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.
Glycerin
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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.
Many thanks to all!!
Chris
Chris
Top notch post Chris.
Hands on experience pays untold dividends when it comes to this stuff.
Steve
Hands on experience pays untold dividends when it comes to this stuff.
Steve
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
aflacglobal
Well-known member
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?
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?
eagle2
Well-known member
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
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
eagle2
Well-known member
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
Al
eagle2
Well-known member
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
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
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.
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.
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
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
aflacglobal
Well-known member
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:
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:
aflacglobal
Well-known member
Here: This should get you started. :arrow: :arrow: :arrow:
Oh, this gets Good.
Oh, this gets Good.
aflacglobal
Well-known member
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.
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.
GeeDub
Well-known member
aflacglobal said:
Except that glycerine is an alcohol, not a lipid. The original tri-glyceride (which was a lipid) has been stripped of its fatty acids.
ashraf25ac
New member
- Joined
- Sep 19, 2015
- Messages
- 2
eagle2 said:
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 .
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).
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).
