AR denying me my gold !!

[bobmin]

I had a batch of AR solution that I had processed some pcb's in and it was pretty spent so I proceeded to stop processing any more boards and to add my SMB to the solution after I filtered it. The AR solution was pretty dark brownish in color when I added the SMB but I figured that was because it was pretty exhausted.

I let it sit in my fume hood for a couple of days then this evening I decanted it and was going to collect the mud. BUT NO MUD ! In fact the solution was black as midnight. I filtered it and saved it ( never throw anything away until you're sure of what you have or don't have). I know that there is gold in there but I really don't know what to do in order to recover it from the state it is in now.

Any suggestions from the experienced ones ?

Bobmin

 

[butcher]

My guess there was nothing in it to precipitate, but why would you just go by my guess, did you test it?

Stannous chloride?

Aqua regia is not a very good method for leaching base metals away and leaving your gold there are much better ways to process.

Cherry pick the values from circuit board, and process them mechanically, remove any solder, remove base metals, understand how to make and use testing solutions.

Read many of the early forums, many things were discussed then, sometimes we said the same ole thing so many times we get tired of saying it, we would like to discuss new things when we can.

Steve had a post (or many) on processing scrap getting it ready to process.

C.M. Hoke http://tinyurl.com/mfnyhs
Waste treatment for the small refiner http://tinyurl.com/78z9v5a
Guided Tour http://tinyurl.com/82ynbxb
Stannous Chloride Recipe and Testing Results

http://www.goldrecovery.us
http://www.goldnscrap.com

 

[niteliteone]

Remember the post from Butcher last week:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=12460&p=123382#p123382

Eliminating tin and solder as much as possible, this is best done at the very beginning, through mechanical or chemical means or both.

Eliminate base metals, your goal is to get the gold as clean from other metals as possible, before trying to dissolve it into solution, putting gold into solution with base metals is another way to loose values and cause yourself many headache's.

Now you are looking at the result of not following the proper proceedures :shock:

DO NOT DISPOSE OF ANYTHING :!: Put everything in a safe location and start reading the many posts of others that have made the same mistakes you have :idea:
There is at least a hundred posts from people on this subject and the solution has been posted many, many times :shock:

Read, Read and read some more.
The answers are all here, Just need to "SEARCH"for them.

I know you don't think this is of any help, but I feel it is the best way to TEACH someone, instead of hand feeding them the answers all the time.

Sorry
Tom C.

 

[patnor1011]

If there was even small bit of metal left on boards soaked in AR when you removed them, your gold was probably cemented there. I do not think much of it stayed in that dirty mix of everything. Doctors work with scalpel, not with butcher`s saw.

 

[patnor1011]

What pcb did you processed or what did you soaked in AR?
Why pcb? Are you after gold plating on some boards? If yes then there are methods posted here how to remove board solder mask and after that AP is method of choice. AR can be used on gold foils obtained from AP however plating on boards is many times so thin you will never see foils. Thin plating will disintegrate to fine powder when base metal will be dissolved in AP.

 

[Dr. Poe]

I had a batch of AR solution that I had processed some pcb's in and it was pretty spent so I proceeded to stop processing any more boards and to add my SMB to the solution after I filtered it. The AR solution was pretty dark brownish in color when I added the SMB but I figured that was because it was pretty exhausted.

I let it sit in my fume hood for a couple of days then this evening I decanted it and was going to collect the mud. BUT NO MUD ! In fact the solution was black as midnight. I filtered it and saved it ( never throw anything away until you're sure of what you have or don't have). I know that there is gold in there but I really don't know what to do in order to recover it from the state it is in now.

Any suggestions from the experienced ones ?

Bobmin

Raise the pH on your 'ink' to pH 7.9 with bicarbonate of soda powder or with a water solution of soda ash. Let it settle over night. Carefully decant the solution taking care not to get the black into the filter until nearly all the liquid has been decanted. Set the clear liquid aside for later. Use a new container to filter. Then add the black to the filter, some will pass through. When the filter starts to clog and the flow changes to a drip, re add the first black that passed through the first time. The filter should catch it this time. If you can, add mild suction, if not have patience it will probably take several hours to finish dripping. Dry it, sinter it at 900C*. Rub talcum powder into the cupel and blow off the excess.
Preheat the cupel to make sure that it's bone dry. Add the black powder to a sheet of bismuth (or lead if you are old school)
Wrap the bismuth around the powder and then cupel it with the cupel that didn't crack. Send us a pic of your button.
*Whatever you do, don't use a torch to sinter the black powder. It will blow away. I'm too embarrassed to reveal how many times that I've been in your predicament. My 'ink' was gold! Dr. Poe

 

[lazersteve]

I had a batch of AR solution that I had processed some pcb's in and it was pretty spent so I proceeded to stop processing any more boards and to add my SMB to the solution after I filtered it. The AR solution was pretty dark brownish in color when I added the SMB but I figured that was because it was pretty exhausted.

I let it sit in my fume hood for a couple of days then this evening I decanted it and was going to collect the mud. BUT NO MUD ! In fact the solution was black as midnight. I filtered it and saved it ( never throw anything away until you're sure of what you have or don't have). I know that there is gold in there but I really don't know what to do in order to recover it from the state it is in now.

Any suggestions from the experienced ones ?

Bobmin

My guess is you had a solution saturated with copper. Adding SMB to a saturated copper soution shifts the color of the liquid from chocolate brown to black after several hours. If you did indeed have a solution saturated with copper, there was no gold in it as copper will cement all of the gold out as a fine black powder which will take several hours to completely settle due to the size of the gold particles and the thick viscosity of the saturated solution. There is no need to add a precipitant as the copper has done the job for you.

As others have asked:

Did you test the solution with stannous chloride before adding the SMB?

Steve