# Fiber CPU's - That's how i do them



## samuel-a

*Scrap Gold Recovery from Fiber CPU*

In this guide we will give a step by step process for the Recovery of Gold from fiber CPU's.

Fiber CPU's does differ in their design and materials from the ceramic type and therefore needs to be treated separately (see CPU's overview).
Fiber CPU's are also different from each other, but they do have one thing in common; the leads (pins) are attached to the body of the CPU with regular solder.

Fiber CPU's contains recoverable gold mostly on the pins and sometimes on the inner side of the heat sink plate.
This article will discuss only on the gold recovery of the.

Two more components to consider when dealing with fiber CPU's are; (1) The heat sinks that are sometimes Gold Plated (2) And the Monolithic Ceramic Capacitors (MCC's) that contain Palladium. Those two components are to be kept separately for later individual recovery of Gold or Palladium.
Once the three components (pins, heat sink, MCC's) are removed from the CPU, discard it to your low grade e-scrap pile.

*Abstract of the process:
A- Gold Plated Pins separation from the CPU body using a torch.
B- Gold and Base metals separation using a Hydrochloric Acid (HCL) leach.*

*A- Gold Plated Pins separation from the CPU body using a torch:*

CPU's Pins are obviously Gold plated and usually gold plating thickness is 10-30 micro inches.
Most new fiber CPU's does utilize 'Kovar' as base metal for the gold plating. Kovar is a strong alloy that composed of mostly Iron (Fe), Nickel (Ni) and Cobalt (Co).
Older fiber CPU's may utilize a high copper alloy as base metal underneath gold plating.

For this step you will need:
Torch (any kind will do).
Lock grip Pliers.
Metallic bowl or a pan.

1- Grab the corner of the CPU with the pliers and start heating the pins on the far corner from the pliers. Use the lowest flame possible on your torch, the idea is to heat the solder enough to melt it without burning the fiber body of the CPU.
You will know when the solder is molten once you hear and see it pops. At this point just swish the CPU's towards the bowl to create enough momentum for the pins to cut loose and land in the bowl. (See attached video)
In some types of CPU's the pins will not detach from the body that easily, so just mount the pliers above the bowl, heat and scoop down the pins to the bowl with a small metal rod.

COUTION: MOLTEN SOLDER, BURNING PLASTIC & EPOXY PRODUCE HIGHLY TOXIC FUMES!! PREFORME THIS STEP OUTDOORS OR UNDER FUMEHOOD.

Note: Some people will perform this step with acids, the writer think that the use of acids at this stage will do more harm then good, that's including a possible loss of gold.
With little practice and proper setup, using the torch method, you can easily do several dozens of CPU's in an hour.







*B- Gold and Base metals separation using a Hydrochloric Acid (HCL) leach.*

Now that you have the gold plated pins all separated from the body, it is time to separate the gold from the base metals. As said before, the most common base metals that are present in the pins are 'Kovar' (Fe+Co+Ni) alloy, the solder (Sn+Pb/Sn+Ag) and Copper.
The separation is done chemically by boiling the pins in a solution of 32% Hydrochloric acid (HCL).

Basic Principle 1: It is not recommended to dissolve gold with base metals in the same solution (i.e. Aqua Regia).

Basic Principle 2: The combination of Tin (Sn) and nitric acid is an invitation for troubles. Stannous Nitrate (Sn(NO3)2) is a white gelatinous compound in solution and are to be avoided.

For this step you will need:
Hot plate
Erlenmeyer flask
Cork / condensation setup
Full strength Hydrochloric Acid 30-32%
Filter + funnel + receiving flask

1- Weight the pins and add them to the flask.
2- For each gram of pins calculate 12 ml of 32% HCL solution and add the amount to the pins, make sure the liquid level does not exceed half of the flask height. If needed, use a bigger flask (If bigger flask is unavailable, perform two or more consecutive leaches).
3- Place the flask on hotplate and slowly allow the solution to reach gentle boil. Careful not to add to much heat or it will boil over.
4- Place a cork of fit a condensation setup to keep evaporation to a minimum.
5- Let the solution boil for 3 hours.

After three hours of boiling the solution will turn very dark blue, almost black. The black solution indicates saturation of the solution. You will also notice Gold Flakes and foils floating on top.






6- Decant the solution with all gold foils and powder to the filter, leaving any un-dissolved pins in the flask and allow complete draining. (Comment: Vacuum filtration shorten this step down to few minutes)

You might see some left over un-dissolved pins that can still trap a bit of gold, you can add fresh acid to dissolve them or just wash them thoroughly with plenty of water and decant to the filter.
Wash the foils and the filter well with water until its back to white color.

You now have the gold foils and powder in the filter. With the gold, there will be small amount of un-dissolved base metals and left over organic matter.






This is the end of the Gold Recovery stage.
On the next article we will explain the Gold Refining Stage of the foils.

*Source - Gold-N-Scrap*


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## lazersteve

Sam,

Why the incomplete post?

Steve


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## Barren Realms 007

lazersteve said:


> Sam,
> 
> Why the incomplete post?
> 
> Steve



It's not incomplete. The link for the complete thing is at the end of the post.


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## lazersteve

Barren Realms 007 said:


> It's not incomplete. The link for the complete thing is at the end of the post.



I realize that, but to someone reading the forum the post is only a teaser and not complete, what if Sam's site goes away? 

I can understand hosting documents, pictures, and videos off site to save space on the forum server, but to split the text of a post midstream seems kind of odd to me.

The purpose of the forum is to share information, not to harvest clicks.

Steve


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## Barren Realms 007

lazersteve said:


> Barren Realms 007 said:
> 
> 
> 
> It's not incomplete. The link for the complete thing is at the end of the post.
> 
> 
> 
> 
> I realize that, but to someone reading the forum the post is only a teaser and not complete, what if Sam's site goes away?
> 
> I can understand hosting documents, pictures, and videos off site to save space on the forum server, but to split the text of a post midstream seems kind of odd to me.
> 
> The purpose of the forum is to share information, not to harvest clicks.
> 
> Steve
Click to expand...


I think he will understand that and post the rest of the articale when he sees this.


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## samuel-a

Steve

I can understand your moderator point of view.
but...



lazersteve said:


> The purpose of the forum is to share information, not to harvest clicks.



The whole purpose of my website is about information sharing for free, I'm sorry that you failed to understand that.
My intent is to sort and share what i have learned and create guides or tutorials based only on my experience. In some cases i post other people's articles with their consent and the proper credit.

Yes, i do have commercial ads/banners on my website to help reduce hosting costs, that's the price of free information handed out on sliver plate this days, you know that just as well as i do. I don't think that i should be ashamed of it, even if i could make a little profit out of my website.
You are doing the same and promote you products by handing out free information (and sometimes not for free) to the forum members, it's a simple deal.

With that being said, won't you say it's a bit hypocrite on your behalf to "blame" me with "clicks harvesting" while your main source of costumers is right here on the forum ? (which, by the way. seems to never have bothered anyone to date and that's including me)

On a side note, from the moment i published Gold-N-Scrap site, i placed a link to the GRF and other sources (including your website), sometimes with and sometimes without a back link without any jealousy.

I think that most members will agree, that with more then 600 posts, I'm far away from being a 'spammer'.
If posting just the beginning of the article with the rest of it on a link is non compliant with the forum rules i will remove it and leave only the link.

Sam


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## lazersteve

Sam,

You missed the point. 

The article as posted on the forum is incomplete. It would be nice for our members not to have to go off site to finish reading the article. Feel free to place a link to the same article on your site article in the post as well. 

I've never split any of the text of my posts across two sites for any purpose. I'm of the mindset that it's best to keep the information in one place. That's why you'll notice I don't host a forum of my own, post instructional text off of the forum, or blog on my web page. You may also notice that when answering questions I consistently link to previous forum topics as opposed to repeating the same information in multiple threads around the forum. The more sources of the same information, or slightly different versions of it, the more confusing it will be to the reader. 

By splitting the text of your instructional you are not giving the forum as a whole the ability to accurately respond to your instructions. Splitting the text of your post breaks the continutiy of the forum and opens up gray areas which could result in errors for the readers using the process. It also disrupts the chronological order of the replies and suggestions that may arise from a healthly discussion on the open forum. For example if I make comments on the current version of the instructional you posted today and you edit your web page off site later, my reply may not mean the same thing after your web page is edited.

With the text all posted on the forum in one thread we can all collaborate on the process and make it better for everyone reading.

Your website is yours to develop as you wish. If you want to direct traffic to your site post a link to you site in your post. For the sake of the integrity of the information and continuity of the conversation here please post complete topics or drafts of works in progress.

In closing let me pose this question to you:

Would you start an article on your website and half way through it stop and link to the forum for the remainder of the discussion? 

Steve


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## patnor1011

I personally would not take out pins with torch. They fell out from CPU in your next stage when heated in HCl. You can save on cost of gas and time if you just heat whole CPU in HCl. Of course not applicable on fiber CPU with metalic heatspreader.


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## chefjosh77

You may want to proof read your site a bit. It looks like it has good potential. Keep it friendly. The forum, and Steve's site, have provided me with tons of great info. It is only right to share the information with the people who want to really learn, and aren't looking for a quick buck. I agree with the comment of the half posts. It can be confusing enough for people to get the info they need, and incomplete posts add to that. Good luck with your site, and I look forward to seeing its progress.


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## dtectr

I kind of thought the split article was inappropriate, but was going to let it slide. But since you've gone to the effort to defend it publicly, then take a jab at moderators publicly, i feel it proper to express my feelings on the matter - publicly.

Quote from referenced article: _"Some people will perform this step with acids, the writer think that the use of acids at this stage will do more harm then good, that's including a possible loss of gold."_ 
You then go on to describe use of HCl, an acid, which wouldn't lead to loss of gold, except in the most extreme circumstances. 

You, like the rest of us here, have the right to follow your own steps for recovery. But linking it from here makes it appear that yours is the accepted or recommended process.

Almost no one I know of, who processes any quantity of these, has time to use "a torch and pliers." Try it with 25-30 lbs. of them. In fact, to make any serious money on them, you'd need to process pounds of them, anyway.

Though I'm sure it was not your intention to do so, it could appear to the casual observer that you are the fount of this knowledge, perhaps even preventing them from coming here, where they could benefit from close to a hundred years of combined experience, and that's just the moderators. It also, to me, smacks of the teaser excerpts from books that Amazon & other online sales outlets use to "hook" potential customers.

I do not presume to speak for anyone other than myself, and my inexperience is obvious to any who have to be patient with my questions, but I feel that my kind of inexperience may just be the kind that makes me & others like me vulnerable to "sniping", which, IMHO, could be the result, if not the purpose, of that self-promotion.

Please take this in the spirit it is intended - we all want & need your voice of experience here to round out the "orchestra".


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## samuel-a

Thank you all for your comment.

I've completed the post with the entire article.

dtectr 

Please don't take it so personally... i did not took a jab on Steve, only respond to 'accusations' and pointing out what i think to be double standards. 


Anyhow, my original intent was to make this thread the Q&A and comment's page for this article to the benefit of us all, specially newbies.

The use of torch is obviously intended for the home brew refiner and not for the industrial scale. don't rule it out, especially if you have few pounds to do.
see the video, it's only 30 seconds for that piece and can be reduced further, not to mention that one can develop it further and do them in a kiln.


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## joem

A while back to subject came up on who and what people "share" and it seemed to end with all members share what they want and keep what they want. Sam you did a great job sharing and have done a great in the past. The spirit of ths forum is still intact and not harmed by your post, in fact it has made it better with useful information. As I tell my students "Take the knowledge". Kudos to all for if it not for the members I would not be in the position I am - which is a good one. 
( Thumbs up smilies here if we had one)


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## silversaddle1

We all have the same end goal in sight, make money! 

Just post a link to your site and we will check it out. 

If it's good, readers will return.

Good job on posting the whole guide on GRF. 

One note: If you use a heat gun to melt the solder, the pins will still fall out, and you can do that indoors as the plastic will not burn like with a torch.

Scott


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## samuel-a

Hi Scott

That's right, heat gun will not burn the plastic. but i must admit that it took me quiet a while to loosen the solder when i tried it, of course, each person and his way to skin a cat.

That is great !! and those suggestions and comments are exactly what i intended this thread to be. Thanks.


Another note made by a member at another forum (james - micron gold group) and i thought might worth mentioning, was, to separate the copper based pins from the kovar based ones. He notices (and so did i) that the copper in solution actually cementing on the kovar based pins and slowing down the reaction and causing it consumes more acid. 
He suggested AP process for the copper based pins and HCL boil (as per the guide) for the kovar based pins. His suggestion to identify the is to scrape one pin and see if it's copper or not. Since they both magnetic, i don't see any other fast way to tell which CPU contains which type of pins. 

