# Glycerin



## Smitty (Nov 5, 2007)

What is the purpose of Glycerin used for in the reverse electroplating process?

Can I use Glycerin,usp found in walgreens labeled under the brand Fleet if I am not able to get lab grade Glycerin locally?


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## goldsilverpro (Nov 5, 2007)

Has anyone ever tried this without glycerin? Someone should try it. If it doesn't work without it, you can always add it. I used the sulfuric stripper, on a grand scale (up to 500 gallons), for 30 years, without any glycerin.


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## Noxx (Nov 5, 2007)

I think it's used to reduce the water surface tension. This way, gold does not float. Or maybe it's something else ?


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## Smitty (Nov 11, 2007)

I figure it was used to prevent the corrosion of the alligator clips or splashing. The gold should sink anyway regardless of the surface tension right? I Noxx's point of view because there are no chemical reaction between the Sulfuric acid and Glycerin. I hope Steve reads this, I know he can shed some light on this subject.


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## lazersteve (Nov 11, 2007)

I've stated this many times before, but it bears repeating. 

The original recipie that I have called for a small amount of glycerin (1/16 teaspoon = 0.31 mL ) per cup ( 236.6 mL ) of concentrated sulfuric acid. 

The recipie did not explain what the purpose of the glycerin was, but I used it to follow the recipie. 

I have tried the cell with straight concentrated sulfuric acid and it works.

Steve


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## eagle2 (Nov 13, 2007)

Noxx said:


> I think it's used to reduce the water surface tension. This way, gold does not float. Or maybe it's something else ?


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## eagle2 (Nov 13, 2007)

eagle2 said:


> Noxx said:
> 
> 
> > I think it's used to reduce the water surface tension. This way, gold does not float. Or maybe it's something else ?


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## eagle2 (Nov 24, 2007)

Glycerin as an additive is used to reduce the ionic tension at the cathode. This results in a denser more adherent plate of the metal that happens to be in the electrolyte onto the cathode. There are many better additives, but usually they are proprietary. The better plating action supposedly keeps more of the base metal off the bottom where the gold is. My electro-winning cell for gold plate uses sulfuric acid about 4 molar with distilled water, some glycerin and a surfactant called triton x-100. I have a power supply that needs to be limited to about 10 amps, so it has two ohms of resistance in series in circuit. Never-the-less I can strip the plate off a large object in about 5-10 minutes. This is still a tedious business and I don`t use it much. Also, the electrolyte always gets overloaded with base metal sulfates too quickly, no matter how quick you are with changing anodes. I am very thankful for finding this site with the tips and huge amounts of priceless info. Thank you all! And by the way never use an additive in a silver nitrate - silver recovery cell, because you want to easily scrap the coating off the SS cathode.


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## PhillipJ (Nov 24, 2007)

So Eagle. You're saying that glycerin will help copper or nickel stick better to a cathode.

But in a de-plating cell, with a lead anode, nothing seems to go onto the lead anyways.

Do I dare add glycerin to my copper & nickel plating tanks?

What do you think of this GSP?


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## eagle2 (Nov 25, 2007)

Hi Phillip. I think you mean the cathode. That`s where the plating takes place. There was a guy named jason on e-bay selling info and setup materials for a electrowinning-cell. He used concentrated sulfuric or battery acid and a lead cathode. You have to use lead, it holds up in strong sulfuric. I bet most got this recipe there or passed it on from one to another. 
It`s unnecessary and dangerous to use strong concentrations of acid. you always get fume and spray. He ran the battery charger wide open. You still get all the current you could use with dilute solutions. To get a good plate you want to watch the current density. that means running the cell at 2-3 volts from cathode to anode. I`m not into additives, but I think you can find a lot of info on just googleing keywords. To just strip gold plate you can run a higher voltage, but protect yourself from the fume. I use a copper cathode, and get sticking. But still scrape any black residue off it. Your always going to get copper mixed in with the gold. I don`t melt, but always use chemical separations. 
Sorry, I don`t know what GSP is? --- Al


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## lazersteve (Nov 25, 2007)

Eagle said:


> There was a guy named jason on e-bay selling info and setup materials for a electrowinning-cell. He used concentrated sulfuric or battery acid and a lead cathode. You have to use lead, it holds up in strong sulfuric. I bet most got this recipe there or passed it on from one to another.



