Best practice of filtering copper anodes slimes

[Ayham Hafez]

Copper anode slimes filtering is very hard and almost impossible without gravity method, but to make slimes settle down it take couple of hours and at the end we will not get a dry slimes.

Hope someone in the forum have a good technique for filtering the slimes without missing any value.

 

[Yggdrasil]

Copper anode slimes filtering is very hard and almost impossible without gravity method, but to make slimes settle down it take couple of hours and at the end we will not get a dry slimes.

Hope someone in the forum have a good technique for filtering the slimes without missing any value.

How about treating them in dilute Sulfuric with a gentle boil.
That should dissolve all Copper and let the rest agglomorate.
Then siphon off all the liquid and process in Nitric for the Silver and Pd?
AR for the rest?

 

[nickvc]

I nicknamed slimes swines for a good reason , they really are a pain to handle whatever you do they get everywhere and block filters as if it’s second nature .
I have one thought that could be worth a try , if you can reduce the volume of solution by settling you could add nitrate powder the same as in poor man’s to create nitric which should remove the copper and the silver and any other base metals leaving the gold which I assume is your goal , if you decide to try this do a small test and see if it works for your purposes .

 

[Alondro]

Copper anode slimes filtering is very hard and almost impossible without gravity method, but to make slimes settle down it take couple of hours and at the end we will not get a dry slimes.

Hope someone in the forum have a good technique for filtering the slimes without missing any value.

Try putting the anode in a tightly-woven cloth bag and submerging that in the electrolyte. Depending on what electrolyte you use, you'll need to choose an appropriate material for the bag that won't break down.

The bag will keep all the slimes inside. Sreetips on Youtube does this with his silver electrolysis, but to keep the waste slimes OUT of his pure silver crystal. It does an excellent job of keeping all the ultra-fine slime out of the electrolyte, so it would certainly work for saving the valuable slimes as well.

Something like a nylon filter bag might work for most electrolytes as long as they're not too acidic. Nylon, since it's an organic material, can then be ashed, and the slimes will be a dry powder mixed in with the ash. Nylon itself, being entirely carbon-based, should leave very little ash when totally incinerated. Most of the powder you're left with will be the PM slimes.

 

[Ayham Hafez]

I nicknamed slimes swines for a good reason , they really are a pain to handle whatever you do they get everywhere and block filters as if it’s second nature .
I have one thought that could be worth a try , if you can reduce the volume of solution by settling you could add nitrate powder the same as in poor man’s to create nitric which should remove the copper and the silver and any other base metals leaving the gold which I assume is your goal , if you decide to try this do a small test and see if it works for your purposes .

I tried before with nitric acid, it was a nightmare, all gold converted to colloidal gold and filtration took more than one week, its not work don't even think about it believe me.

 

[Ayham Hafez]

Try putting the anode in a tightly-woven cloth bag and submerging that in the electrolyte. Depending on what electrolyte you use, you'll need to choose an appropriate material for the bag that won't break down.

The bag will keep all the slimes inside. Sreetips on Youtube does this with his silver electrolysis, but to keep the waste slimes OUT of his pure silver crystal. It does an excellent job of keeping all the ultra-fine slime out of the electrolyte, so it would certainly work for saving the valuable slimes as well.

Something like a nylon filter bag might work for most electrolytes as long as they're not too acidic. Nylon, since it's an organic material, can then be ashed, and the slimes will be a dry powder mixed in with the ash. Nylon itself, being entirely carbon-based, should leave very little ash when totally incinerated. Most of the powder you're left with will be the PM slimes.

Filter bags must be coated with rubber at the bottom of it to avoid loosing slimes, rubber will also prevent electrolyte from go through it, so at the end you will end up with liquid slimes, and don't forget rinsing the anodes with water.

 

[Ayham Hafez]

How about treating them in dilute Sulfuric with a gentle boil.
That should dissolve all Copper and let the rest agglomorate.
Then siphon off all the liquid and process in Nitric for the Silver and Pd?
AR for the rest?

I replied yesterday but I don't know why my post not appear, maybe because I was log out.

Anyway, I tried to deal with slimes by acids, any acid will increase the issue, the only way is to filter and dry.


Really I wonder how big companies deal with slimes, I have 500 amps cell and weekly I have to spend 2 to 3 days for filtering with missing some small slimes particles.

 

[nickvc]

The other option is to increase the size of the filter bed and use gravity not vacuum filtering , with slimes they tend to block the filter if you add vacuum pump very quickly.

 

[Yggdrasil]

I nicknamed slimes swines for a good reason , they really are a pain to handle whatever you do they get everywhere and block filters as if it’s second nature .
I have one thought that could be worth a try , if you can reduce the volume of solution by settling you could add nitrate powder the same as in poor man’s to create nitric which should remove the copper and the silver and any other base metals leaving the gold which I assume is your goal , if you decide to try this do a small test and see if it works for your purposes .

So how do the big boys treat them?
Direct s/melting?

 

[nickvc]

I’m not too sure what processes the large copper refiners have but I’m guessing they remove the copper as a first step to reduce the volume of material and if the slimes are similar to silver cell slimes they will be the vast majority of material, from what I could find it seems it’s a long process utilizing dilute sulphuric , heat and pressure , another thought that may be worth a try is to use AP to remove the copper and other base metals , again try with a sample and see if it works to reduce the copper content , if that works getting the gold should be easy using HCl and peroxide and any silver would be left as a chloride which again is easy enough to recover.

 

[Ayham Hafez]

I’m not too sure what processes the large copper refiners have but I’m guessing they remove the copper as a first step to reduce the volume of material and if the slimes are similar to silver cell slimes they will be the vast majority of material, from what I could find it seems it’s a long process utilizing dilute sulphuric , heat and pressure , another thought that may be worth a try is to use AP to remove the copper and other base metals , again try with a sample and see if it works to reduce the copper content , if that works getting the gold should be easy using HCl and peroxide and any silver would be left as a chloride which again is easy enough to recover.

For very small scale like 1 or 2 liters of mud its possible to go with acids treatment but with small scale copper cell you end up weekly at least 8 gallons of mud mixed with rinses water.

No way to go with acids unless you want to spend a week for processing one week mud, we have to filter and smelt, I think the only way for filtering is to use pressure filter, I'm not ready to get a one now so I tried to find another way.

 

[nickvc]

As I said I did try to look for how the big boys deal with the slimes and most talk about weeks if not months treating the slimes , that could be old technology , processes or because there really is no quick way to deal with them , the problem you have is copper is just above precious metals on the reactivity scale so you need to find a work around or be very very patient.
I’m no chemist so perhaps some of our clever chemists can suggest other routes to try but I’m guessing if the big copper refiners struggle you will too