# Refining Pentium Pro with AR



## Metaphore (Oct 19, 2015)

I've successfully used AR for recovery of gold foils as well as black powder from a sulfuric cell. This time, decided to try a few Pentium Pros. It all started out well but after several hours on the hot plate and several additions of nitric, the solution stopped reacting to more nitric. At this point, the solution was VERY dark green. I poured it off and found that there is still plenty of gold left on the chips. Put it back on the plate and added more HCL, nothing. More nitric, nothing.

Please direct me to some information that may help me out of this.

Thanks!


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## NobleMetalWorks (Oct 19, 2015)

Metaphore said:


> I've successfully used AR for recovery of gold foils as well as black powder from a sulfuric cell. This time, decided to try a few Pentium Pros. It all started out well but after several hours on the hot plate and several additions of nitric, the solution stopped reacting to more nitric. At this point, the solution was VERY dark green. I poured it off and found that there is still plenty of gold left on the chips. Put it back on the plate and added more HCL, nothing. More nitric, nothing.
> 
> Please direct me to some information that may help me out of this.
> 
> Thanks!



You may need to expand your solution.

Scott


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## geedigity (Oct 19, 2015)

Could the gold be covered by a coating? Since gold will dissolve in nitric and HCL (and reportedly you have both in solution), then it is either covered with a coating, maybe isn't gold, or maybe it is just dissolving very slow. I may be wrong, but if so, please correct me.

Why not remove a few chips with the "gold" on them, rinse and put the chips into a new container with some HCL and a small amount of nitric let sit for about 30 seconds after mixing well, then take a drop and test with SnCl, heat, and test another drop 5 minutes later. If test shows darker result, then gold may still be dissolving.

Just a thought anyway.


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## Metaphore (Oct 19, 2015)

Took a much closer look and shined a flash light through it. Close enough to get a tiny whiff through the respirator. Sucked. But I did see that there is a reaction. It's very slow and very hard to see in the extremely dark liquid.

The gold isn't covered, it's all exposed. I took the ceramic plates off with a blow torch and the rest are the pins and the top cover. When I drained the AR, I saw the top covers flaking and about 10% of the pins intact. I could also see some gold inside the processor, where the ceramic cover used to be. It was all exposed.

@NobleMetalWorks, what does expanding the solution mean?

Should I be concerned about the color of the solution? With the foils and black powder, my solution was a nice deep gold color. This one seems like it has a ton of copper in it. Will I need to do anything different with the AR to drop the gold?

Thanks!


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## geedigity (Oct 19, 2015)

I would think that when you were dissolving the foils and black powders, you were refining. When you are dissolving the gold and base metals as in your current situation, you are reclaiming. Therefore, you would have more base metals in solution since you chose to dissolve everything. 

so after everything is dissolved, you will first have to get rid of the extra nitric, then drop the gold (probably more contaminants in this batch than in prior ones), then refine the dropped gold.


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## NobleMetalWorks (Oct 19, 2015)

Metaphore said:


> Took a much closer look and shined a flash light through it. Close enough to get a tiny whiff through the respirator. Sucked. But I did see that there is a reaction. It's very slow and very hard to see in the extremely dark liquid.
> 
> The gold isn't covered, it's all exposed. I took the ceramic plates off with a blow torch and the rest are the pins and the top cover. When I drained the AR, I saw the top covers flaking and about 10% of the pins intact. I could also see some gold inside the processor, where the ceramic cover used to be. It was all exposed.
> 
> ...



Your solution can only hold so much dissolved metal before it becomes exhausted. Metal is dissolved into solution according to the reactivity series: https://en.wikipedia.org/wiki/Reactivity_series. It seems your solution is pregnant with dissolved metals. When you add acid, it is most likely attacking the exposed metals under the gold plating and thus making it seem like your solution is no longer dissolving gold.

Think of it like this. You introduced many different types of metals into a solution of AR. The metals that are exposed are the first to dissolve into solution. Since you have gold plating that was covering base metals, the gold plating goes into solution until the base metal is exposed, then the AR solution attacks the base metals instead of the gold, you can refer to the reactivity series so that you might understand what I mean. The metals at the top of the scale I posted the link for, will dissolve into solution before the metals at the bottom. Once enough gold has been dissolved to expose the base metals to AR, the AR no longer attacks the gold, but rather the base metals. Until the base metals are completely dissolved, or you remove them, your AR solution will only slowly dissolve gold into solution.

This is one of the many reasons why it's better to remove the pieces that contain gold, from the ones that do not. As well, we try not to dissolve metals into solution that might cause issues in precipitation of the metals we are after. If for example the heat spreader of the CPU is made of Kovar, you are metals into your solution that you don't really want to deal with.

When a solution becomes saturated with base metals, it no longer can dissolve or hold in solution anymore metals. I would suggest removing those parts of the CPUs that still have gold on them, and dissolve in a new AR solution.

The heat spreader also has solder that might contain lead solder which could also cause problems and should be removed prior to precipitating gold.

