# Isospropol alcool & Nitric acid



## Paige (Aug 2, 2007)

Following the logic espoused by Harold_V (I think) I tried to resolve the problem of oil (usually from your fingers) on your gold during processing causing gold bits to float.

I washed my gold scrap in 91% Isopropol alcohol as my first step. To remove the oil which came off of my fingers and the sellers's fingers and countless other persons's various body parts.

I let my gold soak for about 1/2 an hour and then drained it off and plopped my scrap on a paper towel. I cleaned out my beaker with soap and water.

Next step, replaced scrap in the beaker and added Nitric acid to dissolve any non gold that might be present before going to AR.

BOY, did I ever get a cloud of reddish brown gas!!!

Obviously dangerous, I stayed away.

Anybody know what happened? Is Nitric and Isospropol known for anything?

Paige


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## aflacglobal (Aug 2, 2007)

I'm no expert, But i would say 2 things could have happened. One might be dangerous, not sure. The alochol could have been asorbed into the boards. Two it could have been the Nitric acting with the base metals.


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## Paige (Aug 2, 2007)

This scrap was all karat gold.

Paige


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## lazersteve (Aug 2, 2007)

Paige,

This sounds pretty normal to me. When nitric reacts it tends to produce brown fumes. If you had added water to the karat gold then followed it with an equal volume of nitric you may not have seen as many fumes.


Steve


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## aflacglobal (Aug 2, 2007)

Fingers :roll: :roll: :roll: 

Dam, no wonder i was lost. You mean on the human body. :lol: :lol: :lol: 

I was thinking you were talking about circuit board fingers. :shock: :shock: :shock: :shock: 


Duhhhhhhhhhhhhh. I'm new, I'm new. :lol: :lol: :lol:


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## Harold_V (Aug 3, 2007)

Paige said:


> Following the logic espoused by Harold_V (I think) I tried to resolve the problem of oil (usually from your fingers) on your gold during processing causing gold bits to float.



That principle is used to advantage in milling ores. Oil is used to float the values away from the gangue in flotation mills. It gathers as a froth on the surface and is skimmed. 

Harold


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## fixinator (Aug 5, 2007)

I was reading it a chemistry dictionary recently about nitric acid. It completely decomposes in alcohol. This may be why the intense reaction!


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## P_CARROLL (Aug 20, 2007)

If it completly decomposes in alchol it may be easier to use it for neutralization than might be worth looking into.


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## scavenger (Aug 21, 2007)

I like the floating gold part. Could dip fingers in oil before AP and the foils will float to top and be easily skimmed off. What kind of oil would be the best?


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## Harold_V (Aug 21, 2007)

Don't give that idea anymore than a passing thought unless you fully intend to incinerate your gold before any further processing. Oil should be avoided in the process as much as possible, so your gold won't float when you prefer it did not, such as after precipitation from AR. 

Having said that, it's possible any light oil would serve the purpose-----I have no first hand knowledge on floatation. That is a whole different thing from refining----a part of smelting, not to be confused with melting. They are not the same thing. We do not "smelt" our gold-----we "melt" our gold. Smelting is the process of furnace reducing ores with various fluxing processes for the recovery of metals. 

Harold


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## Lou (Nov 4, 2007)

(Apologies for the double post, I don't quite understand why that happened. I kept getting an error on posting).


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## Lou (Nov 4, 2007)

Definitely avoid isopropanol (or any easily oxidized organic) coming into contact with concentrated nitric acid. Also should mention that nitric will ruin most non-fluorinated plastics if left long enough, even phenolic resins. If it is fluorinated, then even the most concentrated acids have no effect on it.

I use 96% red fuming nitric acid, and have had some scary ''pops'' when I inadvertently let it contact a few tenths of a milliliter of ethyl alcohol in the bottom of a large graduated cylinder. Remember that concentrated nitric was /is used as an oxidizer for rocket engines (some of which run off furfuryl alcohol).


Instead of cleaning your fingers to avoid getting grease from your hands on the gold, I'd suggest wearing gloves.


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## eagle2 (Dec 13, 2007)

You can heat your gold with dilute Sodium Hydroxide to clean it of grease. 
Does a much better job and your acids will work better.


