Chemical process

[michael1311]

I am currently doing my research with refining gold and have noticed there are different methods of getting the gold to 999. Before I go off and start reading
different ways to do this, can anyone tell me the basic advantages and disadvantages of these methods? I am looking to get the gold to 996 and extract the silver.

Thanks guys

 

[martyn111]

If you could be more specific about the material you are trying to refine you will get a more specific answer to your question.
Are you trying to refine karat scrap, ewaste etc, as the saying goes, there is more than one way to skin a cat, and your starting material will determine which method of 'skinning' to employ.

 

[patnor1011]

I am currently doing my research with refining gold and have noticed there are different methods of getting the gold to 999. Before I go off and start reading
different ways to do this, can anyone tell me the basic advantages and disadvantages of these methods? I am looking to get the gold to 996 and extract the silver.

Thanks guys

You have to learn about most of different methods if you really want to refine gold. You will need that in future anyway.

 

[nickvc]

I am currently doing my research with refining gold and have noticed there are different methods of getting the gold to 999. Before I go off and start reading
different ways to do this, can anyone tell me the basic advantages and disadvantages of these methods? I am looking to get the gold to 996 and extract the silver.

Thanks guys

You have to learn about most of different methods if you really want to refine gold. You will need that in future anyway.

Excellent and spot on advice from Pat as usual, do the studying, there are no shortcuts unless you know all the processes and methods used and they are all in detail here on the forum.
Start by reading C.M.Hoke it gives you a good basic understanding of most of the important processes and details testing techniques that are vital to any refiner and read the forum handbooks, free as downloads of several members signature lines, also visit lazersteves site, special attention should also be taken to read and understand the safety section, this could save your health or life.
Welcome and good luck.

 

[michael1311]

thanks for the quick responses. Its all mixed jewelry scrap that i've melted into a block.

 

[martyn111]

Quick answer then is look up 'inquartation' using the search engine either at the top of the page or via lasersteves website

 

[michael1311]

been reading that CM Hoke book. Could some clarify something for me. In the book it states you can stop the procedure after only using the nitric acid to dissolve away the base metals and still have a high quality fine gold. What purity of gold would this be?

 

[nickvc]

If done to completion and correctly you could get 99%, some jewellers especially those who use high karat alloys do just this, if working with known alloys you can gat a good result but mixed alloys will rarely get better than 97% as some base metals will not dissolve in nitric.

 

[michael1311]

right so continue on reading about the aqua regia. So just to understand this correctly about the inquarting, I typically buy around 500grams a day of karat scrap and I assay around 55% mark give or take depending on what I buy. That would mean I need to add around 600 grams of silver to bring it down to 6k? Thats quite an expensive procedure....

 

[philddreamer]

Hi Michael!

That would mean I need to add around 600 grams of silver to bring it down to 6k? Thats quite an expensive procedure....

It would be to start with, but you can always cement your silver used in the inquartation & re use it on the next batch. Try buying scrap silver instead of pure silver for your inquarting.
You can use copper for inquarting, is much cheaper than silver, BUT, it takes up to 4 times more nitric for digesting the copper!

Take care & be safe!

Phil

 

[nickvc]

It's also self funding eventually as you will reclaim any silver in the scrap, also should you have platinum group metals in the mix it will report with the silver for later recovery via a silver cell.

 

[michael1311]

sounds very interesting thanks for all your help guys. Is this the method most refineries use as well?

 

[nickvc]

In honesty no, it's too slow for most large commercial set ups but it is used in smaller refineries as it works and works well. The bigger companies will melt assay and then ensure that the mix of metals has low enough silver to go straight into AR, there are several other methods used like the Miller process and atomisation but nearly all commercial set ups are looking for fast turnaround of values, if they don't get it all at first it doesn't matter it will be recovered at a later stage the same with the silver and any PGMs present. It's all about economics when you have maybe 20-30 kilos of fine gold tied up it's a lot of money so they want it out and the money back in to do the same the next day.