short question about cpu-pins in sulfuric acid deplating cel

[frank-20011]

Hello everyone,

why it is not common to process the pins in a deplating cell?

i've only found one article about it:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=4748&p=40934&hilit=processing+cpu+pins+in+sulfuric+acid+cell#p40934

and i ask why? cooking them in acid for hours and hours seems to me not as comfortable as using a sulfuric acid cell.

Regards, Frank!

 

[patnor1011]

That depend on person.
Some people do have access to cheap nitric and are set up to treat and dispose waste solutions - they do use wet methods on pins.
Other people do have a lot of time so they do use HCl and CuCl or H2O2.
But the most economical way is reverse electroplating (it does not create that much of hazardous waste to deal with) but it does involve hot concentrated sulfuric which does have its own set of challenges.

 

[frank-20011]

Hello,

and thanks...i was wondering only about almost NO threads about processing pins in the cell, so i thought: ther must maybe a catch (a difficulty).

Kovar (the inner of the pins) in AP, how long does this take? and cooking them in Hcl, no....HNO3 outdoors is one option for me, but i have more then 8kg gold plated low and high grade stuff and so i will process my few pins with these material.

Thank you and nice weekend!

 

[goldsilverpro]

Hello everyone,

why it is not common to process the pins in a deplating cell?

i've only found one article about it:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=4748&p=40934&hilit=processing+cpu+pins+in+sulfuric+acid+cell#p40934

and i ask why? cooking them in acid for hours and hours seems to me not as comfortable as using a sulfuric acid cell.

Regards, Frank!

So, you found one thread. You sure didn't look too hard. If you search for different keywords or combinations of keywords, such as: reverse electroplating, sulfuric stripper, pins, copper mesh, basket, cell, battery charger, lead cathode, etc., you'll surely find at least 500 more threads. It"s a common subject on here. Often, the older threads are better for things like this. When this forum started 9 years ago next month, I think, the 2 most popular subjects were the AP process and the sulfuric stripper.

 

[frank-20011]

Hello,

sorry, a little misunderstanding: not one thread about sulfuric deplating cells (you are right, there are maybe hundreds of them), but one thread about -PROCESSING CPU PINS- in these deplating cells.
Please take care, only these special kind of pins handling threads i am was looking for and such a thread i have linked above.

Regards, Frank!

 

[g_axelsson]

Speaking for my self, I process the pins with the CPU:s because it's easier.

For modern fiber processors I use old CuCl₂ as it removes the pins easily by dissolving the solder. When it's in CuCl₂ I just let it run to completion.

For ceramic processors it's really hard to remove the pins as they are brazed to the body. They go into AR with the rest of it.

And for the black fiber processors, the pins are soldered straight through the fiber base so here I dissolve the solder and covar pins in HCl. It takes some time but removing the pins would take even more time.

I would never even think of running so tiny pins in a sulfuric cell. In my opinion the cell is better used on material where the surface to volume ratio is lower. Yesterday I removed a mobile CPU from a laptop and I could hardly discern the single pins. It was a forest!

But that's only my opinion. Different people have different set of circumstances so there might be people running CPU pins in the cell.

Göran

 

[goldsilverpro]

Hello,

sorry, a little misunderstanding: not one thread about sulfuric deplating cells (you are right, there are maybe hundreds of them), but one thread about -PROCESSING CPU PINS- in these deplating cells.
Please take care, only these special kind of pins handling threads i am was looking for and such a thread i have linked above.

Regards, Frank!

By CPU pins, do you mean those made from kovar? Kovar (magnetic) is 29%Ni, 17%Co, and 54%Fe. Co and Ni are very similar, chemically. I have observed that high Ni alloys are susceptible of dissolving slowly in the anodic sulfuric. The solution can turn greenish. This dissolved Ni (and Co) can eventually reduce the stripping efficiency. At some Ni concentration, the stripping might stop completely. To hinder the dissolving of the Ni/Co, I would use low current and make sure the solution doesn't get too hot. I would also attempt to prevent water dilution of the solution and would use concentrated sulfuric (say, 96%) without any water being added in the makeup.

I have long thought that the addition of a little hexavalent chromium to the sulfuric would improve the passivation of the nickel/cobalt and prevent dissolution. HNO3/Cr+6 solutions have been used widely for this purpose. I have a pound of potassium dichromate somewhere. I just never got around to doing the experiments.

 

[frank-20011]

Hello,

and thanks to all... thanks for yours tipps.

processing the whole fiber (green and brown) cpus WITH the pins in AP is good for future but in my collectiveprocess i've desoldered the pins from the fiber cpus, store them and litter the fiber parts. ceramic cpu i safe extra and so i should maybe process the pins from the fiber cpu together with the ceramic cpu.

I've red at the forum, that ni makes problems in a sulfuric cell (for instance when somebody use stainless instead copper as basket)...first i try only a few of the desoldered pins and look for color changing of the sulfuric...if something happen, they should go to AR.

to the pin basemetal: i have store alle the different pins from different cpu together so there should be some made off kovar and some made of other material too.
if it's required i can select kovar pins by magnet.

very interesting point, the chromium improved passivation...i have two little flasks with K2Cr2O7 at my chem cabinet but i have never worked (and im really not kenn on it) with it and sadly i am the absolute wrong collocuter for speaking about that but reading about these theme somedays in the forum should be interesting!

i collecting pm electronic stuff for a while and i have almost 100 cpu's but not one and only of them is/was black...are they so rare in home computers?

to göran: with the fact above, for me its (sadly) no problem to desolder the cpu pins that i have found...i work on very very small scale and so ist it like yours say:
"Different people have different set of circumstances"

nice evening, day, morning...to all, regards, Frank!

 

[g_axelsson]

i collecting pm electronic stuff for a while and i have almost 100 cpu's but not one and only of them is/was black...are they so rare in home computers?

Well, it depends on your source of scrap how common they are. It's the generation between ceramic CPU:s and fiber based later ones. Pentium, Pentium MMX and Centrinos used this package as far as I know.
http://www.home.neab.net/gandalf/CeramicCPU-2015/Pentium/SL26J.html

Göran