# Processing of ceramic processors with cyanide



## scorpion1971 (Dec 21, 2017)

Hi valuable forum members,


In a work I did the other day, I used ceramic cpu's with cyanide. I broke both the veneer and the pins and the crest, and took all the gold in it into the cyanide solution. Then I settled with zinc. I put 2 zinc rods in the solution and let them stand overnight. Then, the solution was filtrated and the precipitated solid was washed with hot water 3-4 times. I cleaned base metals with nitric acid. I then processed it with aqua regia and precipitated gold with SMB. I need help on a topic. As an example. 30 Gr NaCN = 15,93 Gr Free CN. (For Free CN = NaCN x 0.531). I used 2 zinc bars to prevent the gold from dissolving in the solution. To avoid doubt, 15.93 Gr. if I use zinc dust to correspond to the free cyanide, can I prevent the gold from being left undisturbed and the gold from being re-dissolved again? The help will be really appreciated. 
Sorry for the bad english.

Best Regards,
Mehmet


----------



## anachronism (Dec 21, 2017)

Mehmet

What pH were you running the cyanide solution at and what were you using as your pH regulator?


----------



## scorpion1971 (Dec 21, 2017)

Anachronism,

I work at pH 12. I use NaOH if necessary, but I do not need it.

Best Regards,

Mehmet


----------



## anachronism (Dec 21, 2017)

Thanks - what amount of NaCN did you use per litre?


----------



## scorpion1971 (Dec 21, 2017)

I used 30 Gr NaCN per litre.


----------



## anachronism (Dec 21, 2017)

Thanks for the info - final question are you using an oxidant?


----------



## scorpion1971 (Dec 21, 2017)

Of course. m-NBSS.


----------



## anachronism (Dec 21, 2017)

scorpion1971 said:


> Of course. m-NBSS.



OK thanks for the info. Can I ask why you used that as opposed to peroxide and how well do you understand the differences between the two?


----------



## scorpion1971 (Dec 21, 2017)

Of course. If I use peroxide, I need to finish it in a short time. Because he's starting to crack cyanide. But there is no such problem for m-NBSS.


----------



## silversaddle1 (Dec 21, 2017)

I have a question. I thought the cyanide would only strip gold off the exposed surfaces. How can it be effective to strip the gold that in contained inside the CPU? Maybe a stupid question, but you know, the more you know!


----------



## scorpion1971 (Dec 22, 2017)

You are absolutely right. I broke the processors to get the gold in the ceramic. But I forgot to take photos.  

Mehmet


----------



## nickvc (Dec 22, 2017)

You may want to run the cpus again because if they have solid bonding wires or gold soldered lids the cyanide will not remove it all easily, using m-NBSS will make full recovery difficult to say the least whereas peroxide makes for a simple and easier recovery of the gold.
With the cpus I’d suggest a very good rinse and then into AR to check you have recovered all the gold, you can do a small sample to test and check for gold using stannous.


----------



## silversaddle1 (Dec 22, 2017)

scorpion1971 said:


> You are absolutely right. I broke the processors to get the gold in the ceramic. But I forgot to take photos.
> 
> Mehmet



Thanks for the answer. I don't refine but it doesn't mean I don't read up on the processes! :G  :G


----------



## anachronism (Dec 22, 2017)

The free cyanide isn't your issue it's the oxidant. As Nick alluded to it's simpler to use Peroxide as it degrades thereby losing it's oxidant properties. I'm not au fait with destroying m-NBSS because having tried it a couple of times I steer clear of it like the plague.


----------



## nickvc (Dec 22, 2017)

I think Jon will agree that just leaving the cpus in cyanide will not dissolve any solid materials even plated materials need to be agitated to strip effectively, if you had a constant flow of fresh solution going over the solids it will ecentually strip the gold but just dipping will not remove any decent percentage.


----------



## goldsilverpro (Dec 22, 2017)

The cyanide will strip the plating. It won't touch the gold/tin or gold/silicon brazes, if those were used to attach the lid and/or the chip. Also, it would take a long time to dissolve the gold wires, which are at least 14 times thicker than the gold plating.


----------



## scorpion1971 (Dec 22, 2017)

I have previously read on the forum that the cyanide process is not suitable for CPUs. But when I tried, I uncovered both the cover and the pin covers, and the whole of the broken wires. I checked it thoroughly with a magnifying glass. The result is great. What I wonder is to settle all the solved gold. At the same time, gold does not dissolve. I used 2 thick zinc bars for this. But I do not want to leave the job to chance. Would it be right to use too much zinc dust for this?
Mehmet


----------



## Topher_osAUrus (Dec 22, 2017)

Ill buy your cyanide ran cpu's!
50 cents a lb!


----------



## scorpion1971 (Dec 23, 2017)

Topher_osAUrus said:


> Ill buy your cyanide ran cpu's!
> 50 cents a lb!




It's not funny ! You first learn this process, then you comment.

Mehmet


----------



## nickvc (Dec 23, 2017)

scorpion1971 said:


> Topher_osAUrus said:
> 
> 
> > Ill buy your cyanide ran cpu's!
> ...




Mehmet I and think everyone else is trying to tell you that you may well still have gold left on your treated cpus, somrun a small sample in AR after rinsing all the cyanide off and test the solution with stannous.
The one big problem with using cyanide is that there is no simple way to test you have all the gold out of solution apart from an assay of some sort.


----------



## Topher_osAUrus (Dec 23, 2017)

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

----

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.


----------



## anachronism (Dec 24, 2017)

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


----------



## g_axelsson (Dec 24, 2017)

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


Yes please, do that.


----------



## goldsilverpro (Dec 24, 2017)

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.


----------



## scorpion1971 (Dec 24, 2017)

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


----------



## goldsilverpro (Dec 24, 2017)

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,
> ...


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


----------



## Topher_osAUrus (Dec 25, 2017)

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.


----------



## im1badpup1 (Dec 26, 2017)

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!


----------



## anachronism (Jan 1, 2018)

g_axelsson said:


> 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.
> ...



Here you go Goran.


----------

