Refining Pentium Pro with AR

[kadriver]

My purpose is not to save time or money, I'm trying to learn as much about this as I can. I believe separating the different materials and running them separately will aid in the learning process even if it lowers the yield.

One thing I'm still somewhat hazy on - what is the best way to remove the lid from a PPro? Will a map gas torch do it?

Here is a post that shows how to remove the lid from a Pentium pro;

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=52&t=12845&p=52836&hilit=pentium+pro+heat+spreader#p52836

kadriver

 

[Anonymous]

Gents

You do what you need to do. I've processed this material whilst you admit that you haven't. Yet even though this is the case it doesn't appear that you think my advice is sound so you're taking advice from all over the place and thinking that it's automatically better than mine. I've tried to help and done my best but I think I'll now leave you to over complicate a very very simple process for some obscure reason that escapes me. 8) 8)

Post edited for context.

 

[kadriver]

Take your 2 litre beaker. Place 5 prepared processors into it carefully (prepare as I said previously.)

Top the beak up to 1 litre volume with your 36% HCl and put on heat. Warm it thoroughly through. Don't boil it, just get it warm for now.
Add 5ml of Nitric and leave it. The process will start a lot faster because your HCl is hot.
Once your Nitric is working you'll see the solution darken, fizz, bubble and do all the usual things. when it stops add another 5ml. Rinse and repeat until the metals have disappeared. don't be afraid of your last 5ml nitric addition requiring denoxing. You want to make sure the whole process is complete.

Once you have seen the whole 5 digest properly you will be able to reduce your initial quantity of HCl for the next batch OR use the same solution for more processors but that takes a few more steps along the learning curve. I have suggested this volume to allow you to see the process through from start to finish with no problems.

The breaking up of the processors is essential as it give the acids a better foothold on both the lids and the gold plate under the die. 6 to 8 pieces each should be enough though, you don't need to go too mad with the hammer. 8) 8)

I'm assuming that you're following all relevant safety procedures. Enjoy.

Jon

Jon, I'll be using your process outlined above to produce my video but I have a couple of questions;

After adding the first 5ml nitric, how long before the reaction starts - approximately? I remember this reaction taking about 15 or 20 minutes, then it took off vigorously. Can I expect the same here?

In your process it says, "rinse and repeat until the metals have disappeared" does that mean to siphon off the spent acids and add fresh acids?

also where is says, "Once you have seen the whole five digest properly" are you referring to the five processors?

Everything else looks straight forward - thanks for the help!

kadriver

 

[kadriver]

Gents

You do what you need to do. I've processed this material whilst you admit that you haven't. Yet even though this is the case it doesn't appear that you think my advice is sound so you're taking advice from all over the place and thinking that it's automatically better than mine. I've tried to help and done my best but I think I'll now leave you to over complicate a very very simple process for some obscure reason that escapes me. 8) 8)

Post edited for context.

Sorry Jon, I didn't mean to offend you. Not knowing what to expect, and wanting to avoid the yellow material that Metaphore experienced, I just wanted to educate myself before I got started.

Im still going to use the process you described, if that's OK.

kadriver

 

[Anonymous]

I'm not offended mate, I was more bothered that the whole thing was almost taking a life of it's own when it could have been simple but hey ho.

To answer your question - if you add Nitric to warm/hot HCl it can begin within a minute in fresh AR and instantly in "working" AR which is why I suggested smaller amounts. If it makes you more comfortable with adding Nitric to hot HCl, then try it 1ml at a time until you get comfortable.

As you already know the reaction does take a little while to get up to the full speed so don't misjudge your addition. Experimentation is good with this, and erring on the side of caution will benefit you. It's one of those things that is once learned and never forgotten.

 

[Barren Realms 007]

Take your 2 litre beaker. Place 5 prepared processors into it carefully (prepare as I said previously.)

Top the beak up to 1 litre volume with your 36% HCl and put on heat. Warm it thoroughly through. Don't boil it, just get it warm for now.
Add 5ml of Nitric and leave it. The process will start a lot faster because your HCl is hot.
Once your Nitric is working you'll see the solution darken, fizz, bubble and do all the usual things. when it stops add another 5ml. Rinse and repeat until the metals have disappeared. don't be afraid of your last 5ml nitric addition requiring denoxing. You want to make sure the whole process is complete.

Once you have seen the whole 5 digest properly you will be able to reduce your initial quantity of HCl for the next batch OR use the same solution for more processors but that takes a few more steps along the learning curve. I have suggested this volume to allow you to see the process through from start to finish with no problems.

The breaking up of the processors is essential as it give the acids a better foothold on both the lids and the gold plate under the die. 6 to 8 pieces each should be enough though, you don't need to go too mad with the hammer. 8) 8)

I'm assuming that you're following all relevant safety procedures. Enjoy.

Jon

Jon, I'll be using your process outlined above to produce my video but I have a couple of questions;

After adding the first 5ml nitric, how long before the reaction starts - approximately? I remember this reaction taking about 15 or 20 minutes, then it took off vigorously. Can I expect the same here?

In your process it says, "rinse and repeat until the metals have disappeared" does that mean to siphon off the spent acids and add fresh acids?

also where is says, "Once you have seen the whole five digest properly" are you referring to the five processors?

Everything else looks straight forward - thanks for the help!

kadriver

Jon was making a joke. :mrgreen:

 

[kadriver]

Jon, in your process you said to rinse and repeat, does this mean to remove the spent acids and add fresh acid? Thanks

 

[Anonymous]

No. It meant add another 5ml of Nitric, watch until used up or more is required. Then do it again, and again until you have a final result.

