my gold turned copper

[jimmyreece]

i did a gold recovery with AR using gold plated items from a combination of several sources (pins,jewelry,etc)this is the first time i did a mixture of different sources like this. being a small amount i didnt see the harm. but what happened was after 20 mins on the hot plate my items in the AR all turned copper. well my first conclusion was all the gold plating dissolved of the metal. then when i pulled some of it out to see, the so called copper rubbed off the metal and exposed the gold underneath. can you tell me what that copper slime was, how did it come about and what i can do to avoid it from happing again(aside from the obvious,not mix my metals)

 

[lazersteve]

You made two major mistakes:

1). You processed mixed scrap types. Keep your scrap sorted and process the various types of scrap separately.

2). You went straight to AR and did not remove your base metals first. Always remove the more easily soluble base metals from your scrap before attempting to dissolve the gold.

Do some reading, follow the Guided Tour Link below and you will understand more. Slow down read, then do some small scale samples to learn what to look for.

The copper cemented back out because the solution was saturating with a higher activity metal (eg: iron). Study the Activity Series chart (download from my website if you need to) until this makes sense.

Welcome to the forum,

Steve

 

[jimmyreece]

you are right and thanks. im glad i joined and learned much since. thanks steve