# Brass



## Ky.Sam (Jul 25, 2007)

How fast will Brass dissolve in Aqua Regia?

I have some switches that take about 2 days to totally dissolve.
Hydrochloric acid and sodium nitrate.


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## Dog Biscuit (Jul 25, 2007)

I just completed a 1/2oz test of brass based material yesterday using nitric/HCl (50mL of each). Total elapsed time of reaction was about 15 minutes.


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## Ky.Sam (Jul 25, 2007)

Dog Biscuit thanks. 

The switches I have came out of a ADC analog box. It is for office phone systems.

It takes about 2 days for these to totally dissolve. I check on the alloy that may be used to make these switches. 

ADC site said something about a nickel silver alloy. If thats the case the silver might be slowing the reaction.


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## goldsilverpro (Jul 25, 2007)

There is no silver in nickel silver. Another name for it is german silver. It looks sort of like silver. Thus, the name.

http://en.wikipedia.org/wiki/Nickel_silver


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## Harold_V (Jul 26, 2007)

The best question is why are you dissolving brass in AR? It's smart to dissolve base metals with an acid that won't dissolve values along with them. Not saying you might not have a good reason in any given case, for there are times when it's necessary. Brass isn't usually one of them. Nitric would be the acid of choice in this case. 

Harold


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## Ky.Sam (Jul 26, 2007)

Harold I was just asking how brass reacted in Aqua Regia.

I took a couple of the switches I have to a recycler to get them to shoot them with there alloy gun. The guy looked at it and said thats stainless.
I told him it wasnt so he hit it with a grinder. Thats yellow brass he said.
Itold him it wasnt brass but he still wouldnt shot it for me. So I left and took my switches with me.

I have put some in nitric acid and they were slow to react. So I just took them out and didnt mess with them. 

One day I was running some stuff through Aqua Regia it took 2 days for them to dissolve and it wasnt complete then.


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## Harold_V (Jul 26, 2007)

Ky.Sam said:


> Harold I was just asking how brass reacted in Aqua Regia.



Ah! Now it makes sense, although I'd still not do it that way. Simple nitric dissolution would allow you to test for copper and nickel. A tiny sample is all that's necessary, and a few drops of nitric and water. You need not dissolve much of a substance to test it. 



> I have put some in nitric acid and they were slow to react. So I just took them out and didnt mess with them.



Do you have any DMG (dimethylglyoxime)? My hunch is a copper/nickel alloy, which would be really easy to test--------if you had DMG. 



> One day I was running some stuff through Aqua Regia it took 2 days for them to dissolve and it wasnt complete then.



Cold?

Heat is so important here------wish I could get that message across to readers. What takes hours (or days) when cold will often occur within minute when heat is applied. 

Harold


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## Noxx (Jul 26, 2007)

Exactly ! Heating a solution make a reaction reacts MUCH faster.

But when adding chemicals to hot solution of acid, do it slowly. You don't want to have a «runaway» situation lol. :lol:


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## Harold_V (Jul 26, 2007)

Noxx said:


> Exactly ! Heating a solution make a reaction reacts MUCH faster.
> 
> But when adding chemicals to hot solution of acid, do it slowly. You don't want to have a «runaway» situation lol. :lol:



Very true! Especially if you're dissolving finely divided metals. The reaction can be violent.

Harold


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