That guy started selling cell plans modeled after Loren's. I bought Loren's plans a full year before Jason ever started selling electrolytic cell plans on ebay. Jason's first auctions actually used Loren's ebay photo for his cell plans auction until Loren called him on it.

All that being said, there are so many variations of the cell, and the electrolytic cell has been around longer than any of us.

Steve


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## PhillipJ (Nov 25, 2007)

Kinda odd in Hoke's book that it said de-plating gold was in the process by Western Electric at the time of printing. You'd of thunk that would have been figured out in the 1800's.


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## goldsilverpro (Nov 25, 2007)

I started using the sulfuric cell in 1971. I first set up a 50 gallon tank. I used the same solution every day, without replacing it, for about 2 years. About the only common metal that will foul the solution is nickel.


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## eagle2 (Nov 25, 2007)

Hi Steve. Thank you for the info. I never met Lorens, But yes the E-cell has been around a long time with large variations. I even read a scientific article describing some aspect of electro-refining and the author said its yet more of an art than fully laid out science. 


Hello Goldsilverpro! My Cell is a glass 3 gallon fish tank. When I tried stripping small gold plated objects such as pins and small flat pieces, the gold came off unevenly. If I waited till all the gold was off I knew a lot of copper was going into solution and on the bottom. Also, much gold plate has a plate of nickel over the copper base, then the gold plate. After about 30-40 hours the current flow drops off. Cleaned out the cell and put the electrolyte back in. I then use a carbon anode to plate out the base metals in solution and reuse it again. Now if I use it that way, its only for large objects. 
You say that you didn`t hardly ever clean out the solution. What did you have for anodes? Did you use 50 gallons of concentrated sulfuric?

Al


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## goldsilverpro (Nov 26, 2007)

*PhillipJ,*

Somewhere, I have read of glycerin being used as a grain refiner for certain plating baths. However, I certainly wouldn't add any of it to your nickel or copper baths unless the original formula called for it, which is very doubtful. Plating formulas are pretty much carved in stone and it's best not to tinker with them. Plating success depends on following the original formula to a T and keeping the ingredients well within the suggested ranges. To do this right, you really need to be set up to analyze the bath ingredients.

*eagle2,*

I'm GSP

Welcome to the forum. I shouldn't rub it in to a Kansan, but I sure liked the outcome of the MU/KU football game Saturday night. It got pretty scary at the end, though. And now, Mizzou is #1 in the polls! I thought I'd never see that in my lifetime. Go Tigers. 

I covered my version of the sulfuric process in this thread:
http://goldrefiningforum.com/phpBB3/viewtopic.php?t=226

I think you're making a mistake by using weak sulfuric. As I understand it, you're using 4 Molar, which is only 20-25% sulfuric. This is why you're having problems with the copper dissolving and plating out. The stronger the sulfuric, the less copper (or, anything else) will dissolve. 

I always used concentrated (~96%, by weight) technical grade sulfuric with about 5% to 10% water, by volume, added (add the acid to the water!!). You need a little water to perk up the speed. A 10% water addition, by volume, is equivalent to about a 5% addition, by weight, since the sulfuric is almost twice as heavy as water. Conc. sulfuric can be used without the water but, a little water will speed it up. If you're in a humid climate, only use 5% water as the sulfuric will absorb water from the air.

I daily stripped the gold and gold braze from reject, sealed, side-braze CPU packages in this system, at the rate of about 50,000 to 100,000 of them per week. This was a commercial venture. I mounted them on bare brass or copper racks, using piano wire spring contacts to hold the parts. There was little or no attack on any part of the rack, tank, or other portions of the packages, when using the strong sulfuric (it was slightly modified - my invention - in order to strip the brazes). I then re-plated the packages and returned them to the customer for re-use - Intel, AMD, and AMI were my biggest customers. We basically recycled their reject parts, for re-use, and charged them half the cost of a new package. Since most of the gold value was in the brazes used on the chip and the sealing lid, we removed much more gold than we put back on. The extra gold recovered essentially paid for the process.

