Ceramic CPU gold plated Lids

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ahmadbayoumi

ahmadbayoumi

Well-known member
Joined
Sep 21, 2013
Messages
196
Location
Egypt
Hello Dears,

I have some Ceramic CPU gold plated Lids and I need to process them for gold recovery.

I searched the forum here and found 2 ways:

1- Multiple soaks in HCL

2- Diluted Nitric (50% Nitric/50% water) leach

I need your help to understand the pros and cons of each way PLS.
 
Thanks a lot Topher :)

I'll go for the 2nd one of course as it's fast

But should I introduce some heat or leave it to finish the task whatever the time it takes ?
 
I always heat. Even heated, it still takes a while for it to work. Not nearly as long as HCl, but dont be expecting instantaneous results. If its done in a day, you will be lucky
 
Are these with gold braze?
If so mix some AR and put onto heat and slowly add a few at a time to the solution, make sure you have plenty of space for the reaction and only add a few at a time after all reaction has stopped, this method allows you to process them very quickly.
 
Easiest but uses a lot of nitric acid and produces a lot of waste : Use nitric acid to dissolve the base metal and then process the gold foils.

Cheap and easy, produces a lot of waste : Use HCl and copper chloride to dissolve the base metal and then process the gold foils.

Fast but produces a lot of waste, not as easy as a two step process : Dissolve straight into aqua regia. You will be working with dirty solutions or carefully adjust the amount of aqua regia used to optimize. Not something I would recommend to a novice.

Cheapest and quite fast : Sulfuric acid cell to deplate the gold. Base metal can still be sold as scrap and produces least amount of waste.

And of course, there are a lot more to each method than I just wrote, the devil is in the details.

Göran
 
Will the sulfuric cell strip the braze? I was under the impression that it wouldn't, and AR is one of the very few things that will.
 
It would probably not strip gold braze, but as I said, the devil is in the details.

Nothing is said of what type of base metal it is, copper based, kovar or tungsten-copper. Neither do we know if there is any gold braze.

Ceramic CPU:s doesn't tell us much actually.

Göran
 
Complete digestion of the lid is the only sure fire method to get all of the Au. I have seen many of the cpu bottom lids with multiple layers of nickel and gold plate. The nitric soak only works to remove the outermost gold layer in many cases unless you use extended soak times and lots of manual scraping in the rinse and recovery stage. Even then, you still can not be sure all of the layers have been removed.

Steve
 
I just did some of these, I guess I can try to dissolve some completely.
 

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Lids on my picture came from mostly i960 and 486. These do not have multiple layers. The foil is the best to strip slow in a water with the just tiny splash of nitric. It is crucial to start with a tiny amount of nitric with even smaller additions and let them strip over a couple of days. Plating comes off like nice chunky foils. Overdo with nitric and you end up with a mess where you will have to dissolve it all.
 
patnor1011 said:
Lids on my picture came from mostly i960 and 486. These do not have multiple layers. The foil is the best to strip slow in a water with the just tiny splash of nitric. It is crucial to start with a tiny amount of nitric with even smaller additions and let them strip over a couple of days. Plating comes off like nice chunky foils. Overdo with nitric and you end up with a mess where you will have to dissolve it all.
Click to expand...

Great, did most of the foils strip off with this technique ? Did you do any stirring or agitation ?
 
It is quite a slow process but saves a lot of chemicals.
What we did is that we put about a kilogram of lids in a beaker with about 700ml of water. To that, we added a tiny bit of Nitric - about 10-20ml. Nitric was added in like 10ml increments 2-3 times a day. I stirred them a little bit every two hours or so, just to let solution to get to all of them. Stirring that amount in one pot is quite a task as they are small so a lot of them are packed together. They started releasing foils on the second day and I can say that 80% of foils were loose after 2 days. If you add too much of nitric it will attack Kovar making a bubbling brown mess from it.
As I said 80% of foils were loose after 2 days I recovered them with a sieve with big holes in a bucket filled with water. Rest will strip eventually in a few days but as Steve mentioned it is quite labour intensive process trying to get all of them so we just left them sitting in a beaker till rest of them come loose. Foils from them are quite a sight, foils from fingers look like poor relatives to this type of plating.
 
Well, it is not my method, I learned it from Jon and it worked for us. Never seen nicer foils in my life. When we dissolved them and precipitated solution with SMB we have seen the gold drop as metal It was sparkling, shining like gold snow... I took a short video on my phone so cool it looked I was staring at it for a long time.
 
I'm a little confused Steve. Your post directly above mirrors Pat's posts unless I am reading something awry, however you previously make mention of the requirement to completely digest lids as many are multi layered. Would you please clarify which position is correct in your view?

Personally I've yet to see a multi layered lid with gold between the layers on a mainstream ceramic processor but I would genuinely be happy if you would point me towards them, as I'm sure would most of the membership.

Jon
 
There are lids with several layers of plating on them. I have seen numerous types over the last 10 years of my refining ceramic cpu lids. I typically run 40-100# batches of gold lid ceramic cpus (gross weight of cpu and lid) and find numerous multilayered lids in every batch.

As for the specific part number I can not say. Typically lids with several layers of plate tend to have squared off corners as opposed to rounded corners as a general rule.

My statement to digest them completely is on the context of achieving 100% recovery (or as close as one can get). I run my lids in acid to get the foils, sort out the multilayered ones and digest these types completely.

I will find some pictures to prove my statements as you do not sound convienced by my post.

I have run litetally hundreds of pounds of gold plated cpu lids (no ceramic housing lid weight only) in the last 10+ years. The largest batch of lids I have run in acid at one time is 25#. I have run 25# batches multiple times. Trust me on this, their are multilayered gold plated cpu lids.

Pictures to follow.

Steve
 

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