I never tried to scrape and look, and i don't know if i will embrace this test or not, but i sure will try it. it's nice to hear how others do things.

I will promptly add a link to this page in the article as the Q&A + comments page.


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## joedirt

I was wondering if anyone has completed this process? I have removed the pins and run them through 5 or so HCL washes and still have color change when I add more HCL. I have the gold plus what looks like a black powder, but I don't think the black power is gold. Has anybody gotten a gold button from this process? If so, did you check the purity? I'm trying to figure out if I should keep washing with HCL until there is no change in the color of it? Any suggestions/opinions would be appreciated!

JD


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## samuel-a

joedirt



joedirt said:


> , but I don't think the black power is gold.



Don't be so sure, dissolved and re-cemented gold can look just like that.

The next part of that tutorial is in editing as we speak and hopfully next week I'll finish it.



joedirt said:


> I'm trying to figure out if I should keep washing with HCL until there is no change in the color of it?



There isn't actually a dire need for a complete dissolution of the pins, as stated in the artcle, you can wash left over pins with planty of water to remove most of the gold (powder and foils) and catch them on the filter.

the next steps are very srtight forward actually:
1. grab the filter with foils and remove it from the funnel.
2. place the filter paper in a chemical cup and add HCl, just enough to cover it.
3. Now start to add slowly the oxidizer of choice (i.e. - hypochlorite, nitric).
go slow with the oxidizer, small incriments at a time, let it react and if needed add more until the powder/foils are completly dissolved and the paper is white again.
4. dilute the gold solution with water, 2-3 times it's volume OR add cuple of ice cubes.
5. let it sit for the night.
6. filter the solution.
7. add SMB to drop the gold.
8. wash gold powder as per usual (H2O 3x, HCl 3x, Distilled H2O 3x)
9. Dry and melt

Steps 4-9 are well descibed here on the forum as well as in my KARAT jewelry refining tutorial.

Good luck
Sam


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## joedirt

Sam,

Thanks a lot for the detailed response. I'm looking forward to the next part of the tutorial. This discussion leads me to another thing that has been bothering me, which is the benefit of purifying the gold to over 99%. I live in the Houston, TX area and have not found anybody who can test to this purity. As a matter of fact I had to go out of the Houston city limits to sell the melted gold because an ordinance was passed to stop jewelers from buying it; I think for the same reason that scrap metal buyers have to have ID and fingerprints from sellers. I sell to a jeweler, and as far as I can tell, he can only test to 22 carat. My thoughts are to not dissolve the gold and drop with SMB. Again does anyone have any thought on the purity of the gold before the dissolving and dropping with SMB?

JD


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## seawolf

From what I have read there are several places to sell refined gold, shipping and insurance required? If you strip and melt to a bar the results can be tested with some accuracy with a test kit. Either way if you are selling to a refiner you are at the mercy of the refiner.
If you are refining toward a retirement and doing small bars for the bunker I would want as pure as I could make.
Mark


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## Dutcherkan

Hello everyone,

i'm new to the forum and this is my first post 

i was wondering how do you get the gold that's inside the ceramic cpu-package?..

brake open,.. dissolve in... (what?) etc...

thanks for the info!

kind regards,
Dutcherkan


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## aarontm1985

i also want to findout about the caramic cpu's also the black once if any1 can help thx 
Dutcherkan did u find anything out?


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## patnor1011

All that info is there use search function.
Gold is primarily located on pins, on and under heatspreaders. Some members crush remaining ceramic body of CPU after gold was extracted from mentioned places to get any gold which may be inside. However that will be minuscule amount and may be reasonable to do it only if you acquire large quantities of them.


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## samuel-a

joedirt said:


> Sam,
> 
> Thanks a lot for the detailed response. I'm looking forward to the next part of the tutorial. This discussion leads me to another thing that has been bothering me, which is the benefit of purifying the gold to over 99%. I live in the Houston, TX area and have not found anybody who can test to this purity. As a matter of fact I had to go out of the Houston city limits to sell the melted gold because an ordinance was passed to stop jewelers from buying it; I think for the same reason that scrap metal buyers have to have ID and fingerprints from sellers. I sell to a jeweler, and as far as I can tell, he can only test to 22 carat. My thoughts are to not dissolve the gold and drop with SMB. Again does anyone have any thought on the purity of the gold before the dissolving and dropping with SMB?
> 
> JD




JD

Don't stop shopping around your area.

If you just melt it as it is with the filter, gold contant can be anywhere from 90-99%, crapshoot, i don't know, that's totally up to you and how you do things.
In this case, both you and your buyer will have no clue about gold content.

In any case, you can always sell refined gold on line, if you are trusted, people will buy from you at spot price or near it, after fees you wil probaby be left with 90-95% of the spot gold value, i think that manageable, given your situation.

You also can refine it, then alloy it back to 22K or less to sell like that to your jewelr, though i doubt it will be better price (per gram of gold conent)then 24K gold.


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## samuel-a

Hi aarontm1985 and Dutcherkan

Patnor is right, the info is here on the forum.
When i'll get the chance and have enough ceramic's I'll make a guide of my own for it.

dig it up. :idea: :mrgreen: 

Good luck


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## aarontm1985

hi thx 4 that will look 4ward to it 

im having troble with the gold drop added the smb and nothing
and one thing if i get the gold drop on this attempt how do i wash it and dry any ideas thx


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## samuel-a

aarontm1985 said:


> hi thx 4 that will look 4ward to it
> 
> im having troble with the gold drop added the smb and nothing
> and one thing if i get the gold drop on this attempt how do i wash it and dry any ideas thx



You will need to post more details.

What scrap exactly did you processed, how much of it and what process did you used ?

This way, we could understand (maybe) what went wrong, if at all.


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## Harold_V

aarontm1985 said:


> hi thx 4 that will look 4ward to it



Let me give you a friendly tip. 

*Lose the texting lingo* if you expect to have a pleasant visit on this forum, especially if you hope to get advice from those of us with experience, speak in clear, concise English, using punctuation and capitalization as required. We don't appreciate anything posted that lends itself to being confusing. If you don't have enough time to use acceptable protocol, I expect few of us will have enough time to waste in answering any questions you may have. 

Thanks for your cooperation and understanding. 

Harold


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## jmdlcar

Hi all

I remove all the pins on that I could see on my 4 junk motherboards. Can put them with the cpu pins and recover the gold? And next I'm going to work on pci and memory slots for recovery of gold.

Jack


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## Obi

Hi - I am new to the forum and am looking for the refining tutorial. Has it been finished yet? If so can someone link me to it please?

The information on here has been very useful so far. Thankyou.


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## Claudie

http://goldrefiningforum.com/phpBB3/viewtopic.php?p=6873#6873


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## Acid_Bath76

Obi said:


> Hi - I am new to the forum and am looking for the refining tutorial. Has it been finished yet? If so can someone link me to it please?
> 
> The information on here has been very useful so far. Thankyou.


I think HAROLD and LAZERSTEVE have the link to HOKE on their signature line. Welcome to the forum, and enjoy the reading! Between that book, and the search bar, you'll be on your way to a great foundation with all this.


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## jimdoc

For Hoke's book link, that would be Palladium and Patnor1011 in their signature.

Jim


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## Acid_Bath76

well... there you go. Sorry for the misinformation... glad someone squared me away! Thanks Jim.


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## Palladium

:arrow: :arrow:


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## Claudie

I posted a link to the guided tour & Hokes book link is just below my name.... :|


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## Dude4ever

Hi. I want to ask a question here. But I can see this post is a little old.
Want to open this up again as this actually is the Q&A post for fiber CPU's and HCl leach.

I started a batch with fiber CPU pins today, and boiled it for 3 hours in HCl in a erlenmeyer flask. The solution turned green pretty fast, that is copper right?
I sat up a condensation setup with a cork and a tube, I watched it for an full hour and the evaporation rate did not seem to be very high, so I left it to do something else for about 2 hours, and then the acid got boiled off, it was all dry when I got out again  Good experience  It was a little as 350W I used on the hotplate, but this in fact seems like too much. The first lessons comes forward 

But I just poured in some fresh HCl and let it stand COLD for 4 hours more. But nothing major happened. The foils have not been separated from the pin, but the solution has a deep green colour, so it seems like most of the pins were copper-based, because this copper has cemented onto just about all of the pins.. I read that this could happen in this very post if it was both kovar based pins, and copper based pins. Facinating.

So.. Should I add some more HCl and also a little H2O2 to this solution and just dissolve everything beside the gold, filter it and proceed with a HCl wash and then AR? Im also going to test it after filtering, with stannous obviously.
I can't think of a better way to clean this up, but that is why I ask if anyone else have some tips? Especially you Sam that is the author of this guide 

Thanks


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## butcher

If these pins on the CPU's were made of kovar, you could have made ferrous chloride, a green solution, as well as nickel and cobalt in solution, copper is not the only solution that looks green, although copper does give a green or blue solution.

it could also be copper, one way to tell would be to add clean iron to the solution (after you checked for gold), if copper is in this solution it would plate out onto the iron as the copper colored metal you can recognize. The green solution that did not plate out would then most likely be iron, cobalt, or nickel. 

Decant this leach; let it settle well, there may be some fine gold powder liberated.

Continue to leach for base metals, HCl and 3% peroxide will help to remove base metals, as long as you are leaching these base metals, without dissolving your gold, you are removing these other metals and getting closer to recovering and then refining the gold


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## Dude4ever

Hehe OK butcher, thanks 

Yes it is indeed tiny flakes of gold floating in the solution. This have settled all night and day now, so I will do what you suggest, decant the green solution into anther flask without distubing the powder/pins, test it for gold, then try some iron in it, and just resume with leaching of the metals in the first flask  Good analytical procedure for finding out what to expect of these pins in the future


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## samuel-a

Dude4ever 

I'll second every word Butcher said.

Also, to save on the acid consumption, remember that most chlorides salt are soluble in water, some to better degree then others.
If you happen to run in such situation again, you might want to first dissolve as much salts crystals with boiling hot water, then go on with acid to go after oxides, anhydrous Chloride compound and base metals as per Butcher instructions.


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## Dude4ever

samuel-a said:


> Dude4ever
> 
> I'll second every word Butcher said.
> 
> Also, to save on the acid consumption, remember that most chlorides salt are soluble in water, some to better degree then others.
> If you happen to run in such situation again, you might want to first dissolve as much salts crystals with boiling hot water, then go on with acid to go after oxides, anhydrous Chloride compound and base metals as per Butcher instructions.



Hmm. Makes sense 

You are right on Sam, I used a clear excess of acid to leach the rest of the batch. But I did what I wrote earlier, and now I have some beautiful foils in my solution ready to be filtered  but this was valuable information, I did several different processor types at once, that was probably the issue, pins weighted in at 16g, not a large batch, but that was the point.

What butcher said was what I thought at first, so that seemed right to do. But as you said, too much acid got consumed, and I have a lot to filter at this point. So next time I will use water, but should I decant the water boil through a filter also? 

Thanks guys


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## samuel-a

Dude4ever said:


> but should I decant the water boil through a filter also?



Yes, the preceeding water wash and the following acids wash would be considered as one.

Remember that micron scale gold particles may easly be washed away, that's why, it is advised to filter any liquid that comes in contact with the gold.
Either filter it all, or combine all washes and allow to settle for few days, later siphon the majority of liquid.


Dude4ever, you are on the right track. I'm looking forward seeing your results.


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## Dude4ever

samuel-a said:


> Dude4ever said:
> 
> 
> 
> but should I decant the water boil through a filter also?
> 
> 
> 
> 
> Yes, the preceeding water wash and the following acids wash would be considered as one.
> 
> Remember that micron scale gold particles may easly be washed away, that's why, it is advised to filter any liquid that comes in contact with the gold.
> Either filter it all, or combine all washes and allow to settle for few days, later siphon the majority of liquid.
> 
> 
> Dude4ever, you are on the right track. I'm looking forward seeing your results.
Click to expand...


Thanks Sam 

Now I have filtered the solutions, and I came up with nice gold foils, some minor "debris" and some very fine black powder 
I have read that this powder could be gold that got dissolved, and then re-precipitated because of copper saturation of the solution, comments?

Stannous test did not show any colour at all on the cotton swabs; I dipped the tip of the swab in the different solutions(3), it showed a yellowish greenish colour, when I dripped a drop of stannous (freshly made, chilled), it turned clear/white again and stayed that way 

I have to take some pictures, my SMB hasn't arrived at the pharmacy yet  but I will dry the foils and powder, and weight them before proceeding with AR. But what about just preparing a HCl-NaOCl solution, and pour it slowly over the batch in the filter? I need to get familiar with the AR process though.


