# processing ceramic cpu's commercially in Manila....



## Redders (Oct 10, 2007)

This last year I have done a bit of IT business with a man who has been reclaiming gold from IT components for about ten years. He does this in Manila in the Philippines. 

With ceramic processors, they knock off the lids (and process separately), they break up the chips into large-ish pieces and incinerate in a cast iron crucible. The heat is usually from a torch which may be kerosene and air (to cut costs) but could be oxy-acetylene. They add lead and melt it into the mass. They skim off slag from the top and they fish out the ceramic from the bottom. The pins and the fine gold wire within the cpus melt into the lead.

The molten metal is cooled. Later, the metal is reheated and the gold migrates to the middle and can be clearly identified. The straight lead is carefully poured off. The gold bearing lead is treated with nitric.

He believes that some values are lost but this is how it is done by many small companies in Manila.

I told him that I would post this up on this site. I will show him any responses and ask him to respond to them.


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## Harold_V (Oct 10, 2007)

You've been lead down a path, or you're talking with someone that doesn't have a clue. 

I'd like you to consider a couple things, ----then decide the truth about the balance of what you've been told.

Lead and gold, either combined, or individually, weigh far more than ceramic materials, so such material would not be on the bottom, but on top. 

Lead and gold, alloyed, will NOT stratify, let alone permit the gold to occupy any particular place in the mass, such as the center. That's total nonsense. Assuming any stirring at all, the gold should be somewhat distributed throughout the lot. When litharge is used to collect values, it is generally cupelled, leaving the values behind. To my knowledge, it is impossible to separate lead from gold via stratification. 

Harold


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## Redders (Oct 10, 2007)

Roly, he is called and I have spent quite a bit of time with him. There is no doubt that he is genuine sort of bloke.

I put it on here because I couldn't quite get my head around it. The ceramic being submerged was my fist query. I will communicate with him via emails and follow this up....

nice to communicate with you, Harold, I'll get back to you....


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## goldsilverpro (Oct 10, 2007)

Doesn't sound right to me, either. There must be something you're missing. About 30 years ago, the US Bureau of Mines came up with a method to remove gold from the tin/lead solder that was used in wave solder machines to solder components to circuit boards. They melted it and stirred in some aluminum. The aluminum picked up the gold and floated on top of the solder. It was skimmed off and the gold was extracted from the aluminum. Lead fumes, of course, are toxic.


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## Irons (Oct 10, 2007)

Try precipitating Gold out on Aluminum and you will get a purple color on the Gold that is an alloy of Gold and Aluminum. It drove early IC manufacturers crazy with Gold/Aluminum bonds going bad, hence the name Purple Plague.

Interesting technique.

http://en.wikipedia.org/wiki/Gold-aluminium_intermetallics

Gold-aluminium intermetallics are intermetallic compounds of gold and aluminium that occur at contacts between the two metals. These intermetallics have different properties than the individual metals which can cause problems in wire bonding in microelectronics. The main compounds formed are Au5Al2 (white plague) and AuAl2 (purple plague), which both form at high temperatures.

White plague is the name of the compound Au5Al2 as well as the problem it causes. It has low electric conductivity, so its formation at the joint leads to an increase of electrical resistance which can lead to total failure. Purple plague is a brittle, bright-purple compound of AuAl2. The process of the growth of the intermetallic layers leads to creation of voids in the metal lattice.

Other gold-aluminium intermetallics can cause problems as well. The compound Roberts-Austen's purple gold, is composed of 79%Au-21%Al, with a melting point of about 750°C. Above 624°C, purple plague is replaced by Au2Al, a tan-colored substance. It is a poor conductor and can cause electric failure of the joint that can lead to mechanical failure. At lower temperatures, about 400–450°C, an interdiffusion process takes place at the junction. This leads to formation of layers of intermetallic compounds with different compositions, from gold-rich to aluminium-rich, with different growth rates. As the denser faster-growing layers consume the slower-growing ones, cavities form. This process, known as Kirkendall voiding, leads to increase of electrical resistance of the wire bond and its mechanical weakening. When the voids are collected along the diffusion front, a process aided by contaminants present in the lattice, it is known as Horsting voiding, a process similar to and often confused with Kirkendall voiding.

All problems caused by gold-aluminium intermetallics can be prevented either by using bonding processes that avoid high temperatures (e.g. ultrasonic welding), or by designing circuitry in such a way as to avoid aluminium-to-gold contact using aluminium-to-aluminium or gold-to-gold junctions.


