Processing of ceramic processors with cyanide

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When nick, gsp, and anachronism tell you something, take it to the bank. They know their refining like precious few other's do.

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Ive never ran cyanide, but have read every thread on it, and a couple books. More than that if you count books based on plating with it (which requires using CN to dissolve PM's)

The black tone on the processor pins reminds me of the anecdote gsp gave, where a company he ran (maybe worked for? -its been awhile), bought "black copper pins" that were already ran in cyanide.
-long short of it, the black was gold from them being processed improperly. They made a mint off the previous "refiners" error. (Sorry, thats an idiom for "made lots of money" -they [idioms] dont translate well)

Also, I have read numerous threads relating to the difficulty of dissolving bulk bits of gold in cyanide, this being the bonding wires. Which the reactant cant even reach since they are not broken to bits. So you cant even see if they have or have not went into solution.
-i believe you were referring to the pins as the wires?

Anyways, good luck.
 
A cyanide leach is actually pretty aggressive- especially at the concentrations you are using which is too high at 30g per litre. The stronger the leach, the faster the leach but the trade off is that it also becomes a lot less selective. As such you'll take up a lot more base metals and attack the pins more.

Ideally you want a weaker leach that takes the gold and doesn't cut through any nickel barriers down to the base copper. Topher has the measure of the black deposit 8) . That's precious metals redepositing back onto your base metals so if you are getting that then there is your problem. That given I've re-read your posts and I don't see it being mentioned but it's early here and I haven't quite woken up yet.

Cyanide leaching is often presented as the quickest way of getting your surface gold from material into solution and in it's simplest form that's certainly correct however once you start delving into the chemistry of the cyanide leach you learn there is a lot of understanding required to get it to run at best efficiency. In essence you end up with a process that involves as much if not more chemistry knowledge than using AR.

You can do the bonding wires but they will take longer than the surface gold- however I would suggest another method for the gold based solder because it's a lot thicker than either the plating or the bonding wires.

The point I made about the oxidant is the relevant one for re-dissolving gold. GSP do you know of anything that will degrade m-NBSS to the point where it doesn't function any more?

Ive got some plated material here with gold re-deposited back on if anyone wants me to, I'll put a pic up so you can see what to look for.

Jon
 
anachronism said:
Ive got some plated material here with gold re-deposited back on if anyone wants me to, I'll put a pic up so you can see what to look for.

Jon
Click to expand...
Yes please, do that. :)
 
Jon,

I only used m-NBSS a few times in large production and that was with a tumbler I always ran the NaCN from 30-45g/l and the m-NBSS about 8-15 g/l. I'm thinking we heated the solution to about 130-140F. The only parts processed were those that were plated. No gold in the form of braze was put through this solution because we knew that, through months of experimentation, the cyanide would not dissolve it. The m-NBSS was quite stable and we were able to run several batches through the solution before it became saturated with gold.
 
Thank you for your valuable comments and your tutorial comments,
Unfortunately, I threw the remaining pieces after the process, but it is a logical idea to work with AR for control purposes. When I looked through the magnifier, I saw that there was no gold, but I will check with AR about whether it is cemented. (One more chapel) In the meantime will be a major responsibility. For cell phone board or rams; Is it possible to dissolve the tin in the solder with HCL at room temperature?
Thank you for your help.
Best Regards,

Mehmet
 
scorpion1971 said:
Thank you for your valuable comments and your tutorial comments,
Unfortunately, I threw the remaining pieces after the process, but it is a logical idea to work with AR for control purposes. When I looked through the magnifier, I saw that there was no gold, but I will check with AR about whether it is cemented. (One more chapel) In the meantime will be a major responsibility. For cell phone board or rams; Is it possible to dissolve the tin in the solder with HCL at room temperature?
Thank you for your help.
Best Regards,

Mehmet
Click to expand...
The 80 gold/20 tin braze used on gold lids is a dark gray color with no yellow at all. It is often lumpy and quite ugly. The gold/silicon used under the chip is usually dark but sometimes has a light yellow cast. When you looked through the magnifier, you may have missed it because of the color
 
I dont think HCl would attack the tin in the braze, Id bet the gold protects it from dissolution. Very similar to how too much gold in the alloy during inquarting will protect the silver. Or how too much silver will protect the gold in certain karat alloys being dissolved in AR.

Dont know for certain since Ive never tried it, but, its a pretty well educated guess.
 
When i used to do organic synthesis id extract post reaction 3 times. Its very unlikely in any reaction you obtain 100% yield from extracting only once. Even more so if the reaction youre doing is one youre unaccustomed to and still learning the parameters.

I think in this inorganic chemistry extracting twice would be sufficient, the 3rd would be financially uneconomical.

It really helps to somehow agitate your reacting solution with for example an overhead stirrer or sit securely on a vibrating pad. It can cut reaction times and help completion.

I dont like bottom stirring with stir bars, one day youll get one bounce and break the pyrex glassware and itl be expensive!
 

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