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## maynman1751

> I will dry the foils and powder



Dude! just keep the powder and foils in a little bit of water or HCl.....don't dry. Or, you could just go ahead and dissolve with HCl/Cl. I'm not sure if you will get complete dissolution through a filter. If you go that way make sure you rinse the filter well with water to get all the values. Then keep the filter for incineration later when you have enough to do.


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## butcher

What would I do is (crush foil tubes with glass rod, this also lets me know if these tubes are hollow or if they still have metals inside, it also helps to keep them from floating around), the powders and foils after rinsing well, incinerate them red hot but do not melt them, if you used a filter just burn it too, cool add HCl to cover and boil, dilute with just a little water (not too much) lower heat but keep very warm, let powder settle, and siphon off the liquid while solutions are hot. Then boiling water washes decanting hot, till color of liquid is clear.

The incineration would oxidize tin from solder, the HCl boil would help to remove base metals and tin oxides, the boiling hot water will also help to remove lead chlorides.
This helps to clean up the powders and foils before dissolving the gold, keeping some of the unwanted materials out of your gold solutions, and improving your final product.

HCl and bleach would be my choice to dissolve the fine foils.


----------



## Dude4ever

OK, interesting.

So if I understand what you mean correctly, first crush up the foils, then I should burn the filter and incinerate the foils _and_ the ashes, and then add everything to a flask and HCl - boil - siphon, then water boils and finally dissolving?

In my other flasks that I poured the excess leach of acid/peroxide into, there were visible tiny gold flakes that floated around, I tried at first to _carefully_ siphon out most of the liquid to ease filtering, but flakes did come over, and that flask stood untouched for 2 days before this. Would not crushing the foils make the siphoning a pain in the a** regarding the tiny flakes??  And with the ashes and all in the solution, wouldn't it be hard to spot if this happens?

This is a very small batch, so I think the burning of the filter is unnecessary - this time  (Heard of ash-free filters? expensive, but it turns only to gases when combusted)
But guys, what about spraying the filter clean into my flask with water and dry it so I can put it somewhere for incinerating (Can I use a butane torch?)?
Then wash it with acid and water, and then dry it and weigh it? I have a pocket-diamond-scale that measures 0.000g with a tolerance of 0.002g, so I want to weigh larger and larger batches, and log the results before and after dissolving and precipitating. 

Thanks ;-)


----------



## butcher

Gold is heavy even as powders or foils, and tends to sink, the small tubes from the pins can hold air or gas this is why I would smash them (less likely to try and float), oils (even from your fingers, or dirty glass ware) can make gold float, incineration helps as well as clean vessels, surface tension of water will sometimes allow small flakes of gold to float, a fine mist from a water bottle will usually sink these.

If you do not want to burn the filter now you can clean the filter paper off into a vessel (but I would save the filter paper to burn later). 

If all you have is a tiny bit of gold I would save it up until I got more, I feel tiny amounts of gold through the processes are more of a chance to lose small amounts, than processing one Larger batch.


----------



## Dude4ever

Here is the results so far:




Big question: Can I incinerate this batch inside a erlenmeyer? (my research suggests that borosilicate glass can withstand 500 degrees celsius for a short period of time).
This does not seem like enough heat to me, but maybe sufficient to remove the impurities?


----------



## Geo

dont incinerate in borosilica glass. use either steel or pyroceram bakeware. pyroceram includes Corningware white casserole dishes with flower patterns.incineration involves heating material to a red hot state for a prolonged period of time.borosilica glass will melt at those temps.


----------



## Harold_V

Geo said:


> dont incinerate in borosilica glass. use either steel or pyroceram bakeware. pyroceram includes Corningware white casserole dishes with flower patterns.incineration involves heating material to a red hot state for a prolonged period of time.borosilica glass will melt at those temps.


It won't melt (although that depends on the heat source)---it melts at a much higher temperature (well in excess of red heat), but it isn't stable. It suffers from thermal shock and is readily broken by uneven heat, in particular if the cross sections are quite thick. That's why beakers are made thin, and of relatively uniform cross section. 

Harold


----------



## Geo

Harold_V said:


> Geo said:
> 
> 
> 
> dont incinerate in borosilica glass. use either steel or pyroceram bakeware. pyroceram includes Corningware white casserole dishes with flower patterns.incineration involves heating material to a red hot state for a prolonged period of time.borosilica glass will melt at those temps.
> 
> 
> 
> It won't melt (although that depends on the heat source)---it melts at a much higher temperature (well in excess of red heat), but it isn't stable. It suffers from thermal shock and is readily broken by uneven heat, in particular if the cross sections are quite thick. That's why beakers are made thin, and of relatively uniform cross section.
> 
> Harold
Click to expand...

 
thanks Harold, i was taking a stab at it. i know that the glass tubing i use is borosilica glass and it melts at around red hot, i guess it melts due to its smaller diameter. ive never tried heating a beaker that hot and hopefully i never will.


----------



## butcher

Geo said:


> don’t incinerate in borosilica glass. use either steel or pyroceram bakeware. pyroceram includes Corningware white casserole dishes with flower patterns.incineration involves heating material to a red hot state for a prolonged period of time.borosilica glass will melt at those temps.



Good stab at it Geo, I agree the borosilicate vessel would be a mistake to use for incineration, I believe you also meant to say stainless steel pan (not regular steel).

I do most of the process in the pyroceram bake ware (corning dish), from incinerating washing and dissolving.

Thermal shock and uneven heating of glassware, makes this grown man cry when he has gold in the glassware.


----------



## Harold_V

Geo said:


> thanks Harold, i was taking a stab at it. i know that the glass tubing i use is borosilica glass and it melts at around red hot, i guess it melts due to its smaller diameter. ive never tried heating a beaker that hot and hopefully i never will.


You're actually not far off the mark. It softens @ 1,510° F, but suffers from thermal issues, as I said. 

Here's some useful information.

http://en.wikipedia.org/wiki/Borosilicate_glass

Harold


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## JesseSShaw

I am new to collecting precious metals from scrap. Since I am out of work and have no income to speak of, I had to try something. This seemed like it could provide some income for me and my family. I figured it is worth a shot since I have basic, scientific comprehension and learn quick. I decided to try this method for fiber CPUs first since it requires only HCL and the method is pretty straight forward. Unfortunately, it didn't work for me. I used 15ml of HCL per gram of pins instead of 12ml. I boiled for three hours each time as suggested. I went through the same process four times until the solution would not saturate any longer. Yes, four times, trying to dissolve all the contaminant metals. The solution wouldn't saturate anymore and yet there is still contaminant metals at the bottom of the flask trapping a lot of the gold. The fourth time I added some H2O2 3% and hoped it wouldn't attack the gold as well but it still wouldn't dissolve all the contaminants. The HCL I used is 31.45% concentration since I don't easily have access to 32% but it should still be strong enough. I included a picture of what I was left with at the end. Any ideas?


----------



## Geo

it takes upwards of one to two days to digest the Kovar in straight hcl. it can be done. when the solution is hot and you see small bubbles being evolved, thats the Kovar being attacked. it is a completely different look than just liquid boiling. when liquid boils, it evolves rather large bubbles where ever the heat is greatest. when the metal is dissolving, tiny bubbles will evolve over where the metal is regardless of heat dispersion.when you were doing the dissolution, was the tiny bubbles visible? if there were some, the reaction was taking place, maybe not as fast as you would have liked, but still progressing. 

do not leave solution heating unattended. do not let the reaction run dry. add hcl as needed. cover the reaction. be patient. its takes some time on the larger pins from the big green chips.


----------



## JesseSShaw

Geo said:


> it takes upwards of one to two days to digest the Kovar in straight hcl. it can be done. when the solution is hot and you see small bubbles being evolved, thats the Kovar being attacked. it is a completely different look than just liquid boiling. when liquid boils, it evolves rather large bubbles where ever the heat is greatest. when the metal is dissolving, tiny bubbles will evolve over where the metal is regardless of heat dispersion.when you were doing the dissolution, was the tiny bubbles visible? if there were some, the reaction was taking place, maybe not as fast as you would have liked, but still progressing.


I understand the difference between boiling and chemical reactions actually. I could tell by the way it was bubbling just as you said. Unfortunately, the reaction stopped after the first process. But I proceeded three more times just to make sure it wasn't reacting any longer. No more tiny bubbles coming off the materials after the first process. 


Geo said:


> do not leave solution heating unattended. do not let the reaction run dry. add hcl as needed. cover the reaction. be patient. its takes some time on the larger pins from the big green chips.


I Never left it unattended nor let it evaporate too much. For me, that is just logical. :mrgreen: It's unfortunate that some people need to be made aware of that. :| I closed off the opening of the flask with only a tiny opening to cut down on evaporation. I was regularly adjusting the temperature in order to find that happy medium between no boiling and boiling out of control. I processed the batch four times with fresh HCL each time. That is 12 hours of boiling. I would think that would be enough time to complete the dissolution. Am I incorrect in my thinking?

*EDIT:*
The image I uploaded in my previous post is a little misleading. I took the picture after I had decanted the floating gold foil and micron particles. There is a thin layer of HCL just barely covering the pins in the flask. You just can't see it. My apologies.


----------



## Geo

when iron is dissolved in hcl in the presence of oxygen, it creates ferric chloride. ferric chloride is an etchant for printed circuit boards and will attack the iron aggressively when heated. when the reaction stopped the first time, there was no need to discard the pregnant solution, just add more hcl. when you removed the ferric chloride, you slowed the reaction down. i know it sounds unrealistic, but that's what happens.replace some ferric chloride and the reaction will start back when heated. i cant think of anything that could cause the iron to passivate.


----------



## JesseSShaw

Geo said:


> when iron is dissolved in hcl in the presence of oxygen, it creates ferric chloride. ferric chloride is an etchant for printed circuit boards and will attack the iron aggressively when heated. when the reaction stopped the first time, there was no need to discard the pregnant solution, just add more hcl. when you removed the ferric chloride, you slowed the reaction down. i know it sounds unrealistic, but that's what happens.replace some ferric chloride and the reaction will start back when heated. i cant think of anything that could cause the iron to passivate.


Thank you for your quick replies and information. I will try the process again, this time boiling much longer in order to try and generate more ferric chloride. If I don't see a reaction after a few hours then I just might try adding some fresh (not oxidized) iron to the solution so as to manually generate ferric chloride and "kick start" the process again. Will post the results. Thanks again for the information.

:!: *EDIT:*
I decided to create some ferric chloride right from the start this time. I dissolved a pinch of iron filings in HCL before I tried to dissolve the rest of the pins. It seems to have worked. I am now seeing a reaction as I boil the pins again. I will update in a new post the end results.


----------



## gold4mike

One thing I've noticed when dissolving pins in HCl is that, while the liquid is hot, even at a rolling boil, it appears mostly clear as if no reaction was occurring. I apply heat for an hour or so, then remove from heat and let it sit overnight. 

In the morning the liquid will be very dark. I pour this liquid off, add more HCl, heat again, let sit overnight. When I find the liquid clear in the morning I know I've dissolved all that the HCL can dissolve.

Then it's time to move to the next process.


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## JesseSShaw

gold4mike said:


> When I find the liquid clear in the morning I know I've dissolved all that the HCL can dissolve.


Were there any undissolved contaminants when the HCL stopped working? What I'm shooting for here is gold that is pure enough to sell without further processing.


----------



## eesakiwi

Jesse, are you just boiling the pins in 35% HCL without anything else in it (ie Hydrogen peroxide).

How much acid are you using?


----------



## JesseSShaw

eesakiwi said:


> Jesse, are you just boiling the pins in 35% HCL without anything else in it (ie Hydrogen peroxide).
> 
> How much acid are you using?


Refer to my first post on this:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=9693&p=147064#p146922


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## JesseSShaw

This time I kept heat applied just below the boiling point so that I could monitor the reaction. I eventually had to call it a day so I let it cool and corked it so I could continue the process the next day with heat again. I noticed that when the solution cools down, it becomes very dark. After applying heat again, the solution reverts back to a semi-opaque state. I kept adding HCL as needed while keeping heat applied so as not to remove the iron chloride and disturb the reaction. Now I am thrilled to say that the contaminant metals are continuing to dissolve. Maybe another day of applying heat should complete the dissolution. Considering this was my first time attempting this procedure, I made mistakes and used a tremendous amount of HCL. I am not sure how much HCL would actually be consumed for this procedure if done correctly. That will have to wait for the next time I attempt it.

I am not sure if this question was already asked somewhere on this forum. Forgive me if it was answered already. But does anyone know where I can find filters under 1micron pore size? I found some on amazon.com but they are unbelievably expensive. I would like to filter out as much of the gold as I can before storing the solution for later processing.

Thanks for sharing information and the help. It is much appreciated.


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## Geo

you dont need to filter. just let everything settle and gently decant. you can use Butchers method of using a suction bulb to draw the solution off. you will need to rinse anyway, so keeping the material in the vessel will keep you from losing any gold during these steps.