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## goldsilverpro (Oct 10, 2007)

A long true story.

In about '72, I invented a method and formed a company, with a money partner, for the service of recycling all-gold plated, old type CPU, side-braze packages (mainly 40 lead) for reuse. These were rejected parts, in various stages of production. Most were rejected on final testing, after sealing. 

I went to the Silicon Valley to hustle business. I hit about 10 huge electronics concerns, cold, and showed them before and after samples. Every company I went to was very eager to talk to me and they all gave me samples of their rejects. 

I also found out that Fairchild Semiconductor had spent a lot of money trying to do this same thing and had failed miserably. There were also a couple of smaller companies that had worked on this, but their methods were Mickey Mouse and they produced unacceptable parts. I think they were the ones who got the patents that are mentioned below. 

Purple plague was one of the reasons for rejection. 

My biggest customers were Intel, AMD, and AMI. At the end, we were doing about 100,000 packages per week. We *(1)* Removed the lid and chip with heat and a vacuum probe and removed the bonding wires; *(2)* Chemically stripped (electrolytically) the gold plate and gold alloy brazes selectively without attacking the base metals (the crux of my invention). These base metals were Kovar legs and sealing ring, plus moly-manganese chip pad, internal traces, bonding fingers, and pads to braze the legs to. Also, silver/copper braze was used to attach the legs. There was also nickel plating under all the gold plating. I should mention that cyanide (the first thing I tried) wouldn't work because it attacked the copper and silver; *(3)* Replated the gold; and *(4)* Returned them to the companies for new chip attachment and reuse. Our recycled packages had a higher yield than new packages. We charged half the price of a new package. The new price of these same packages now is about $4 or $5, although there are far fewer of them used today. The extra gold we removed from the gold brazes (80/20, Au/Sn for the lid; about 96/4, Au/Si for the chip) nearly paid for our processing. At that time, when the companies put out a new chip, the early manufacturing reject rates were as high as 98%

The business ended in '74 (I think) when Nixon devalued (10%) the dollar twice and there was a 6 month dock strike. The electronics industry died. No parts could then be shipped to or from from the overseas assembly facilities. Right before the strike, a company in Texas promised us 100,000 parts per day. When the strike hit, they went down to 5,000 per week. We shut our doors. Oh well.

The same process can be used for high dollar ($10 to $1,000), all-gold, hybrid packages, which are used widely today in specialized applications. The process costs are about the same as on the cheaper packages and the 50% charge still applies. Lower volumes, lower setup costs, much higher profits, on the hybrids. I set up a small hybrid process in '80. We rented a booth in a ISHM show (International Society of Hybrid Microelectronics). We laid out about 20 different before and after packages on black velvet and got over 100 electronic companies that were interested in our wares. However, at that time, my main business was gold and silver refining. 1980 was also the year that the PM prices went through the roof. We sometimes had 20 people waiting in line, when we opened the door, to sell us gold and silver scrap. There just wasn't any time to concentrate on the packages.

As far as I know, no one else has ever come up with viable process to rework these packages. There are a couple of patents out, but they require a lot of hand work and are far slower, much more expensive, and inferior to mine. I didn't patent my process but it's still in my head (and in my head only, I think). My process is still very viable.

About once a year, I feel a need to rant about this. If only that frigging dock strike hadn't happened! Oh well.


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## Irons (Oct 10, 2007)

I remember some of those old white ceramic 40 pin dips that Intel used. They had so much gold on the pins, you could literally shave it off with a knife.

Wouldn't it be nice to have a few tons of those.


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## goldsilverpro (Oct 10, 2007)

There were white ones and purple ones. We also did 14, 16, 18, 24, and 28 lead sidebraze packages. There was about 50 to 60 millionths of an inch of gold plating on them. This is the thickness required to prevent degradation and discoloration at die attach temperatures. The gold plating is 9999 pure. The same packages are used today with the same amount of gold. You can see them being offered for sale on the websites of package manufacturers - Kyocera, etc. I don't know where they're used today. Probably on military applications, etc. I think they (and the hybrids) are still the most reliable, long term, package made.

