Leach Color. What is it?

[shadybear]

O.K. here is what I have done.
I used 1 quart of distilled water
1 quart of battery acid with 4 ounces
of sodium nitrate dissolved in it.

To this I added 1 pound of what I call pin heads.
These were taken off of gold plated pins, they were the
tips of the total pin and were held in with a spring and ball
set-up.

I have been wondering what they were made of.

So I left this set for 24 hours and then
rinsed with water to re-dissolve everything

Now I have a leach liquid it,s color looks light
brown with a strong yellow tint.
Like weak iced tea but you can see the yellowish
look.

If I dilute some of the leach liquid with distilled water it looks yellow brownish in color.

Any thoughts!

 

[shadybear]

I forgot the remaining junk in the jar now looks like
the pin heads but they look copper color.

 

[Noxx]

Could you put some pictures ?

 

[shadybear]

I can not put up pictures at this time I will work on it tomorrow
and hopefully be able to get some up by then

 

[lazersteve]

Shady,

Have you tried testing the solution for gold using Stannous Chloride?

Steve

 

[shadybear]

No I have not tested for gold.
I was led to believe that nitric
acid does not take gold into solution

 

[lazersteve]

It's possible since you have listed some of the key components of a persulfate compound. Persulfates CAN leech gold under the right conditions.

Steve

 

[Noxx]

But there isn't much change that his nitric acid eats gold

 

[lazersteve]

Nitric acid on it's own won't dissolve gold.

 

[catfish]

Shady Bear:

Couple of points:

I tried the same thing as you did in using Battery acid and nitrate soda mix. It did not work. I put 150 grams of good grade pins in the solution. The solution turned brown and did not dissolve the metal and leave the gold plated material.

I found out that Battery acid, ( purchased from NAPA) (electrolite is diluted about 10 to 1 with distilled water. It is very weak.

I then tried the same process with rooto professional drain cleaner and sodium nitrate solution, and ah-la it worked. You will only have the gold plated material (gold) left only. (hundreds of small hollow gold pins) The solution disolved all the other metals except the gold. I then strained the gold metal off and then ran it through a normal aqua regia solution and refined some very good gold from it.

You may want to check your battery acid strength. I also used some concentrated sulphric (70%) in the same test and it works good too, but pure sulphuric acid is hard to get.

note; This does not work on pins that have no metal exposed. It has to have a way of getting to the metal. Steve is correct, It will not dissolve gold.

PS. You may want to take your spent aqua regia and throw a hand full of pins, that have some metal exposed , in it and leave for about a week. You can accomplished the same thing. I do most of my Pentium 2 or 3 cpus this way.

Catfish