CPU pins not going well

[punkymunk]

Ok guys… PLEASE don’t rag on me too hard since I’m a newbie. I have been researching here and there on various processes and what not (including reading some of HOKE) before I even attempt to experiment on PM recovery except for one… CPU pins. I figured that should be a fairly easy attempt to see how much I’ve learned thus far. Obviously not much.

I had about 9 ounces of pins from green & brown fiber CPUs (roughly 40% older big square w/no heatshield ones and roughly 60% newer ones that were smaller w/heatshields) which did have some solder on a lot of them from the scrapping of them off while using a heat gun to heat them up. I read somewhere that I should soak them in just HCL for 24 hours 1st to knock off the solder before AP. I wound up soaking them for 3 days actually in the safer 20-something% Muriatic Acid because I couldn’t find out what strength I should have used. Then I filtered out most of the HCL through a coffee filter which left behind a lot of dark grey sludge like powdery stuff. I’m assuming that’s not gold but correct me if I’m wrong please because I did save the filter just in case. Since there was plenty more of that dark grey stuff still in the beaker I did a water rinse. That got some of the dark grey stuff out as well as some shiny-like filaments of some sort that I can’t for the life of me find out what it is. I tried researching more about gold recovery of CPU pins in particular to see if I could find out if I’m still on the right path or not. I hadn’t found anything except here recently I finally found where GEO was telling another that from the beginning the PINS only needs a good long boil in HCL then all should be left is gold foils. But given I couldn’t find that sooner I just assumed maybe an AP bath is next and proceeded with a 50/50 HCL & Peroxide mix and let them soak for about a week. Filtered off but not much headway was made although the filter once again had that dark grey sludge matter but this time a couple gold flakes came out into the filter. Tried a 2nd AP bath thinking maybe a week wasn’t long enough and gave the 2nd bath a week. Results were basically the same as the first. The CPU pins in the beaker was showing gold but also a good deal of dark pins. This is when I finally found GEO’s advice to another and therefore I used the non-safer Muriatic Acid and boiled the pins for roughly 2 to 2:30 hours. After cooling down, the HCL was so dark green you’d swear it was black although some gold foils and specs were floating around. But looking from under the beakers it appeared that there was STILL a good deal more of non-gold grayish pins. At that point I just covered the beaker and set aside until I could maybe find out where I went wrong or should do next and I didn’t come here for advice sooner in fear of the backlash I’ll get and probably deserve. I left the beaker alone for the better part of 2 weeks until earlier today I decided to filter off the HCL and add a good deal more than I had the first time to see if maybe what I tried last time wasn’t enough to “eat” the rest of the non-gold metals. Yes more seemed to be gone after filtering again but there is STILL a hefty amount left of the non-gold looking pins.

So now I just poured out the entire beaker content into a triple layered coffee filter so I could fully water rinse and take a picture to go along with this post as to where I am now and in case it helps anyone to know what I did wrong other than what I’ve described thus far. I now have the pins back in a beaker with a tad bit of water from rinsing the filter but… I’m leaving it alone in the beaker, letting the water evaporate, and then cover until I can find out what to do next (hopefully) from one of you guys if someone will be willing to assist me on finishing this one experiment off and not just bash me for my lack knowledge. Thank you to any who may be willing to offer any advice. And yes I will openly admit I need more and more research time and just keep collecting material for a later time to be processed. I have probably another 9 ounces or so of pins to get off of more fiber CPUs plus other materials.

 

[butcher]

HCl is normally around 20% (its azeotrope).

Safer HCl this may be some of the types that have added inhibitors, for metals, or some other reason low fuming...
Like many other common chemicals nowadays they seem to try and make them smell like lemons, or add some coloring and a label with new and improved, to sell the product, usually under another name... where the common chemical worked just as good or better and was a lot cheaper...

Just use regular HCl (hydrochloric acid) (muriatic acid{salt acid}), around 20% is just fine.

A white powder can be metal salts from the acid and metals, like sodium metal salts, sodium chloride NaCl (table salt), or lead salts PbCl2 lead chloride, another white metal chloride salt is AgCl silver chloride, these are the most common you may encounter.
NaCl will dissolve in cold water.
PbCl2 is not very soluble in cold water not much will dissolve.
AgCl2 is also very insoluble in cold water.
So here we have a way to separate the NaCl from the lead or silver salts.
Lead chloride becomes much more soluble as the temperature of the water is raised, so using boiling hot water we can dissolve the lead chloride, (chilling the same water the lead can be recovered from the solutions as long needle like crystals), salts of metals have certain solubility's and amny times temperature can play a role here, we may also only be able to dissolve so much salt in so much water or solution so if you have a lot of lead salts you may have to treat the same mix several times to remove all of the salt, with lead chloride the same water can be reused after you precipitate the lead previously dissolve after cooling it to remove most of the lead salt, reheating the water for another wash, this way you have less waste water contaminated with lead to treat and dispose of later.
OK now we remove the lead salt from our silver salt, silver salt will darken when exposed to light like sunlight, there are other test you can use or solutions to dissolve the silver but I will let you learn that later, as it can be dangerous if improperly done or handled.

Sounds like you need to study about the copper II chloride leach or etch, Laser Steve's web site has a great document, many of us on the forum have gone into great details about how this leach works and its chemistry, and how to use it, and keep reusing it, the forum is just loaded with good information and discussions you will find very helpful in understanding it.

