Motherboard pins, the logical sequence

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mike6

mike6

Well-known member
Joined
Jan 26, 2015
Messages
65
Location
South Africa
Gentlemen

Allow me to open my enquiry with a quote by British labour party politician, Denis Healey.

Healey’s First Law Of Holes: "When in one, stop digging.”

I have spent the past few months exploring the feasibility of extracting gold from “small socket” and “large socket “ motherboards, as defined by “Boardsort”.

To date my efforts have been focused mainly on the pre- refining task of de-populating the boards, and sorting the components into value sequences.

To this end, I procured 1100 pounds (500 kg) of motherboards, and set about reducing the motherboards to “bare board level. I made use of two industrial Ryobi MP 300 multi tools, both of which are on the verge of failing mechanically at the oscillating head.

Aside from the CPU’s, some 29.76 pounds (13.6 kg) of IC’s (including flat packs, both large and tiny) were harvested. North/south bridge chips yielded 12.56 pounds (5.7 kg)

The remaining gold bearing material is contained on the plated pins found in the PCI slots, IDE connectors, AGP slots, DRAM memory slots, serial ports, parallel ports, LAN ports, usb ports and CPU socket connector pins.

It is this vast collection of pins that frustrate me to my core.

I have taken a representative sample of these mixed pins, and after pyrolysing and ball milling them to remove the plastics, cast a bar for XRF scanning. The scan shows the presence of Au, Cu, Pb, Zn, Ni, Fe, and Ag.

I have worn out two pairs of glasses reading the “pin” posts, only to discover that I am now more confused about pin processing than when I started.

I am not clear on the sequence of chemical events that need to take place to remove the undesirable elements prior to the aqua regia process.

My major confusion lies in which sequence to use the Nitric, Hydrochloric, and sulphuric acids.

Please understand, that I am not looking for a quick recipe on how to process pins, but rather a lesson on why one should first remove copper and zinc before iron and nickel, and leave the lead for last, or vice versa if that is the case.

Thank you for your consideration.
Mike
 
Mike, this is just my opinion, but dissolving pins to recover the gold plating is an expensive way to go. Pins are primarily base metal, so it takes a lot of acid to get a little gold.

By contrast, using a sulfuric acid stripping cell dissolves the gold and leaves the base metal intact. Most of the sulfuric acid can be reused. It is not without its hazards. Concentrated sulfuric acid is dangerous, so be sure to study the process thoroughly before putting one together.

If I had a large quantity of gold plated material to process, I would build an appropriately sized stripping cell with a tumbler basket to ensure complete stripping.

Dave
 
Please don't take this wrong.

But if you are not sure on which sequence or how to use your chemicals then you possibly have not done enough reading and studying.

There is a good chance that you have left gold in your ball mill, pyrolyzing ( loosing some PM's from the exhaust) and in your flux during your melting procedure.

Basicly you have made a large ingot equal to the gold drop ingots sold on ebay that is of low quality and content of gold.

Most of the components you named are of low quality in gold content.

You might want to look into a copper sulphate cell to process the ingot you have.
 
Thanks Dave and Barren, for your replies.

I have been under the impression that a tumbler type sulphuric cell would not work for the minimal gold plated area contained in these low grade pins. I seem to recall Chris having some reservations as to its efficacy for this type of raw material in one of his posts. I will search out the relevant posts and review.

I apologize for not being clear enough in my post, that the bar cast from the representative pin sample was meant only to determine composition metals, and their percentages. I have no intention of casting Ebay bars, nor do I wish to refine the indicator bar that I cast. It's primary purpose has been fulfilled, and it now serves its secondary purpose as a paper weight.

With regard to reading and studying, foolish is the man who believes that this activity is finite. A point, however, is reached when studying, that questions on the subject matter need to be clarified by the student to enable a fuller understanding.

Theoretically, I am aware of which individual acids react with specific metals, as well as what the byproducts of these reactions will be. My question is simply the following: When processing the types of pins described in my OP, is it suggested that the Nitric step take place before the Hydrochloric step, or should it take place vice versa.

I gratefully take your answer in the spirit in which it was intended, along with your caveat, "Please don't take this wrong", but the reason that I asked the question, is that I genuinely do not comprehend the Nitric/Hydrochloric sequence, and reading and studying in isolation is not providing me with an answer.

Being a new student on the GRF, and being fully versed in forum culture, I take great care in looking for answers on my own, prior to wasting anyone's time, I further agonize for hours on the content of my posts, so as to be taken seriously, and just as importantly, to avoid thinly disguised admonitions, which I feel should be reserved for the "quick fixers", "fly by nights" and those with entitlement issues. Please don't take this the wrong way.

Mike
 
Sulfuric cell is your best bet Mike. What are you doing with the now stripped mother boards? What is the weight of the sample bar you made from the pins?
 