When I made the suggestion to expand your solution, what I am meaning is to provide more room for metals to be dissolved into solution. You can expand a solution by adding more acids, or water or? All dependent upon what type of solution you have, and what your intent is. You expanded your solution when you added more acid, but as the acid was attacking the base metals instead of the gold, it seemed that your AR solution was not working, or working on slowly.

Hope this helps...

Scott

Scott


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## Shark (Oct 19, 2015)

"Expand your solution"

*This is just an extreme example and not meant as a method to follow by any means. *

I may be wrong but I think he means you don't have enough total solution (AR) to hold all the metals you are trying to break down. An extreme example would be trying to process 100 of your Pentium Pros in an ounce of AR. We know that isn't likely to happen so you would need to expand your solution to a point that all 100 processors could be fully taken into the AR solution. This could mean that you may need 5 gallon of AR for the 100 processors instead of an ounce.

I see NobleMetalWorks beat me to it, but I will leave it anyway.


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## MarcoP (Oct 20, 2015)

I think NobelMetalWorks is also saying that you could use the reactivity series in your favour. Initially some gold and base metals will go in solution and if you don't add nitric or hydrochloric acid the gold will be cemented out by the base metals, test with stannous chloride and if you don't have gold in solution you could use fresh AR. Basically it would remove most base metals first letting you reduce the gold from a cleaner solution.

Marco


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## kadriver (Oct 20, 2015)

I've had some experience with this.

I used nitric to try to dissolve the base metals in some gold filled eye glass springs, the pieces that loop around the back of your ear to hold the glasses on your face.

What I didn't know is that nitric acid is a bad choice for dissolving steel, it doesn't do it very well.

I should have used hydrochloric acid instead, it will dissolve iron (steel) much better than nitric acid will. In fact, concentrated nitric acid can be stored in stainless steel containers.

The spring steel had iron in it - you can test your dark green solution with ammonium or potassium thiocyanate, it will turn blood red if dissolved iron is present.

I knew I had gold foils, I could see them (what I didn't see, or recognize was that because dilute nitric doesn't dissolve steel very well, there were many pieces of steel in with the gold foils).

Not knowing any better, I drained off the dark green solution, added hydrochloric acid to the foils and then small amounts of nitric acid to form Aqua regia. The foils dissolved as expected.

I filtered the solids out of the solution and got a few pieces of spring steel with a bunch of brown powder I thought was dirt.

Then I did a stannous check of the filtered solution to verify that I had Gold in solution before I precipitated the gold with SMB.

I got real confused - the stannous test was NEGATIVE.

How could this be? The Gold foils were gone, dissolved by the Aqua regia, yet there was no gold in solution?

It turns out that the iron from the spring steel was cementing the gold out of solution as fast as it dissolved.

That brown powder in the filter that I THOUGHT was dirt was really the gold that had been cemented out by the pieces of steel! Good thing I save all my filters.

I Retrieved the filter with the brown powder and pieces of spring steel and put it into a beaker and dissolved it again with AR. This time everything went into solution. I did a stannous check and there was gold in solution, I precipitated and all went well from there.

The point is that if you have iron present in with your pregnant gold solution then the iron will cement out the gold as fast as the gold dissolves. AR will dissolve gold faster than it will dissolve iron so the iron will just sit there, immediately cementing out the gold as a brown powder just about as fast as the gold dissolves.

Another confusing aspect is that the iron will consume the acids so no more fumes will evolve. It looks like the reaction is done because the foils are gone and there are no more fumes. But what happens is the iron consumed the acids and cemented out the gold while being masked by the dark green solution so you can't tell what's going on inside the beaker!

If you keep adding fresh acids then the gold will finally go into solution and stay in solution once all the iron is dissolved.

This is why it is so important to understand the reactivity series of metals chart.

kadriver


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## Anonymous (Oct 20, 2015)

Hi Can we get some perspective on this please as it would help with the answers?

How many Pentium Pro processors are you recovering from and what is the total volume of liquid in the original AR solution?


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## NobleMetalWorks (Oct 20, 2015)

spaceships said:


> Hi Can we get some perspective on this please as it would help with the answers?
> 
> How many Pentium Pro processors are you recovering from and what is the total volume of liquid in the original AR solution?



So long as the OP is adding Nitric acid, only as needed in order to dissolve all the gold into solution, I'm not sure that the quantity of CPUs matters so much. The only difference in quantity is the amount of acids required to dissolve the gold properly. This being said, the OP did say that it was "a few" Pentium Pros. I would wager this means around 2, but may mean a few more. I think after the OP reads what has been posted, he will be well on his way to resolving any issues.

Kadriver,

I wish there was a like button on this forum. Your posts are some of the best, not only because of the information you impart, but also your willingness to be utterly honest even to the point you express your own mistakes. You add value to the forum. I appreciate your posts!

Scott


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## Anonymous (Oct 20, 2015)

I hear you Scott.

However - if the guy is trying to recover from 2 Pentium Pro chips and he has literally covered them with HCl and added Nitric that's far too small a solution to dissolve the metals involved, as I'm sure you'd agree. We all do have a tendency to offer advice based upon a small portion of the relevant information, and then often end up having to amend said advice when the true facts emerge. 

