# i cant figure out



## denmark1982 (Feb 2, 2017)

i know i have done something wrong in the progress but where i dont know 

its the first time i see this 

i used aqua regia and waited to all me gold foils was dissolved and it was beautiful gold color and then i add 

Sodium Metabisulfte and then its chacnge color to light green and i dont know what is happen  

http://www.ebay.com/itm/Stannous-chloride-testing-solution-made-with-24k-gold-Check-your-Stannous-/152417006590?hash=item237cc2f3fe:g:K3AAAOSw-zxWnC5w

i used this to check the gold 
but could not see nothing but i know there are gold all my gold foils is dissolved


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## Topher_osAUrus (Feb 2, 2017)

How many fingers?

How much nitric?

How much smb?

All details that are needed before any good responses can be given.


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## denmark1982 (Feb 2, 2017)

Topher_osAUrus"
said:


> How many fingers? about 1 pound ( dont how much in gold foils in gram)
> 
> How much nitric?
> 
> ...


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## canedane (Feb 2, 2017)

You have to learn before you try to recover any gold.
First read,study and understand, then you can give it a try.
Forget all you have seing on youtube, and forget about using AR to proced fingers.

Use the "google search" in the right top of your screen, and write "fingers".Read and learn.
Stannos is simple to make, it is HCl with stannum. (tin). Make your own and only a few ml. Stannos is best when it fresh.


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## Topher_osAUrus (Feb 2, 2017)

In a pound of fingers, theres maybe a gram to 2 of gold (closer to 1 usually).. You used way too much nitric.

I dont see you mentioning denoxxing (removing excess nitric), so more likely than not the gold has not began to precipitate, as it is being redissolved by the excess nitric.

Did you dilute the solution at all before adding the smb?
It helps, a lot...but, I'm not sure if it will help in your case, as there seems to be a LOT of excess nitric..

I agree with canedane, youtube is no good. And, you should really have the entire process planned out as well as you can, before you even start. Also taking note of what issues could arise, and how to fix them.


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## denmark1982 (Feb 2, 2017)

Topher_osAUrus said:


> In a pound of fingers, theres maybe a gram to 2 of gold (closer to 1 usually).. You used way too much nitric.
> 
> I dont see you mentioning denoxxing (removing excess nitric), so more likely than not the gold has not began to precipitate, as it is being redissolved by the excess nitric.
> 
> ...



and what is the right to make aqua regia and have read about and there so many various explanations so i try.. 

so tell me what is dilute and what is denoxxing


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## denmark1982 (Feb 2, 2017)

http://goldnscrap.com/index.php/find-scrap-circuit-boards-auctions-at-ebay-and-learn-how-to-evaluate-prices/85-gold-fingers-how-to-recover-gold-from-electronic-scrap


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## Topher_osAUrus (Feb 2, 2017)

I could easily sit down and type up the answers to your questions, but, those answers will lead to more and more questions. 

To efficiently refine precious metals, one must have a basic understanding of the principles and terminology that is used. Luckily for you, this is the perfect place to get to that level of understanding. The only thing, is you must do the legwork. You have to read and read and read. Then read some more. Read it until it begins to make sense.

CM Hoke's book will get you up and over that learning curve. It is a free download here.

As far as those questions. Dilute it with an equal amount of water (or more, sometimes. That will be something you learn with experience)

Make your aqua regia by firstly calculating how much HCl you need, and then your nitric. But, DO NOT add all of the nitric at once. Add it in small increments. Maybe add 25% of it initially, then once the reaction begins to slow down, add another 25%...after it slows down again add more nitric, but start to cut back on it some, maybe adding 10% this time. Small additions... They are your best bet.

But, your key to success comes from reading the abundant information contained on this forum.


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## denmark1982 (Feb 2, 2017)

Topher_osAUrus said:


> I could easily sit down and type up the answers to your questions, but, those answers will lead to more and more questions.
> 
> To efficiently refine precious metals, one must have a basic understanding of the principles and terminology that is used. Luckily for you, this is the perfect place to get to that level of understanding. The only thing, is you must do the legwork. You have to read and read and read. Then read some more. Read it until it begins to make sense.
> 
> ...



so i can save the gold in this clas or what can i do


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## nickvc (Feb 3, 2017)

The beat way to make up any solution to dissolve gold is to use an excess of HCl and add small increments of the chosen oxidiser allowing each addition to finish reacting, after the last addition with no reaction add a little more HCl and watch for any reaction, if you get a reaction you still have gold to dissolve.


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## denmark1982 (Feb 3, 2017)

nickvc said:


> The beat way to make up any solution to dissolve gold is to use an excess of HCl and add small increments of the chosen oxidiser allowing each addition to finish reacting, after the last addition with no reaction add a little more HCl and watch for any reaction, if you get a reaction you still have gold to dissolve.




looks like that now like ice


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## kurtak (Feb 3, 2017)

denmark1982 said:


> Topher_osAUrus"
> said:
> 
> 
> ...