FrugalRefiner said:
Mike, this is just my opinion, but dissolving pins to recover the gold plating is an expensive way to go. Pins are primarily base metal, so it takes a lot of acid to get a little gold.

By contrast, using a sulfuric acid stripping cell dissolves the gold and leaves the base metal intact. Most of the sulfuric acid can be reused. It is not without its hazards. Concentrated sulfuric acid is dangerous, so be sure to study the process thoroughly before putting one together.

If I had a large quantity of gold plated material to process, I would build an appropriately sized stripping cell with a tumbler basket to ensure complete stripping.

Dave
Click to expand...

I believe this would be the easiest way to process pins also. I have dissolved pins in the past, but it takes a while and creates a good amount of waste, besides costing more.

mike6 said:
Gentlemen
Click to expand...

This is off subject but,

Might I add, that you have exemplary linguistic skills. I too, am well versed in speaking with others. (I just act like I don't because people look at me wierd :lol: ) I do occasionally have the tendancy to configure my speech pattern according to those of whom which I converse. It has been my utmost delight having the privilage of reading this thread.

I regret however, that I am incapable of furthering your studies upon the subject at hand, for the time being. Good luck to you sir, may you achieve the solution to your query forthwith.

Edit - This is the link to the thread, I have been posting in regarding the pins that I have dissolved, if you feel that it may help you. (I didn't use nitric, just HCl/H2O2) http://goldrefiningforum.com/phpBB3/viewtopic.php?t=22285
 
Gentlemen

Thank you for your responses, and kind words.The bar cast for metal identification weighs 96 grams. I did however grind a few flat surfaces on the bar after casting, using a sanding disc on an angle grinder to facilitate the XRF reader.

The general consensus that a sulphuric cell will be the best method of processing the pins, is indeed good news. The thought of the volume of chemicals and resultant wastes produced by total dissolution of pins in a hydro metallurgical process was beginning to further erode my confidence.

Fortunately, I have been collecting components, such as a barbecue rotisserie, salad spinner and pvc components to put together a prototype rotating sulphuric cell. I have in the past seen devices on the forum, from which I will take my inspiration.

Thank you to all participants in this discussion, for spending some of your valuable time on me.
Mike
 
Disclaimer: I've never built one. [Edit: And my first cell attempt went horribly nothingly.] But I am but keenly interested.

Your barbecue rotisserie may be on the 'overkill' side of thing. The idea of mechanising it has been discussed in one of the threads to which you refer. The consensus was that motorising it is probably unnecessary, given that it takes but a minute or two in each position. If I remember correctly this came from GSP/Chris and I'm inclined to fully agree; that turning a shaft turned by hand every minute or so should be more than sufficient.

If you had so much material that you needed a conveyor belt feeding stock in/out, that would be a different story.
 
mike6 said:
Theoretically, I am aware of which individual acids react with specific metals, as well as what the byproducts of these reactions will be. My question is simply the following: When processing the types of pins described in my OP, is it suggested that the Nitric step take place before the Hydrochloric step, or should it take place vice versa.
Click to expand...
I'll answer your question in a general way. It depends. :p

You've probably seen conflicting information for several reasons. First is that different refiners have personal preferences based on their own experiences. We are all creatures of habit. If we've tried something and achieved a positive result, we'll probably do it again.

Second is the availability and cost of the acids. If nitric is expensive/hard to obtain, HCl becomes the go to tool in the toolbox. If nitric is cheap and readily available, it can be a fast, efficient way to dissolve many metals.

Third, and probably most important, is the type of feedstock you're working with. If there is no tin present, you might go straight to nitric for a fast dissolution. But tin and nitric don't play well together, creating metastannic acid, which is difficult to filter and can tie up your values. If tin is present in the form of solder, HCl will dissolve it cleanly. But tin can also be part of the alloy of the base metal and it would not be fully removed until the base metal is dissolved.

If I had a lot of pins, and I could not use a stripping cell, I would do small scale tests with both acids. It's the best way to know what will work best on your pins. Choose what seems to work best and scale it up a bit. What works on a test tube scale might not work at the 5 gallon bucket level, so move up to a small beaker level. If that still works well, scale up some more.

I hope that helps. It's not a definitive answer, but that's just the nature of what we do. And as always, if you're going from either acid to the other, be sure to incinerate between the two.

Dave
 
I mentioned the copper sulphate cell for the bar that had been poured, not for doing the pins. I would stear away from the sulphuric cell for pins off of mother boards as the values are too low and it takes to much time to recover with the pins being low grade. I would only use the sulphuric cell for high grade pins or large plated items with a large excess of base metals. For low grade pins or other items from mother boards I would suggest you use the chopper chloride method so you are not spending a lot of time for the low yield and it is a lot less dangerous than working with a sulphuric acid.
 
Thank you, Dave, Jason and Barren, for your responses.