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## JesseSShaw

Just to be clear, what you are saying is that *ALL* of the gold will settle to the bottom of the flask? There will not be micro particles suspended in the solution? I want to make absolutely sure of this since I am a greedy bugger and want to salvage all the gold. :lol:


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## samuel-a

JesseSShaw said:


> Just to be clear, what you are saying is that *ALL* of the gold will settle to the bottom of the flask? There will not be micro particles suspended in the solution? I want to make absolutely sure of this since I am a greedy bugger and want to salvage all the gold. :lol:



Given enough time, it will all settle.
Usually, 24-36 hours is enough.


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## rewalston

Even if it all doesn't settle, that's what the stock pot is for


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## JesseSShaw

samuel-a said:


> Given enough time, it will all settle.
> Usually, 24-36 hours is enough.


Seems to me that surface tension would trap some particles on the surface of the liquid and with micro air bubbles. But you are one of the professionals so I will trust the information provided for me. Thanks for the reply.


rewalston said:


> Even if it all doesn't settle, that's what the stock pot is for


I understand that. The reason I am looking for high efficiency filters is because I want to extract as much of the gold as I can BEFORE putting the solution on a shelf for later processing. Either way, if I get enough together to melt and sell then I have no choice but to be satisfied.


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## Geo

when you filter gold powder, its the tiny particles that get trapped in the filters fibers. the only way to liberate them is to incinerate the filter. i never filter powder of any kind.even filtering foils ties up a small portion of your values as does filtering gold bearing solutions.these are somewhat unavoidable, but filtering powder is.


----------



## JesseSShaw

Geo said:


> when you filter gold powder, its the tiny particles that get trapped in the filters fibers. the only way to liberate them is to incinerate the filter. i never filter powder of any kind.even filtering foils ties up a small portion of your values as does filtering gold bearing solutions.these are somewhat unavoidable, but filtering powder is.


Now that makes sense. 100% extraction is impossible (correction, highly unlikely) regardless of the method. Well, if that isn't a big downer.

I suppose my question should be if anyone knows where to find ashless filters under 1 micron pore size (Inexpensive). I don't know if the ones I found on amazon.com are ashless but they sure are expensive. It seems to me that I would only need these type of filters for this method or any method that does not involve the dissolution of precious metals. If they are all expensive then I will just have to settle for losing minute quantities. The desire for precision and perfection is a downfall of mine if you haven't noticed. Depending on the situation, eventually I give up however, I do spend a significant amount of time striving for it in some cases when it seems worth it. :lol:


----------



## Harold_V

JesseSShaw said:


> Geo said:
> 
> 
> 
> when you filter gold powder, its the tiny particles that get trapped in the filters fibers. the only way to liberate them is to incinerate the filter. i never filter powder of any kind.even filtering foils ties up a small portion of your values as does filtering gold bearing solutions.these are somewhat unavoidable, but filtering powder is.
> 
> 
> 
> Now that makes sense. 100% extraction is impossible (correction, highly unlikely) regardless of the method. Well, if that isn't a big downer.
> 
> I suppose my question should be if anyone knows where to find ashless filters under 1 micron pore size (Inexpensive). I don't know if the ones I found on amazon.com are ashless but they sure are expensive. It seems to me that I would only need these type of filters for this method or any method that does not involve the dissolution of precious metals. If they are all expensive then I will just have to settle for losing minute quantities. The desire for precision and perfection is a downfall of mine if you haven't noticed. Depending on the situation, eventually I give up however, I do spend a significant amount of time striving for it in some cases when it seems worth it. :lol:
Click to expand...

You'll come to understand that a filter will trap almost any sized particle as it is used. The surface of the filter gets coated with the solids contained within the solution, so everything filters through the solids. Even very fine particles will be trapped if you recycle the solution once that occurs. The negative side is, as it plugs, it slows down, and if there's tin present, it can come to a virtual stop. The ultra fine filter you seek would most likely yield nothing but problems with filtration, as you'd be working with rather dirty solutions that will be difficult to filter, even under good conditions. 

I highly recommend you reserve the use of very tight filters to solutions that bear almost no contamination. That might be gold that is refined a second time. For that operation, I used a Whatman #5 with excellent results. Otherwise you'll spend endless time filtering. As has been suggested, solids will settle readily--even miniscule particles. You'll see an excellent example of that when you precipitate and minute particles of gold are formed. They often take a day to settle, which is very visible. They form a layer and slowly sink to the bottom. 

Harold


----------



## JesseSShaw

Harold_V said:


> You'll come to understand that a filter will trap almost any sized particle as it is used. The surface of the filter gets coated with the solids contained within the solution, so everything filters through the solids. Even very fine particles will be trapped if you recycle the solution once that occurs. The negative side is, as it plugs, it slows down, and if there's tin present, it can come to a virtual stop. The ultra fine filter you seek would most likely yield nothing but problems with filtration, as you'd be working with rather dirty solutions that will be difficult to filter, even under good conditions.
> 
> I highly recommend you reserve the use of very tight filters to solutions that bear almost no contamination. That might be gold that is refined a second time. For that operation, I used a Whatman #5 with excellent results. Otherwise you'll spend endless time filtering. As has been suggested, solids will settle readily--even miniscule particles. You'll see an excellent example of that when you precipitate and minute particles of gold are formed. They often take a day to settle, which is very visible. They form a layer and slowly sink to the bottom.
> 
> Harold



I appreciate all this wonderful information. Look at you guys go, very willing to offer up an extended array of information for an amateur in this field of science. I have seen 0.2micron filters included with vacuum filtration apparatuses. That leads me to believe that with forced filtration, a very fine filter will not hinder filtration time. The Whatman #5 is a 2.5micron filter and coffee filters are anywhere from 5microns to 20microns if the information I gathered is accurate. I have yet to test any filters other than coffee filters so I can not argue any point on this subject with any real accuracy. After extrapolating from my thoughts, it stood to reason that I could use a very small pore size to extract as much of the gold as possible from the solution even with dissolved contaminates. If it would take an unreasonable amount of time by gravity then I would eventually invest in a vacuum filtration unit. I am a man of practical application so I am perfectly willing to test theories so that I may accurately state information based on first hand experience rather than relying on the fallible nature of communicating information. That is not to say I will not listen and no offense was intended in that statement. I have no choice but to listen to the voice of experience in this situation because I have no personal experience to draw from. However, I would still like information about the filters I asked about "if anyone possesses the information" so I at least have a source in which to go for filters no matter which size I am looking for. For this particular process, I am going to limit the washes to decanting. But for the future, I would like to experiment with filtration. This will provide me with the experience and you with the ability to say "I told you so" :lol: which I don't mind considering I learn best by personal experience. So, does anyone have any information on where I could acquire filters of a wide range of filtration? The large pore filters are covered as I have easy access to coffee filters. It is the fine filters I am finding difficult to locate at a reasonable price. Is there such a monster as a filter under 1 micron that isn't unbelievably priced?

Again, thanks for the information. Do not think for a moment that it is not appreciated.


----------



## samuel-a

JesseSShaw

Medium flow filter papers will serve you perfectly. the pore size is usually aound 7 microns.
As far as i know, filter papers graded below one micron are unbelievably expensive beside the fact that they are very slow. As harold mentioned, as soon as filtrate start to pile up, the fine particles will slowly clog the filter anyway.

In my video, i have used medium flow paper. The resulting filtered solution didn't contain any particles what so ever. 
Filtering that way, usually require vacuum due to clogging but can be done by gravity if you have the time.

The next step of this process (the way i like to to it and i think it the most efficiant) is to put the entire filter + filtrates in hot AR.
Some may not agree with me, but that's my opinoin and experience. 
The point is to accumulate as much gold as possible into one filter. Now, If you have one filter paper which is loaded with gold foils/powder, burning it may cause some losses if not done currectly. 
In hot AR however, all of the gold and left over BM are dissolved and the paper breaks down to a pulp which is very easy to filter out and wash.


----------



## JesseSShaw

I finally have been able to acquire some experience with this process. I have theorized a couple possible solutions to the gold that is not recoverable using this method. First, let me explain. I have theorized that using the method outlined here, there will still be gold suspended in the solution by means of surface tension and insufficient filtration. Also when dealing with micro-size environments, fluid mechanics changes. The fluid becomes viscous.

I was determined to get an answer as to where I might be able to acquire filters under one micron in pore size. That proved to be a dead end endeavor. I was able to get my hands on a single filter that is of 3 micron pore size which was given to me by someone who happen to have one laying around. After playing the waiting game of filtering through said filter, a microscope was able to show me that there was still gold in the solution as expected. I would guess about 1 parts per 1000. Also, there were particles trapped in the filter itself as expected.

In summary, this method should only be used for bulk removal of gold. The filter and solution are to be stored for further processing. This was never in question. I did attempt to remove as much of the gold from the solution as possible through experimentation with only HCL as a dissolvant and was seeking information on where I could acquire the materials to perform my experiments. One can only do so much with the materials available. Since I was limited by the availability of materials, I could only make certain determinations and leave the rest up to continued theory. Be aware, many may not see the minuscule amount of unrecoverable gold as worthy of extraction. I made the attempt in the name of science.


----------



## nickvc

Which ever method or process you use to refine gold you will never get 100% of the metal back in that single process. If your really careful and take your time you might recover 99%, that's why we use various methods to recover the small amount that escapes including the stock pot, saving used filters for further processing when we have a decent volume, saving any fluxes used, traps on fume hoods to catch any spills and filters and traps on the extraction to recover any values that escape during dissolution or incineration, I personally always put any solution that had values through a settlement tank or holding tank and leave it to settle and test it for values before passing it on to the tanks to neutralise the acids and remove the other dissolved metals, over a period of time you do get some values back which are always a bonus to me.


----------



## JesseSShaw

nickvc said:


> Which ever method or process you use to refine gold you will never get 100% of the metal back in that single process. If your really careful and take your time you might recover 99%, that's why we use various methods to recover the small amount that escapes including the stock pot, saving used filters for further processing when we have a decent volume, saving any fluxes used, traps on fume hoods to catch any spills and filters and traps on the extraction to recover any values that escape during dissolution or incineration, I personally always put any solution that had values through a settlement tank or holding tank and leave it to settle and test it for values before passing it on to the tanks to neutralise the acids and remove the other dissolved metals, over a period of time you do get some values back which are always a bonus to me.



If you review my previous posts, you will see that my goal was to recover as much gold as I could during the first process. The fact that 100% recovery is nearly impossible was never in dispute. I inquired as to where I could obtain the materials I needed for experimentation. With my inability to acquire specific information along with the limited supplies and materials I was forced to work with, I came to the only conclusion possible. I appreciate whatever information I can acquire through experience or shared. Experience remains my best teacher in any case. :mrgreen:


----------



## nickvc

My post wasn't aimed directly at you but was more of a general observation to all newbies that might read this thread. It's easy to lose a big percentage doing small amounts, maybe 1/2 gram on a 10 gram job but you might only lose 1/2 - 1 gram on a 100 gram job. The point I'm trying to put over is we keep everything and even more important we test all solutions for values, tiny amounts of the materials we recover and refine can add up over time to a nice amount when we recover and refine them and the more refining you do the bigger the amount to recover and the one point to remember is that when we start we tend to be less skilled and loses are going to be higher generally then than later in our processing career.


----------



## Geo

JesseSShaw said:


> nickvc said:
> 
> 
> 
> Which ever method or process you use to refine gold you will never get 100% of the metal back in that single process. If your really careful and take your time you might recover 99%, that's why we use various methods to recover the small amount that escapes including the stock pot, saving used filters for further processing when we have a decent volume, saving any fluxes used, traps on fume hoods to catch any spills and filters and traps on the extraction to recover any values that escape during dissolution or incineration, I personally always put any solution that had values through a settlement tank or holding tank and leave it to settle and test it for values before passing it on to the tanks to neutralise the acids and remove the other dissolved metals, over a period of time you do get some values back which are always a bonus to me.
> 
> 
> 
> 
> If you review my previous posts, you will see that my goal was to recover as much gold as I could during the first process. The fact that 100% recovery is nearly impossible was never in dispute. I inquired as to where I could obtain the materials I needed for experimentation. With my inability to acquire specific information along with the limited supplies and materials I was forced to work with, I came to the only conclusion possible. I appreciate whatever information I can acquire through experience or shared. Experience remains my best teacher in any case. :mrgreen:
Click to expand...


theres a method of drawing fluid from solids without filtering and does a much better job. the method i am referring to is called wicking. i wont explain what it is, not to be hard to get along with, but you will learn more about it than me typing a pamplet on how it works by searching for it yourself.