I used a 50 gallon welded mild steel tank and made the tank the cathode. After using it daily, at room temp, for about 2 years, there was hardly any visible attack on the tank, except a little at the solution surface, where the acid, the steel, and the oxygen in the air all met. Don't use stainless - it will be slowly eroded, due to the presence of the Cr and Ni. Nickel (and probably cobalt) is the bad actor in this system. If too much is dissolved, it will stop the action. I have thought about adding a little potassium dichromate to the sulfuric to inhibit the attack on the nickel, but I've never actually tried it.

Your use of a glass fish tank is scary. I sure wouldn't want 4 gallons of sulfuric in my lap. If you go to the strong sulfuric that I suggest, you must go to a steel tank because it will likely attack the cement that holds the glass tank together. Search around a scrap yard and you will find some sort of mild steel container that is just the right size and shape for what you need - cheap. I would try to find a container that is at least 1/8" thick.

When using the stronger sulfuric, you will get far less fizzing than you will with a weaker solution. The trick is to start the rectifier at zero and slowly crank it up. At first, the amps are high and the volts are low. After about a minute, the amps will drop, somewhat, and the voltage will increase. As you slowly crank up the voltage, the amps will first increase and then will decrease. At some point, when the gold is completely stripped, the volts will be at about 9 (or, higher, if desired) and the amps will be zero. At this point, all of the gold is stripped. This won't work with a more dilute sulfuric because it will continue to attack the base metals and will therefore continue to draw current.

With the stronger sulfuric, nothing deposits on the cathode (the mild steel tank). The gold forms as a powder and settles to the bottom. The solution is then drained off and the gold is easily recovered and then refined in aqua regia.

I might mention, eagle2, that there's a hell of a lot of difference in concentrated sulfuric (96%+) and battery acid (about 40%) in this system. The battery acid will dissolve almost everything. Conc. sulfuric, with a little water, will only essentially dissolve and precipitate the gold. There will only be very minor amounts of base metals in the gold sludge.

When using the conc. sulfuric with only 5-10% water, by volume, regular gold plating will completely be removed in a minute or two. Sure beats 30-40 hours. With my modification to the solution, the gold brazes took about 15-20 minutes.

I've only dented the surface of this subject. I have maybe 20 years experience of working daily with this solution on a grand scale. I'm game, if you want to go deeper into this.



*TERMS:* My definitions. There are variations but these give the general idea.

*Electrowinning*. The electrodeposition of metals that have already been put into solution before the solution is put into the electrowinning tank. Uses an inert anode. Pure metal deposits on cathode. Impurities remain in the solution.

*Electrorefining*. Electrolytically dissolves an impure anode and simultaneously deposits pure metal at the cathode. Those impurities that dissolve remain in the solution. Those that don't dissolve are usually collected in an anode bag.

*Electrostripping.* Selectively removing a metallic coating, electrolytically. The dissolved metal either plates onto the cathode or immediately precipitates out, as in the gold/sulfuric system, above.


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## aflacglobal (Nov 26, 2007)

Great piece Chris. :wink: :wink: :wink: 
I take it the extra addition of the H2O is the oxidizer that drives the reactions you don't want to happen.

Word of caution :!: :!: :!: Chris is correct about the acid affecting the glue. I ran a little experiment. I went to Lowe's and cut a sample of all their hoses and then got plexi glass, Lucite, and other items to experiment with. 

I also tried a small fish tank. Wrong. :shock: 
My work top has a box made out of 2 x 6's and lined with a pool liner for just that occasion. Please watch it. I have gotten one or two spits of acid on me. That's all i need of that. :? 

I won't go into all the details. It is a little something i have been working on for awhile now. If you want to remove the base metals you should be able to do so by chilling the acid. I have a cooling compressor from a water fountain. I use a pump to circulate the water thru a series of glass tubes that surround the tubes that the acid runs thru after it leaves the stripping tank. The acid is then returned back to the tank to do its work again. It's modeled after a commercial method for etching boards.

