A questions from a newbie

[Golder]

I was looking for an answer to the following question. If there is an answer in the archive, sorry that I did not find it.
The Question ist: If I have a solution with gold- , iron and copper-ions as a result of using AR and now I want to precipitate the gold from the solution with SMB, will this also precipitate the copper ? ? ?

My Idea (better: my hope): The copper an the iron will further be in solution and only gold will precipitate with the SMB, right? Than I only have to wash the gold-powder as the following step?

Thank you!
Joerg

 

[Noxx]

Joerg,
SMB is a selective precipitant. This means it precipitates gold without touching other metals like copper, nickel, iron, etc.

 

[Golder]

Thank you Noxx! That is a good and clear information.

Yesterday I had the idea, to make salts with weak acids. I was trying to separate the copper from the copperchloride in the chloride-mix as a coppercarbonate-powder with sodium carbonate for getting a copper-free solution with just gold- and iron-ions. This is a indirect-newbie-idea I do not know, if it works. The resulting solution looks very ugly.

But this information about SMB makes me really happy. Now I am going to drink a coffee.

Joerg

 

[lazersteve]

SMB will convert copper II chloride (water soluble) into copper I chloride (insoluble except in strong acid) if excess SMB is` used.

Steve

 

[Golder]

Hi Steve,

that means, that the SMB-precipitated gold is still contaminated with insoluble copper-1-chloride if I use to much SMB?

Than it is better, to make the precipitation-procedure with an excess of muriatic acid, right?

Joerg

 

[butcher]

if there is alot of base metals in your solution (like copper) one way I handle it is to use copper to precipitate the gold, this removes the metals in the electromotive series above copper(left in solution), and then my precipitant is also lower in copper value than before, I decant this evaporate dry, then incenerate, then disolve this again for a more purer solution and drop my gold from it. would probably need refined one more time,
I use SMB with high copper but it is not as succesful as doing the above procedure has been( for me).

 

[Golder]

Hello Butcher,

thank you for this idea! Practically I will hang a piece of sheet copper in the solution, yes? I will test it overnight with a part of my solution.

Joerg

 

[butcher]

I use powder, gold will plate onto copper black specks, if high gold content and acid level is right will be a petty gold coating,

 

[Golder]

My problem is to estimate the gold content in the solution. Think, its not high. I will test the precipitation with SMB and also with copper powder (your idea). I think, it would be necessary for me to think in processes, not in "yes or no". That is, what I had to realise. Fight against the copper-contamination is a process. First Step is to overweight the cold content . After that the other steps should minimize the contaminations.

 

[Harold_V]

My problem is to estimate the gold content in the solution. Think, its not high. I will test the precipitation with SMB and also with copper powder (your idea).

I'm a little troubled by this response.

Are you familiar with stannous chloride? Ferrous sulfate?

Either of them would be better if you're trying to determine the presence of gold. I would not use copper unless I was attempting a recovery from very dirty solution, then I'd use solid bits, not powder. It makes no sense to continue to create the same problem you're trying to avoid.

Neither will behave as an assay, but if you use them routinely you start getting a general idea of the content of a solution.

I think, it would be necessary for me to think in processes, not in "yes or no". That is, what I had to realise. Fight against the copper-contamination is a process. First Step is to overweight the cold content . After that the other steps should minimize the contaminations.

Plain and simple, you should attempt to eliminate any and all base metals before ever dissolving precious metals. There are a few exceptions.

If you find yourself with a well contaminated solution, there's nothing wrong with precipitating with any of the common precipitants, washing well to eliminate drag-down of base metals, then re-refining the recovered gold to improve its quality.

Harold

Edit: Remove unwanted punctuation. No change in contents otherwise

 

[Golder]

Harold,

I tried to precipitate gold with oxalic-acid. But without any success. I will try it now with SMB and with copper. After that I will test it with other precipitants, for instance ferrous sulfate.

I will post the result next days, because I have to wait for my SMB shipment.

Joerg

 

[Harold_V]

Harold,

I tried to precipitate gold with oxalic-acid. But without any success.

I had only one experience with oxalic acid, and was not impressed. It is only fair for me to say that I also did not apply it properly.

I will try it now with SMB and with copper. After that I will test it with other precipitants, for instance ferrous sulfate.

I see no mention of stannous chloride yet again. While it is not used for recovery, it is one of the most important of solutions you will use. It is the method of determining which solutions have value, and which should be discarded. If you are not using stannous chloride, I advise you stop where you are in your refining and acquire some tin. Make the solution, following the advice given here on the forum (lazersteve discusses stannous chloride extensively), or you can read about it in Hoke's book. Stannous chloride is the eyes of a refiner.

I will post the result next days, because I have to wait for my SMB shipment.

I hate to belabor the point, but you would use stannous chloride to determine when you have recovered your values when you apply SMB. Without it you may not know if you should discard a solution, or not. It is not a good idea to allow solutions to accumulate. It doesn't take long until you have a huge number of unknown solutions, which may or may not contain values.

Copper should be used only as a recovery process, when other methods have not worked well. It is not selective, although it does not precipitate other base metals.

Harold

 

[Golder]

Newsflash

Next days I will post my results of my very first precipitation and refining of approximate 0.3 gram newbie-gold. But absolutely I have to say: Muriatic acid plus hypochloride works very, very smart. I could not believe that. Thanks on the gurus here

My problem with the goldtest with stannous chloride was the copper- and iron in excess. The strong green color bred by these ions were overlaying the soft purple color of the test. Fortunately I was knowing, that the solution contained gold. Any Ideas, how to test a strong colored solution?

Joerg

 

[lazersteve]

Ferrous Sulfate will precipitate a dark brown powder from strongly colored gold bearing solutions.

Add a small crystal of ferrous sulfate to a test tube containing a very small amount of the strongly colored solution under test. If you see a black/brown powder form this is a good indication of gold.

Steve

 

[Golder]

Thank you Steve! I will test your idea soon! Also will test a whole precipitation with this iron salt next time.

 

[butcher]

that looks good!

 

[qst42know]

Out of curiosity what was this melted in?

 

[Golder]

Melted with some borax in steatit. I do not know, what is the right US_name. Call it talc or steatit. You can easy carve a mould in it. Also an experiment for me..