New side braze, hybrids, etc.:
http://www.ntktech.com/products_scd.asp?categoryid=13
http://www.chelseatech.com/packages.htm
http://www.spectrum-semi.com/index.html
http://www.addisonengineering.com/HTML/ceramic-packages.html
http://www.amkor.co.kr/products-sidebraze.html

New Hybrids, etc.:
http://www.twmtech.com/hybrid.html
http://www.inseto.co.uk/products/micromaterials/centuryseals-hermeticpackages.shtml

Old stuff:
http://www.cpu-collection.de/?tn=0&l0=md&l1=1975&l2=Intel#C8080A
http://cpu-museum.de/?m=Intel
http://www.chips.5u.com/

I have, literally, had tons of them. Ah, the good old days, when a package was a package and I was right in the middle of things.


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## Irons (Oct 10, 2007)

I know the ones of which you speak. The type i'm referring to look like the leads were hot-dipped in Gold and you could cut off a curl with a knife.


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## Redders (Oct 10, 2007)

Hi Redders, 

If Harold V concluded that I don’t have a clue as to what I have seen over the years, he has to go there himself and observe it.

I am not going to argue over something petty which I know is true.



If his reasoning is sound, why would anybody lie over trivial matters such as primitive procedures in recovering gold from obsolete IT equipment?

Why would someone lead you down a path over nothing? Your guy makes hasty conclusions. Or he must have a very high regard of himself

and thinks that anybody who contradicts his beliefs is a liar. 



From your description of the procedure, what he should have questioned as amiss is “incinerating in a cast iron crucible” because

the iron will melt with the material being recovered. The crucible is made out of a type of clay, not iron, which sometimes cracks during the 

firing process and has to be cooled and redone again



Obviously, your Harold V hasn’t tried this procedure of recovering gold from processors because of the following errors in his statement:

1) that the molten mass will not “permit the gold to occupy any particular place in the mass such as the center”. Well it does everytime!!!

2) that the “ceramic” in the processors will stay on top of the molten alloy because the gold and lead, either combined or individually,

weigh far more. (I suppose, Mike, if the processors are finely grounded, the “ceramic” material will float, but you did say in your

email that the processors (chips) are broken up into large-ish pieces, in which case they stay at the bottom of the crucible.



May I suggest he try the procedure first and if he is wrong, apologize. All the best, Roly


(Harold, Redders, here, I am not stirring you both up for fun. I respect both of you and I know that there is no bullshit with either of you two good men).


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## goldsilverpro (Oct 10, 2007)

Redders,

When I read your first post, I thought something was missing. Are you sure they're not adding something to the lead to collect the gold, such as aluminum or maybe zinc, as in the old Parkes Process? That would make more sense to me. Sometimes, people making money from a process don't give you the complete story. In fact, when I was a refiner, I was often guilty of this.
http://en.wikipedia.org/wiki/Parkes_process

I know you will get a little stratification when metal slowly solidifies. For this reason, metallurgists have developed drilling patterns to use when sampling bars. When you vacuum tube sample impure gold in the melt, you have to stir it well first to eliminate any slight stratification. But you're talking about a fairly clean separation using nothing but lead. I have some vague thing in my mind that says that some sort of separation is possible by controlling the temp. to a gnat's ass and thereby solidifying only certain parts of the melt, while other parts are kept liquid.

I don't doubt that this is somehow being done in the Philippines. I am very interested in how it works. However, it seems that your explanation leaves a lot to be desired. You gave no details at all on *how* to really do it. You didn't give us any info on *why* it worked. The statements you gave made no technical sense at all. I know you're smarter that that. On this forum, no one is going to accept a vague blanket statement without calling you on it, especially if it makes no technical sense at all. 

And, just out of curiosity, why did you say they used cast iron, when you knew they used clay?

If you don't know why it works, please, at least, enlighten us more on how it works.


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## Redders (Oct 10, 2007)

I am, in fact, a 'newbie' and I was just wanting to take a bit of an active part by putting something up here that would be interesting to you 'old hands'. I will copy this thread again and email it to Roly and I will see if he will come on here and discuss it with you.

I have to add that Roly is the owner of the business and he spends most of his time purchasing. He employs the gold reclaimers in Manila but they have more gold-recovery expertise that him.

I will contact him now and give him a link and my password and see if he will join us.

(by the way, thanks for all of your posts, I appreciate yours (and others).....


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## aflacglobal (Oct 10, 2007)

Ok, this is going to sound crazy, but i think their might be some madness to his method. Or is it the other way. Dam voices.

He said they raked the hulls out the bottom and skimmed the slag off the top. This sounds exactly like a sweat furnace he is describing here.
I sweat furnace is used to reclaim metals from such things as copper and aluminum motors, Irony aluminum transmissions and alternators. Ect.