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## Geo

dont forget the angels part. prospectors i used to hang around with used to say "if you worry about trying to get every speck, you'll go crazy. dont worry about what gets away because its just the angels part"


----------



## JesseSShaw

Geo said:


> theres a method of drawing fluid from solids without filtering and does a much better job. the method i am referring to is called wicking. i wont explain what it is, not to be hard to get along with, but you will learn more about it than me typing a pamplet on how it works by searching for it yourself.



Right. Fluid mechanics. Basic physics. Though terms may differ for the sake of comprehension, the physics remain the same. Adhesive forces allow some fluids to "cling" to the surfaces of some solids, giving the ability to "draw" liquids against gravity. I never considered this method of removing solids from solutions. Thanks for bringing it to my attention. Now I have something else to consider. (Wish I thought of it first. but one can't think of everything.)



Geo said:


> dont forget the angels part. prospectors i used to hang around with used to say "if you worry about trying to get every speck, you'll go crazy. dont worry about what gets away because its just the angels part"



Not every "speck". Just what is possible. :mrgreen:


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## tuliopercussao

this is just one of my works!! not mastered the English very much!! just want to contribute to research and science!! I hope you enjoy the information!!


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## luiggiphilipi

Sorry for my possibly dumbness, but i'm new to this...

but when you say:

4- Place a cork of fit a condensation setup to keep evaporation to a minimum.

i need to put something to filtrate the gases being exausted right?

like a filter in the up side (in the cover)...

or am i a way too wrong?


----------



## maynman1751

luiggiphilipi said:


> Sorry for my possibly dumbness, but i'm new to this...
> 
> but when you say:
> 
> 4- Place a cork of fit a condensation setup to keep evaporation to a minimum.
> 
> i need to put something to filtrate the gases being exausted right?
> 
> like a filter in the up side (in the cover)...
> 
> or am i a way too wrong?


A watch glass or saucer that seals relatively well will suffice, but you DO NOT want to build pressure!


----------



## xALmoN

As this is about fiber CPUs, how do i actually get that piece of copper off the cpu? They're stuck on pretty hard, would a heat gun work? Though after getting the pins off and the whole CPU is pretty hot, the copper still does not separate. Anyone has any hints on getting the heatsink off?


----------



## patnor1011

Chisel works fine. Only small percentage of them heat sinks are with what look like small area of gold plating.


----------



## philddreamer

Try boiling them in water:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=38&t=16006&p=161278&hilit=boiling+cpu%27s#p161278

The lids that have the gold plating inside you still need to pry off, or :
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=14045&hilit=removing+cpu+heat+sink#p141025

Take care and be safe!
Phil


----------



## xALmoN

I could give the boiling a try. Thanks a lot for the pointers in the right direction, but at this point, it really doesn't seem like there's much point in prying them off for minimal gain. Copper isn't even worth that much.


----------



## philddreamer

> but at this point, it really doesn't seem like there's much point in prying them off for minimal gain.


xAL, maybe at this point in time there's no profit, but later on you could find yourself with many pounds of them. So, it would be good for you know how to recover ALL the values from them, including the copper. I just came across my first 100 pounds of them and I'm glad a remembered the post on boiling them! 
Thank you superten67!

Take care!
Phil


----------



## aok

Sam,

I do not understand what you meant when you wrote that removing the pins prom the processor using acid might result in the loss of gold. Can you please elaborate? Isn't this what you do with the pins on ceramic processors? Why would it work with ceramic and not with fiber CPUs.

I also want to know if these CPU pins that were removed can be processed in a sulfuric acid electrolysis cell like some people do with other types of gold plated pins.

Thanks.


----------



## Mikemurphy

With respect to the discussion regarding the recovery of 100 percent of gold from the inital bath due to filtration falability im am wondering whether or not it is possible to employ electrolosis whilst the gold is still in the acid bath. I can appreciate it may be 20 percent copper but having ollected presumably 100 percent of the available gold the rest could the sepperated using the less wastful AR filtration/purification process.

Regards Mike.

(noob) 

Ive just finished bathing 100 home computers worth of golden fingers I have accesd to around 600cpu's a year and thought best to start with 100 as a test sample to try to average out the potential yeild 
So far ive removed 90 percent of the gold from the fingers in HCL and hydrogen peroxide, and the solution is settling hence my keen interest in not employing a paper filter due to loss of gold.


----------



## patnor1011

What loss of gold you mean? In filtering? Try what we call charmin plug. Take big funnel pack tightly some toilet paper on bottom. I can guarantee that if you pack it tight you are not going to lose any of gold.


----------



## VanMarco

Hi!
I've been trying to dissolve pins are samuel described, the first time I did those I did some errors and It took along time to do it.
Ok fine, I thought that's my error, (putting too little acid) ok.
Next time, I've put 12ML of acid per gram and boiled it in a double boiler with a condensation setup in place (dimroth condenser)
after the said three hours, some pins started to detach from the bottom all right, but the majority of them where still on the bottom.
It appears that the pins are now "lighter" as they move easily in the bottom of the flask, but still I didn't get complete dissolution.
Now Either i'm doing something wrong, Using something wrong, or three hours are too little. tomorrow I'll keep heating for another
couple of hours and we'll see. Also an idea crossed my mind, maybe I'm wrong you tell me.
As I've noticed that the reaction between HCl and the metals in the pins take place *anyway* even if there is no heat applied,
I thought, why Don't I get a large beaker, I put the pins in it, add 6 Ml of acid per gram and leave it stay for couple of days, a week, 
or wel, until it looks good, and then, get some of those pins put them in the flask and add the remaining 6ml of acid per gram
and only then, boil. to me it would help, what's your thoughts?

Thank you very much!


----------



## AUH-R

Samuel, thanks for a great guide this got me started as it filled in the blanks in Hoke's guide. 

My journey so far has been fun and on this batch of 225grams of pins I have learned a great deal, as Hoke would say practical experience replaces a 1000 words. 

My first batch of 50grams I added 600ml of HCL and boiled for 3hrs, I observed the clear liquid change from clear to light blue then dark blue almost black. I assumed it was done as I saw gold flakes floating around as per your guide. I then filtered out the flakes and washed the residue with tap water and tipped this wash down the sink, thankfully I kept the brown pins :idea: . First mistake -  as I did not realise there was still gold mixed in the solution.




The picture above shows the first lot of pins I treated on the left with fresh acid added and a fresh untreated batch ready on the right. These were both clear when I first added the HCL. I left these overnight ready for their boils in the morning. Notice how the pretreated and H2o washed pins (Left) have turned the HCL light green. The HCL on the right remained unchanged until the boil.






Solution starts of light green coloured.



After an hour or so changes to the usual light blue.






After 3hrs + you will see the dark blue solution with foils floating.






Foils were put to one side, I had about 7 of these after various boils.



I could not understand why I kept having waste after my 3 hour boils, I have since learned that it could take days to get rid of all the base metals.

Part 2. The rest of the journey so far and some questions coming tomorrow..................
Good night,
Edit added part 2.

Next step was to boil my last lot in HCL - picture below of the filtered waste acid - not quite there as still coloured



I then washed all my filter papers off into a 1000ml beaker, see pictures below. I retained the papers for the incineration at the end of this stage.






I then boiled these pins until almost all liquid was evaporated, see picture below: 




So this is the stage I am currently at, all my separate lots have been treated multiple times in HCL, washed, boiled and are now all united in one vessel. This weekend I will boil again in HCL until no trace of base metals is left, I will then evaporate down. I will then place all material in my corning ware dish, along with the filter papers and incinerate. I may loose some gold at this point as I will be doing this out side without a hood, but this is a practice run so I will just have to accept this.

When this is done I will add a bit of water and test with blue litmus to make sure I have expelled all acid. 

SUMMARY: I really went about this a long winded way and also used 4 litres of HCL for 225 grams of pins not cost effective. I used about £10 worth of electricity as well with all the boiling on the hotplate. However, it was worth it as I believe I learned plenty.

WHAT WILL I DO DIFFERENTLY NEXT TIME:
If I was doing this size lot again I would nominate one vessel where all materiel enters and stays until the evaporation stage.
I would boil all 225grams in HCL for 4hours to remove solder.
I would then evaporate down and keep adding water and evaporating down until I had no reaction on blue litmus paper.
I would then incinerate following Harold's guide on the forum. 
I would then follow Hoke's guide and use Nitric acid to remove base metals.

I believe following the steps above will save me considerable time in filtering, washing and acids.

Part 3 will be posted after the weekend weather permitting. Incineration of material and filter papers.


----------



## AUH-R

Ok, just about managed to get my next step done as it has been raining for a few weekends. I ended up fixing an umbrella over the top of my stove, which allowed me to get this step done. 

I did my last HCL boil which was clear. I then poured away most of the acid and filtered.

I then put all my filter papers into my corningware dish and set them on fire. I then washed my foils into the Corningware and added the last wet filter. I then boiled away remaining acid + H20. I kept adding H20 and boiling away until I was sure there was no more acid present. (I did this at least 6 times)

Lastly I boiled down and left it on full heat for 10 minutes as a crust. This was the nearest thing I could do to an incineration.




Uploaded with ImageShack.us

My gold ready for AR treatment.

Regards,


----------



## AUH-R

Some nice weather today so managed to get set up in the corner of the garden to proceed with my AR stage: Firstly I added water to my corning ware dish that contains my flakes and brown residue, see previous post. Boiled this down again. Learnt another lesson, left it attended and it splattered when the last of the water was boiled off so lost a bit of gold. Next I covered with HCL and added about 2 ml of HN03, evaporated down to a syrup, added a few more drops of HCL, evaporated down to a syrup - added a few drops of HCL - evaporated down to a syrup - added hot water, see picture below:






I then tested the liquid for gold with my Stannous solution, success my first Au in solution!:






I then transfered this into a clear vessel, which I will leave overnight. Not sure what the brown powder is at the bottom according to Hoke it is silver chloride or lead, not sure it can be silver as I was not aware fibre cpu's contained any:








Sam, thanks again for the great guide!

Will post results of SMB drop tomorrow.

Best wishes & be safe,
AuH-r


----------



## AUH-R

I weighed out 4 grams of SMB. I then put some ice cubes into my beaker, I then added some of the SMB and stirred. At this point nothing seemed to have happened apart from the solution turning blue, I then added the remainder of the SMB. Apart from a slight brown residue forming at the top of the beaker and on the glass rod, nothing like the reaction I was expecting to see from what I have read and seen on youtube happened. I tested the solution with Stannous and got a positive, see picture below. I then cleaned my glass rod with the filter paper and I could see metallic gold on the paper and also purple stains. As a result of this I added more SMB as I thought I had not used enough, again no change. I then left the solution to stand for 3-4 hours, while I did some work. On my return I could see metallic gold floating on the top and also brown power at the bottom of the vessel. However, there seems to be a thin layer of white material at the bottom underneath the brown power, which I suspect is Cu-Cl. This tells me I have used too much SMB. 

Tomorrow morning shall I just decant the solution into a holding vessel, recover the floating Au with a syringe. Then put the Au from the syringe back with the residue in the beaker and dissolve again in AR, this time not adding far too much H20 after the evaporation stage? I say this because I think one of my problems is everything was far too diluted.

Once I have done the above shall I drop again in SMB using a small amount and give it a few hours before deciding if I have used enough.




Reaction after a few minutes.



My Stannous test and also where I cleaned my glass rod.



What is this residue likely to be?



After 4 hours.



4-6 hours.



4-6 hours.



4-6 hours.

Thanks for any guidance!

Best wishes,
AuH-R


----------



## butcher

AUH-R,

I read the last few posts you made and tried to get an understanding of what you were doing, I did not completely understand it because I was unsure of the process you were following when you mentioned Sam's guide.

But it sounded to me like you may have been removing the copper and base metals from pins using HCl and peroxide, and then moved onto aqua regia with your remaining material.

First let me say a few concerns I have, you mentioned pouring off your acid with some fine gold down the sink, this should never be done, not only could this destroy the plumbing in your house, but it could get you put in jail for endangering the lives of others when they trace the copper and hazardous waste back up the pipe to your house, what you flush others will have to drink, and you will drink what others flush, either way these toxic metal acidic solutions are way too dangerous to all of our health to be poured down a sink, learn to use a stock pot, and learn to treat your waste, this should be done before you even think about dissolving metals in acids.

You talk of expelling the acid and testing with litmus paper to decide when you have done so, if you are talking about getting rid of free nitric acid in this discussion, you would still have a very acidic solution, you are not trying to change pH with this procedure, you do not need to or would you want to remove the acid completely, the metal salts would be acidic and it is desirable to have free acid in solution, you are just trying to remove the oxidizer (nitric) not HCl, although in the evaporation process to remove the nitric we will normally lose some of the HCl in the process, the litmus paper would do you no good here, and if you evaporated down so far as to change PH you would have a dried powder of cooked gold or base metal oxides (with much of your gold lost as fumes.

