Plated CPU tops and bottoms

Anybody have any yield data on gold plated cpu caps? You know the ones(gold plated on metal tops/bottoms) Old ceramic chips from days of yore?

If there is 80/20, Au/Sn solder around the edge of the bottom, they can run as much as 1 tr.oz./pound.

This was asked a short time ago and back then I placed 1/2 pound of lids in a slow room temperature HCl soak. Now they look like the foils have all lifted and I can process them to determine a yield.

I'll post the results soon.

Steve

Hey!....look who is back!.....

All,

Today I processed the 1/2 pound of soaking lids to the mash stage.

Here's a photo of the mash after it's been extracted with hot HNO3 to remove any remaining base metals and silver that remained after processing with an extended soak in HCl.



I'll finish up with HCl-Cl and the usual washes.

I'll post the results and a photo of the button tomorrow.

Steve

Welcome back Chris. :wink:
So did you move to China. lol
God i hate moving. But you do find things you forgot about.

Steve,

Nice photo of the foils. Is there any advantage to processing the tops in HCl versus a cell? How long did you soak them?

Cheers!

All,

I finished up on the cpu lids today.

227 g of mixed cpu lids = 5.55 g yield.

5.55 / 227 = 2.445%

Not a bad yield, very near the yield of 1/20 12 kt gold filled scrap.

If you get your hands on some of the older milspec or aerospace cpu lids you can expect even better returns.

Steve

Good thing I saved those old MilSpec chips untill I knew what I was doing! LOL!!!

Glynn

skyline said:

Is there any advantage to processing the tops in HCl versus a cell? How long did you soak them?

Click to expand...

Skyline,

The HCl soak is very slow, but it is very easy to manage and requires no fancy setup (just a beaker or bucket). If you do the lids in a Crockpot with some heat it may go a little faster. I just set mine up in an old pyrex coffee pot and changed the acid out every week. I keep a cover on the pot to keep the acid from evaporating off. When I pass by the pot, I give it a few swirls to break any loose foils free from the steel lid.

After the first week or so, I pour off the old dark green acid and filter out any loose foils. I water wash the foils and lids throughly. I repeat this until the foils are 75% removed, then I move them to a 50/50 hot nitric bath until the rest of the foils come off (about 20 minutes). The HCl will dissolve some of the iron, but I find it also separates the foil from the steel an allows the nitric to work very fast.

The foils from all the washes and the first nitric bath are combined in a clean beaker with 50/50 nitric and heated until no more bubbling occurs. Finally this is all vacuum filtered and the foils dissolved and precipitated as usual with HCl-Cl and SMB.

I would think that after the first HCl soak the lids would be easily stripped with hot 50/50 nitric if you are in a hurry. Be sure to wash all the HCl out of the foils and lids before putting them in nitric or you could end up dissolving some of your gold.

Steve

I think a hot water boil wash a few times would be a good idea - I ended up with the very same deal Steve mentioned in his post - some nitric was still in some of my media even after I rinsed three times (it must have been inside the plating) and when I added HCL I had a little AR type reaction going on - complete with a little nitric oxide / nitrogen dioxide gassing - I guess I am going to have to vacuum filter and stanous chloride test the spent solution to see if the gold is still held or if it got dropped out by the steel base metal?

Glynn

Amazing what a little incineration would do in cases like this.

Will you guys ever learn?

Harold

Thank you Harold!!!!

That's what I bought my torch for - I get so caught up in trying to do it right I forget sometimes!!
Next time I am going to incinerate as you have told me time and time again.
I have a batch of gold rice shaped media that I will burn before I switch acids!!!!

Thanks and I appologize for missing that one repeatedly Harold.

Glynn

Harold_v said:

Amazing what a little incineration would do in cases like this.

Click to expand...

Would you recommend incinerating the CPU's, BGA IC's and fingers as well?

Despotic said:

Harold_v said:

Amazing what a little incineration would do in cases like this.

Click to expand...

Would you recommend incinerating the CPU's, BGA IC's and fingers as well?

Click to expand...

Understand that I have almost no experience with e scrap.
What I would recommend is that the values be stripped by dissolving the base metals, then incinerate the recovered values before they are refined. That way you will incinerate only a minimum amount of undesirable substances. You don't really want to get involved with incinerating boards or related components unless you are able to do so properly.

In fact, what I'd do is incinerate the recovered values, then give them a wash in HCl, followed by a good rinse with tap water. Then I'd dissolve the values. The added steps insure the material will filter easily. As a bonus, you're likely to produce a higher quality of gold.

Harold

to add to this... a company that makes hermetics lids i found while surfing, states it is 275uin gold plate on top and 225uin under neath

thanks steve , this is a brillinay tecnic, all in a jar in the cupboard week or some later some nice fresh foils for refining, can i ask what it removes, am i right in saying there is still copper after the hlc? or will hlc dissolve copper, or am i right off the track and the lids and type of scrap like this does not contain copper?

even if the lids are iron based,it will still have a copper layer under the gold.

The lids shown in the example above had no copper content to them at all. The base metal is kovar. The lids all came from the bottom of the Intel 486 class cpus.

You will only find copper in the top heat spreaders of ceramic cpus with gold plated tops. The copper is sintered with tungsten to form the heat spreader plate which is then brazed to the cpu housing to couple heat away from the cpu silicon die.

Steve