The term sweating is used because the material is brought up to just above the melting point and the metal begins to melt or sweat like butter from the objects.

Now this helps that maybe. 

The clay pots they are using is also basically refractory. He said they cracked and had to be repair frequently. This sound about right .

Next i guess we need to look at bouncy and density of metals. ( Chris you got this one )
I know some what how they behave in aqua solutions, but molten solutions behave different. Remember we learned from the guy that wrote me from South America that they melt catalytic converter material in a induction furnace and the metals all concentrate at the center of the mix. That's how they would concentrate thousands of pounds of material into several KG.

I'm wondering, He said they leach ( Basically ) melted the crushed up processors if you really think about it. Using heat instead of liquid.

Could the copper maybe that’s in the material form a bond like in solution.
He said they reheated it. If you only raised the temperature up above the melting point of lead would the copper or gold complex settle.

I remember a demonstration in high school where we took mercury and put quarter in it. They floated. Why ? The mercury is a liquid and the quarters being solid should sink. Hummmmmm Density. :idea: 

Just some thoughts.

Oh yeah, He's using something more than just a regular fire. Maybe some bellows ?


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## goldsilverpro (Oct 10, 2007)

Redders,

That would be great to get Roly on the forum. I'm really pleased that you are taking this well. We would hate to lose you. 

Don't get mad at Harold. He is often blunt and he's not going to let anything slide by (Don't ask me how I know this!). But, I've gotten to know him pretty well and I can assure you that his heart's in the right place. His only purpose on this forum is to help people.


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## Redders (Oct 10, 2007)

I also feel good about Harold. We swapped emails for a fortnight as he nursed me through the production of my first proper button. He has the runs on the board and he can be a cranky bugger if wants to be.... no bother, here.


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## Harold_V (Oct 11, 2007)

aflacglobal said:


> I know some what how they behave in aqua solutions, but molten solutions behave different. Remember we learned from the guy that wrote me from South America that they melt catalytic converter material in a induction furnace and the metals all concentrate at the center of the mix.



Yes, perhaps, but with an induction furnace. The force that would cause levitation of the metallics would be absent in the process mentioned. There is no reason for the gold to concentrate in any place in particular -----not in lead----nor can you, or anyone, present a reason that might suggest a reason it would. Fact is, if the charge mentioned was to be melted by induction, it would be stirred exceedingly well, with the gold perfectly distributed within the lead. 

I've been told on many occasions that it's real easy to separate gold from other metals. All you have to do is melt them, and the heavy stuff will sink to the bottom. 

It just ain't so, folks, so get that out of your head. Once alloyed, most metals are NOT easily separated from one another. 

Harold


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## Harold_V (Oct 11, 2007)

Redders said:


> 1) that the molten mass will not “permit the gold to occupy any particular place in the mass such as the center”.
> 
> Well it does everytime!!!



Words are cheap. I deal with facts. I assume you can provide a picture, at the very least, of this phenomenon, and explain why it violates known principles?



> 2) that the “ceramic” in the processors will stay on top of the molten alloy because the gold and lead, either combined or individually,
> weigh far more. (I suppose, Mike, if the processors are finely grounded, the “ceramic” material will float, but you did say in your email that the processors (chips) are broken up into large-ish pieces, in which case they stay at the bottom of the crucible.



Maybe I'm not fully understanding this, in part because it's not clear who's quoting what, but if the implication is that the pieces of ceramic do anything but float, this conversation has gone over the edge. Breaking a substance into smaller parts does not change its specific gravity-----and anyone that has enough sense to come in out of the rain knows that light things float on heavy things, regardless of size, assuming they don't create buoyancy through displacement (such as a steel-hulled boat). The exception, of course, would be if the metals were being sweat, but that has not been claimed at this point. It's unlikely that is the case, for the sweat furnace constantly runs molten substances to a holding vessel, which would have to be kept fluid until completion of the run. Even then, I'd like one reason why the gold would accumulate in the center. 

Understand this, anyone that cares enough to read my words. I am a person of fact, and am not easily caught up with bullshit claims. I have recovered gold by known means, and have seen the results of efforts of those that think they are clever and can violate the rules and succeed in their quest. To this point, I have seen nothing here that makes sense aside from melting items with lead to effect a recovery of values. The magic gee wiz claims of gold seeking the center of a common mass makes no sense-----none------and violate everything I've learned about the principles of metals in my many years of not only refining, but machining and foundry work. 