It's the "shampoo algorithm."

https://en.wikipedia.org/wiki/Lather,_rinse,_repeat

It's a humorous way of saying "keep doing it until you're done.

 

[Metaphore]

... I was more bothered that the whole thing was almost taking a life of it's own when it could have been simple but hey ho.

Please don't let my stubbornness bother you. I never listened to my father either. I like to do things the hard way.

But seriously, I just want to dissect one for curiosity's sake. When I go for the gold with the next batch, I'll more than likely do it your way.

 

[lanfear]

Hi guys. I am in the middle of a process like this now. I have 2 PP and 2 cyrix with tungsten together with some normal pentium ceramics. I have spent 1 AR solution on them, tested the barren solution for gold and decanted barren solution to waste bucket.
I have now started the final AR process and want to cool the solution and add sulfuric acid to precipitate lead. But could this cause unwated reactions with tungsten in solution?

Jon

 

[geedigity]

I ran a few tests on small batches of Pentium Pros (big thank you to Goren for a simple transaction) to find out if different processing techniques resulted in different yields. I ran two sets of 5 Pentium Pros by merely smashing the cpus into several pieces with a hammer. I didn’t take photos of this process, but for the first set, I yielded about 0.28 grams per CPU and the second set, I yielded approximately 0.33 grams per CPU. Note that I processed each of these sets twice.

The next test I ran was to see if separating the heat spreader from the other parts of the CPU made any difference. Note that I started with 5 CPUs but after removing the heat spreader from three of them, I decided to continue with only the three.

The first step was to remove any thermal compound using a paper towel. I noticed after wiping the heat spreaders, that the thermal compound left a dark residue on the towel.


CPUs before cleaning







I then cleaned the chips with tetrachloroethylene (chlorinated brake cleaner) to remove any residual thermal paste. Next I punched two small holes through the black cover that is located on the same side as the connector pins. I put the holes through the cover so the pressure could escape while I heated enough to melt the brazing and prevent the CPU from exploding. After I installed the holes, I used my oxy-propane torch to melt the brazing on the cover and removed them.

 

[geedigity]

Then I removed the heat spreaders.


After three CPUs, I stopped taking the heat spreaders off, since I didn’t know if I was burning off some of the gold, or if it was absorbing further into the heat spreader. I continued to process only three CPUs at this point.
A word of caution, cardboard can burn when hot heat spreaders fall onto it. I would recommend using something not flammable but that can be easily emptied into the reaction container. As a side note, it appears that the bonding wires are aluminum as shown in the next photograph.


Not sure if all of the Pentium Pros have aluminum bonding wires, but at least two that I examined, did. Before I added HCL and sodium nitrate, I smashed the silicon chip to allow for more complete access to the gold brazing. The following picture has the CPUs ready for action.



Using HCL and sodium nitrate, I heated and allowed to react for about one and a half hours. In a separate container, I added HCL and sodium nitrate to the black covers and heat spreaders, heated and allowed to react for approximately 1.5 hours. Following the completion of the reaction, it appeared all of the gold had been removed from the CPU’s.


I combined the two solutions, and precipitated with SMB. The results of the test indicated that I yielded about 0.37 grams per CPU, and I only processed one time. I am hoping to run another batch following this same method to find out if the process actually makes a difference.
The results could just be that I was getting better at processing them, hard to say. Also, I have not processed the towel with the thermal compound, since I would need a bit more to experiment with. Any ideas on how to separate thermal paste from potential gold?

 

[g_axelsson]

Sometimes it's hard to see the color of bond wires. When in doubt, put a drop of lye on it, aluminum is dissolved while gold is unaffected.

I'm using isopropyl alcohol (also called isopropanol) for dissolving cooling paste on the CPU:s I'm selling to collectors. Works great.

Göran

 

[Dpetes]

Sometimes it's hard to see the color of bond wires. When in doubt, put a drop of lye on it, aluminum is dissolved while gold is unaffected.

I'm using isopropyl alcohol (also called isopropanol) for dissolving cooling paste on the CPU:s I'm selling to collectors. Works great.

Göran

Now I am really confused.

Did you mean HCL instead of lye. The reason I ask is that I have made the mistake of putting aluminum pieces in HCL to separate some boards that I wanted to take the solder off, and had one heck of a reaction to it. Aluminum and solder disappeared but the reaction was something else.

I have seen ( I think) on here a thread that gave info about using Lye and warm water to clean up the painted aluminum before selling it. I have not tried this yet!!

Please advise!

Thanks
Dwayne

 

[g_axelsson]

Both lye and hydrochloric acid dissolves aluminium.

I prefer using lye as it doesn't add chloride to the object and doesn't risk forming AR if I go to nitric in the next step. Just a personal preference.

There might be another advantage for lye, it will attack the protective oxide surface and reach the metal when it is heavily oxidized.

Göran

 

[Refining Rick]

I have done many of these Pentium Pros myself. I have on occasion run into the same problem with the dark a/r and seemingly no reaction left. I found, and this is only my experience, that if I add a little more HCL and a bit of peroxide, the solution clears up and gets going again. Not to much peroxide, maybe 50 ml and 100 ml of HCL. After the addition I stir and find my bubbles and nasty red fumes again. I have never had to do more then this. Hope that helps someone in the future. (P.S. I use sodium nitrate)
On a side note I did have some aluminum chips once that cemented out the gold after it went into solution. Very hot, Very ugly. Mulligan time. I did get it out tho.