I was just thinking that in many cases we'd be able to help better and cut down on the "ifs buts and maybes" by just getting the proper facts to start with. It would save a lot of time and confusion in many of the cases we deal with. 

Does that sound reasonable or just daft?

Regards

Jon


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## Metaphore (Oct 20, 2015)

spaceships said:


> Hi Can we get some perspective on this please as it would help with the answers?
> 
> How many Pentium Pro processors are you recovering from and what is the total volume of liquid in the original AR solution?



15 Pentium Pros in a 2L beaker with 500ml HCL and 500ml water. Nitric added 3ml at a time.

Here is what it looks like now: https://www.dropbox.com/s/8nznh75wnvx6gb3/2015-10-20 20.38.25.jpg?dl=0

There is still quite a bit of gold left on the chips. I think I'll crush the rest and run them through a fresh solution.

https://www.dropbox.com/s/l0v6iwizrkz3qpz/2015-10-20 20.23.26.jpg?dl=0
https://www.dropbox.com/s/fdk894ob6depzvn/2015-10-20 21.02.34.jpg?dl=0


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## Anonymous (Oct 21, 2015)

Thanks that puts some better perspective on it I appreciate that. Would anyone care to amend their advice?


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## Metaphore (Oct 21, 2015)

geedigity said:


> I would think that when you were dissolving the foils and black powders, you were refining. When you are dissolving the gold and base metals as in your current situation, you are reclaiming. Therefore, you would have more base metals in solution since you chose to dissolve everything.
> 
> so after everything is dissolved, you will first have to get rid of the extra nitric, then drop the gold (probably more contaminants in this batch than in prior ones), then refine the dropped gold.



Reclaiming vs refining - that was an epiphany moment for me. Thanks!!



kadriver said:


> I've had some experience with this.
> 
> This is why it is so important to understand the reactivity series of metals chart.
> 
> kadriver



I see your point. Thank you very much for a very educational post!



NobleMetalWorks said:


> When I made the suggestion to expand your solution, what I am meaning is to provide more room for metals to be dissolved into solution. You can expand a solution by adding more acids, or water or? All dependent upon what type of solution you have, and what your intent is. You expanded your solution when you added more acid, but as the acid was attacking the base metals instead of the gold, it seemed that your AR solution was not working, or working on slowly.
> 
> Scott



Thank you for that explanation!



spaceships said:


> Thanks that puts some better perspective on it I appreciate that. Would anyone care to amend their advice?



I should have included this information from the start. Will make sure I do so in the future.

Thank you everyone for your help. You are all awesome!


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## kadriver (Oct 28, 2015)

I've got some pentium pro CPUs on the way - about 10. When they get here I'll make a detailed video showing how to recover the gold, then how to refine it to high purity.

The ferrous metals MUST be removed first with straight hydrochloric acid boils. The foils can then be easily dissolved with AR with the ceramic still in the beaker. Hydrochloric acid by itself should not dissolve the gold, but hot hydrochloric acid will dissolve the ferrous metals.

I believe that it is the presence of any ferrous metals that is causing the problem here. Hot hydrochloric acid should be the remedy.

This will be my first attemp at recovering and refining gold from Pentium Pro CPUs. Should be interesting!

kadriver


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## Barren Realms 007 (Oct 28, 2015)

kadriver said:


> I've got some pentium pro CPUs on the way - about 10. When they get here I'll make a detailed video showing how to recover the gold, then how to refine it to high purity.
> 
> The ferrous metals MUST be removed first with straight hydrochloric acid boils. The foils can then be easily dissolved with AR with the ceramic still in the beaker. Hydrochloric acid by itself should not dissolve the gold, but hot hydrochloric acid will dissolve the ferrous metals.
> 
> ...



I feel you should do some more research and refine your process.


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## Anonymous (Oct 29, 2015)

You have too many steps in your process Kadriver. 

Smash the thin black ceramic caps off the base of the chips and remove the waste. Then simply break up the whole processor with a hammer (the gold plated lids do actually break) and process the whole lot at once in AR.

I can't agree with your suggestion of ferrous metals causing a problem I am afraid because I have processed many of these and never had that issue.

Regards

Jon


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## Metaphore (Oct 29, 2015)

kadriver said:


> I've got some pentium pro CPUs on the way - about 10. When they get here I'll make a detailed video showing how to recover the gold, then how to refine it to high purity.
> 
> The ferrous metals MUST be removed first with straight hydrochloric acid boils. The foils can then be easily dissolved with AR with the ceramic still in the beaker. Hydrochloric acid by itself should not dissolve the gold, but hot hydrochloric acid will dissolve the ferrous metals.
> 
> kadriver



I did the hot HCL rinse with the leftovers. The bath ended up a deep purple, almost black. I guess it dissolved lots of impurities.

They've been in hot AR for the past 3 days. Had to add HCL a couple of times and add about 10ml nitric a couple of times a day. This morning the reaction was still going. 