It is not incumbent on me to pursue a matter that makes no sense. If you'd like me to have a different opinion, address the issues I've raised, and present some evidence that the asserted claims work. Otherwise, leave me out of this discussion. You asked my opinion, and I gave it. Right now, I'm calling bullshit. 

Harold


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## Harold_V (Oct 12, 2007)

aflacglobal said:


> He said they reheated it. If you only raised the temperature up above the melting point of lead would the copper or gold complex settle.



No, they would not, and there's no reason for them to do so. They are also not simply copper/gold complexes. They are a sum total of all elements that are included, *assuming they will willingly alloy*. You have to understand that molten metals are much like water in that they have considerable solvent capabilities. 

Lead is used for two reasons, which I feel can be substantiated by GSP. It is introduced to an assay sample as litharge, which is reduced to elemental lead upon heating, liberating oxygen, which then oxidizes other substances, oxidizing them. The molten lead then collects miniscule traces of values that otherwise might not have agglomerated and reported in the assay. 

Once molten, the lead, which may never achieve the melting point of gold or platinum, dissolves these elements, along with others, and forms an alloy. Once combined, the eutectic point is established and all elements will then melt at that temperature when reheated. You can not (normally) selectively melt one metal from another. 



> I remember a demonstration in high school where we took mercury and put quarter in it. They floated. Why ?



That's a no brainer. The specific gravity of silver is lower than the specific gravity of mercury-----so the lightest substance floats on the heavier one. I think I said that already. Not only does it float on the mercury, but it is slowly dissolved by the mercury as well. Given enough time, the entire coin would be consumed by the mercury, assuming there is enough mercury present to hold in solution the amount of silver and copper present. 



> Oh yeah, He's using something more than just a regular fire. Maybe some bellows ?



Any maybe the hair from three frogs and the hide from a black cat?

We're men of science here, not witch doctors. The source of heat, unless it's an induction furnace (which introduces strong magnetic forces to the heat), makes no difference. 

For your consideration: The idea of gold accumulating in the center of lead is not impossible, but highly unlikely. Zonal refining works on that principle, but under well controlled conditions. If it was as easy as it's been presented, it would be difficult for foundries to pour castings that were homogeneous. They don't suffer that fate. 

Harold


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## aflacglobal (Oct 12, 2007)

If it was as easy as it's been presented, it would be difficult for foundries to pour castings that were homogeneous. They don't suffer that fate.

That makes sense. :wink:


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## goldsilverpro (Oct 12, 2007)

LEAD REDUCTION

I haven't looked at the chemistry of fire assaying for quite awhile but, concerning the reduction of litharge to lead metal, and the subsequent release of oxygen, here's what I remember. 

The heat is not what causes the litharge to give up it's oxygen. This is shown in the scorifying process. One purpose of scorifying is to reduce the weight of a lead button to a convenient size so it can be cupelled. This is done by melting the lead in a shallow wide dish, called a scorifying dish. The oxygen in the air oxidizes the surface of the lead to form litharge, lead oxide. The longer this is done, the more the lead oxide will be produced and the less the weight of the lead metal that remains at the bottom of the dish. The point is that the heat does not re-convert any of the lead oxide back to lead metal. Also, all of the precious metals that were originally in the lead metal, before scorification, are now retained in the lead metal (most probably, very uniformly) that exists, after scorification. None goes into the lead oxide phase.

Reduction of the litharge, and the subsequent release of oxygen, requires some ingredient in the fusion melt which will act as a reducing agent. Commonly, this would be carbon, sulfides, or iron. Ideally, when assaying electronic parts, the fusion should result in a 30 gram chunk of lead. If no reducing agents are inherent in the sample, an exact amount of lead can be reduced by adding an exact amount of some ingredient that contains carbon. Sugar, flour, or charcoal are commonly used. I learned to use sugar when I started. If I remember right, 1.4 grams of sugar (depending on the brand) will produce 30 grams of lead. I think that the ancients used lees, a substance that settles out in wine. A couple of times, I forgot to add the sugar. I ended up with no lead button - zero. All of the litharge had gone into the slag.

CERAMICS AND LEAD

In my days, I have assayed many 100's of PM containing, ceramic electronic component samples. With no exceptions, the ceramic pieces, large or small, floated above the lead. If I remember right, the ceramic even floated on top of the slag which was on top of the lead. If any ceramics had sunk into the lead, this would have made cupellation of the lead impossible.

