Copper ?

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aumoon

Member
Joined
Mar 21, 2017
Messages
23
Hello all,
I did a small scale experiment on some pins...disolved them in a nitric/water mix...got a reddish sludge as by product. Is this copper ? Can you get rid of it ? A fair amount of gold foils mixed in, did I screw up and now have to just toss it ? Reddish brown...more red than brown tho
 
aumoon said:
Hello all,
I did a small scale experiment on some pins...disolved them in a nitric/water mix...got a reddish sludge as by product. Is this copper ? Can you get rid of it ? A fair amount of gold foils mixed in, did I screw up and now have to just toss it ? Reddish brown...more red than brown tho
Click to expand...


Don't "just toss" anything. The EPA may come knocking on your door, and you may be throwing your gold away. Study the forum a lot more. Especially dealing with waste, and safety.
 
aumoon said:
Hello all,
I did a small scale experiment on some pins...disolved them in a nitric/water mix...got a reddish sludge as by product. Is this copper ? Can you get rid of it ? A fair amount of gold foils mixed in, did I screw up and now have to just toss it ? Reddish brown...more red than brown tho
Click to expand...
You didn't mention what kind of pins, or whether they were magnetic. Maybe Kovar?

If you used nitric, it is unlikely your sludge is copper, as it is quite soluble in nitric, unless there is still metal left.

When you ask about problems like this, providing as many details as possible helps guide the advice you'll receive.

A small scale experiment - how small? 1 gram, 10 grams, 100 grams?
Some pins - What was the source? CPUs? What kind? Pins from circuit boards, connector cables,..? Were they magnetic?
Dissolved them in a nitric/water mix - How much nitric? How much water? Distilled or tap water? What was the total volume?
Got a reddish sludge - How much? A dusting or a thick layer?
You can see foils. Can you see any undissolved metal? Is it a smooth consistency or are there chunks?

We can all try to guess, but we'll just be guessing, which may or may not help you.

Give us some more details, and a picture or two of your starting material and what you have now and we'll try to figure it out.

Dave
 
Must be frustrating for you some times Dave, dealing with new refiners.
First of all let me start by saying that when I say "toss" I, in no way mean just wash it down the drain or something like that ! Of course I mean dispose of it accordingly. I lived in California for years and the "greenie" most assuredly rubbed off ! But how is anyone to know any different about me when on this forum I am known about as well as Adam's house cat. So no , I will not just toss any waste in the literal sense.
As far as the conditions under which the experiment was performed....As follows:

Pin source: ribbon, blade, general connections on motherboard both partial and full plate, some solder not an over abundance though (no CPU).
Pin weight: 50 g give or take a gram or two.
Magnetism: most were not, exact ratio unknown.
Solution used: Nitric/water, distilled water 75 ml, nitric 25 ml NOTE: small amount of nitric added now and then to keep reaction active, exact amount unknown but not more than 15 ml.
Result: A very thick smooth layer of reddish brown sludge with foils visible throughout.
Note: This result was achieved after the removal of undisolved pin cores (plating was gone, extreme corrosion on core). and several washings in distilled water, allowed to settle. Before cores were removed the reaction had ceased, approx. 1 hour 40 min. overall time start to finish.
 
I am so sorry to ask for help with this...but can someone tell me how to post a pic...please forgive my ignorance on this procedure.
 
Iron.

Its best to separate ferrous from non. And run them separately.
It's just easier. The iron powder can be taken into solution with a little dilute sulfuric.

But, Lino is correct, you're chasing a very small amount of powder. Good for an acquaintance test, but for a meaningful recovery you will need pounds of pins. Even then, the amount of gold can/will be relatively small with the type of pins you are running
 
Yeah, just a test to get my feet wet and check the outcome, I figure that if I get the math right, whatever works on small scale will do the same on a larger scale (to a degree I believe). Anyway, thanks to all.... you guys are most helpful !!
 
There is wisdom in starting with small experimental batches. Even when you're experienced, it's a good idea to do small tests when you start dealing with a new material. But going too small has its problems too.

The first time I tried ewaste, I put one finger in some AP I had started. I wasn't able to get back to it for a prolonged period, and when I did my gold was gone! If I had thrown in a bunch of fingers, there would have been enough copper to use all the HCl and the gold would not have dissolved.

As a couple of the guys have said, there will be very little gold, and there are always losses, especially when you're just starting. So don't get frustrated if you don't see a lot of gold when you're done.

Some processes scale well, others don't. Exothermic processes, for example, can give up their heat efficiently enough on a small scale, but when scaled up too far could build too much heat and cause a runaway reaction. Start small and scale up in increments. There are plenty of posts on the usual processes that will give you a good idea of the scale other members work with.

Dave
 
Caveat: I'm a relative noob, too ;)

I suspect Ye Olde Reactivity Table is at play here. If you had mixed pins, then yes, the nitric would start to dissolve the copper on the nonmagnetic pins, and relatively quickly. Once the nitric got down to business and started dissolving the magnetic pins, more active metals (like nickel, iron, chromium) went into solution, displacing the copper. The copper was then cemented onto the bottom of the beaker, and voila: red-brown powder.
 
Looks more like rust than copper powder to me.

Probably scenario... 50 g of pins and 25 ml of nitric acid, the acid runs out and iron left oxidizes to rust from oxygen in the air.

Göran
 

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