Nitric? - SOLVED

[SteveDodds]

I seen in another post somebody talking about nitric. I'm guessing they were talking about nitric acid. Is this right? What do ya do with it? If it is used to determine whats gold then where can I find some.

 

Amazon Forum Fav 👍

Treasure of Victoria Peak - Grab it through Amazon!

[Mackaydon]

Re: Nitric?

One use of nitric acid is to test whether jewelry is composed of genuine gold. I suggest you DONT buy any until you have read up on its proper use and have bought protective gear; it's real nasty stuff and could do more than just spoil your day if improperly used.

 

[Charlie P. (NY)]

Re: Nitric?

Yeah. If the jewelry, when exposed to nitric acid, is completely destroyed it was probably only a little valuable.

Testing Gold

Scratch the object with a file and apply a drop of Nitric Acid. If the object turns a bright green it is gold plated or gold filled on base metal. If the object turns a pinkish cream colour it is plated or gold filled on silver. 10 karat gold will turn dark brown. 12 karat gold will turn light brown. 14 karat or higher will have little or no reaction.

http://www.lacywest.com/t_goldt.htm#testgoldintro

 

[mrs.oroblanco]

Re: Nitric?

http://wardsci.com/product.asp?pn=I...le-_-cpc-_-ward-_-nitricacid&bhcd2=1205045223


http://shorinternational.com/TestGold.htm

http://www.nationaljewelerssupplies.com/page/NJS/CTGY/gold-testing?referral=Adwords+Gold_Test


B

 

[chong2]

its a real pain in the butt to get. i had some a few years ago, used it up and needed some last year, its hard to get someone to sell it to you. twice i have had people "give" it to my as long as i bought a glass container from them. speaking of, i just did a little nitric test on a necklace. it turned out fake. and its dirty, so i decided to CLEAN my necklace with the nitric.......... ummmm to much reaction . and what appeared to be a cloud of brown gas from WW1 started rising from my sink. i knew water would flush the acid safely, so i turned it on and got out of the house while it ventilated. i only used about a tablespoon. scary stuff.

 

[mrs.oroblanco]

It IS scary stuff - especially if you are unaware - and don't forget that nitric is volotile with water, too. (it reacts differently if you add water to nitric, than if you add nitric to water). Especially if there is any trace chemicals (like a little left over comet in your sink), or if there are organics in your trap. It sure can get hot!!

Pulp mills use a nitric acid wash to clean out their evaporators, and we used to have to have special suits, head gear, boots and gloves.
Of course, they are using 30 totes full of nitric, too, and it takes about 3 hours to fill up the system.

Nitric is easier to get in person, than by mail, because you sign a 2 sheets, one for a MSDS, one that you are buying it for personal use only and you are read the MSDS and understand the danger.

We had to sign the same set of forms for mercury. If you do that - KEEP your copy.

There is a little mining store in Apache Junction (Pro-Mack) that used to sell both.

I don't think we have ever used more than a little (like on the head of a matchstick - a drop), except for when we cleaned up a gold sponge after retorting. (and never in my sink).

B

 

[jewelerdave]

I use a lot of it for refining of gold and silver.

There are good reasons why it is hard to get a hold of. I mean you add a little bit to Glycerin and guess what you get...Nitroglycerin. And I am sure you know what that does. Many people have killed them selves and others trying to make it, or by mistake.

You do not want to get it on you, or breath the fumes it makes when dissolving metals.

Its key in Refining gold when mixed with HCL

Its key in refining silver when mixed with water.

 

[chong2]

so for example, if i were to put a 10k ring in a small ammount of nitric, will it eat/ break down all the metals away except for gold?

 

[Bigcypresshunter]

I know what you mean about that brown cloud. lol Seen it a few times. Maybe thats why my lungs are so bad. I bought mine long ago when it was not a problem. We used it to clean copper prior to soldering if it couldnt be sanded. Will clean up dirty copper in a few seconds. Mixed with Potassium Dichromate for an all metals test solution. Maybe its better to buy a jewelers test kit pre-mixed. The Nitric Acid bottle is glass but the plastic cap keeps melting.

 

[Bigcypresshunter]

To make up a jewelers test solution. You will need to buy the items at a chemical supply. I have posted this many times. Solid gold has no reaction.


Mix
1 oz. Potassium Dichromate.
6 oz. Nitric Acid
2 oz. water.



Find an obscure spot and scratch with a knife or file to get to the base metal.
A)apply a drop of solution- watch for color reaction and compare with chart.
B) Wait one minute, recheck the color of the solution, wipe it off and check the color/mark on the metal and compare with chart.

`~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
(start) ( after one minute )
Brass--Dark Brown --------------------------light brown
Copper--Brown--------------------------------cleaned copper
Gold--None-------------------------------------none
Nickel--Blue------------------------------------scarcely any
Lead--Yellow----------------------------------leaden
Tin--Yellow------------------------------------dark
Silver(pure)--Bright Red-------------------grayish white
Silver .925--Dark Red----------------------dark brown
Silver .800--Brown-------------------------dark brown
Silver .500--Green--------------------------dark brown
Palladium--None-----------------------------non
Platinum--Vandyke brown---------------none
Iorn --various -------------------------------black
Zinc --light chocolate---------------------steel grey
Auluminum---Yellow ---------------------no stain




Note: If you use this test solution, be sure to wash item with water when finished. And of course wash hands and be very careful using this or any acid solution.