Another thing that I seen, you said you wiped off your stir rod after adding the SMB you said you seen brown powder and a violet color of gold left on the paper, the brown reduced gold could be normal, but the violet color makes me think you have tin in solution, and so you could very possibly have a solution of colloidal gold that will not settle.

You talked of a brown precipitant that you think is silver or lead chloride, these chlorides are white not brown, copper I chloride is also normally white, gold will look black to brown or even light tan as a precipitant depending on how much other base metal is involved.

You talked about boiling it down and leaving it to settle as a crust, you should not boil any solution with gold involved, and you should not evaporate it down to a crust.

you also say you think you are having trouble because solution is too dilute, you say this after you have added your SMB, dilution at this stage is no problem, your problem are an accumulation of problems all the way through your process.

What I see is you do not yet have an understanding, of the processes, what you should be doing when and why, and what you should be expecting to see and understand what it is you are seeing.

My suggestion to fix this problem is something you may not wish to hear, but you are the one who asked for help, I say at this point get a large piece of clean copper buss bar and sit it in the solution you have now, check on it and stir it for three days, while doing this go to the safety section and study dealing with waste, brush off the copper into solution let the powders settle, decant the liquid and treat it for waste, rinse the powders and add rinse to your waste to be treated.
save these powders until you have read Hokes again (I know you said you read it 10 times, but you still need to understand it), practice the getting acquainted experiments, these will be a big help in understanding the reactions, and with these you get hands on practice to where you can see the reactions, and get hands on experience of what to expect, study more on the forum, now that you have seen some things, when you do you will have a better Idea of what we are talking about.

Before you try to dissolve gold again I think you need a better understanding of the processes you use, spend the time needed to study and understand them.

You have worked on a hard material here for a beginner with little understanding, and you chose some processes to begin with that would not be easy (at least until you gain a little more hands on experience), I suggest after you do study some more (do not skip the study, as the more you study the less problems you will have and the better your understanding to deal with them when they do rise), after you study try a more simpler process like memory fingers, to get a better understanding of how to process, without the problems of some of the more complicated methods, or materials.

I do hope this helps, I would also like to be able to give advice to help you out of this present mess, but at this point I do not think any other answer would help you to understand what you need to, to be able to recover and refine.


----------



## Claudie

I couldn't help but notice the background in some of the photos. I hope you are not working with this on a kitchen table. That is definitely something that you don't want to do. :|


----------



## AUH-R

butcher said:


> AUH-R,
> 
> I read the last few posts you made and tried to get an understanding of what you were doing, I did not completely understand it because I was unsure of the process you were following when you mentioned Sam's guide.
> 
> But it sounded to me like you may have been removing the copper and base metals from pins using HCl and peroxide, and then moved onto aqua regia with your remaining material.
> 
> *Firstly, let me say thank you for the detailed response. I used HCL only.*
> 
> First let me say a few concerns I have, you mentioned pouring off your acid with some fine gold down the sink, this should never be done, not only could this destroy the plumbing in your house, but it could get you put in jail for endangering the lives of others when they trace the copper and hazardous waste back up the pipe to your house, what you flush others will have to drink, and you will drink what others flush, either way these toxic metal acidic solutions are way too dangerous to all of our health to be poured down a sink, learn to use a stock pot, and learn to treat your waste, this should be done before you even think about dissolving metals in acids.
> 
> *I just reread what I wrote and can understand where the ambiguity comes from. Please let me clarify. I filtered all my acid off into my waste drum and washed the residue left 4-5 times. This was then filtered into my waste store. When I was looking at the rust coloured pins left in the bottom of my coffee pot indoors I decided to rinse again a few times with H20 and this is what was poured down the sink. I take safety very serious, when I joined the forum I followed Steve's guide and read all the recommended threads. Here is a picture of my waste so far about 4.5 litres of purple/black used HCL mixed with about 2-3 litres of washes.*
> 
> 
> 
> 
> 
> 
> You talk of expelling the acid and testing with litmus paper to decide when you have done so, if you are talking about getting rid of free nitric acid in this discussion, you would still have a very acidic solution, you are not trying to change pH with this procedure, you do not need to or would you want to remove the acid completely, the metal salts would be acidic and it is desirable to have free acid in solution, you are just trying to remove the oxidizer (nitric) not HCl, although in the evaporation process to remove the nitric we will normally lose some of the HCl in the process, the litmus paper would do you no good here, and if you evaporated down so far as to change PH you would have a dried powder of cooked gold or base metal oxides (with much of your gold lost as fumes.
> 
> *I think you're referring to the section where I said what I would differently next time. Having read the forum I would use a cell next time as the acid consumption was ridiculous for such a small amount of potential Au. However, I was trying to follow Hoke's guide specifically Chapters 7 & 5. Now Hoke advised in Chapter 7 to boil in HCL to rid the material of solder, she gives no mention of amounts to use and simply says scrap it off. This is when I found Sam's guide with much more detail on this part of the process. So what I was trying to say is next time I did this procedure rather than spend days boiling in HCL, I would do one long boil say 6 hours filter solution to waste, then keep rinsing with H20 and filtering until I was confident that there was no remaining HCL left. My thinking was then I could follow chapter 5 and use HN03 to get rid of the base metals, now most of the tin and lead was gone. Using the litmus paper I thought was the only sure way I would know if the HCL was absent.*
> 
> Another thing that I seen, you said you wiped off your stir rod after adding the SMB you said you seen brown powder and a violet color of gold left on the paper, the brown reduced gold could be normal, but the violet color makes me think you have tin in solution, and so you could very possibly have a solution of colloidal gold that will not settle.
> 
> *As soon as I added the SMB I had the brown powder on my stirring rod. I then tested my solution with Stannous to check if there was Au in the solution. I cleaned my rod on this same filter paper to see what would happen.*
> 
> You talked of a brown precipitant that you think is silver or lead chloride, these chlorides are white not brown, copper I chloride is also normally white, gold will look black to brown or even light tan as a precipitant depending on how much other base metal is involved.
> 
> *I have brown powder in the beaker with the SMB and also a small layer of copper I chloride. The brown/tan coloured residue left in the filter paper, what could that be?*
> 
> You talked about boiling it down and leaving it to settle as a crust, you should not boil any solution with gold involved, and you should not evaporate it down to a crust.
> 
> *I was trying to clean my flakes up at that point, the Au was not in solution, and I now conclude from your helpful post that the brown residue in the picture surrounding my flakes is some sort of copper/metal oxidize. *
> 
> you also say you think you are having trouble because solution is too dilute, you say this after you have added your SMB, dilution at this stage is no problem, your problem are an accumulation of problems all the way through your process.
> 
> *Thank you, I only thought that because when I evaporated the AR and added the HCL drops I was left with a tiny amount of syrup, say 10 ml and with all the additions of H20 I ended up with over 700 ml.*
> 
> What I see is you do not yet have an understanding, of the processes, what you should be doing when and why, and what you should be expecting to see and understand what it is you are seeing.
> 
> *Just having this chat with you has helped me a tremendous amount. I read Hoke almost daily and also C.W Ammen, I read this forum and various posts everyday. However, it does not matter how much I read, it was the same at university, It will not stick unless I do it myself. Also for me having a teacher/tutor is also very important for reassurance that I'm on the right track , if we could just do it from reading books there would be no need for lecturers, teachers etc...*
> 
> My suggestion to fix this problem is something you may not wish to hear, but you are the one who asked for help, I say at this point get a large piece of clean copper buss bar and sit it in the solution you have now, check on it and stir it for three days, while doing this go to the safety section and study dealing with waste, brush off the copper into solution let the powders settle, decant the liquid and treat it for waste, rinse the powders and add rinse to your waste to be treated.
> save these powders until you have read Hokes again (I know you said you read it 10 times, but you still need to understand it), practice the getting acquainted experiments, these will be a big help in understanding the reactions, and with these you get hands on practice to where you can see the reactions, and get hands on experience of what to expect, study more on the forum, now that you have seen some things, when you do you will have a better Idea of what we are talking about.
> 
> *Thank you again, I did this, this morning:*
> 
> 
> 
> 
> 
> 
> 
> 
> Before you try to dissolve gold again I think you need a better understanding of the processes you use, spend the time needed to study and understand them.
> 
> *Could not agree more! I learnt a lot through this experience, so even though I have no button to show this time it was a worthwhile journey and I feel valuable.*
> 
> *In summary; I never removed all the base metals especially copper as I had the tell tell signs of green all the way through the process I followed. I would never use HCL to remove the bulk of base metals. I would only use it for solder, then I would switch to HN03. When using SMB calculate the amount you suspect you need, if you don't see a dark cloud straight away, wait at least 2-3 hours, do stannous test before adding more SMB if you are sure you need too.*
> 
> You have worked on a hard material here for a beginner with little understanding, and you chose some processes to begin with that would not be easy (at least until you gain a little more hands on experience), I suggest after you do study some more (do not skip the study, as the more you study the less problems you will have and the better your understanding to deal with them when they do rise), after you study try a more simpler process like memory fingers, to get a better understanding of how to process, without the problems of some of the more complicated methods, or materials.
> 
> I do hope this helps, I would also like to be able to give advice to help you out of this present mess, but at this point I do not think any other answer would help you to understand what you need to, to be able to recover and refine.



*It helps very much and thanks for taking the time to respond.

A couple of questions if I may:

If you boiled in HCL to remove solder, washed your residue several times in H20, how would you know it was safe to use HN03 to get rid of the rest of the metals so you did not make some AR by mistake, using litmus paper?
When I evaporated the AR down to a syrup, am I losing Au during this evaporation process?

All the best,
AuH-R*


----------



## AUH-R

Claudie said:


> I couldn't help but notice the background in some of the photos. I hope you are not working with this on a kitchen table. That is definitely something that you don't want to do. :|



Thank you for your concern. I do all my work outside when dealing with acids and any fuming substances. I just bring in the solutions I feel are safe for photographs.

Best wishes,
AUH-R


----------



## Geo

AUH-R, acidic solutions are fuming whether you can see it or not and sometimes you cant even smell it. keep acids out of your living space.


----------



## AUH-R

Geo said:


> AUH-R, acidic solutions are fuming whether you can see it or not and sometimes you cant even smell it. keep acids out of your living space.



I thought 2ml of pregnant HN03 diluted in 700 ml of H20 to be safe, obviously not, thanks for the advice. I won't do it again.

All the best,


----------



## butcher

AUH-R,
When I answered you last I could not see your pictures, that and the fact that I was not exactly sure what all you were talking about, just reading through the few posts.

The pictures add a whole new meaning.

It seems like I misunderstood a few things about what you were doing and how, you were doing them.

Now that I can see the pictures I have a little better Idea, I will not go back and try to correct my miss-understandings, but I will add just a few things I noticed from looking at the pictures.

What it looks like to me is you are working with Kovar iron based pins, these will include lead solder and the dreaded tin, HCl will attack these, and put them into solution, copper will not normally dissolve in just plain HCl without an oxidizer, but with heat and air from the atmosphere, or boiling some copper can be attacked. Gold will not be attacked, by HCl alone, or with HCl and a mild oxidizer like dilute hydrogen peroxide or oxygen from air. For copper to dissolve to much any extent needs an oxidizer like air, or oxygen which we normally add with H2O2 or an air pump.

Iron in solution as a chloride should not be boiled, heating is OK but, if boiled strongly we can precipitate the Iron out of solution as an oxide of iron, which will not dissolve in acids, I see what looks like iron oxides in your pictures above in that brown mud (probably iron copper and other metals, also in the ceramic dish with the foils where you say this is as close to incineration as you got.

I believe it is not the boiling hot solution that forms the red insoluble iron oxides, but it seems to me to be the bottom of the vessel where it comes into contact with the burner that cooks the iron out of solution forming the oxide (just speculation here).

This red rouge of iron will not dissolve very easily at all, even in strong acids or combinations of acids like aqua regia (which at time can be a good thing to help us separate our gold from the iron red rouge), other times we want to dissolve the iron away from our gold keeping the iron soluble (iron chloride in this case).

Looking at the picture of your foils in the ceramic dish, by the way the picture does not look anywhere near an incineration to me, you still have acidic chloride salts that have not been incinerated, the iron hydroxide’s and your gold foils, from the picture it just looks like you just dried these, before I would attempt an incineration on this type of material that had come from acidic chloride solutions, I would have rinsed the material and foils in a solution of sodium hydroxide to neutralize any remaining acid(or acidic metal salts), forming a salt water solution, and then rinse the powders very well to remove as much of the traces of chloride salts as I could, as gold chloride 

The reason I would try to remove chlorides or any residual HCl is because at high temperatures we can cook off chlorine and HCl from the salts or powders, these gases can dissolve gold or platinum group metals and carry our values off in the fumes.

