Activated carbon filtration

[golddigger2]

Hi everyone
I have been struggling to find a quicker way of filtering solutions, as you all know it is a very time consuming part of the refining process. I was wondering if anyone had used activated carbon purely as a filter to remove debris and contaminants from auric chloride prior to precipitation? I have been using coffee filters for some years now and although they work great they are painfully slow and don't always get the very fine particulates without multiple passes of the filters. If your aucl3 is very clean they are quite fast but anything with a lot of debris and you are sunk. Any thoughts would be appreciated

 

[4metals]

Lose the carbon idea, it will absorb values from your solution which you will have to recover.

Post some details as to how, and what you are refining and we can point out any steps to add or avoid.

Filtering can go quite rapidly in the right situation, vacuum also helps over the drip drip of gravity.

 

[Militoy]

Lose the carbon idea, it will absorb values from your solution which you will have to recover.

Post some details as to how, and what you are refining and we can point out any steps to add or avoid.

Filtering can go quite rapidly in the right situation, vacuum also helps over the drip drip of gravity.

Running gold in solution through stacks of activated carbon is actually the way SX-EW (solvent extract electro win) gold mining operations recover their gold. The carbon adsorbs ALL the gold. If you want the process to move faster, use some vacuum as 4metals suggests - or switch to filter paper with a larger filtering area than the coffee filters.

 

[samuel-a]

Vacuum filtration is your best choice.

When gallons upon gallons of pregnant solutions needs quality filtering, Diatomaceous earth filters are used in enclosed pumping system.

 

[golddigger2]

Thanks for the info everybody. Sounds like vacuum filtering is the way to go. Four metals we are doing cpu's, gold trace on cb's and fingers. Cpu's with A/R (ceramic) after dilute nitric leach. Pins from cell with lots of h2o rinses and then HCL/chlorox and fingers A/P followed by HCL/chlorox

 

[Harold_V]

One of the things readers rarely address is how to treat their materials prior to dissolution of values. Filtration, even using gravity with a #5 Whatman paper, can be reasonably fast, although for a first refining, a Whatman #2 is more than adequate. Process dirty materials without incineration and a wash with HCl prior to dissolution of values is pretty much a recipe for difficulty.

Incinerate to redness.
Screen.
Remove magnetic particles with a magnet (they should go to your stock pot for recovery of traces of included values).
Heated wash in HCl.
Rinse until solution is clear. No filtration required. Gravity settle and siphon. Use hot water to accelerate settling.
Dissolve values.
Evaporate.
Take up with water.
Filter.

Simple.

Harold

 

[golddigger2]

Thanks Harrold as usual your information is invaluable.