 

[mrs.oroblanco]

Good info, BigCy,

As far as using nitric to get everything except for gold, I'm not sure I would try that on jewelry. Pure gold is very soft, and other metals are used to make it viable for use as jewelry (which is one of the reasons we have 10K, 14K, 18K jewelry).

If you are wanting to "separate" the gold from the other metals in the jewelry, there is a different process. (similar to getting the silver and platinum and gold out of electronic components)

Nitric has been know to take a little gold with it in solution.

B

 

[Bigcypresshunter]

Good advice. My work with Nitric on jewelry has been one drop at a time and only for a minute. Even cleaning old copper radiators for soldering, I washed it off after a minute.

 

[mrs.oroblanco]

Same experience here. And a drop to clean up a nugget or two. (except for the nitric acid washes we did at Procter & Gamble).

B

 

[Bigcypresshunter]

And not in my sink either. Outside in the open air.

 

[mrs.oroblanco]

DEFINITELY!!

I don't mess with ANY chemicals in the house. That's always great advice!

B

 

[Fast_Dave]

I remember back when I was in high school and we could buy nitric acid from the corner drug store. We dropped a penny in a small cup and poured in the acid. After a few seconds of bubbling and frothing, we poured off the acid and were the proud possessors of a penny so thin that you could shave with the edges. The really cool part is that all the details wore down at the same rate, so you could see Lincoln's head and the memorial on back. This was back when pennies were still made of copper.

 

[chong2]

enough about the sink, i learned my lesson

 

[jewelerdave]

so for example, if i were to put a 10k ring in a small ammount of nitric, will it eat/ break down all the metals away except for gold?

No it wont but good thinking, its actually the next step in gold refining that you have almost come upon with that Idea.

10K is too resistant to most acidsThe 38-41% gold is too much gold, Even Aqua Regia has some trouble breaking it down if its too rich in silver.
however the way you do get pure gold from 10K is to melt it with with an equal weight in silver. So say you have a 5 gram ring of 10k In theory there should be about 2 grams of fine gold in there.

So for this example the melted button would have your 5 gram ring with 5 grams of silver meaning you have a silver copper gold alloy that is about 20% gold.

This is called inquartation, So long as the mix of gold is one quarter gold or made to be one quarter gold or less the nitric when mixed with 2 to 3 parts water will dissolve the silver, copper, and other leaving behind the gold in the bottom.

It is a common misunderstanding that nitric dissolves a little gold, this is not true. Most likely this incorrect information was published somewhere and as many authors do, dont check the research, and propagate incorrect information. Most Authors are not chemists and or if someone herd something and though it was correct and wrote it down.

The Gold in the bottom will be a dark brown mass, One pours off the metal impregnated nitric acid and rinses the gold many times, This carries off trace copper and silver left in solution and in the mass. The brown mass is then melted and in theory you should get .995 pure gold. Good enough for re-alloying in jewelry.
To get it to .999 fine see my posts on refining.

 

[chong2]

so for example, if i were to put a 10k ring in a small ammount of nitric, will it eat/ break down all the metals away except for gold?

No it wont but good thinking, its actually the next step in gold refining that you have almost come upon with that Idea.

10K is too resistant to most acidsThe 38-41% gold is too much gold, Even Aqua Regia has some trouble breaking it down if its too rich in silver.
however the way you do get pure gold from 10K is to melt it with with an equal weight in silver. So say you have a 5 gram ring of 10k In theory there should be about 2 grams of fine gold in there.

So for this example the melted button would have your 5 gram ring with 5 grams of silver meaning you have a silver copper gold alloy that is about 20% gold.

This is called inquartation, So long as the mix of gold is one quarter gold or made to be one quarter gold or less the nitric when mixed with 2 to 3 parts water will dissolve the silver, copper, and other leaving behind the gold in the bottom.

It is a common misunderstanding that nitric dissolves a little gold, this is not true. Most likely this incorrect information was published somewhere and as many authors do, dont check the research, and propagate incorrect information. Most Authors are not chemists and or if someone herd something and though it was correct and wrote it down.

The Gold in the bottom will be a dark brown mass, One pours off the metal impregnated nitric acid and rinses the gold many times, This carries off trace copper and silver left in solution and in the mass. The brown mass is then melted and in theory you should get .995 pure gold. Good enough for re-alloying in jewelry.
To get it to .999 fine see my posts on refining.

wow, how long have you been a jewler? great information!

 

[jewelerdave]

Not that long actually, Just the last 8 or 9 years. but its not so much the time doing something as the experience and how frequently one does something. Most Jewelers Dont dare do what I do. most are just sales people and say ohh look how pretty it is. its only X$
I am in on the practicality side. More manufacturing than anything else. Like recently I started minting these fun gold coins!