THE REFINING THRILLA IN MANILA

I'm no longer a betting man (unless it's on my pool game) but, I would wager that zinc (or maybe aluminum) is being added to the lead to get the gold out - the old Parkes process. This may be done through sleight of hand. It's the only thing that makes any sense to this whole thing. It sort of fits into the original explanation. It's a fairly dangerous process since, at the end, to get rid of the excess zinc in the silver, it is evaporated off into the air by heat. 

POOL - A MISSPENT YOUTH

In case there are any pool players out there, here's an article I wrote that may interest you. That's my brother in the picture that was taken a couple of years ago. My brother and I play Corners every Friday night on the six pocket pool table in his basement (for only a measly dollar a game). Playing Corners on a six pocket table is kinda like kissing your sister but, all the 2 pocket tables are gone from the pool halls. I could play it on the 2 pocket Corners table at the Elks lodge but, every time I go there, I seem to get into trouble, at least in my own mind.

http://onepocket.org/Corners.htm


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## Harold_V (Oct 12, 2007)

Thanks for the clarification on cupellation, Chris. 

Aside from having done a little with a torch, I never got involved. I did no assaying in my years in the refining business. I relied on the expertise of local assay labs, all of which are now defunct. 

Harold


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## Redders (Oct 12, 2007)

Ok Mike, hereunder is the complete procedure for recovering Au from processors as I have observed:



STEP ONE

1) break the processors (cpus) into smaller pieces (not too small) with a hammer. Make sure you can collect even the tiny pieces .

2) The minimum ideal quantity is about 10 kgs of processors; once all broken up, put in a clean container, separating the “gold plated lids” from the other broken pieces;

3) use a crucible (in the Philippines, made of clay, oblong shape, approx 30 cm x 40 cm), sit it on a bed of sand, heat it up, using fire from two separate tubes, one dispensing kerosene and

the other tube dispensing air from a compressor. Once lit, the resulting fire can be controlled by the amount of air coming out of the tube; the fire should be from the

top of the crucible; 

4) put powdered “borax” (handful will suffice) into the crucible; then put about 3 kgs of processors, then add 10 kgs of lead (for easy handling, the lead are either pellet size or washer size.

It doesn’t really matter what shape or size because in the heat, the lead will melt quickly;

5) mix every now and then for about 30 minutes to 1 hour, observing if the metal pins or legs underneath the processors have melted;

6) remove the “ceramics” from the crucible using a metal bar hook-shaped. Fish the ceramics slowly so the molten metal stays in the crucible;

7) add another 3 kgs of processors, and repeat the process, until all the processors are done;

8) the above procedures are done while the heat is constantly on;

9) when the last of the processors’ ceramics are removed, as well as any slag on top are removed, keep mixing while maintaining the fire;

10) let the mixture settle (while the heat is still on) for about 5 to 10 minutes;

11) using metal tongs, slowly tip the crucible, allowing a tiny amount of molten metal, out. Additionally, to continue the flow out of the crucible, use the metal bar, tap lightly into the liquid metal, allowing it to flow out of the crucible.

12) Turn off the fire (kerosene), but not the air. The result is a gust of smoke containing lead gas. After about 3 minutes, light the fire again. Max heat the molten metal. At this stage, the center of the molten metal will have a different color from the surrounding liquid. The center will have a light yellowish color with black streaks occasionally emanating from the center. The surrounding liquid metal will have a brownish dark color; the center is where most of the gold is, the surrounding area is mostly lead;

13) Keep repeating the process of slowly letting a little amount of molten metal out of the crucible while rotating it counter-clockwise. Turn the fire off and on to let lead gas out;

14) Eventually, you are left with the center. At this stage, turn off the air and kerosene supply.

15) Let the molten metal cool and solidify. At this stage, you may have around 200 to 300 grams of solid metal (“nugget”), depending on when you stopped the thinning process



STEP TWO

1) using a smaller crucible, say 10 cm x 15 cm, heat it up, add a handful of borax;

2) at this stage, you will need SILVER three times the weight of the “nugget”; add the gold plated lids as well, melt together in the crucible;

3) max heat till thoroughly mixed;

4) prepare a small drum, filled with water, just below the edge. Let another guy stir the water with a paddle in a round like motion;

5) pour the molten metal (nugget and silver) into the drum of H2O; the super heated crucible is picked up with metal tongs;

6) the result is “popcorn” metal, containing, gold, silver and other metal remnants;



STEP THREE

1) Using a stainless steel bowl, put the “popcorn” metal over a gas stove. Using a plastic cup with handle, pour nitric acid into the bowl with the popcorn. The reaction will be instantaneous, 

lots of toxic smoke. The process will have to be repeated several times. The intention is to remove the silver and other metals eventually leaving the gold which appears as brownish mud or ovaltine like

material. Mike, I am not going into details here now as I am sure the other guys know what follows.