I'm not using it in a reverse stripping cell though. I'm using it to strip copper from items. It's been kind of placed on hold while i chase the Barrick thing. I will pick it back up after the first of the year hopefully.


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## eagle2 (Nov 27, 2007)

Hi GSP; Thank You for all those tips. Well taken. 

Kansas will come back next year, you were lucky.

First my fish tank cell is close to three gallons. It is all glass, no seams. Has a plastic cover, I feel very safe with it. I can still do a limited amount of warming. 
Also, I can strip the gold plate in a few minutes, my solution has to cleaned in about 30-40 hours of use, because the current has dropped off and the cathode is full of deposits.

I am looking at my Merck Index, It has basic characteristics of most common chemicals. It states: Copper very slowly attacked by cold Hcl or dilute sulfuric acid; readily by dilute nitric acid and by both hot concd H2SO4 and HBr. 

Iron: Readily attacked by dilute mineral acids and attacked or dissolved, by organic acids; not appreciably attacked by cold concd H2SO4 or HNO3, but is attacked by the hot acids. 

Nickel: Slowly attacked by dilute HCl or H2SO4; readily attacked by nitric acid (I found Nickel would not dissolve well in nitric unless I heated it).
(Dosn`t state what concd H2SO4 would do to nickel.)

I take it then that you had to keep your tank and solution from getting hot. 

I have read electro stripping articles that describe the stripping action on gold plate or bullion. The gold never goes into solution in sulfuric. The underlying base metal is attacked through microscopic imperfections in the gold plate. These metals oxidize and go into solution. This loosens and breaks up the gold plate into fine bits. You can see the yellow glitter falling or floating. Some of its black. (thats why I like to use that Triton x-100 surfactant).
In the case where you have gold brazes or kt gold, the gold will be so fine that you see a black mud. And here the base metals have to go into solution or plate out; or if the solution is overloaded fall to the bottom with the gold . 

That 10% water you mixed with the sulfuric acid provided a place where the base metals could go into solution. The metal sulfates are ionized here and this increases the current flow. I think concentrated sulfuric does not ionize as well as dilute sulfuric.
I think it all depends on what your anode is made of, which helps you decide how to run the cell. Temperature also figures.

It does take a lot of experience! 

I`m going to try concentrated sulfuric in the cell with some CPU`s I have (10% water!). That was a great tip on the fact that CPU pins are electrically connected. I can hang them by one pin and zap em! The pins are magnetic and must be some flexible alloy of iron and cobalt. I had a previous tedious separation with ferric leach and a AR procedure with CPU`s. I had to get rid of a lot of ferric before I could precip the gold. This should be much easier. 

Thanks to everybody for all your comments, much appreciated. 
 ------- Al


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## eagle2 (Nov 27, 2007)

Oh GSP, I wanted to add I will also use a mild steel cathode in the cell. Thank You. ---Al


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## eagle2 (Nov 27, 2007)

Hi Aflac; Yes, chilling should work well on cleaning out solutions. I used a carbon anode and a copper cathode. It works. The carbon does erode and black bits fall to the bottom, but none of it goes into solution. You can leave it in and remove it with the next gold cleanout. Or drain the tank and remove it from the bottom. but I would hesitate if using concd sulfuric. ---- Al


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## macfixer01 (Nov 28, 2007)

eagle2 said:


> Hi GSP; Thank You for all those tips. Well taken.
> 
> ---Snipped!---
> I`m going to try concentrated sulfuric in the cell with some CPU`s I have (10% water!). That was a great tip on the fact that CPU pins are electrically connected. I can hang them by one pin and zap em! The pins are magnetic and must be some flexible alloy of iron and cobalt. I had a previous tedious separation with ferric leach and a AR procedure with CPU`s. I had to get rid of a lot of ferric before I could precip the gold. This should be much easier.
> ...




To Eagle2 (or anyone else who knows)... I was confused by your comment. What does the reference here to the CPU pins being electrically connected mean? Does this imply there is some high resistance connection perhaps between every pin on a CPU? I really don't think that's likely but I suppose it's possible? I can't say I've ever tested for that.

