plate in catch pan and reaction chamber on hot plate now place condenser 90 with Teflon seal in the mouth of the chamber tightly.heat slowly as to not thermally shock the glass.acid will not be produced till sulfuric begins boiling.unsure as to the temp needed,i just did it by sight.yield will be 1cup sulfuric + 1 cup potassium nitrate = 1 cup tech grade nitric acid.best to use rated extension cord so you can unplug at a safe distance should the reaction chamber fail.NEVER BREATHE FUMES!! nitrogen dioxide is poisonous and can kill days after inhalation.i don't recommend anyone follow these directions,I'm just describing how i do it.also before anyone should ask the nitrate has to be potassium nitrate,all others have impurities that will hinder the reaction.
 
Lino1406 said:
By product KHSO4 can be used for
dissolving rhodium
Click to expand...
thnx for the info.i knew it was something more than just salt but i just neutralized with baking soda and discarded at the county waste center.
 
Distilling Nitric Acid from Sulfuric Acid/Potassium Nitrate mixture is rather hazardous and expensive. Perhaps you should consider just purchasing concentrated Nitric Acid (69% ) from a lab chemicals supplier. If you are in the USA it should be easy.
Les Hochhauser
V.P. Product Development
American Dental Supply, Inc.
 
leshochhauser said:
Distilling Nitric Acid from Sulfuric Acid/Potassium Nitrate mixture is rather hazardous and expensive. Perhaps you should consider just purchasing concentrated Nitric Acid (69% ) from a lab chemicals supplier. If you are in the USA it should be easy.
Les Hochhauser
V.P. Product Development
American Dental Supply, Inc.
Click to expand...
to be cost effective to buy nitric acid where i live means to order from chemical supply house at 5 gallons at a time.im not unapposed to this but i seldom use more than a few cups in a months time.plus my storage space is limited so i make what i can.all told it cost about $45 a gallon to make.
 
I always bubble the gas threw a aquarium aerator(i have a scintillated glass one) into cold water, anything not dissolved is passed into NaOH solution via the same process. If everthing is sealed, thier are no nasties to escape. Be Safe be smart, cause and effect, think it threw (through) before you act.

Live to learn, learn to live.

Deano
 
Geo
Can i not use sodium nitrate as the nitrate ? I have made sodium nitrate from amonia nitrate and lye, the product produced looks very clean (snow white fine powder) and passes the burn test with sugar well. I have used it to make a 50% nitric acid and disolved several coprocessors (after incinerating them) along with some connector pins from motherboards to produce a blue solution of about 7.5 ph with gold foil flakes and a bit of coper chloride percipitate. Most likely from the addition of undistilled water rinsing out the beeker and washing the foil flakes to the bottom of the filter (or possibly ashes due to the grey color) just as a learning exercise. I will put this cup of solution aside for future processing as I have not checked it yet for disolved gold. Your post here makes me question my use of sodium nitrate as opposed to potassium nitrate espically since the biproduct of the latter can be used to process other PMs
 
sodium nitrate can be used to make nitric acid but it is not recommended that you use it to distill nitric acid the way i described. for some reason the reaction doesn't work the same, the only thing i can think of is the chemical composition of the nitrate effects the reaction with the sulfuric acid. i don't know if this is accurate its just my opinion. I've just never had any luck using sodium nitrate this way. god knows I've tried it in many different ways. sodium nitrate is cheap and can be purchased at any large building supply outlet store. the reason i use this method is you don't have to worry about reducing salts and after you insure the liquid that's being produced is acid it is ready to use as soon as it is distilled.
 
thanks Geo:
I am in the process og making a distilation apparatus similar to the one you described but mine will incorporate a used freezer(slightly overcharged to control lower temp range) I will isolate the fridge compartment so no cold gets over on that side. this side will house the heating and vaccume components. the condensing tube will cross over to the freezer comp where the nitric acid will be collected and stored. fumes will be perculated through water or peroxide under a vaccume to strip fumes and generate a lower concentration of nitric. The process I am using now is simply to generate some acid to familiarize myself with the reactions as I have no formal chemestry education. I anticipate a couple of years before my company (CCR computer componets recycling) begins full scale operations, meanwhile the pile grows. I have a few computer repair shops that are giving me old computers just for hauling them off. they are removing HDDs and cpuS as well as other componets they can sell but there are still many things to recycle. the aluminum is the primary cash generator @ this point and is paying for my equipment as I learn.

P.S. I am having trouble finding recomended vaccume pressure for optimum effenciency any insight here may save me some experimentation
 
if the condenser is cooled correctly there will be no fumes, all of the nitrogen dioxide should be condensed to liquid. too the reaction chamber will be under pressure there should be no need for vacuum at all. dont forget that even a depopulated circuit board has value. solder in older boards have a % of silver and the printed circuits themselves are copper. a large motherboard without components can have as much as 1 and 1/2 pounds of copper.at todays prices thats almost $6.00 in just copper.
 