[/quote][/quote]

If I understand the above right you used 1 (coffee cup) of 53% nitric along with 3 (coffee cups) of 35% HCl to dissolve the metal from 1 pound of fingers - meaning you put the whole fingers in the AR (nitric plus HCl) & not just foils that had been removed/recovered from the finger

In ether case (whole fingers - or just gold foils) you used WAY to much nitric & I do mean WAY to much nitric :!: 

The result is that you still have a LOT of "free nitric" in your solution

Free nitric means nitric that has not been used up dissolving metal - which means the nitric (that is not used up & therefore still free) has the power to keep dissolving metal

The result of this is that when you go to drop (or precipitate) you gold - it will not do so - because the free nitric keeps the gold dissolved thereby preventing it from dropping out of solution 

Therefore - in order to get your gold to drop --- you MUST get rid of (use up) the free nitric BEFORE trying to drop the gold

If there is just a "little" bit of free nitric - when you try to drop the gold - it "may" precipitate - at first - but then the gold will start dissolving again because of the "little" bit of free nitric 

If you have a LOT of free nitric (as in your case) it simply will NOT drop - at all - because there is so much free nitric that the SMB does not have the power to overcome the "large" amount of free nitric keeping the gold dissolved

Therefore - to get your gold to drop - you have to get rid of &/or use up the free nitric FIRST (we refer to getting rid of the free nitric as de-noxing)

There are a number of different ways to get rid of the free nitric - with out going into a lot of detail the different ways are --- 

1) an evaporation method - this is best used if you only have a "little" bit of free nitric

2) de-noxing with chemicals like sulfamic acid (preferred) or urea (not preferred) - how much chemical you need to de-nox depends on how much free nitric you have --- so though you can do it this way if you have a lot of free nitric it will result in increasing the amount of chemical waste you create --- so again this method works best if you only have a little bit of free nitric

3) or you can dissolve more metal to use up the free nitric - you could dissolve more gold - or more copper - or even some other metal like iron or zinc - this is the method I would use

First you need to understand how acids work at dissolving metals --- when dissolving gold with AR it takes "about" 1 ml of 70% nitric to dissolve 1 gram of gold ( I say about - because depending on conditions - it may take less - or it may take more) --- BUT it will take "about" 4 ml of 70% nitric to dissolve 1 gram of base metals

In other words - using 70% nitric --- it takes "about" 4 times more nitric to dissolve 1 gram of base metals then it takes to dissolve 1 gram of gold

Now then - I know that the nitric you used was 53% --- I am not going to take the time to do the math to figure out how much metal 1 ml of 53% will dissolve - in stead I am going to use the 70% nitric as an "example" to explain this

So using 70% nitric as the example - IF - your coffee cup is the same size as a "measuring" cup we use here in the U.S.A. that would be 236.58 ml of 70% nitric (used in your AR) that is enough to dissolve "about" (more or less depending on conditions) 236.5 grams of gold --- so you could use up the free nitric by dissolving that much more gold --- but that is a LOT of gold

However - because it takes about 4 time more acid (nitric) to dissolve the same amount of base metal - that means you can use about 4 times less base metal to use up the free nitric - copper is the best base metal to us in this case

That means you only need "about" 59 grams of copper to us up the nitric

BUT - here is the added benefit to using copper to use up the free nitric --- copper is more reactive to the acid then gold - therefor the acid likes to dissolve the copper more then it likes to dissolve the gold - BUT - because you already have gold dissolved in the acid - when the free nitric is used up dissolving the copper - the nitric that was already used to dissolve the gold is also going to work at trying to dissolve more copper & the reason for that is that the copper is more reactive to the acid then the gold --- so - the result is that as the nitric that originally got used to dissolve gold & is now trying to dissolve copper - causes the gold to be forced out of the solution as the "extra" copper goes into solution

We call this "cementing" your gold out of solution by using a "more" reactive metal to "displace" the less reactive back out of the solution

In other words it is a metal ion "exchange" that takes place with the more reactive metal going into solution - which in turn "forces" the less reactive metal "back out" of solution

It is based on the reactive series of metals which you will find here :arrow: https://en.wikipedia.org/wiki/Reactivity_series

How it works is that more reactive metals will cause less reactive metals to be forced out of solution - even though ALL the acid was used up to dissolve the original less reactive metal

In other words - say you have 10 grams of gold dissolved in AR - AND - there is NO acid left to dissolve more gold because ALL the acid has been used dissolving gold --- if you put copper in the solution - the copper will start replacing the gold - thereby forcing the gold out --- then when all the gold has been forced out - & the solution is now loaded with copper (instead of gold) you can then put iron in the solution & the iron will go into solution - & force the copper back out

So - you can use a piece of copper to not only use up the free nitric - BUT - also to "cement" any gold in solution back out of solution --- you want to use a heavy piece of copper like a piece of copper pipe rather then using tine copper like copper wire - & you want to be sure the copper is fully submerged in the solution with no copper sticking out of the top of the solution

the other option would be to dissolve more gold plated items like gold plated pins so that the base metals help to use up the free nitric plus adding the extra gold to your recovery 

Kurt


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## obix (Feb 6, 2017)

Thanks Kurt!! I'm new to the forum and have been browsing looking for these types of answers, I find what you've written here to be extremely helpful, thank you!  

obix


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