gold wont precipitate

[jimmyreece]

i disolved a respectful amount of gold i found cemented to the bottom of a 3 gal container that was unknowingly left over from my iodine leach attempt not long ago.
interesting as it is because during darkspark's and a few others and mine seemingly failed attempt at the "passive iodine leach method", we all, well i was anyways, still rather clueless as to how to retrieve the values in the iodine solution.....well i found them.
i should have just added the hcl + cl to the empty container and left it at that, but after testing positive,both the cemented gold on the container and the solution, i went ahead and disolved it all in the hcl & cl.
it disolved easily and quick. i filtered, diluted 3x, heated up some hot water to disolve the smb, approx 4-6 grams. cleared up good and still it sits with no precipitation.
any answers to this ?

 

[Claudie]

How long has it been sitting since you added the SMB?

 

[jimmyreece]

about 45 min

 

[jimmyreece]

of course 45 min isnt very long and it still may. but im used to seeing the precipitation real soon after adding the smb. im just wanting to know what could causing the no reaction in the mean time

 

[Anonymous]

Personally,I would throw copperas at it,I don't normally have too many problems with smb,but if I do,copperas always comes through,which is why I have primarily used copperas for a couple of years now.
Do you know what your PH is at?You may have dilluted too much.Youc an always evaporate to bring it back into check.
If nothing else works,slowly evaporate back into a powder in VERY clean beaker,and process the powder in AC like normal.The cleaner the beaker is,the easier the powder will release from the beaker when it is dry.

 

[jimmyreece]

no i havent checked the PH. but i think evaporation like you said would be good....its a pretty thick concentrated solution even at 3x with water.

 

[Anonymous]

You said this was an "Iodine" leach? Did you check for silver first? If not then you may want to evaporate everything,and process as (potential) silver bearing gold.

 

[Oz]

It could be you still have free Cl2 gas in solution from your HCl/Cl2 digestion. Heat it up to drive out the free Cl2.

 

[patnor1011]

4-6g of smb indicate you suspect or expect like 4g of gold. If your solution even diluted with water is over say 0.1-0.2 l you will have hard time to see gold drop. It will drop but very slow and in superfine particles. They will be settling hours if not days. Introduce some heat it will help but try not to boil solution, evaporate very slow, you will want to see only faint steam rising from beaker.

 

[donnybrook]

I posted something on three passive leaching processes. The main thing with iodine leaching is to keep your pH at 2 (at least this works with me) as this has a lot to do with ORP. I have also found that when all PM's are depleted or taken the pH alters rapidly indicating to me at least there is nothing more to leach. Other pH's are recommended for other PM's apart from gold.

I filter my materials using a plastic sieve and tissues. I then adjust the pH to 7 with sodium hydroxide and correcting any inbalance with HC. I then add SMB at a rate of 100 grams per litre of water for every 60 grams of gold I am after.

SMB does take time depending on temperatures etc. It is effective. Filter the precipitates out,dry and then clean using recommended procedures. That should produce your gold ready for flux and smelting.

You can also make your own precipitate using iron and sulfuric acid but why when the product is available on the shelf.

I have had problems redissolving preciptates with AR and must first smelt then grannulate then a digestion with nitric.

If you have a problem dropping your Au with SMB and the Chlorine Leach check to ensure it is fresh. If all else fails add aluminium foil or even beer cans to this and will bring all metals within its range in the periodic table down.

Hope this helps.

donnybrook

 

[etack]

don't use Al you will have problems in a Cl process . use Cu or Zn to start over

Eric

 

[donnybrook]

Thanks Eric donnybrook

 

[gmiller]

I had a similar problem an found that the gold was being redissolved due to the HCL-CL being too strong. I diluted my solution and finally raised th pH to get it to drop.

Hope that helps

Gary

 

[jwbrdkllr]

Edited by Moderator:

Please do not double post:

Duplicate question found here.