Not sure if the hot HCL will improve the yield or not, but it certainly improved the color of the AR solution. It's amber instead of green.


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## Metaphore (Oct 30, 2015)

Processed the solution, got a few grams - less than 5 - of dirty gold powder and started again with the processors.

This time, I crushed them to an average of about 6 fragments each and lots of dust. Boiled them in HCL until that got too dark to see if the color was changing. Added that to the stock bucket and repeated the HCL boil. After the color stopped changing, put that in the stock too. Added clean HCL, heated it and started adding nitric. Added about 50ml over 2 days. Added more HCL, added more water, keep adding nitric and the reaction is still going after 4 days. There is also a yellowish film forming on the beaker.



Should the reaction be going this long or is it having a Ground Hog's Day complex? Like something pushing the gold out of the solution and it getting re-dissolved over and over? And what is that film on the glass?


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## kadriver (Oct 31, 2015)

Good stuff here Metaphor, thanks for posting those photos. I don't usually refine computer scrap because the yields are so low and I don't have time because the jewelers keep me so busy - just like Harold said they would.

But I did want to make a video that shows how to do it because computer scrap videos are so popular right now. Eventually, when it sinks in that you can't make any money with computer scrap (unless you get it for free) then the fervor will die down.

There is a guy on eBay who wants $350 for 10 Pentium Pro CPUs. I bought my 12 Pentium Pro CPUs for about $23 each including shipping. Yet there is only about $10 or $12 worth of gold in each one. I paid twice what they are worth but I did it so I could make a video, NOT to make a profit.

Everybody thinks there is much gold in computer scrap, but this just isn't true.

I plan to use the 12 CPUs to make my video. I've done MLCC with hot HCl boils to remove the ferrous metals, then dissolve the gold in hot AR and they came out great. I'm going to make a video using that process.

Please note that this is not going to be THE WAY to process these CPUs, but rather a way to do it. I've seen Barrenrelms Video on YouTube using HCl and peroxide to lift the gold foils, but it didn't show the complete process, just part of it.

I believe that folks want to see the whole process, watching just part of a process is frustrating! I hope to make a video (if I can pull it off) of the ENTIRE PROCESS start to finish.

There seems to be an unwritten rule that refining processes are top secret and must be guarded to prevent others from learning the "secrets of refining". In the end I wish to be remembered as one who chose to help others learn rather than one who hid my knowledge so I could gain more than my fellows.

kadriver


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## kadriver (Oct 31, 2015)

Barren Realms 007 said:


> kadriver said:
> 
> 
> > I've got some pentium pro CPUs on the way - about 10. When they get here I'll make a detailed video showing how to recover the gold, then how to refine it to high purity.
> ...



Barren, you've already done all the research, why don't you just set me straight here and share what you know so I can get it right? Help me out brother!

I think the hot HCl will do the trick based on my experience with the MLCCs. I guess the question is; is there ferrous metals in the Pentium Pro CPUs or not?

At any rate, using hot HCl boils to try and clean out the base metals before using AR should work. If it does, then I guess you could say that I invented a new process for recovering and refining gold from Pentium Pro CPUs.

Thank you!

kadriver


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## Metaphore (Oct 31, 2015)

Anyone know what that coating on the glass is?


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## Barren Realms 007 (Oct 31, 2015)

kadriver said:


> Barren Realms 007 said:
> 
> 
> > kadriver said:
> ...




That's not a problem. The best way for you to process them is the break them up into small pieces. Run them in nitric to remove the base metals till the copper/tungsten heat sink separates from the ceramic. Siphon off the solution. Wash the parts and the gold then run them in AR. You can look at the copper/tungsten heat sinks and make sure that they are clean and separate them and the ceramic bodies from the gold and run the gold in AR. Make sure the silicone dies are separated during the run in nitric or you can remove them with heat before you run them in nitric. You can remove the copper/tungsten heat sinks with heat but it takes a lot of heat to do it.


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## kadriver (Oct 31, 2015)

Metaphore said:


> Anyone know what that coating on the glass is?



It's probably some kind of salt, especially if it's been on heat and allowed to concentrate.

See if you can get a chunk out with a plastic picnic spoon.

Put some in a test tube and add some solvents to see what, if anything, will dissolve it.

Add a few drops of water, and then in another tube add a few drops of HCl. 

If it dissolves then you can just hydrate to dissolve the salt then decant to recover your gold foils.

kadriver


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## Metaphore (Oct 31, 2015)

It's been going 5 days now, so new plan...

Decanted and filtered the solution then tested with SnO2











kadriver said:


> I've had some experience with this.
> I got real confused - the stannous test was NEGATIVE.
> How could this be? The Gold foils were gone, dissolved by the Aqua regia, yet there was no gold in solution?
> It turns out that the iron from the spring steel was cementing the gold out of solution as fast as it dissolved.
> ...



Based on the SnO2 test of the decanted solution, I'll assume that I'm experiencing the recursive reaction kadriver described.

Here my new plan:

*Assumption 1:* 
The powder in the filter and coating the beaker and chip fragments is gold.

*Assumption 2*
Most Fe and Cu have been decanted and won't cause a repeat of the problem.