Thanks,
macfixer01


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## PhillipJ (Nov 28, 2007)

Hi Max. I have put CPU's in my recovery cell and touch the pins with a piece of wire connected to the + side of my charger. A lot of the pins will deplate. But not all of them. There seems to be a few here & there left gold coated. Also it's hard to tell if the gold is off because the black stuff in the cell kinda covers the gold plate.


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## goldsilverpro (Nov 28, 2007)

> I have read electro stripping articles that describe the stripping action on gold plate or bullion. The gold never goes into solution in sulfuric. The underlying base metal is attacked through microscopic imperfections in the gold plate. These metals oxidize and go into solution. This loosens and breaks up the gold plate into fine bits. You can see the yellow glitter falling or floating.



Hey, Al,

I would suggest you read the original patent on this: #2185858.
http://www.google.com/patents?id=L3FVAAAAEBAJ&printsec=abstract&zoom=4&dq=2185858
According to this, the gold momentarily dissolves due to the presence of persulfuric acid. It then immediately precipitates. I have read elsewhere that this is due to the presence of small amounts of sulfurous acid, which is basically a sulfite. Also, there is no such thing as the existence of gold sulfate in the strong sulfuric. *It has nothing to do with the acid penetrating though the porosity of the gold plate and attacking the underlying base metals.* In fact, the underlying base metals are hardly attacked at all. According to the patent, this is due to the formation of an oxide coating on the base metals. In practice, there will be very, very minor amounts of base metals co-mingled with the precipitated gold. This assumes that the concentration of the sulfuric is above a threshold strength. The patent says this threshold is 60%, but I really don't like it that weak - I would keep it much higher. Also, the patent suggests using nickel sulfate as an accelerator. I think this would be a big mistake, since too much nickel will completely stop the stripping of gold. If this happens, the solution is dead and you'll have to start with fresh solution.

I should also mention that there's no glycerin in the original patent. Down the line, some yo-yo added glycerin for some reason and this myth has perpetuated itself. Reminds me of the lady who always cut the end off on a big ham before putting it in the oven. She said she did this because her Mother had always done it. Come to find out, her Mother's oven was too small to hold a big ham.

The Merck Index assumes that the metals are just soaking in the acid. This is much different than when a voltage is applied. The voltage maintains this oxide film on the base metals. To prove this to yourself, make up a small amount of the conc. sulfuric with 10% water and run a piece of clean copper in it, at about 6V for, say, 30 minutes. After mixing the sulfuric, let it cool down first. Weigh the copper before and after. I would also suggest first to attach the lead and apply some voltage, before putting the copper into the solution. In other words, go in live.

Someone said that this is an art and not a science. I don't believe this at all. An art becomes a science when you can always predict the outcome. In this case, using the strong sulfuric, with a little experience, the outcome is 100% predictable. 

I never worried about the build up of heat in the solution. Probably, this was due to my using a 50 gal tank. With your 3 gal tank, you probably won't have problems with heat if you use the strong sulfuric. With weak sulfuric, the current is always high and the solution will continue to heat up. With the strong sulfuric, the current goes to zero, when the gold is stripped. This should also give you a clue that the base metals aren't dissolving.

I still hate the use of large glass containers, especially when heat is involved. In the early days, we used 5, 7.5, and 10 gallon Pyrex battery jars for aqua regia. Every so often, one would break - all by itself, it seemed at the time. It wasn't a pretty sight. The use of a steel container and making the container the cathode is much, much better. What if you accidentally dropped the steel cathode into the glass container, e.g.? Shatter city, with 3 gallons of sulfuric in your lap. According to this link (about 2/5 down the page), 100 deg F, 88% H2SO4, will attack mild steel at the rate of .03" per year. Certainly not enough to worry about.
http://www.resistoflex.com/sulfuric_graphs.htm

Forget the Merck Index and do your own experiments in small beaker sized quantities. Collect your own data. The Merck Index and the data in the CRC Chemistry/Physics Handbook are based on pure, simple, isolated systems. Quite often, when the system is more complex, as this one is, the results can be totally different, especially in electrolytic systems.