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## Irons (Dec 13, 2007)

They make very powerful explosives. Even filter paper exposed to Nitric becomes very flammable from the formation of NitroCellulose. Be careful with all oxidizers.

If you use any solvents to clean your Gold, be sure to heat the Gold afterwards to drive off any residue or you may have a very unfortunate experience.


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## Harold_V (Dec 14, 2007)

Irons said:


> If you use any solvents to clean your Gold, be sure to heat the Gold afterwards to drive off any residue or you may have a very unfortunate experience.



I refined for more than 20 years, and learned early on to *incinerate before refining.* I am at a complete loss to understand why anyone that is engaged in refining doesn't do the same thing. Very strange. The problems that come when one doesn't are earned, and even deserved, considering good and proper advice is ignored.

Harold


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## Anonymous (Dec 17, 2007)

In my opinion what may have happened is that you nitrated the isopropyl alcohol. it is common in nitration reactions for copious amounts of NOx (brown gas) to be formed. Breathing NOx should be avoided unless you like to have nitric acid form on the inside of your lungs leading to pulmonary edema, and death. as far as isopropyl nitrate goes, it is a very volatile compound that is exceedingly flammable. in general it would be wise to avoid mixing nitric acid with ANY kind of solvent as this could lead to the formation of explosive compounds :shock: 

that bowl of porridge would certainly be too hot.

goldylox


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## Lou (Dec 17, 2007)

Hm, methinks isopropyl nitrate wouldn't be that volatile (think that nitromethane is not very volatile, and this has 2 more carbons and it's iso config.). Isopropyl nitrite would be though, and that's not great for you either, just as flammable! Aw heck, they're all bad anyway you look at it, unless you have high blood pressure!


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## Irons (Dec 18, 2007)

Even if they don't react chemically, the mixture can explode under the right circimstances.

You may get away with it a few times, but even a pop can spray acid in your face and ruin your day.


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## dbrick81 (Jan 5, 2008)

I know there hasn't been any post to this thread in a few months, but I wanted to give my $.02 (And a word of warning). I have a pretty good background in the production of explosives. The reaction between nitric acid and any alcohol forms compounds know as "nitric esters". These should be avoided at all cost!!! They are all very sensitive and very powerful explosives. Let me give you a few examples, the most common nitric ester is nitroglycerin!!!! Don't get me wrong, nitroglycerin is not as sensitive as Hollywood would like to make you think, but it's sensitive enough, something like 3 inches in the drop test (TNT is around 40-60 inches). Also it detonates at about 24,000 to 26,000 feet/sec :shock: (black powder burns at about 90-100 feet/sec). What this boils down to is don't screw around with nitric acid if you don't know exactly what you are doing and what compounds you intend to make. Sorry if I come across as some safety freek.... I just don't want to see anyone needlessly hurt.


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## Irons (Jan 5, 2008)

dbrick81 said:


> I know there hasn't been any post to this thread in a few months, but I wanted to give my $.02 (And a word of warning). I have a pretty good background in the production of explosives. The reaction between nitric acid and any alcohol forms compounds know as "nitric esters". These should be avoided at all cost!!! They are all very sensitive and very powerful explosives. Let me give you a few examples, the most common nitric ester is nitroglycerin!!!! Don't get me wrong, nitroglycerin is not as sensitive as Hollywood would like to make you think, but it's sensitive enough, something like 3 inches in the drop test (TNT is around 40-60 inches). Also it detonates at about 24,000 to 26,000 feet/sec :shock: (black powder burns at about 90-100 feet/sec). What this boils down to is don't screw around with nitric acid if you don't know exactly what you are doing and what compounds you intend to make. Sorry if I come across as some safety freek.... I just don't want to see anyone needlessly hurt.



I've worked professionally with explosives, had advanced demo training and attended the bomb scene investigation class at the FBI Academy. 
I tend to err on the cautious side, having seen how unpredictable improvised explosives can be and the potential for accidents that mixtures of strong oxidizers, organic materials and catalysts such as PGMs and transition metals can pose.
All it takes is a small pop to spray hot, concentrated AR in your face.
The thought of someone spending the rest of their life blinded because they didn't follow basic safety procedures forces me to speak out on the subject.