For an interesting read on this subject, look for the patient by Oskar Erhart (1939 I believe), the patient called process for converting gold, platinum, and other metals of the platinum group into a dissolved form, here he uses a heated jacket reactor, over a burner, with powdered or fine particles of gold and PGM on a shelf sieve above the HCl liquid level he also bubbles chlorine gas into the HCl solution the gases formed from HCl and chlorine pass through the valuable metals dissolve them into the fumes which are condensed back to liquid in the reflux condenser, dripping back through the powders and into the HCl / chlorine solution.


Iron in solution can look like copper in solution green to almost green/black, actually it is fairly easy to have a blackish concentrated solution of iron and copper in the same solution, but if this solution is diluted copper will begin to precipitate out as a whitish copper I chloride.

Iron can also make a pretty yellow solution that can look just like a gold chloride solution.

And as we know if we have a copper chloride solution and if we have elemental Iron it can push the copper back out of solution forming copper metal powders and an Iron chloride solution.

AUH-R,
Actually all in all it looks like you are doing pretty well.
The pictures painted a better picture than your description alone.


With your powders in the ceramic dish on your hot plate, wash them in a dilute hydroxide solution, and hot water washes, let it settle well before decanting the solution, with a suction bulb and pipette.

Through out this process I would leave powders in the dish, only removing liquids of soluble metal solution leaving any insoluble powders, so give them time to settle well.

You do have quite a bit of iron and copper to deal with in those powders, as well as tin and lead.

I would then dry the powders on low heat, raising the heat to high after they are dried, crush the powders after dried, keep them crushed until they finished roasting, use your propane torch and get them glowing red hot, stir the roast well to get plenty of oxygen to oxidize the metals which will also oxidize the tin,.

Before trying to recover your gold from them, we will want to remove the base metals.

Let them cool and give them good boil in HCl after the incineration (taking the solution up with water to remove tin and the soluble chloride metals.
I would try to dissolve as much of the base metals into solution as I could before I tried to put gold into solution,

If the HCl is colored heavily with metals continue with Hot HCl washes till it will pick up no more metal, be sure to let the insoluble powders settle well before you decant liquids.

You can dissolve the lead chloride in boiling hot water rinses.

Moving the decanted solutions to settling jars (any values carried or other insoluble base metal powder will settle in the jar and may need to be reprocessed. 

Your lead chloride washes I would keep in a separate settling jar; the lead chloride will crystallize out as a white crystal after the water-cools, if the water is fairly clear after lead settles out the cool water can be returned to the powders and boiled again to pick up more lead (saving on water added to your waste stream).

After you can dissolve no more metals as a chloride solution, and your boiling hot water washes are picking up no more metals (judged by color or cooling lead crystals), your powders should be cleaned up enough to dissolve your gold, you can leave your gold in the ceramic dish, add HCl and small bleach additions to dissolve the gold, just barely warming your solution, after the gold goes into solution raise your heat a little to drive off free chlorine, when you have removed chlorine (here you can test for chlorine gas from the vapors of your solution, with a little ammonia in a lid of the bottle held in the fume of your solution, looking for that white smoke of ammonium chloride), once the chlorine is heated off you can shut off your stove cover your pot and let it settle out any insoluble salts, later decant your gold chloride solution through a filter into a clean jar for precipitating your gold.


----------



## AUH-R

Hi Butcher, thanks for the great informative pointers. Just to clarify the process you are describing is from the beginning with fresh pins?, as the stage I am at currently at with this particular lot, I believe I have already got rid of the solder.

Update on the cementation:







I have been stirring when I pass and also scraping the powder off the copper, best I can. I will test with Stannous when I get home from work tomorrow and If I get the all clear, I shall decant and filter the solution into a new waste container called SMB waste.

Once I have this powder shall I pick up from your incineration stage? for example; the master plan I have in my head right now to finish this lot is as follows:
1. Incinerate as per your guide.
2. Hot washes.
3. Follow Hoke's chapter 5 guidance - starting with the HNO3 treatment to get rid of the remaining copper.
4. SMB drop.

I had a lovely day off work today, the sun was shining and I did some acquaintance tests with cold HN03, which I found fascinating, surprising and also puzzling:

Firstly according to Hoke copper should be green, but my sample turned blue, I need to repeat this with another piece of copper before I conclude anything:





Brass gave me the colour green as anticipated because of the copper content:





Solder was a slow reaction:





Steel, no visible reaction:





Aluminum, no visible reaction:





Au electroplated, small reaction from the small amount of copper possibly:





I also took a sample of the grey scum, which I believe you suspected of being Lead chloride, I checked it in boiling water no reaction that I noticed. Here is a picture with a couple drops HNO3 added to this substance. It formed a white cloudy solution:







Great day, My wife and I finished some jobs we had in the garden and I got to have some fun for an hour with these tests! most enjoyable.

All the best,
AuH-R


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## butcher

Copper nitrate is actually blue, although it can look green if free nitrate is in solution.

When you dissolve lead chloride in boiling hot water, you will not see any reaction, the solution if pure lead chloride will be clear, when the water cools you will see a white precipitate, either long crystal needles or even a white powder.

It is good you are doing these getting acquainted experiments, keep it up with known substances.

you have fine powders this type of gold which will dissolve in HCl/ NaClO (bleach easily), the solution is much easier to deal with than Aqua regia, Aqua regia will work just fine, if you understand how to use it. 

yes Incineration of these powders would be one of the most important steps in my opinion, which ever process you choose, it will be beneficial in several ways.

Nice hill garden you have there.


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## AUH-R

Butcher,

Thanks again for your guidance, it helped me back on track:

Waste solution decanted and filtered, after copper bus treatment




All 3 copper bus bars looked the same, turned bright green when dried.




Black powder ready for 2nd attempt.




HN03 treatment - Incineration - + H20 washes looking better.




2nd dissolve in AR, I knew this time things were on the right track as the colour was beautiful.




After 3 evaporations and HCL additions.




4 parts volume H20 added.




SMB was added and I awoke to this lovely sight.




H20 boil washed and decanted probably x10 as I was ultra careful - HCL wash only once - then more H20 washes. 




Dried Au powder, ready for melting.




My first Au pea 8) weighing in at 1 gram! I'm one happy man.




Other side.





Thank you so much Butcher for your time, insight and knowledge!

I learnt so much on this journey, things I learnt that come to mind:

1. I need ultra clean, not just soap and water and good to the eye, chemically clean labware.
2. Save my powder and melt in large lots.
3. Incineration and cleaning of material is of the utmost importance, or you will have a headache further down the line.
4. Only use green fibre CPU's if you know that it will cost you a lot of money but on the upside you will learn alot as it is a difficult material, bring on the ceramics and fingers next  
5. Green fibre yield is 0.005grams of Au per CPU
6. As somebody else said on this forum, don't threat about every bit of Au other wise you will go crazy, like I nearly did by doing 10 boil washes trying to remove every bit of dust, as he said that is the angels bit


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## butcher

Looking at your pictures I can see you done a great job and have learned a lot.
great job.


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## AUH-R

butcher said:


> Looking at your pictures I can see you done a great job and have learned a lot.
> great job.




Thanks, that means a lot coming from you.

Best wishes,
AuH-R


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## 9kuuby9

Thanks for the great Post, AUH-R

The best way to complete your refining knowlage after reading Hoke is by conducting experiments around Refining.

You really did a good and clean job  Kudos!


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## Metalgold

Hello AUH-R,

I was curious to get a small idea on the yield for fiber cpu pins. Was the 1 gram you succeeded in recovering from 225 grams of pins or 50 grams? 

Thanks!


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## patnor1011

Your picture number 7 from top - where you added water. I would add distilled water or I would filter it before SMB as it looked cloudy, maybe it is just me but I just like my auric chloride crystal clear before drop. Button look nice. Good job.


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## AUH-R

Metalgold said:


> Hello AUH-R,
> 
> I was curious to get a small idea on the yield for fiber cpu pins. Was the 1 gram you succeeded in recovering from 225 grams of pins or 50 grams?
> 
> Thanks!



Hi Metalgold,

I have just gone through my records - I processed 181 fibre CPU's, the bulk being mobile P4. I had 225 grams of pins by weight, which I processed in full. I have just recently purchased some scales which are more accurate than the ones I used to weigh my pea. My finished weight is 0.75 grams which is accurate to within 0.02-/+ I also have some bits of Au left in the melting dish. 

My yield then is 0.0041 per CPU average. I know I lost Au in filters and also by some mistakes along the way. Hope this helps you.

Best wishes,



patnor1011 said:


> Your picture number 7 from top - where you added water. I would add distilled water or I would filter it before SMB as it looked cloudy, maybe it is just me but I just like my auric chloride crystal clear before drop. Button look nice. Good job.



Thanks for the input, it's nice to have positive comments from the experienced members here. You would not believe how hard it is to get distilled water in the UK at a reasonable cost. I refuse to pay the same for water as I do for my HCL at a £1.00 per litre. I have options to make it, but again I'm tight. When I have some time I will start collecting rainwater. Hoke does say that you don't need to use distilled water for any of the procedures in her book. Where I live they don't add fluoride, what would be the difference in purity between what I have now and if I had used distilled water?

Best wishes,


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## Geo

AUH-R, when rinsing or washing with water, i always put the all the water in a clean container. you would be surprised at how much more powder will settle out in a weeks time. you may have actually misplaced as much as you reclaimed.


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## AUH-R

Geo said:


> AUH-R, when rinsing or washing with water, i always put the all the water in a clean container. you would be surprised at how much more powder will settle out in a weeks time. you may have actually misplaced as much as you reclaimed.



Hi Geo,

I did find that I had more powder in my SMB waste water after a week, also when I was syphoning the hot water off during my washes and after it had settled I was finding some powder. We are talking nothing like half the amount again though. Have you processed green fibre processors before and got a yield of 0.0082 - 0.01 per CPU?

Best wishes,


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## Geo

theres a lot of different green fiber processors. pin-less P-4 has the least gold content and if im not too bad off, i believe the AMD athlon 64 x2 has the most. unless you listed every thing you had in the batch,no one could give you an expected yield and even then it would be a guess. 

i say you may have misplaced that much because from the time you reclaim the gold, every process you do to it leaves a little gold behind.whether its foils, solutions or powders. every time you stir or transfer or filter. the more experience you have, the less you will misplace.


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## gold4mike

For the reasons Geo posted, I use a gallon jug for my spent AuCl solution, one for the water rinses and one for the HCl washes. I don't mess with them until they're full and then, sometimes, only pour off the top half leaving the sediment in the bottom. 

There's quite an accumulation in a couple of them. Don't be too quick to dump ANYTHING!


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## gm19

Very good reading, thanks guys.


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## Geo

AUH-R, i just read over your journey all at once and would like to give a few pointers for your next batch if you dont mind? i think i would have responded sooner but as it went along over the span of time, things that came to mind got put aside. the dissolution of Kovar pins in hcl is a very time consuming process. the reaction with the iron is slow and the pins are basically a gold tube filled with iron (it helps me to think of them like that) the acid must start dissolving at the open end and work its way up to the tip. as the fresh acid moves up the tube, gasses from the reaction is moving out of the tube. this slows the reaction down even more. one thing i did that helped some was to grind the tips off using an emery wheel while they were still soldered to the base. this allows the acid access from both ends. another thing is adding a little oxidizer to the hcl when heated. i used H2O2 while the hcl was boiling. this converted some of the ferrous chloride (iron(II) chloride) into ferric chloride (iron(III) chloride) which in turn attacked the base metal more aggressively. i wasnt too concerned about dissolving any gold because as long as base metal remained in the solution, the gold would be a solid of some form. remember, it takes nearly a gallon of 32 baume hcl to dissolve two pounds of iron. a quart (946 mil's) should dissolve at least 250g of iron. forcing the acid to dissolve more is possible but unnecessary. when you heat the hcl and it evaporate to a higher concentration, the acid will gas off at one atmosphere quickly. it will emit more fumes in a shorter period of time than an AP bucket (if that is an option) will in a week. have you ever boiled hcl outside on a cool night with no breeze? after a short time, it will look like a fog has rolled in from the ocean. these fumes are still present in the bright daylight, its just less humid and you cant see them. since the fumes are hygroscopic, each tiny drop in the air will soak up several times its size in water. its like seeding a cloud on the ground. try and figure out some kind of fume control. it will save all the metal around where you are working, not to mention, your health.

im sticking with the AP buckets. i mix up a batch of solution from old solution that has sit up for awhile and turned bright emerald green and fresh hcl and drop the whole CPU's (minus heat spreader) in the AP and forget about it. after a week, filter out the floaters and rinse the bases back off into the bucket. rinse with clean water and swirl and pour. repeat until all the loose foils are in the filter. normally not a lot of base metal left. the filter for me is a large plastic colander with a piece of linen cloth for the filter. the liquid pours right through. it makes filtering the tiny flakes much easier later. i use a square plastic wash basin and take the cloth and lay it in the water in the tub foils down. almost all the foils will come off the cloth. i use a separate pan for a second rinse and a wringing out. i can either use the cloth again or put it in the filter bag. the foils will settle quickly in the clean water. decant slowly into a clean bucket.dont try to stop every flake as you will filter the rinse water again. you are trying to get the most you can get as fast as you can. use a coffee filter (if you want to see my filter set up its on my youtube channel at 10464jeff) to filter the rinse water and then move to the AP bucket. start by moving as much solution as possible into another bucket without disturbing any solids in the bottom. gently dip out the solution by submerging the dipper bottom first until liquid pours over the top and fills the vessel. when full, slowly lift the vessel trying not to create a vortex that will suck the foils up. the trick is to go slow. once you are close to the bottom, start pouring the solution through the filter. this will catch any solids down to 5 microns or larger. treat these foils as the ones from the cloth. whew, my carpal tunnel is yelling at me.