I think you're making this thing a lot more complicated than it really is. Just try the strong sulfuric. No more dissolving of base metals. No more large amounts of base metals sludge. No more cleaning of the solution itself - just use it over and over, as is. And, as a bonus, the amps go to zero when the gold is all stripped - it tells you when it is finished! When the gold sludge gets so high that it creates a partial short between the electrodes (you can tell when - the amps won't go to zero), let it settle, syphon or decant, and remove the gold. The solution is then reused, as is, without any treatment required. If there's a little gold sludge left combined with the solution, don't worry about it. You'll get it next time.

The magnetic pins are most likely Kovar - 54% iron, 29% nickel, and 17% cobalt. The nickel and cobalt don't dissolve much in the strong sulfuric. Probably due to the high iron content. The only base metals I've had problems with are the high Ni or Co superalloys - inconel, hastelloy, waspalloy, rene, stellite, etc.


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## Harold_V (Nov 28, 2007)

Very nice, Chris. 

Harold


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## goldsilverpro (Nov 28, 2007)

Many thanks to all!!

Chris


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## lazersteve (Nov 28, 2007)

Top notch post Chris. 

Hands on experience pays untold dividends when it comes to this stuff.

Steve


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## goldsilverpro (Nov 28, 2007)

> I`m going to try concentrated sulfuric in the cell with some CPU`s I have (10% water!). That was a great tip on the fact that CPU pins are electrically connected. I can hang them by one pin and zap em!



Al,

As macfixer01 did, I had trouble understanding what you meant. I finally figured it out. Your quote indicates a misunderstanding. Actually, I didn't explain it very well.

To prepare the parts for stripping, we heated the part hot enough to melt the brazes, and removed the lids and chips with a vacuum probe. We then had people that flicked off the bonding wires with an X-Acto knife. We then mounted the parts on the stripping rack.

When I stripped the CPU's, I didn't strip all of the leads (pins). I only made electrical contact to the sealing ring and to that one certain lead (called the #1 lead) that was electrically connected, through the internal traces, to the die pad under the chip. On the side braze CPU's, there was often a dot on the ceramic next to that #1 lead. On those packages without this lead/pad connection, I made direct contact to the pad. Only on those packages with the tiebar still intact, did I strip all of the leads. When we replated the gold, we only plated those portions that we had stripped. Later, when we did hybrid packages, we bought a mini spot welder and attached a temporary tiebar to the tips of the leads. This enabled us to strip and replate all metal surfaces.

To strip the entire CPU package, electrolytically, you must make contact to every lead, the pad, and the sealing ring. Each lead is connected, electrically, to one of the inside bonding fingers. I've been thinking of ways to make all of the connections One way would be to stuff the cavity with coarse steel wool and make contact to that. Another way is to wrap all the leads (pins), one by one, with a single piece of thin copper wire. The simplest way would be to put them in a rotating plating barrel along with some steel shot. The steel shot acts as moving conductors and eventually, every metal portion of the package will make contact and strip.

*Forget all this. You actually should use aqua regia on CPU's.*

My 2 earlier posts were to show the basics of the sulfuric stripper. They weren't to show how to run CPU packages. I was stripping them, but that was for a specialized purpose. Also, I used a modified solution in order to strip the gold alloy brazes on the CPU's. I also stripped many other things, such as the Au/Ni braze on jet engine scrap - stators, mainly.

Chris


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## aflacglobal (Nov 28, 2007)

Let me just throw this out there. 

It the stripping cell you consume amps.
Amps = heat + money.

Their are two components to electricity. Volts and amps.
In an electric circuit amps are consumed to produce work. ( electrons )
Voltage in a circuit has the potential to do work. Voltage is not consumed.
Think of it in relation to water pressure and volume. Now take two plates or in this case a copper basket and lead anode. Now charge both plates with voltage potential. Not amperage. 

Now ions can be negative or positive. One plate will attract one the other plate the other. Like two super strong magnets. The higher the voltage ( not amps ) the stronger the attraction. As long as amperage is not allowed to build or the voltage does not exceed dielectric breakdown their should not consumption of current or production of heat. Basically make the cell a big capacitor.

Just a crazy idea.

Any comments?


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## eagle2 (Nov 29, 2007)

Well, a lot to think about. Thank you for all your help and comments. I`ll study that patent .