Copper II chloride works great with copper, it will work on other metals, but before long using it on other metals like an iron based material like Kovar pins, or other base metals, after long you do not have a copper II chloride solution, but some other salt of the metal like iron chlorides for example, this changes what you are dealing with, and how everything works, so study that as well.

I guess the best Help I can be at this point is to try to get you to study more so that you have a better understanding of what is going on.
the more you study the more you will understand, the more you understand the easier it will be to fill your pocket full of gold, do worry about getting the gold right NOW it comes a little at a time with you knowledge and understanding in due time, work on the knowledge first, and in time you will see your pocket getting heavier.

Your almost there on this batch, set it aside for the time being, and study for your solution to the problem, in doing so you will find many solutions for problems you will run into down the road.
Hope this helps.

 

[punkymunk]

Thank you butcher. Yea I can see I have tons more studying to do on this as well as other processes I've been reading up on. I just looked up Kovar on Wikipedia... I was under the impression the pins were iron & lead based with gold alloy plating but there again... not knowing enough shines through again. I will further my research on this thanks.

As far as what I have so far... should I take the material out and get it into a sealable jar of some sort with or without water (or some other solution?) until a later time or... just leave it to air dry out given it's just been through a water rinse?

 

[UncleBenBen]

Hey there punkymunk. It sounds like you saved your filters, that's good. I suspect you will have some gold mixed with that greyish sludge, although it won't 'look' like gold as in flakes or foils.

Do some research on the effects of too much peroxide. Excess will oxidize gold allowing it to be dissolved into solution. It will then be reduced back from solution by gaining electrons from the base metals in the pins, cementing out as a black powder.

It can be recovered from the sludge, its just gonna take a bit more study to get it. Hope this helps! Good luck and stay safe!

Ben

 

[butcher]

You can save the material wet or dry, just keep in mind that when exposed to oxygen several of the base metals will oxidize especially if they have been around acids or have acid salts involved, powders or finely divided metals have much more surface area which can oxidize, iron forms several different types of iron oxides, copper tends to form oxides and carbonates... these oxides of the metals can react differently in acids than the same metal will in its reduced state, this is not a problem if you understand what is going on, iron can form one type of oxide that even aqua regia cannot dissolve it.

If you do not wish to deal with the oxides of these metal save the material under water.

Save your solution, to test it for values, and then to treat it for waste, or in some cases for reuse, or to make another useful product with it whatever the case may be

 

[punkymunk]

I did find out AFTER I tried the 2 AP baths of 50/50 ratio mixes that the consensus from most is that never more than 3 parts HCL to 1 part peroxide should be used for gold recovery due to that fact of what UncleBen said... too much gold being eaten or oxidized into a fine black powder. Yes I saved my filters because in research that I had done before attempting anything I read that there could be PM metal salts and gold powder, as well as the junk stuff like tin and lead, in the sludge as I call it although I'm sure there is a proper term that is alluding me. Hopefully from the pictures will be of more help to seeing what I've done. Maybe it's my eyes or my understanding of black powder coloring but to me most of the dark stuff isn't black. The filter left of the yellow one has a lot of fine needle like crystals (or salts?) along with some stuff that you see in the other filters.

Ok I will add a little more water to what I have for storage purposes in hopes that whatever iron is left (if any) won't oxidize or rust too much until a later time to pick the project back up.

Thanks guys!

 

[butcher]

punkymunk,
This seems to be simple (and it is), but there is a lot to it, that if you do not understand it there will be a problem at every turn, gaining that understanding is critical to making it simple.
By taking the advice to gaining a better understanding of what you are trying to accomplish will put you much closer to getting that gold from this batch, and help you with many more batches to come.
Keep us posted, and share what you learn.

 

[punkymunk]

A saying I've always believed in... everything is complicated until you learn it and then it is easy. Learn to not fear the unknown, then gain knowledge of the unknown, then tackle the unknown, then you will eventually overcome that unknown to where it'll be then known. Thank you butcher, and the others, for your advice and input. I will keep posted. I do have a day job owning a computer repair & sales company and this PM recovery, processing, and eventually refining is a side thing for me personally. Not necessarily to "get rich quick" or whatever... more or less something I think I might enjoy doing while eventually making a few bucks here n there as it goes along. So my studies and research will be as I can. But in the interim I will keep collecting and separating material of recovery value the best I can (carpal tunnel is a b... errr... pain lol) but there's various components I run across that is hard for me to identify as in what (if any) PM is within or on. Have a great day guys!

 

[butcher]

That is on of the great things about studying here on the forum, you pick up tons of information, even where that gold is hidden, I think you will do great in this new hobby. I look forward to seeing your progress in it.

If you have access to different types of material, I suggest you do the study suggested on the copper II chloride process (and of coarse the safety and dealing with waste), and begin learning with memory fingers, they have less base metals to give problems if you pre-treat them properly, that will give you a better understanding of how the copper II chloride works and reacts without the other base metals reacting to it, putting those monkey wrenches in solution, also study the HCl sodium hypochlorite method of dissolving the gold (after you removed the foils from the base metals, that will be much simpler that aqua regia.
Working with simpler processes when you first begin will make the learning process go smoother.
Read Hokes book it makes a good book for those bedtime stories, doing the getting aquainted experiment is a very valuable tool in your education of the reactions, paying close attention to details you will learn how to avoid many problems, you will better your understanding of the reactions involved, her book wil give you an understanding of the chemistry without going into the chemistry...