processing mass amounts of motherboards

[samuldacamul]

I am a senior in high school this year and my senior project if recycling computers, and part of that is recovering gold. I have already researched the process for hours and have explored this forum in depth. So here is my question.

What would be the best way to process a couple hundred pounds of circuit boards? I am using 5 gallon buckets and the sodium nitrate method for this project and already have a ventilation system so that is already worked out, but I don't know how to get the max amount of gold from the boards. I have tried to crush them by hand, which doesn't work well at all. I have seen where people use head guns and grills to remove components, but then how would you crush then from there? Does anyone on this forum process large scrap other than processors and high yield items? Thanks for any help.

 

[patnor1011]

I do not believe that you will be able to accomplish that task in your garage or shed. What we do here is removing gold plated items and process these selectively. To process whole motherboard is beyond ability of normal person due to huge amount of metals and compounds in them. It cant be done at home if you want to stay safe and not spend more than they can bring in. They are generally incinerated, whatever come off is separated and processed in different settings and ways. There is only very small amount of gold and only on some specific types of motherboards. Most of gold is on pins and contacts and again it is only very small amount compared to weight of motherboards. Fractions of one percent - I believe that I can say.

 

[samuldacamul]

Ok thank you for the reply. But here's another question. How come circuit boards sell for so much on ebay? I collected all mine for free... but I mean I have over 100 pounds of the stuff, and I see like 10 pounds go for like 45 dollars.

 

[patnor1011]

It is because most of people doing that are blind and with gold fever. They fell for nice words, pictures and did not do their homework. It is a known thing that packaging improve sales. It is a good salesman and dumb customer who push prices that high. That is actually one safe way how to extract gold from them. Sell them for that high price and buy bullion. You will have way more than if you attempt to recycle them.
This is pure speculation but pretty close to reality:
So you have 100 pounds of them. That may get you 270$ if sold to middleman. It means that they may be worth 540$ but...
It do not mean that they contain 540$ in gold. Most of money in MB are locked in copper, aluminum, steel, tin. There might be 40-50 pounds of copper there, most of countries (I don't know if USA too) recycles and pay for plastics from them too. There is aluminum, iron, tin which are valuable metals too. All those mentioned are the bulk of that hypothetical 540$ which 100 pounds of MB may be worth.

 

[nickvc]

I think Pat has given you a pretty accurate picture of how e scrap is treated but I will add that certain parts may also contain traces of platinum group metals.
Most of the forum is dedicated to urban mining of one sort or another but we only recover and refine the easier materials due to the problems associated with incinerating safely quantities of very toxic materials and then having furnaces large enough to basically smelt the metallics to get large dore bars which are shipped to the copper refiners.
If you search the forum there's a wonderful post by 4metals on sampling and treatment of this type of scrap which will give you a good idea of how difficult it is for small operators to enter the market and why we cherry pick the best parts and trade the rest as Pat pointed out, and again I agree with his view on the sales of e scrap on Ebay it's driven by hope or greed not knowledge and many items sell for much more than it contains in metal.
I wish you luck with your project but I think you may well have picked an area were recycling can only go so far due to the high cost of recovery for the hobbyist or small refiner.

 

[samuldacamul]

Thank you guys for all the great info. I have already started refining my processors and fingers and it has worked great! Also, I have seen videos where people have just removed the black chips from boards and crushed them and gotten a hefty yield. Has anyone ever done this?

 

[patnor1011]

Yes, but it is hard to determine which one contains what. Generally nearly all of them contains copper, some gold, silver, palladium and maybe platinum. I know that black chips in zip drives boards have nice amount of gold in them or black chips on some network cards made in mexico - I dont remember which one, but there is post on forum somewhere. Try to search flatpack, IC...