single process refining help

[leelandbullock]

Ok so this is my question, after you add sudiom disulfite to persipitate the gold and that is complte. You are still left with gold at the bottom.

So the remaining solition could contain platinum if i add small ammout of aqua regia back to the mix. Then add the ammonium chloride, it wont go boom due to it still comtaining sudiom disulfite. Or with it being aqua regia with sudiom disulfite is there a process to remove the platinum from it.

Iam processing computer main boards cpus, pins, scrap silver, electronics.

So anyone who knows how to get the platinum out after the gold has been removed would be of great help. An no i havent tried big or small scale because i dont wanna accidently blow myself up. Ive removed platinum sucessfully when i knew there was no gold.. but i want the gold and platinum.. i just worry of effects of nitric, hydrochloric, disulfite, and ammonium chloride.

 

[butcher]

You precipitate gold from a dilute solution, to precipitate platinum you need a concentrated solution,
The sulfite (which forms sulfate and HCl in solution) will not cause anything to go boom when trying to precipitate platinum.

If I have PGM in solution with gold, my choice to precipitate gold is using ferrous sulfate (homemade), I believe it works better here.

No need to add aqua regia back to the solution after you precipitate gold and have gone to the trouble to de-NOx solution.

Unless you are sure there is enough platinum in solution to precipitate, (testing solution), it may not be worth trying to recover by precipitation, and here is where your stockpot does its job.
Normally with electronic scrap you probably wont have enough Platinum in solution to go after with precipitation, dental gold can be a different story.

Reading Hoke's book will give you the understanding you need, She answers this question and thousands of others you will have.

 

[leelandbullock]

Thank u and where is this book. Hokes... Everything i know ive leared from u tube an reading wikis and further fourms.

 

[leelandbullock]

I think i ran into a ton of rhodium plated wire. But how can i tell my test kit dosent cover rhodium and nitric acid disolves copper making it blue. But at first i thought it was platinum but its very shiny white wire almost looks like glass its so shiney i put stuff on spoon heated spoon till purpel gold heat color change but the wire didnt change color. But stone rub acid test dosent work cause it rubs plating off to copper an acids react with copper i see almost microscopic silver flecks but they eventually disalpear so i am at a loss to what i have. All of this was tapped out on mobile phone so sorry for grammer n such

 

[galenrog]

What is referred to on this forum as "Hoke's Book" is "Refining Precious Metal Wastes" my C.M Hoke. You will find links to free downloads of the book in many member taglines. Also, if you enter search terms of "Hoke" or "Hoke's Book" into the search tool for the forum, you will find what you are looking for. The book is not a source for all information, but does teach, step by step, many of the processes needed for the refining of precious metals. Read it at least twice. More if your first language is not English. Once you believe you can execute the proving experiments safely, then do so. When you understand the techniques involved, then you can ramp up to small production scale.

 

[butcher]

Franciz has a thread on some work he is doing with Rhodium wire, in the PGM section topic mixed foils from plating wire.

 

[leelandbullock]

You precipitate gold from a dilute solution, to precipitate platinum you need a concentrated solution,
.

dang...but i should be able to concentrate the soulution again shouldnt i..buy evaporation and adding back some AR and evaporation again. then add the ammonium chloride solution..

 

[butcher]

leelandbullock, the information is in Hoke's book, and I know you will be reading that book, and not expecting us to answer millions of questions about every little tiny step to take.