Just how will the gas nitrogen dioxide condense to liquid? Unless it has water, or hydrogen to combine with to form nitric acid?
Nitrogen dioxide (NO2) is the red brown gas.

The NO2 gas will usually combine with water taking an hydrogen from it to form nitric acid (or in your case a hydrogen from your H2SO4) but you will still have gases escaping your system even if you do not see them.

The Nitrogen oxide will need oxygen to form nitrogen dioxide (your method it has no place to get it so it will leave the system as invisible NO gas unconverted, and then there are all of the other nitrogen compounds formed called NOx to simplify them these also can escape as gases.

Geo from your description one cup H2SO4 and one cup KNO3, unless you are backing the salts dry and raising the heat after they are dry you are leaving nitric acid in these salts, this sounds like stuff I have read on the internet to make red fuming nitric not using water in this distillation process, You would be much better off adding water to your solution and making as close to 68% nitric acid as you can (this is the strongest nitric needed in refining metals, and you will not be wasting chemicals in the reaction).

Even if for some reason other than refining metals a stronger nitric acid was needed such as pyro you still would get better nitric from making 68% nitric the first time and then re-distilling this with excess concentrated sulfuric acid (less wasted chemicals Higher grade of nitric acid and less nitric decomposed to NOx gases in solution), some people see these NO2 gases decomposed in the nitric acid seeing it give a red color and believe the nitric is stronger than it actually is, like red fuming, even 70% nitric (clear or slight yellow)without the NOx gasses dissolved in solution and coloring the acid red, will fume when the bottle is opened.

The reaction cold or distilling will also produce's nitrogen oxide gasses (NO) and several other nitrogen compounds called NOx gases, these can be invisible and deadly,
some of these will not combine easily with water to form nitric acid and here the advice of Deano (NoIdea) is very wise (scrubbing his fumes), just make sure not to do this in enclosed environment, fume hood or outdoors so as not to breath fumes.

Sodium nitrate is one of the better salts to make nitric using the cold method and will work well in the distillation process; potassium salts are less soluble and can easily be cooked to the boiling vessel, if trying to get all of the nitric acid from them.
 
the water left in the sulfuric is sufficient for the production of the nitric acid. ive boiled new battery acid till the acid would fume white at ambient temperature and it would still make nitric acid, as a matter of fact it started producing acid as soon as the solution started boiling. if you add water to the nitrate before you mix with the sulfuric the first liquid to be produced will have very little if any at all nitric acid. the bulk of the water has to boil off till the sulfuric reaches the temperature where it begins to boil at 639 degrees F. water boils at 212 degrees F so which do you think will boil off first?
 
just try it on a small scale and if it doesnt work ill admit i was wrong, i dont mind eating a little crow.
 
GEO water will help the reaction.

When you combine H2SO4 and KNO3, you no longer have sulfuric with a boiling point of ("639 deg F), or water with a boiling point of 212 deg F, or an potassium nitrate with a boiling point of XYZ degrees,

But you will have a nitric acid and sulfate salts in solution.

Heating these what product distills off is determined by the Azeotrope of the volatile acids in solution, or gasses formed from the chemical reaction, and at what temperature you heated them to.

Nitric acid has an Azetrope of 68%, this means if you had a higher than 68% nitric acid in solution you would boil off nitric until you reached 68% in solution and then that is the concentration that would distill off till you formed salts in your vessel, but if your solution was say a 30% nitric acid in solution you would vapor off a more water in vapor until your boiling solution reached 68% then you would get 68% vaporizing out of solution until you formed salts in your reaction vessel.

depending on what concentration you have in your boiling reaction vessel that would determine what the boiling point was for the nitric in solution, only if it was pure water will it boil off at 212 deg F, 10% nitric would be a higher temperature to vapor off, and as concentration climbed so would the temperature needed to reach boiling point (at that concentration), the boiling point for nitric acid will climb with the concentration until you reach Azeotropic mixture (here nitric boiling point about 120 Deg C from my memory), the once you pass this Azeotrpe the boiling point for nitric acid at higher concentration goes down again until you reach about 98% HNO3 (boiling point about 83 Deg C from my memory)
 
i know that i tried to use the new battery acid without evaporating first and the result was a very weak acid that was almost unusable, then i started checking the liquid dripping from my condenser and the first half of the reaction was almost totally water and there was still solid nitrate in the reaction vessel. it was only after the nitrate melted(which took about 30 minutes of boiling) that a strong acid was produced. i checked this by putting a piece of clean copper under the dripping liquid.
 
Geo said:
a large motherboard without components can have as much as 1 and 1/2 pounds of copper.at todays prices thats almost $6.00 in just copper.
Click to expand...

Just in the traces ???
 

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