How to neutralize nitric acid

A. Have you considered purifying, rather than dumping this acid? You are correct about the heat problems, it's usually best to dilute the acid before neutralizing. Then you could use a polyethylene tank.

A. I get bad vibes from your question. You can not abruptly add or ever rapidly add the nitric to the slurry or you will have it on the ceiling. It can be done if you have a good mixer and add the acid slowly with a tiny double diaphragm variable pump or a metering pump. Plan on an 8 hour day to be safe. Great care must be taken to not get into an acid condition. Polypropylene (non welded) will take a higher heat than Polyethylene and will stand nitric for a while. Thicker walls would be the best to stand the heat. Fiberglass supported would be great, but that is expensive.

P.S., do not be surprised if part of the sludge turns to a rock after it cools.

A. Holy Moly! Don't get that Nitric Acid anywhere close to a steel container! If Nitric Acid comes in contact in steel it immediately releases a DEADLY orange gas. Even if you have the Mag Hydroxide already in the barrel, chances are the Nitric will splash on the sides of the container. If you want to neutralize the Nitric Acid you must do so in a container that will take the heat evolution that inevitably will take place. I would suggest Stainless Steel. I wouldn't use a plastic container unless the volume was several times larger than the volume of Nitric that you want to neutralize.

If that were the case, you could dilute the acid down to 5-10% and slowly add the Mag Hydroxide which would minimize the heat evolution. If you have dissolved metal in the Nitric you will also need to dispose of that too by legal means. This sounds more like a job for a professional waste handling company. If you make the wrong move with this stuff someone could get badly hurt.

A. Have you considered pre-neutralising in a stainless steel tank, allowing to cool and then transferring to the steel vessel?

A. If you want to be safe and cheap, you should dilute the acid with 20 lb bags of Ice, until, its about 10% nitric (and really cold) then you can add sodium carbonate ⇦ this on eBay or Amazon] slowly or quickly and it won't be a big deal. If it starts getting hot just add another bag of ice.

A. Hi, Ravi.

The neutralization formulas are:

NaOH + HCl => NaCl + HOH

and

KOH + HNO3 => KNO3 + HOH

So the ratios are all one molecule to one molecule. Next you calculate the molecular weight of each compound --

NaOH: 40
HCl: 36.5
KOH: 56.1
HNO3: 63.1

So you need 40 parts by weight of sodium hydroxide to neutralize 36.5 parts by weight of hydrochloric acid, and 56.1 parts of potassium hydroxide to neutralize 63.1 parts of nitric acid.

So you seem to be planning to add roughly 4 times as much hydroxide as you should. But here's the thing:

You should never "fly blind" unless you have to! You either confirm the ratios by doing a test-tube sized titration before trying to neutralize a larger batch, or the neutralization should be very gradual and under pH control or with an indicator of some type. You never neutralize waste based on formula. Good luck.

Regards,

A. Hi, Ravi. If I was a home hobbyist dealing with a half liter of mild acid, I might be tempted to neutralize it based simply on calculations. But in that case, I would use nearly neutral chemicals like sodium bicarbonate (baking soda [in bulk on eBay or Amazon [affil links] ) rather than sodium hydroxide, so that "overshoot" could not cause any problem, as well as to minimize the exothermic reaction. You do realize that your proposed actions are dangerous?

But you used the word "office". Businesses are expected to exercise proper stewardship over the chemicals they use! A business which gains economic advantage over its competitors by doing operations without proper stewardship makes it economically unfeasible for their competitors to be able to do things right either, so it is something the whole world disdains :-)

Call a licensed hazardous waste hauler! Best of luck.

Regards,

Hi TVS. Is some countries only licensed facilities are allowed to do this; I don't know the rules in India. Can we assume that this will be done by a well qualified chemist? I don't think it's trivial; and I understand that once there is this much water in it, it's hard to get it out.

Regards,

Q. Hi Ted, In India too, you need license to manufacture Ammonium Nitrate. Our company does have the license to do so.

In my last communication, I was specifically referring to neutralization reaction between Spent Nitric acid and Spent Ammonia.

Do you know of any specialist/company which has undertaken serial production of Ammonium Nitrate using spent raw material. We have a good resource for getting low cost spent raw material required for Ammonium Nitrate. I know there would be a cost to remove water as well at the end of the reaction.

So I would need the specialist/company to help me in the process as well.

Hi again TVS. Anyone is welcome to post any helpful technical, non-commercial, replies for you; plus, we'll see if any of our supporting advertisers contact you privately about this. Otherwise this forum can't put buyers and sellers together. For one thing we discard over 1000 spams and scams every day; we can't even look at even a fraction of them, and we can't encourage still more by giving people the impression that this forum offers free matchmaking services -- apologies but it doesn't. Camaraderie yes; technical help yes; potential commercial benefit, advertisers only -- sorry.

Regards,

A. Hi Zain. I appreciate your ambition, but to learn enough to be able to properly address this whole situation will be the work of years. You surely waste enough to economically justify retaining a consultant to work with you on recycling the waste, employing acid extender chemistry in the pickling baths so you remove the iron instead of dumping the bath, consider the use of alternative neutralizing agents, improve the mixing for neutralization, suggest additions for your library, etc.

Waste reduction is no longer something that your worry about after your production needs are met, but has become such an intrinsic part of every process step that it's rather hard to give "general" advice; someone has to look at exactly how you use each of those acids, instead of focusing on how to treat them after you have (perhaps needlessly) decided to dump them. Our readers can probably answer specific highly detailed questions for you though. Good luck.

Regards,

A. Hi cousin Momcilo. I am not familiar with local or national laws applicable to Belgrade which might affect your choices, but if you can get this to a school or university or laboratory which can use it, that would certainly be the best resolution.

If it's too dangerous for you to have around, it may be too dangerous for you personally to neutralize. But you could half fill a 5-gallon plastic bucket with ice and then, wearing goggles and gloves as a minimum, slowly pour the nitric acid onto it. After allowing it to melt and mix, you'll have about a 10% solution, and you could very slowly add NaHCO3 to the icy water, mixing with a plastic paddle of some sort, until there is no more fizzing. Na2CO3 (sodium carbonate, washing soda ⇦ this on eBay or Amazon [affil links] ) might be okay, but I think NaHCO3 (sodium bicarbonate, baking soda) is a safer bet.

Be careful to heed the previous advice of not letting it contact any iron or steel until fully neutralized with the NaHCO3

Regards,

  @Ted
Thank you very much. I contacted chemical faculty and probably they will take care of it :)