I cemented out on copper. How do you pro’s handle this?

[Proffshuggarn]

This is how it is.
Before I found this eminent forum, I had tried to process some of the amount of e-scrap I had accumulated, with less good results in terms of recovery, but all the more cans of acid mixtures instead.
When I found this forum, I had given up hope, but the acid mixtures were still there.
Well, I was provided with Hoke's material and lots of other stuff and was advised to pause for a while and read up instead, which I immediately obeyed. Before I had ZERO clue, now I have a small ounce of insight into the most basic of the subject. I am incredibly grateful for this forum and the knowledge many people possess and share here. To the point: I started by dealing with the stock of acid mixtures, about 28 liters. I prepared a plastic tub with dual air hoses from an old aquarium pump. The air hoses are kept down in the tub under the copper I put there. A small black plastic box as protection for the air pump and a plastic lid over the tub, at the top a Stone.
I filled the tub with the acid mixtures and after 3 days the liquid was completely clear and green. A lot of black powder on the bottom and on the copper a yellow/orange sediment (see the pictures).
I haven't found anywhere how to get the yellow sediment off the copper, so I ran all the copper through the ultrasonic cleaner and got it all off... In about 3 liters of liquid consisting of water and the yellow/orange sediment both on the bottom of the containers and freely in the liquid. It took a full day to filter out all of the yellow/orange powder stuck to the copper.
Questions:
-Is the yellow/orange sediment from the copper the valuable material I failed to precipitate in my previous clever attempts?
-How do you professionals handle this yellow/orange sediment? Surely there must be an easier way than the one I used - ultrasonic washing? Thank you for reading and I humbly accept constructive advice and tips.
(Only a little part of the copper and filtered sediment at the pictures)
/Dennis

 

[Christian333]

This is how it is.
Before I found this eminent forum, I had tried to process some of the amount of e-scrap I had accumulated, with less good results in terms of recovery, but all the more cans of acid mixtures instead.
When I found this forum, I had given up hope, but the acid mixtures were still there.
Well, I was provided with Hoke's material and lots of other stuff and was advised to pause for a while and read up instead, which I immediately obeyed. Before I had ZERO clue, now I have a small ounce of insight into the most basic of the subject. I am incredibly grateful for this forum and the knowledge many people possess and share here. To the point: I started by dealing with the stock of acid mixtures, about 28 liters. I prepared a plastic tub with dual air hoses from an old aquarium pump. The air hoses are kept down in the tub under the copper I put there. A small black plastic box as protection for the air pump and a plastic lid over the tub, at the top a Stone.
I filled the tub with the acid mixtures and after 3 days the liquid was completely clear and green. A lot of black powder on the bottom and on the copper a yellow/orange sediment (see the pictures).
I haven't found anywhere how to get the yellow sediment off the copper, so I ran all the copper through the ultrasonic cleaner and got it all off... In about 3 liters of liquid consisting of water and the yellow/orange sediment both on the bottom of the containers and freely in the liquid. It took a full day to filter out all of the yellow/orange powder stuck to the copper.
Questions:
-Is the yellow/orange sediment from the copper the valuable material I failed to precipitate in my previous clever attempts?
-How do you professionals handle this yellow/orange sediment? Surely there must be an easier way than the one I used - ultrasonic washing? Thank you for reading and I humbly accept constructive advice and tips.
(Only a little part of the copper and filtered sediment at the pictures)
/DennisView attachment 56898View attachment 56899View attachment 56901View attachment 56902View attachment 56906View attachment 56907View attachment 56903View attachment 56905View attachment 56904

I doubt your yellow precipatant is a precious metal. More likely a base metal salt, iron for example.

Take a small sample (5ml), add a drop of sulfuric acid. If it clears, then treat the entire solution and filter out the black solids, those will be your precious metals.

Janie

 

[orvi]

Collect small sample of that precipitate, redissolve in HCL and if everything dissolve, you have nothing in it. If you do have some undissolved powdered residue, add a bit of nitric acid or hydrogen peroxide and then test with stannous.

