Chemicals and process

[butcher]

Sandy,
Urea is not needed to refine gold, if you use too much nitric acid in the process sulfamic acid is a better choice to eliminate the free nitric acid, where urea will not.

Urea will work if you did not use too much nitric and only need to remove the NOx gases from very solutions, but it will not remove the free nitric acid, it just converts it to unwanted nitrate salts in solution.

Ammonium chloride is used in the process to recover platinum from concentrated solutions.
Ammonium chloride is not normally interchangeable with urea in the process.

Urea and HCl can form ammonium chlorides and CO2 gas.
Urea and nitric acid can form an explosive compound of urea nitrate and CO2 gas.

 

[kurtak]

Sandy - I am a bit confused - you said ------

I am helping a friend process gold sponge.

are you saying that your friend has already dropped the gold from a solution & now wants to know how to clean up &/or deal with the gold sponge --- or are you saying he/she has gold in solution & wants to know how to drop the gold out of solution to get the gold sponge

after filtering

after filtering --- are you talking about after filtering the already dropped gold sponge - or after filtering the solution before the gold is dropped

does one add ammonia or ammonium chloride

No - nether one of those chemicals are needed &/or used for refining gold

Just curious is ammonium chloride interchangeable with urea.

No - they are completely different chemicals & serve completely different purposes in refining - as butcher has explained

Help.

In order to help you - we need MUCH more info - like

what kind of material are you working with - as in karat scrap - gold filled scrap - some kind of electronic scrap etc. etc.

Are you &/or your friend just wanting to start processing - or have you already started into a process

if you (or your friend) has already started into a process we need clear DETAILS such as the starting material - "all" steps taken up to this point & "all" chemicals used up to this point

The more details you provide the better we can help

Kurt

 

[Rotz]

Hello guys,

I have a problem please let me know how I should process.
Firstly I made a dust my rams. then I leached in nitric. After that I used AR. and I seperated gold in the solution. After that.. it is coming. I seperated 2 part my AR in room temperature. then I added directly SMB in 1. part as dust. My gold just a little bit precipitate. I added FeSO4 to 2. solution..It didn't precipitate. Each solution still acidic. Then I want to recover the gold especially from 2 solution. I also add a copper pine in to second solution for cementation. But I couldn't sure anything afterthat. Is there any way to recover?

 

[butcher]

Rotz,
Putting gold into solution can be fairly easy, knowing where it goes after it goes into solution becomes a problem, it can cement back out onto the undissolved base metals and hide, or it may still be in solution as ions, this is where testing for gold in solution is helpful we can use stannous chloride or ferrous sulfate to test for gold in solution...

How did you attempt to eliminate nitric from your aqua regia?
Gold will not precipitate if there are free oxidizers to redissolve the gold.
How do you know there is gold in the solution?


Use copper to cement any values from the solution, save the material you leached (check it to make sure there are no undissolved metals or your gold left in them).

 

[lekjaz]

I refine smallish batches every week and I use about 500ml of undiluted HCL, small (pipette) quantities of nitric acid, low heat, and patience. Even if the reaction runs all day, it never takes more than 8-10 ml of nitric to dissolve all the gold. My yields are good and the gold is always at least 2 nines. After precipitation, my HCL/SMB solution is always crystal clear.

I recover silver from waste nitric by cementing out with copper and use it again and again. I don't bother running through an electroytic cell - there's no point. Just make rough silver shot and keep inquarting. The pot grows every week with every new batch. Someday this winter when I'm bored and snowed in, I will run it through the cell and make pure silver crystal. I cement out the copper with iron, neutralize the acid with lye, and take to my local transfer station for disposal for free.