*The plan*
Wash as much gold off the beaker and chips as possible, cover with HCL, heat and start adding HNO3.

The solution and rinse water I'll boil down and process with SMB.

Comments, criticisms, suggestions before I start?


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## kadriver (Oct 31, 2015)

Thanks Barren.


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## Metaphore (Oct 31, 2015)

kadriver said:


> Metaphore said:
> 
> 
> > Anyone know what that coating on the glass is?
> ...



Thanks! I'll do this first.


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## Anonymous (Oct 31, 2015)

Ammonia will dissolve that yellowy mess that is caked on your glass. A lot of it is silver Chloride.


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## Metaphore (Oct 31, 2015)

Tried water, HCL, HN03, NH3 and AR. Heated each. Results below (water produced no reaction and I ran out of free beakers).




HCL and HN03 show no reaction.

So, new plan is Ammonia bath, then filter left over gold powder?


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## Metaphore (Oct 31, 2015)

spaceships said:


> Ammonia will dissolve that yellowy mess that is caked on your glass. A lot of it is silver Chloride.



Indeed it did. If I do an ammonia bath in that beaker, I'm assuming the remnants of HCL on the chips will cause some gold to go into the ammonia solution as well. How can I get as much value out of this mess as possible?


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## resabed01 (Oct 31, 2015)

I suggest focusing on getting the gold first. Gold is roughly $38 a gram and silver is $0.50 a gram. At this point don't chase the silver. Accumulate any silver chloride you run across and when you have enough, process it later.


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## Metaphore (Oct 31, 2015)

kadriver said:


> There is a guy on eBay who wants $350 for 10 Pentium Pro CPUs. I bought my 12 Pentium Pro CPUs for about $23 each including shipping. Yet there is only about $10 or $12 worth of gold in each one. I paid twice what they are worth but I did it so I could make a video, NOT to make a profit.
> kadriver



I'm in absolute agreement about prices on eBay. In my case, I bought 30 of these for about $20 apiece. For me, it's not profit either, I'm doing this for the learning process and the fun.

I'm only using half my Pentium Pros for this. Maybe I can film the next batch too.


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## Barren Realms 007 (Oct 31, 2015)

kadriver said:


> Thanks Barren.



No problem, anytime. :mrgreen:


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## Anonymous (Oct 31, 2015)

Metaphore said:


> spaceships said:
> 
> 
> > Ammonia will dissolve that yellowy mess that is caked on your glass. A lot of it is silver Chloride.
> ...



The ammonia will neutralise any remaining traces of HCl in that coating. If there is any particulate gold in that coating my understanding is that it will remain behind. You can take the resulting solution and precipitate any silver Chloride back out of it using some more HCl. As such you're not really complicating things you are merely separating things by doing this. It doesn't take much ammonia to do this either.

Edit: This is actually the only way I use ammonia in my lab.


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## kadriver (Oct 31, 2015)

Here's a short video that shows at least part of these CPUs are magnetic and therefore contain ferrous metals. No matter what anyone says, these ferrous metals are best removed with hot HCl boils first before any AR is introduced into the process.

Metaphor, take a strong magnet in a towel or cloth so you don't break the beaker and see if any of the material in the beaker is attracted to the magnet. If yes then there is iron present and that will cause problems - it did for me anyway.

With iron in the beaker, AR will dissolve the gold foils and then cement right back out onto the bits of iron. I've found that if you keep adding acids then eventually all the iron will dissolve and then the gold won't have anything to cement on and it too will stay in solution.

But I think it's best to get the iron (and any other HCl soluble metals) out before the AR is used.

https://youtu.be/nCsoGA17sy4

kadriver


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## g_axelsson (Oct 31, 2015)

Metaphore, I think the yellow stain is molybdate, it comes from dissolving the molybdenum manganese conductors inside the ceramics. Look at the color where the pins sat and you will notice the similarity. That is also whats collecting in your filters.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=51&p=6525#p6525

Göran


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## Anonymous (Oct 31, 2015)

kadriver said:


> Here's a short video that shows at least part of these CPUs are magnetic and therefore contain ferrous metals.* No matter what anyone says*, these ferrous metals are best removed with hot HCl boils first before any AR is introduced into the process.
> 
> 
> But I think it's best to get the iron (and any other HCl soluble metals) out before the AR is used.
> ...



I respectfully disagree. You cannot make a statement like that which I have highlighted. You are also simply incorrect in your assertation that these processors require an HCl boil to remove ferrous metals before AR is used. They do not.

Edit: Are you sure you are not mixing the ceramic version up with the fibre version of the Pentium Pro? The fibre version has Kovar legs.


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## Metaphore (Oct 31, 2015)

spaceships said:


> kadriver said:
> 
> 
> > Here's a short video that shows at least part of these CPUs are magnetic and therefore contain ferrous metals.* No matter what anyone says*, these ferrous metals are best removed with hot HCl boils first before any AR is introduced into the process.
> ...



I just tested one of my ceramic Pentium Pros with a magnet. The pins are magnetic. The heat spreader is not.