From the first glance, it looks like acid was depleted and your material contained some significant iron - as it looks like iron oxohydroxide goo to me. Check the pH and if it is above 2, add HCL to re-acidify. Then you will see if there is actually something.

 

[Proffshuggarn]

@Janie & @orvi
You were 100% correct, almost everything dissolved in Hcl and after a few drops of nitric acid even the tiny black grains dissolved. Stannous' test was completely blank. Thanks for the help and hopefully the black powder will turn out better tomorrow

 

[Proffshuggarn]

@orvi
Forgot to tell the PH from the green stock pot:

It’s ok isn’t it?
/Dennis

 

[Christian333]

@orvi
Forgot to tell the PH from the green stock pot:
View attachment 56932
It’s ok isn’t it?
/Dennis

Looks good to me.

Janie

 

[orvi]

pH is acidic enough for cementation to happen and also for stannous to work.

 

[bahabully]

How and why would iron precipitate on copper being below the reactivity series of metals ?

 

[Yggdrasil]

How and why would iron precipitate on copper being below the reactivity series of metals ?

Many things may happen if things are left alone for such a long time.
Amongst other, the pH may get high enough to create hydroxides.
I do not say this happened here, just an example.

 

[Proffshuggarn]

I started processing the black "powder" from the bottom of the stock pot yesterday.
-Yes, of course I first had to siphon off the solution and managed to collect the powder in an old coffee pot. Stannous test = Blank/ negative. PH=1.5-2.
-The difference this time was that all the copper I had hanging over the air hoses on the bottom was completely white, in contrast to the last round, when there was an orange coating as you know. Will examine this more closely tomorrow and then also take some pictures. BUT, to my dismay, I ran out of SMB, but I did some reading around here on the forum and found an alternative to SMB that I knew was in the kitchen cupboard -Ascorbic acid! I studied a little more and came to the conclusion that the process looks the same as with SMB, although with a couple of exceptions, which I wonder what you say about:
-I dissolved the base metals first with about 150ml of Hcl, actually a little diluted with a small splash of distilled water . Let it stand under heating for about 20 min, then cool.
-Then I filtered everything and got dark Hcl in the beaker after the filter, but heavy lumps that wanted to remain and these could easily be washed with distilled water in the original beaker.
-Well, I filled up with 250ml of new fresh Hcl and started dripping nitric acid while AR was helped by some heat. I titrated up the nitric as the process progressed and by the time it was all dissolved in the AR I had used 14ml of nitric.
-It took about 40 minutes to dissolve all solid material in AR. -Then I set the pregnant solution aside while I heated a small teaspoonful of Sulfamic acid dissolved in distilled water. When the Sulfamic acid became hot enough, I carefully began to pour it into the AR. And I must have done the right thing, as I stopped the supply of Sulfamic acid just when it gave a "foaming" Instead of a "sizzling" reaction. Let the solution stand for a few minutes and filter again. Now clear dark yellow solution.
-This step, I wonder if it is necessary: -Soda ash, about 3-4 teaspoons dissolved in 150 ml of water. It fizzed and the solution changed a little color but nothing more.
- Took a Stannous test which was strong purple/red at first and then immediately turned black
- In the meantime I had the ascorbic acid about 4 tablespoons dissolved in water on heating.
-I added the ascorbic acid solution gradually when there was a reaction... But like magic, the solution went from dark yellow to pitch black in half a second. Poured another 150ml of plain water.. Before I went in for the evening I could see a centimeter thick layer on the bottom.
-Did a Stannous test = negative
- I think I've succeeded, tomorrow will tell.
What do you think? Will return with pictures etc. tomorrow. Feels good anyway. Good night
/Dennis

 

[eaglekeeper]

I ran out of SMB, but I did some reading around here on the forum and found an alternative to SMB that I knew was in the kitchen cupboard -Ascorbic acid!

Ascorbic acid will work, but it's not completely selective. From what I understand it will reduce all PM's to some extent, not just Au. I've never had to use it yet, but it's another tool in the toolbox.