When you study one paper, the chemists state their methods and conclusions. Then a few years later some Phd publishes a similar work and comes to a different statement. So science advances, but the subject of chemistry is so complex, you have to have experience. Chris, I absolutely do not doubt your statements, and I really appreciate this teaching here. I won`t use that glass fish tank for concd acids, Probably set it up as silver recovery, refining. 

I`ll try some small experiments with concd sulfuric cells as you suggest. 

I`m a semi-retired tv and electronics tech. CMOS chips are so highly susceptible to static charges because of the very high reverse resistance. So they have designed into each lead that connects to an array a protective diode. but these diodes only have a rating of about 50 volts. Any static charge higher than this will short the diode and ruin the chip. So, If you`re trying to electro-strip a bad CPU it should strip differently than a good one. Here`s an idea for someone. Find the ground leads and hit the others with maybe a copper strip for multiple contacts and about 60-70 volts. You would still have to decide weather its worth handling again to open the center cover. This might work for poor stuff like AMD K6`s where I wouldn`t care about opening up the center.

If I go with AR and CPU`s again I would first be very though with a ferric leach :? Or has any one ever tried using HCl + Chlorine on CPU`s? It seems you would have to watch them and when the gold looks like its off, pull them out one by one. 

Al


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## eagle2 (Nov 29, 2007)

Hi Aflac: Amps do the work. A capacitor`s purpose is to remove DC from passing through. You could then apply an alternating waveform and have it go through. 
Al


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## Smitty (Nov 29, 2007)

I'm actually glad to see that this simple question created a nice thread on this subject.


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## eagle2 (Nov 30, 2007)

Hi Smithy;
Yeah! poor old glycerin. Looks like its done. It should work to give you a better plate if thats what you want, but as Chris pointed out in stripping there`s no reason as there`s hardly any deposit on the cathode. 

USP on a label means its fit for human consumption. Better than technical grade, probably a bit less than reagent grade. Certainly good enough for a cell, where there are all sorts of trace impurities coming from the anode into solution. 

I`ve got some AMD K-6`s. I think I`ll try shorting one out to see how that de-plates the pins.

Al


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## Smitty (Dec 19, 2007)

Here is an idea I need someone with a working cell to try and please post a reply hopefully with pics. I would do it myself, but I am still a newbie in the process of harvesting and do not have enought material to do this. 

1. Cut a Steal plate or copper plate making sure it is nice and flat. 
2. Clamp the cpu with the pins touching the plate that you have just made.
3. Connect the the Clip to the metal plate and lower it into the acid and run the cell.

Hopefully your pins are nice and straight so that it will all contact the plate.

If it works then maybe there is a small copper mesh size out there that you can jam the pins thru to try and contact all pins.


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## lazersteve (Dec 19, 2007)

Smitty,

Been there, done that, on both counts.

The key to success (and the difficulty) as you pointed out, is the contact with every pin on the part.

In theory this is a great idea and should work, but in reality, it's hard to cut a piece of perfectly flat metal and then bring it in contact with scrap cpus that have perfectly straight pins. 

The copper mesh idea suffers from similar short comings, it's very difficult to get every pin in good electrical contact with the mesh base.

You end up spending a lot of time handling each cpu and the process still doesn't strip every pin without making multiple passes. Once a part has been exposed to the cell acid, it becomes more difficult to handle.

I've even toyed with the idea of using some fine copper or SS wool to push the cpu pins into, but the pins are typically not all straight on scrap cpus.

Ultimately the problem with processing cpus in the cell efficeintly is making a reliable contact with every pin on the core. 

Another idea is to remove the bottom plate and clamp a square copper tubing around the core wires. This makes a convienent contact point for the clamp that is consistantly flat. These wire pads in turn connect to all the pins and internal wires. The problem with this idea is that when the wires dissolve, you loose continuity to the pins.

For me acid dissolution is the way to go with cpus.

Steve


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## aflacglobal (Dec 21, 2007)

OK, it's midnight and I'm bored. :lol: 

Glycerin

I think i have just about figured out the myth. :shock: 

Just remember this >> Whether it be a fable, a story, a lie, a myth, or what have you, They all are usually based somewhat in fact.