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## Anonymous (Oct 31, 2015)

I'm not saying that the pins are not magnetic. I'm saying that they do not need an HCl wash before processing in AR. If we look at this logically there's absolutely no benefit. For starters how is the HCl going to get to the iron?


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## g_axelsson (Oct 31, 2015)

Metaphore said:


> I just tested one of my ceramic Pentium Pros with a magnet. The pins are magnetic. The heat spreader is not.


Second that, checked 81 ceramic PPro and all had magnetic legs. So did all the 386, 486, MMX, K6, i960, pentium and P3 processors I tested too. Kovar seems to be the rule... now, can anyone name a ceramic or fiber CPU with non kovar pins? I'm going to check the stash of 3000 CPU:s that I have...

... back now. I checked 286, 386, 387, 486, pentium, and overdrives made by Intel, IBM, AMD, Cyrix, Fujitsu, ST, SGS Thomson and Siemens and I only found one non-magnetic. IBM 286 with aluminum can was made with non-magnetic legs, but that's a rare chip. Mostly found in IBM PS/2 systems from the early 90:es.

For CPU:s packaged in plastic capsule, DIL and surface mounted ones with lead frame it seems that both magnetic and non-magnetic alloys are common.

Göran


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## Anonymous (Oct 31, 2015)

Goran I refer you to my post above yours mate. 

Jon

Edit: If as you say 99% of all ceramic pins are based upon Kovar then of course I'm not going to disagree with the facts that you've found. If that is the case then logically the recommendation to HCl wash these Pentium Pro chips would apply to all the ceramics we process. We know it isn't necessary in other ceramics so therefore it isn't necessary here. I rest my case gentlemen unless someone can give me a reasoned and logical explanation otherwise.


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## g_axelsson (Oct 31, 2015)

spaceships said:


> Goran I refer you to my post above yours mate.
> 
> Jon


I saw that and have no more comments than we all prefer different styles of refining.

If you prefer to drop your CPU:s in AR and extract the gold from a solution heavy in base metals, it's ok and it works. Some of our members are doing that and it works for them.

If you prefer to remove as much of the base metals first with either nitric or hydrochloric acid it's okay. It adds a step and takes longer time, but the final drop is from a solution not as heavily in base metals and that could be important for some of our members.
As most scrap we refine has been used the surface of the plating is probably damaged so the acid can get to it even when fully plated. When it starts to dissolve the foils easily breaks. Some pins might survive but a lot base metal will be removed.
This process should work and I'm certain that some of our members are using it just fine.

My favorite is what I call modified AR, add AR to the CPU:s but don't use enough to finish the job. Then in the end the gold will cement out on the base metals and you can pour off the barren liquid with most of the base metals. Add more AR (and possibly also more CPU:s) while removing any ceramics where all the metals are gone from, it just takes up space. In the end you have a quite concentrated gold solution with less base metals.
This method takes a bit of experience and longer in time but suits me well. It's not a process I would recommend to a newbie.
This process is used by some of our members and it works great for them.

I would like to add a disclaimer to this. I'm not that experienced in refining CPU:s but I'm gearing up for the 80 kilo CPU lot I bought this summer. All I've made so far is started a 1 kilo test run of black MMX fiber CPU:s to assay how much gold there is in them. For these I decided to boil them in HCl to remove the legs, then I'm going to incinerate to get to the bond wires.

We all have different styles that suits our self, so chill out, there is more than one way to refine gold.

Göran


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## Metaphore (Oct 31, 2015)

What I'm getting is that it would be best to separate Pentium Pros into 4 components before processing:


Heat spreader
Silicone chip
Pins
Ceramic base

Silicone chips and pins processed in AR.
Ceramic base crushed and processed in AR.
Heat spreader - I'm not too clear on. Is it nitric?


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## Anonymous (Oct 31, 2015)

Goran I agree with you. I don't need to chill out because I am completely chilled, I can promise you. Maybe my post didn't read that was because of our language differences but it was meant to be succint not rude. 

My whole diatribe was based upon the advice to "boil in HCl to remove the iron." That advice was incorrect, and not just a "difference in refining methods." You can boil a gold plated item in HCl if you like but I would love to see how the HCl is going to reach the iron substrate?


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## Anonymous (Oct 31, 2015)

Metaphore said:


> What I'm getting is that it would be best to separate Pentium Pros into 4 components before processing:
> 
> 
> Heat spreader
> ...



No. This whole thread has set you on the wrong path my friend. My initial advice is correct. Remove the black base, break up the processors with a hammer and process in AR complete. I am talking from hands on experience here and have lost count of the amount of these processors I have done successfully. 

Regards

Jon


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## Metaphore (Oct 31, 2015)

spaceships said:


> No. This whole thread has set you on the wrong path my friend. My initial advice is correct. Remove the black base, break up the processors with a hammer and process in AR complete. I am talking from hands on experience here and have lost count of the amount of these processors I have done successfully.
> Jon



But that is exactly what I did and had the never ending reaction going. Poured off the first AR and had the same happened with the second. Something in my process needs to improve, no?