I’ll talk to you soon,



Best regards,

Roly


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## goldsilverpro (Oct 12, 2007)

This was a long drawn out post, that said nothing, that I decided to summarize. 

All in all, this seems to be a shallow crucible about 12" X 16". When 10kg of lead and 3kg of parts are put into it, they would only be about 1" deep


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## lazersteve (Oct 13, 2007)

This process can best be likened to large scale cupellation. The lead is being oxidized to litharge which gathers the base metals in the borax. The molten lead gathers the gold and the air re-oxidizes the lead back to litharge which in turn oxidizes more base metals to be removed by the borax. 

The resulting 'nugget' is bound to contain considerable amounts of impurities. This explains the need to cornflake and inquart the resulting nugget with silver.

My only question is why doesn't the lead stay alloyed with the gold? In cupellation the lead oxide* is absorbed by the cupel. Does the clay crucible absorb the lead oxide *?

It would seem a lot cheaper/easier just to dissolve the copper with your nitirc or AP and skip the cornflaking and inquartion. Especially when you consider the toxicity of lead and it's vapors. Then process the resulting gold powder/foils as usual. You'll also save the cost of the lead, the kerosene, the power for the compressor, borax, silver, and the environment.

Steve

*Corrected lead to lead oxide Thx GSP.


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## goldsilverpro (Oct 13, 2007)

Steve,

In cupellation, the lead doesn't go into the cupel. The furnace door is cracked open a bit to allow a little air in. The air oxidizes the surface of the lead. The lead is rounded up in a convex meniscus. The lead oxide (litharge) formed slides down off the meniscus and is absorbed by the cupel. Any base metals are oxidized and also absorbed. The cupel absorbs oxides but not metals.

The borax is removed in step 9

Lead oxide is yellow. He says the center turns yellow following the air.


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## lazersteve (Oct 13, 2007)

So where does the lead go here? Up in smoke and into the flux?

Steve


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## goldsilverpro (Oct 13, 2007)

Are you thinking the crucible is a big cupel? Interesting. Cupels can be made mainly with Portland Cement, which is pretty strong.

Silver used to be removed from lead in a big 5' diameter cupel furnace. Except, the lead oxide was removed from the surface by skimming, I believe.


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## lazersteve (Oct 13, 2007)

Not the same container material just a similar process on a larger scale. 

I still don't understand why the gold doesn't alloy with the lead.

Steve


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## Harold_V (Oct 13, 2007)

That's as close as this entire concept has come to making any sense. It's a far cry from the original statement of gold accumulating in the center of lead, which is poured off, leaving the gold behind. 

Assuming that's what's happening, didn't I make mention that lead is usually removed via cupellation when it's used as a collector? I get the idea that the person relaying the information isn't privy to what's really going on. 

Harold


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## goldsilverpro (Oct 13, 2007)

The gold has to alloy with the lead, unless something like zinc is added. That would be the simplest way to get it out of the lead. If I were to do this idiocy, that's the way I would do it. The zinc doesn't alloy with the lead, at all, and silver has a 3000 times more affinity in zinc than in lead. The Wiki article says gold works the same way.

I still think zinc could be the hidden ingredient.


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## Platdigger (Oct 13, 2007)

Hey guys,
I may have an idea why this works. With the exception of the first lead that is poured off, this could be the deal. 

When they shut off the kerosine for 3 minutes at a time, obviously lead is oxidized. Especialy since the air is left on. Much of the lead oxide going up in smoke.

Now, when the fire is relit, if this is a reducing flame, oxidized lead is rereduced. 

Now, without stirring this newly reduced lead shouldn't have much gold in it besause when it was oxidized the gold stayed with, (if you will) the formerly reduced molten lead. Or, the lead that was not oxidized.

OK, this newly reduced lead should be on the outside, at least at first.

Now, if this newly reduced lead was being carefully poured
off.............yea?........ 