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## goldsilverpro (Jan 5, 2008)

Every once in awhile, in the literature, you'll read a procedure that uses alcohol to eliminate nitrogen oxides from aqua regia. Besides the possible explosiveness of doing this, I never liked using it. I hated the smell and the sputtering reaction. The only thing I used alcohol for was to quick-dry gold powder.


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## dbrick81 (Jan 5, 2008)

Just one more thought... I know a lot of people use the sulfuric acid drain cleaner for prosesing and refining PM's. If you plan to use it to make nitric acid be very careful and reed the MSDS or the ingredients if they are listed on the container. I know at less one suppliers brand in my area has 5% Ethelin glycol added to it for what reason I don't know. But I'm sure Irons would agree with me when I say this could make for a bad situation :shock: But any way just one more reason to double and triple check things.


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## Irons (Jan 5, 2008)

Ehelyne Glycol Dinitrate

Used as a substitute for Nitrglycerine in Dynamite and SLBM rocket fuel.

Hot stuff.

It might be better to use battery acid which is free of buffers and such additives.

EGDN will put you in orbit if you're not careful.


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## Lou (Jan 5, 2008)

It's also more stable than nitroglycerin, and has a lower VOD and is less brisant. Also less prone to the hazards of being acidic. Still, good information both of you, that's important to note!!!

I wouldn't worry about it terribly: with a few exceptions, esterifications that produce a nitro ester require sulfuric acid to remove the water formed as the alcohol (hydroxy) groups are replaced by the NO2. There are exceptions to the rule, but it's all determined by equilibrium.

General rule is just to keep alcohols away from nitric acid, or any oxidizers in general.


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## Irons (Jan 6, 2008)

Is where someone adds excess sulfuric acid when making Nitric then distills it down to make it concentrated.
If you concentrate your Nitric by distillation and notice what looks like an oily liquid floating on the surface,or the acid looks cloudy, I would be concerned.


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## Silver (Jan 6, 2008)

EGDN also has a lower freezing point than NG making it safer to use in cold weather. Frozen NG is not very sensitive but partially frozen it is extremely dangerous and many accidents happed when melting frozen NG. NG "ice cubes" collide in the liquid NG and that easily causes detonation.


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## Irons (Jan 6, 2008)

Commercial explosives tend to be very stable because they are made under controlled conditions and tested to ensure stability. Explosive compounds made accidentally as part of reagent manufacture for dissolving Precious Metals may not be that stable.

Remember, It's not the big one that gets you, it's the little pop that blows hot, corrosive material in your face and ruins your day or worse.


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## Silver (Jan 6, 2008)

I agree.


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## eagle2 (Jan 6, 2008)

In the field of small pops and safety, it would be good to mention again, the problem of `bumping`. 

Bumping happens when you have a heavy precip on the bottom, like gold, and your washing it by boiling with an acid (dilute H2SO4?). 

I`m sure the experienced refiners know this, its the new refiner that might when he hears the first bump, bend over the beaker to see whats happening. That`s when the next pop gets him.

A good piece of lab equipment to have is a watch glass on the beaker.
Stirring stops bumping and leaving the stirring rod in the beaker with the watch glass on, also helps some. 

Al


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## Anonymous (Jan 31, 2008)

The reddish-brown gas observed is nitrogen dioxide. It is very often seen in reactions involving nitric acid, and during the purification of nitric acid. Even so, nitrogen dioxide is a very toxic gas that cause fatal lung injury with even a couple of good size breaths. When you're using nitric acid in leaching or other PGM operations, assume that nitrogen dioxide will be produced as well. Ventilate your work area and wear a suitable respirator. Very cheap insurance, if you ask me.

As for what happens when isopropanol is mixed with nitric acid, the results will vary with temperatures and so forth, but almost surely, very toxic and explosive compounds will be produced. AVOID mixing isopropanol and nitric acid unless you have a specific chemical objective, and know exactly what you're doing. At temperatures and conditions typical of metal refining, such mixtures are dangerous and improper.


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## aflacglobal (Jan 31, 2008)

Welcome Contrablue


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