So what could be the facts of this one? Actually i think their is some good scientific basis for this. I had to look at the human body to find the real key. It is amazing what science has done with the study of the human body. Their are reactions going on ( chemically ) that would blow your mind.

Anyway, I'm still going to look a little more.

See what you can find, It might suprise you.
Let just say lipids. :wink:


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## aflacglobal (Dec 21, 2007)

Here: This should get you started. :arrow: :arrow: :arrow:

Oh, this gets Good.


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## aflacglobal (Dec 25, 2007)

Hydrated-Electrons

Been off researching something new. The one's of you who really know electro chemistry might find this somewhat interesting. :arrow: http://www.lbl.gov/Science-Articles/Archive/CSD-hydrated-electrons.html

I was reading about how current ( electrons ) are transfered from one atom to the next in a handing off process. Like in the stripping cell. That's where the lipids come into play. Metals are totally different. Same with insulators. Different atomic structures.


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## GeeDub (Feb 14, 2009)

aflacglobal said:


> I was reading about how current ( electrons ) are transfered from one atom to the next in a handing off process. Like in the stripping cell. That's where the lipids come into play.



Except that glycerine is an alcohol, not a lipid. The original tri-glyceride (which was a lipid) has been stripped of its fatty acids.


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## ashraf25ac (Dec 22, 2015)

eagle2 said:


> Well, a lot to think about. Thank you for all your help and comments. I`ll study that patent .
> 
> When you study one paper, the chemists state their methods and conclusions. Then a few years later some Phd publishes a similar work and comes to a different statement. So science advances, but the subject of chemistry is so complex, you have to have experience. Chris, I absolutely do not doubt your statements, and I really appreciate this teaching here. I won`t use that glass fish tank for concd acids, Probably set it up as silver recovery, refining.
> 
> ...



dear sir 
I have hanging steel and copper contain multi layer plating (gold / nickel / copper ) and its repeated several time . I try hydrochloric acid / hydrogen peroxide its remove only first gold layer. so I hope to help me to find right way remove all gold layer . sorry for language very weak .


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## butcher (Dec 22, 2015)

ashraf25ac,
This thread is discussing the concentrated sulfuric acid cell used to strip gold from a base metal like copper or iron leaving the base metal pretty much untouched.
The HCl/Dilute H2O2 which forms a copper II chloride solution used to dissolve copper, iron or other base metals.
These are two different processes that work very different from each other.

My suggestion for now is do not try anything yet chemically, it would most likely result in failure, and putting yourself and others in danger.

Before trying anything, spend your time to gain an understanding, and learning what you will need to know to be successful, and to be able to work safely, and know how to deal with the toxic waste, when you create it.

Learn first by study, then you will be able to use your education and knowledge to do this work successfully.

Safety first, study this first and continue to study it, we have a safety section that can help you begin with that, dealing with waste in that section will help you with those problems.

Hoke's book, understanding the information from this book it is very important, this is where you will learn many of the basic principles which will help with most any process, even those not discussed or used at the time this book was written.

Then study each of the different processes you plan on using, sometimes there may be one or more processes to choose from, that may accomplish a similar goal, sometimes one can be better to use than another, for one reason or another, and there may be many different processes to get you from a pile of scrap to the refined and melted pure gold, so you may have several different processes to study before being able to recover and refine one certain type of scrap from start to finished product.

It would help if you pick one type of scrap to study and learn to work on, and to learn it, and all of the different processes needed to recover and refine the valuable metal from it, before going to another type of scrap. It also helps if you pick a type of scrap that has less base metals, or related problems, like karat gold, sterling silver, or memory fingers (memory fingers are a great place to begin learning with).

We can work around the language problem, but we cannot help you if you have not spent time to understand the basic principles first, or if you do not understand the processes your plan on using.

You need to study first, that is the right way you need, without it we will only be able to help you struggle from one problem to the next problem, until both of us get tired of looking for where the problem is to find out where you are loosing all of your gold, (that would not only be very dangerous for you and others, but would get you nowhere except more frustrated).


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