......therefore more and more gold is concentrated to the center as this process is continued.
Think?
Randy


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## Platdigger (Oct 13, 2007)

In other words, it is the inertness of the gold, not being oxidized with the lead when the kerosene is shut off......that makes this process work.
Randy


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## goldsilverpro (Oct 14, 2007)

Maybe, Randy. 

Most of the primitive refining processes that I've seen are based on old mining methods.

I just read about an old method of separating silver from lead called the Pattinson Process. It was the state of the art in the mining industry from 1833 to 1850, when it was supplanted by the Parkes Process (the zinc process that I've talked about). This was based on the fact that pure lead had a higher melting point than a lead/silver alloy. The lead/silver was vigorously stirred as the temperature was reduced. A little below the lead melting point, fairly pure lead, containing little silver, crystallized out. The liquid phase contained most of the silver. 

According to T.K. Rose and, in looking at the phase diagram, it also worked for gold.

Are the pins on these processors made of copper? The lead-copper phase diagram sure looks a lot different. With any amount of copper in the lead-copper alloy, the melting point is higher than pure lead.

Unfortunately, I couldn't find a ternary phase diagram of a lead-gold-copper melt system. This might be the answer.

If the pins are Kovar (Fe, Co, Ni), that would really make it complicated

It could be a combo of cupellation (from Steve), Randy's idea, the phase diagrams, or whatever. Who knows. My brain hurts.

Since no once else has posted on this for awhile, I assume we give up. So, Roly, it's time for you to give us the complete technical details of why and how it works. 

*Another thought.* 

We all agree that, when the air is blown on the surface, lead oxide is produced. Lead oxide has a melting point of 1630 F and it's color is yellow. If anyone can figure out why the gold would be combined with the lead oxide, that may be the answer. Maybe, with all that copper (or Fe, Co, Ni) in the lead (possibly the brown color), at the high temperature, the gold is forced out of the lead and combines with the molten lead oxide (Randy). My brain hurts even worse.


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## Platdigger (Oct 14, 2007)

Molten lead oxide? I thought lead had to be reduced to be molten. As with any metal.
Randy


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## goldsilverpro (Oct 18, 2007)

Lead oxide, as a chemical, will melt at 1630 F. It doesn't have to be reduced to lead metal first.


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## Rhodium (Oct 6, 2009)

:mrgreen:


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## qst42know (Oct 8, 2009)

This method is more or less a scorification process. It is described by Fulton beginning on page 123. It is also very simillar to the Perkins Excess litharge assay method. described on page 116.

http://books.google.com/books?id=AJANAAAAYAAJ&pg=PA193&lpg=PA193&dq=fulton+fire+assay&source=bl&ots=c4KBsC_rH4&sig=mN2C4OqAc4HnZHJ_zgkHX7S6AYc&hl=en&ei=7F7NSqP-Bomm8Aap0-juAw&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=assay%20of%20impure%20ore&f=false


I have used this primitive technique several times (before I knew better) on these chips. The surplus lead oxide can be poured off, it is very fluid while hot but glass like when cooled. Ceramic pieces do want to float but will often get stuck to the bottom and sides. As a primary collector of gold it does work though not very efficiently. Most of these tiny buttons started from a scorification.

As far as the chemistry involved I can't explain it, but in another chapter in the same book they describe the formation of borates of various oxides formed being important to the process.


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## T3sl4 (Oct 9, 2009)

FYI, if you have just lead and gold, the eutectic will be moderately rich with Au, while the Pb crystallizes out at a fairly high temperature (my graph shows the eutectic at 488K, while lead melts at 600K). If the lead is cooled slowly, possibly directionally, then solid, fairly pure lead (99.9%?) can be seperated from the rest. Especially if zone refining is employed (remelting a zone from end to end, repeatedly, in the same direction).

What little eutectic is present would indeed solidify in the center (if just cooling in a crucible).

This method is plausible if the lead is reused, so that the concentration of gold in solution remains fairly constant as gold-bearing lead is removed and more gold added.

Tim


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## qst42know (Oct 9, 2009)

This should only be seen as a very crude means of collecting the gold values together. The beads shown were cupeled to remove the great excess of metallic lead. Before cupeling it only looked like a ball of lead covered in slag. None recovered from scorifying alone ever resembled gold at all. At no point in the process did it ever appear to be separate metals.

Refining? not really. A very coarse recovery? yes.

A eutectic may theoretically exist on a chart, but if you could reach that point control and sustain it for a period of time what would you do then? Motion alone can change a crystallization point.


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