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## Anonymous (Oct 31, 2015)

Yes I agree. I questioned the advice that you were given initially and nobody who had offered that advice came back and altered theirs based upon the information you gave. Ok then here goes:

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


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## g_axelsson (Oct 31, 2015)

spaceships said:


> Goran I agree with you. I don't need to chill out because I am completely chilled, I can promise you. Maybe my post didn't read that was because of our language differences but it was meant to be succint not rude.
> 
> My whole diatribe was based upon the advice to "boil in HCl to remove the iron." That advice was incorrect, and not just a "difference in refining methods." You can boil a gold plated item in HCl if you like but I would love to see how the HCl is going to reach the iron substrate?


I'm sorry too, I should have added a few smileys to my post. It was more in a friendly jokingly tone I added the "chill out" and it wasn't just directed to you, more to the thread generally before people start taking too firm positions.

I'm looking forward to kadriver's video as it will show yet another persons way of solving how to refine ceramic CPU:s. If he runs into any issues along the way I know he's proficient and systematic enough to solve any problems along the way.
I've just looked through Sam's two part video of ceramic CPU refining. I'm missing any mentioning of denoxing and most newbies will use too much nitric. He also used what seems to be a metallic spoon to mix the SMB in the gold chloride, something I would never do out of principle. Neither does he mention what he is doing with the gold plated lids. But it works for him and that's the direct AR method. (He actually uses poor mans AR)

When time allows me I'm going to test boiling a PPro in HCl just to see how hard it is to break through the plating. Then I can answer your question. :mrgreen: 
Right now, winter is coming and my refining season is mostly over, but I'm looking to purchase a small house in the countryside just for storage and refining space.

Still friends? 8) 

Göran


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## Anonymous (Oct 31, 2015)

Hehe always friends Goran. 

Disagreeing isn't a declaration of war mate 8) 

Jon


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## Barren Realms 007 (Oct 31, 2015)

Pre treatment of ceramic CPU's in HCL is really not a necessary step that needs to be done. It serves no use in refining them. Mostly all it does is create extra waste solution to deal with and add more cost and time to processing them.


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## kadriver (Oct 31, 2015)

Ive never broke these up before. Is there a certain way to do it or do I just put them on the concrete and hit with a hammer?

I have zero experience with these CPUs, I held one in my hand for the first time today, they are much heavier than I thought they would be.

Ive got 12 CPUs on the way. I'll make one video just like spaceships recommends with 6 of the CPUs since he has experience with these.

Then I'll do the other 6 using HCl treatments before the AR is added. This way we can see if there is a difference.

kadriver


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## Anonymous (Oct 31, 2015)

Kadriver

I'll break one up tomorrow and post a pic up for you with pleasure 8) 

Jon


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## Anonymous (Oct 31, 2015)

Broken with a hammer. You can break it further if you wish but this was a quick "demo" pic hence the mess.

Take note of the heat spreader being in pieces, and the gold plating under the die being visible as some of the die has broken off. That's where you want to be before processing. Sorry about the mess around it!

Jon


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## g_axelsson (Oct 31, 2015)

This two part video is missing denoxing, but except for that it's quite good and shows the process.

https://www.youtube.com/watch?v=tQ_R8Gr26kk
https://www.youtube.com/watch?v=Hv4CcaTVJqY

It shows what spaceships is talking about. As PPro:s are almost twice as big, 6-8 pieces should be fine, but that's not a critical number.

As for your original problems, what did you do with the heat spreader? Did you try to dissolve it? It can take a lot of acid and it's hard to dissolve thanks to the tungsten. The heatspreader is made from a tungsten copper alloy. It might also be able to cement gold out of solution. As I haven't refined any PPro yet I don't have any recommendations here.

Shameless plug : I'll sell PPro:s to anyone that want's to test refining for $15/+postage. It's more than the gold is worth but compensates me for the extra work of packing and shipping.
Edit : All sold.

Göran


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## kadriver (Oct 31, 2015)

Got it Jon, thanks for that tip. I'll break them up just like you showed.

Metaphor, I just thought of something with respect to the process you used.

You added HCl and small doses of nitric.

After heating for several hours, and after several doses of nitric, and after there are no more fumes being produced, you could check the solution with stannous to make sure that you have no gold in solution.

Then siphon off the acids and put in fresh HCl and more nitric doses. This should prevent the build up of base metals that you experienced.

Spaceships and barren realms both say that the AR approach should work fine. But you had problems with other substances in your batch. This is what I would like to avoid when I do my videos.

I looked up solubility of tungsten and the site said it is soluble in a mixture of nitric and hydroflouric acids. But it is barely soluble in hydrochloric acid alone. 

It also said that the tungsten has a YELLOW component, much like the yellow substance that you formed in your reaction;



TUNGSTEN [[[symbol]] W, atomic weight 184 o (0=16)], a metallic chemical element found in the minerals wolfram, an iron and manganese tungstate, scheelite, a calcium tungstate, stolzite, a lead tungstate, and in some rarer minerals... It is soluble in a mixture of nitric and hydrofluoric acids, and the powdered metal, in aqua regia, but slowly attacked by sulphuric, hydrochloric and hydrofluoric acids separately; it is also soluble in boiling potash solution, giving a tunstate and hydrogen.