Dave, your post makes perfect sense. The fact that home refining is a series of compromises, becomes clearer to me with each passing experiment, day, batch, article read. (Select one or all)

I am fortunate that my access to the work horse chemicals (HN03, HCL and H2SO4) in most concentrations, is not limited, and pricing is not prohibitive. As long as I toe the line regarding safety and environmental affairs, I am not hindered by the bureaucrats. In most cases, I am able to build or procure the equipment required for the home refining processes. A working knowledge of the chemical processes, as well as healthy respect for personal and work space safety rounds off my current personal refining position.

One might say that this particular combination of resource and skill sets, places me in the position where compromise in process can be drastically reduced, and that, for lack of a better word, the “correct” process can now be followed.

I believe I should qualify and quantify my statements in the previous paragraph, for as you have stated, personal process preference, as a variable, certainly does play a role, and as the old saying goes, “One man’s meat, is another man’s poison.”

Technically speaking, the low grade pins sourced from small and large socket motherboard connection ports, (and indeed, these are the subject of this thread), could be refined using pyro metallurgical, hydro metallurgical, or electro metallurgical processes as the dominant, or primary step, followed, of course by a possible combination of all or some of the processes for the final steps. Quite obviously, the individual now selects his process choice based on his personal appetites regarding return on investment, both time and financial, process efficacy based on personal circumstance, or perhaps he tries all three processes for the satisfaction of gaining knowledge.

Elsewhere on this board, I have asked for and received invaluable advice pertaining to the pyro metallurgical processing of motherboard components, so that particular process is already under discussion.

As you stated in your post, Dave, I understand that the “conflicting information” surrounding the hydro metallurgical processing of low grade pins, remains in the vast majority of cases theoretically sound, and the fact that individuals achieve the desired result, which in essence is a piece of gold for their efforts, is not in dispute. The question, however, remains, all things being equal, what would be the best way?

I am certain that as an administrator, you would agree that the subject of low grade pins resides in the murkier waters of the forum, with almost daily new questions, (most of which have already been answered a multitude of times), being added to further cloud the issue.

The processing of low grade pins using the hydro metallurgical process is finite. It becomes infinite and conflicting when an individual’s personal variables are introduced, and technically, these variables should have absolutely no influence on the establishment of an efficient core process. Only once the question,” how best should it be done?”, has been answered, should individual variables be introduced, and the core process modified to an individuals personal circumstances.

I feel that by taking the above approach, the horse will change its location from the rear of the cart, to the "before" position, and instead of conflict, forward motion will occur.

I would appreciate the forum’s constructive criticism of my argument, as well as suggestions, in broad strokes, to my proposed “low grade pins, core process”

As always, thank you for affording me your valuable time.
Mike
 
Barren Realms 007 said:
I mentioned the copper sulphate cell for the bar that had been poured, not for doing the pins. I would stear away from the sulphuric cell for pins off of mother boards as the values are too low and it takes to much time to recover with the pins being low grade. I would only use the sulphuric cell for high grade pins or large plated items with a large excess of base metals. For low grade pins or other items from mother boards I would suggest you use the chopper chloride method so you are not spending a lot of time for the low yield and it is a lot less dangerous than working with a sulphuric acid.
Click to expand...

Hello everyone.

Being as I am, I usually like to go deep on the processes I use and learn what's behind everything that happens.
For example, I've been using the AP method for a while with gold fingers, and searched a lot to understand what happens "behind the backstage" :) I think I currently have a solid understanding of how the AP process works, the reactions involved and how to get it going. And the rest comes with time and experience, I think.
Knowing this, and considering I am thinking about using the sulphuric cell for the same purpose as the OP (deplating pins from motherboards), I came up to this post while searching on the forum, and coming across the above statement from Barren, I would like to question why wouldn't the sulphuric cell be the best option for the gold plated pins. I understand that the plating may be thin but, is it a matter of time consumed vs gold value recovered? Are there more reasons why the cell is not the best process to use?

From your knowledge, is there any document/webpage I can read to get a deeper knowledge of the sulphuric cell? Been searching in the forum and have not been sucessfull in finding what I'm looking for.

Kind regards,
Winged
 
One time a few years back, I got a 5gal bucket ful of gold plated flat where. After reading a few things on reclaiming the gold. I figured one would be worth a shot. (Experiment time) I went and got a old battery out of the back of the truck, a battery charger and a gold ring. I dumped the sfuric acid into the container, clipped the gold ring to the positive to the side of the container with the ring in the solution as much as possible. Then took the negative and clipped it to a few pieces of the gold flatware. What ended up happening was the plating on the flatware returned to the gold ring. A 4g ring was 15 grams after a week of repetitive swapping out with freash plated flatware. I was going to try this with pins.
It also works with silver as my first test was plating a stainless butterknife with silver then removed that silver plate to a sterling ring with the same process.
 

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