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## AUH-R

When I have enough low grade pins, fiber cpus and odds and sods. I will try this method. I think it may be really slow though. I have been soaking 486 lids for over 4 weeks in hcl outside and only now are the foils coming loose.


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## Feenixb1o7

Can gold recovery be done without boiling? I have no hot plate but I have a world of time. So if I just leave the pins in HCL for say a month, topping up regularly. Will that achieve the same?


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## Geo

Feenixb1o7 said:


> Can gold recovery be done without boiling? I have no hot plate but I have a world of time. So if I just leave the pins in HCL for say a month, topping up regularly. Will that achieve the same?



search for the AP process here on the forum.


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## Feenixb1o7

What I don't get is that HCL doesn't dissolve gold. So why can't I just leave gold plated pins in a HCL solution 'till the rest of the stuff is dissolved leaving the gold foils?


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## butcher

http://en.wikipedia.org/wiki/Reactivity_series

Metals below hydrogen will not dissolve in Hydrochloric acid HCl, so copper will not dissolve in HCl, but if the copper is oxidized to CuO then HCl will form copper chloride CuCl2, so metals below Hydrogen in the reactivity series need oxidizers to oxidize the metals before they will dissolve into solution.

Base metals above Hydrogen in the reactivity series will dissolve in HCl.

Gold is less reactive than copper, so it does not oxidize (lose electrons) as easy as copper does, so it takes a stronger oxidizer to oxidize (remove an electron from the gold atom) or to dissolve the gold, we can use this to oxidize copper and dissolve it into solution as a chloride, and leave the gold atom whole or undissolved, so we can recover the gold from the base metal.

The trick here is to have just enough oxidizer to dissolve copper, but not so much oxidizer that we will put gold into solution.


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## Feenixb1o7

Ah, nice thank you a full answer. Thanks for taking the time to explain. I'm a complete noob when it comes to chemistry so I'm still learning the very basics.
At least now I know why it can't be done like that, and why there are more steps.
Thing is, I'm not looking to get 99.9% gold, just enough to then mix with other metals to make a ring for an old friend, chances are I could leave the copper in it as I'll be adding some anyway.


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## Geo

CPU pins are different in composition. they are iron instead of copper. while AP will dissolve the iron in the pin, adding iron to your AP solution is not a good idea as it will eventually foul the solution. the Kovar (iron) pins can be digested in hot hcl unlike copper. in this way, you can process iron pins without fouling your AP.


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## Feenixb1o7

Ah, well I have only collected CPU pins, so then surely HCL will remove almost all the unwanted metals by itself? 
I never did find out, is it at all possible to do it with cold HCL, best I can do is make a small hot plate that hits 80c max as I have a small Thermoelectric Cooler/heater.


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## Geo

that much heat should work ok but at a slower rate. using cold hcl will have very little impact on the overall digestion of the iron base metal. it needs to be hot enough to keep the water evaporating. as the water evaporates, it concentrates the acid. do not leave unattended. do not let the reaction run dry. it will need to have hcl added to the reaction when the level gets low.


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## Feenixb1o7

Can you over heat it? Say if I put it on a camping stove and let it go will it be too much? It's the same camping stove I use to melt pewter so easily hits 300c


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## Geo

i dont recommend a boil, but if you do allow to boil, be sure to cover. the hotter you allow the solution to become, the faster the acid will be depleted. you dont want the acid to evaporate, just the excess water in the acid.


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## Feenixb1o7

Okay, then 80c it is, as long as it works, just takes longer I'm fine with that. I have latex gloves, goggles, a rubber apron and a cheap respirator, flasks and beakers. Next question, filters. Anything you recommend? Ideally I'd like to spend as little as possible because I'm a cheap bugger. Will coffee filters work


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## Geo

coffee filters works great for gold foils. a coffee filter filters to about 5 microns.

personally, i try not to filter as it just traps some gold every time you use one. after the dissolution is complete, spray down any floaters with a spray bottle (water) and after everything settles, decant slowly leaving the gold foils behind. do this down to the point you cant remove more without pouring out foils. add fresh hcl to cover the foils and warm. decant after rinsing well. refill with water and repeat until the water stays clear.


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## jure

Hi,
i am new to this forum so please excuse me if i am posting in the wrong topic, i came to this post from sam's page. So to my conserns, i am going to try this procedure for my first time and i need some help.
First of is it better to use just HcL and boil as described here, or to add some H2O2 to HcL ? If H2O2 is better how much should i use it ? 

I am allso wondering if there is a diferent procedure for other goldplated things from computers ore are you using just pins becouse they are the easyest to colect? For example can i mix pins and (board conectors)* in the same batch?

* i dont know if that is the real name for what i have, i mean the gold stripes on a green board on the edges of motherboards. Hope you understand me 

Thanks for your help!

Jure


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## butcher

jure,

Welcome to the forum, I would like to help you get started, but in order for me to do this, you need to understand, that you will need to study, your best bet for now is to forget about getting gold of of your scrap with chemicals, at this point all that is going to do is have you loosing your gold, and making dangerous messes, you do not know how to handle, and toxic chemical waste that you would be creating with no understanding of what to do with , basically putting yourself and others in danger.

To begin concentrate on study of this forum, download Hokes book and begin reading it, start the forum in the guided tour (in the general chat section), when you are ready for chemicals begin with the experiments you read about in Hokes book, study the safety section and dealing with waste.

While you are studying collect your scrap, learn how to identify and separate it by types of material, learn how to prepare the material before you even begin recovery, learn what processes are used to recover that type of material...

While this sounds like it will take a long time to get gold with all of this study (it is true, it will) but without this study you will have little chance of learning how to get that gold.

Then you will learn how much of this or that you need, you will know how the reactions work and in what cases the will not work, how each type of scrap needs to be processed, and how to recover and refine gold.

There is much more to this than just simply answering your question, and telling you how to get the gold, you need to gain an education first.


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## trix

I am newbie to this forum and i am looking for an answer ,i have a big amount of gold plated pins ,collected from several items ,including ,exchange servers,cpu , boards etc they weight around 50 kg ,what i would like to know is beside AR process is there any way i can separate gold from pins without loosing pins , means i dont want pins to be dissolved and gold get separated , i hope i am able to make my point clear any help would be highly appreciated and thankx in advance 
you guys are doing great work


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## butcher

trix,
To do what you are asking will take quite a bit of study.
There are several methods to get the gold and base metals like copper or iron separated.
some methods can take the gold off of the pins without attacking the base metals much,what comes to mind, cyanide (very dangerous) and the concentrated sulfuric acid cell (also dangerous but with study can be done safely).

There are also methods where the base metals are dissolved away leaving the gold as foils which can then be refined to pure gold.

All of these use dangerous acids, and procedures that can present dangers, although not that hard to do , they are not necessarily simple, and it takes quite a bit of study to learn, you may see some video or read about it and get the idea it is simple, like seeing a mechanic repair a car can look simple, but without the knowledge or skills of the mechanic, if you tried the repair it most likely would not go well, especially if you had no understanding of the mechanical workings.

If you wish to learn it is all here on the forum, but you will have to be willing to spend a lot of time studying.

There are no easy answers to most of these questions. 
You either remove the base metal or you remove the gold, easier said than done.
I may not have understood the question.


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## drlakic

Can HCl/Chlorox/water in specific proportion dissolve just gold and not iron on an iron pins?

drlakic


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## butcher

drlakic,

No.
Many metals will dissolve easily as chlorides, especially one as oxidizing in nature as the Hydrochloric acid and hypochlorite solution, the more reactive the metal the easier it will dissolve into solution, this solution can hold several metals at once, the more reactive metals will dissolve into solution and push out the the less reactive metal like gold out of solution.

To get a better understanding do some research on the reactivity series of metals, and displacement chemical reactions, Google these terms to find the material to study.

These are a good place to begin with:
http://en.wikipedia.org/wiki/Single_displacement_reaction
http://en.wikipedia.org/wiki/Reactivity_series


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## sharkhook

What a great read. I will be reading this one again.


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## Captobvious

Feenixb1o7 said:


> Ah, well I have only collected CPU pins, so then surely HCL will remove almost all the unwanted metals by itself?
> I never did find out, is it at all possible to do it with cold HCL, best I can do is make a small hot plate that hits 80c max as I have a small Thermoelectric Cooler/heater.



I realize I'm a bit late to the party, but you can get a hot plate for not that much at Walmart, here's the one that I use and it works GREAT!

http://www.walmart.com/ip/Farberware-Double-Burner-Black/22866796


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## kennith76

when doing Pins from fiber chips:
I have followed the steps posted on your website. I find that gold foils are not in fact floating they mix in the sediment (which there seems to be alot of). what could I be doing wrong to cause this? now that being said, is there a simple way to separate the gold from the sediment? Thank you for your time and resources, they have been very helpful


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## joubjonn

If you don't see foils then you may have too much oxidizer and the gold is being dissolved and cemented back out as sediment as long as copper is still available to cement the gold. Test your solution with Stannous to check for dissolved gold. It's probably not an issue.


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## kennith76

joubjonn said:


> If you don't see foils then you may have too much oxidizer and the gold is being dissolved and cemented back out as sediment as long as copper is still available to cement the gold. Test your solution with Stannous to check for dissolved gold. It's probably not an issue.



how do i prevent this from happening?


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## joubjonn

BUMP

Good thread. I was searching around, I have 100 green fiber various intel cpu's. Mostly the Xeon's from 2005 era. Small pins, some MLCC's. Also had a dozen or so P3 with big pins and some older Xeon (2001 era) on those the pins do not seem to want to come off at all. I'm using a small propane torch with a box fan sucking the air as I do this. 1 hour and I have 40 grams of CPU pins (nice pile of MLCC's) and still have 70 cpu's to go. I will incinerate the pins after I remove all of them as they are dirty with grease. Then I'll do a quick HCl bath to remove some tin, decant, top off with new HCl and add small amounts of Nitric until they dissolve. This seems like the best method for kovar.


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## saadat68

Hi
Why many members here advise add pins to AP?
These pins have tin and it isn't good even in AP solution

What do you think about this process
1- Add pins (mixed pins) to hcl for couple of weeks to dissolve kovar pins and tin then decant and wash

2- Add residue to AP solution to dissolve copper pins then decant and wash

3- Boil residue in hcl then filter gold foils


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## saadat68

Also we can do this process. It is faster
1- Boil mixed pins in hcl for 3 hours then decant and wash
2- Add AP to pins 
3- filter gold foils


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## Geo

Some people just doesn't have enough time to wait. Tin is not a problem in the copper(II) chloride leeching process. The tin does cement copper while it is dissolving but is overcome by having a highly acidic solution. The tin does not remain in solution for long. Simply by the nature of the process, the highly oxidized solution will oxidize the tin(II) chloride much faster that stannous chloride test solution. The tin oxide is a white, non-soluble powder that gives little to no problem when dissolving the foils. In the instance that the pins have a higher amount of tin than normal for whatever reason, the oxidized tin can be treated hydroxide and rinsed from the foils before dissolving the foils.


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## saadat68

Thanks Geo
-------
Sam doesn't explain how recovery foils in his process
Because these foils have base metals and some undissolved pins do we must add them to aqua regia? Or just hcl-cl do the job?
Is it better first recovery gold with hcl-cl and then add residue to aqua regia?
Thanks


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## Geo

If there is any other solid metal besides gold foils, HCl and bleach will cause you to lose some gold. I recommend aqua regia. If you know there is still base metal, the HCl/Cl will dissolve some foils but any metal from the pins will start cementing the gold as soon as it dissolves. You will have a finely divided black gold powder that will be very easy to rinse out. When you dissolve the foils, you should make sure that ALL of the metals dissolves.


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