Tungsten dioxide, W02, formed on reducing the trioxide by hydrogen at a red heat or a mixture of the trioxide and hydrochloric acid with zinc, or by decomposing the tetrachloride with water, is a brown strongly pyrophoric powder, which must be cooled in hydrogen before being brought into contact with air. It is slightly soluble in hydrochloric and sulphuric acids,* giving purple solutions.* It dissolves in potash, giving potassium tungstate and hydrogen, and is readily oxidized to the trioxide.

tungsten trioxide, W0 31 occurs in nature as wolframine, a yellow mineral found in Cumberland, Limoges, Connecticut and in North Carolina. It is a canary-yellow powder, which becomes a dark orange on heating; the original colour is regained on cooling.



This may be an explanation for the yellow material in your beaker.

kadriver


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## kadriver (Oct 31, 2015)

Goran;

Those are Samuels videos. He does an excellent job. I've watched them several times. Thanks for referring as I'll review them before I do my video.

I'll be doing the same thing with the Pentium Pro CPUs.

Looking forward to starting this project.

kadriver


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## g_axelsson (Oct 31, 2015)

The question is what to do with the heat spreader? Since it's made up of a copper wolfram powder sintered alloy it's a bit difficult to process. They doesn't behave as normal metal, for example you can shatter it with a hammer as shown above. I know Lazersteve removed them with a torch and processed them separately.

Use this search to find quite a number of relevant postings about the problem above.
http://goldrefiningforum.com/phpBB3/search.php?keywords=pentium+pro+heat+spreader&terms=all&author=Lazersteve&sv=0&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

I'm going to read them now...

Göran


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## kadriver (Oct 31, 2015)

Excellent reference Goran.

Here is some relevant info on separating the gold foils from the tungsten on the CPUs;




glondor wrote:
If the heat sink breaks, you do not want to do them directly in A/R. That is a sintered tungsten/ copper heatsink

Samuel-a wrote:
Actually, the opposite is true.
W bearly reacts with AR, the only difference is that it will later precipitate (when cold) a small amount of yellow WO3 that is easly filtered out.

Lazersteve wrote:
Glondor is 100% correct here, putting the tungsten topped cpus directly in AR is a bad decision for several reasons:

1) The yellow powder (oxidized tungsten) requires lots of rinsing to remove the gold solution from it's structure,
2) The yellow powder's slight acid solubility allows it to make it through several stages of filtration,
3) Soaking in nitric acid first allows the tungsten plates easily to be collected in tact without breaking them up,
4) The yellow powder will give false positives to stannous chloride as a cornflower blue color,
5) In effect, if you do not remove the tungsten heat spreaders first, you are putting unnecessary garbage into your AR reaction (GIGO). 
6) The yellow powder tends to stick to buckets and beakers leaving 'ring around the beaker' if it is not removed before AR treatment. 
7) Unnecessarily making the yellow powder by going straight to AR with gold topped ceramic cpus adds another waste stream (the yellow powder) to your processes.

Steve


In Steve's post he removes the tungsten caps by deforming it with a hammer blow - he does not break it into pieces. Then he separates the gold plated cap and removes any pieces of ceramic that cling. The hand-cleaned gold plated caps are then soaked in dilute cold nitric acid. The foils came off nicely leaving the tungsten intact and easily retrievable before going to AR to dissolve the foils.

This is an older post and the method Steve used may have changed. Spaceships and Barren Realms both say their experience with AR right off the bat works fine.

Metaphor, this may explain how you got that yellow substance by adding AR to the CPUs. I truely want to avoid the formation of this yellow tungsten powder.

Here is the link to that post by Lazersteve; http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=18680&p=188873&hilit=pentium+pro+heat+spreader#p188873

kadriver


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## Metaphore (Oct 31, 2015)

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?


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## kadriver (Oct 31, 2015)

Metaphore said:


> 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


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## Anonymous (Nov 1, 2015)

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.


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## kadriver (Nov 1, 2015)

spaceships said:


> 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.
> ...



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


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## kadriver (Nov 1, 2015)

spaceships said:


> 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


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## Anonymous (Nov 1, 2015)

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.


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## Barren Realms 007 (Nov 1, 2015)

kadriver said:


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




Jon was making a joke. :mrgreen:


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## kadriver (Nov 1, 2015)

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


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## Anonymous (Nov 1, 2015)

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.


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## Metaphore (Nov 1, 2015)

spaceships said:


> ... 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.


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## lanfear (Nov 4, 2015)

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


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## geedigity (Nov 23, 2015)

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.


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## geedigity (Nov 23, 2015)

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?


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## g_axelsson (Nov 23, 2015)

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


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## Dpetes (Nov 23, 2015)

g_axelsson said:


> 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


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## g_axelsson (Nov 23, 2015)

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


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## Refining Rick (Mar 29, 2016)

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.


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