# Printed Circuit Boards recycling system



## kjavanb123 (Mar 31, 2013)

All,

After consulting with a firm in Singapore as I am waiting for him to provide me with the list of equipments and prices I had a brainstorm on how to process PCBs for precious metals.

Following is the concept design for a system that will recover 98% plus of precious metals along with base metals. I am sure your input on upgrading this system will help a lot.

1. PCBs feed, 200 kgs per day, on a 24 working day per month it would be around 2.8 metric tonnes of PCBs per month.

2. Manual Separation of components:
2-A: South/North bridges ICs
2-B: Pins from slots
2-C: Pins from CPU sockets
2-D: Pins from connectors
2-E: The remains of the PCBs

3- Process 1:
To process the 2-A, suggested incinerating, following by a grinding and using either centrifugal separation to extract the free gold particles from the black ICs

4- Process 2:
This process will extract gold from gold plating components which is 2-B, C,D also the plastic layer which black ICs from 2-A are laying on top of it. Suggested method for this process is either sulfuric cell, or cyanide leach.

5- Process 3:
The remaining of dismantled PCBs are to be crushed and milled into 0.5mm by size, then dissolution by reagent such as sulfuric or nitric acid to remove base metals such as copper, tin, and nickel from the boards, extract copper from the solution using electrolysis. The spent solution after copper stripping which contains tin, nickel and I assume some silver could be sold to the tin/nickel refiner.

6- Waste Solution treatment:
Any of these processes would produce some solution that need to be taken care of to be released into the sewage system, waste in this design are cyanide leach waste solution, and waste from process 3 which still contain some value metals such as tin and nickel. So only cyanide leach waste solution, and waste solution
from process 1 need to be taken care of. 

7- Fume hood:
Each of processes would require some fume hood that is connected to the a central fume scrubber. Different fume hood designs are discussed on the forum.

9- Fume Scrubber:
The collected fumes from processes would be safe using fume scrubber, can an automobile catalyst converter be used as fume scrubber?

Your input on this system is appreciated.

Thanks
Kevin


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## rusty (Mar 31, 2013)

kjavanb123 said:


> All,
> 
> After consulting with a firm in Singapore as I am waiting for him to provide me with the list of equipments and prices I had a brainstorm on how to process PCBs for precious metals.
> 
> ...



You forgot a filter press to handle the mass amount of leaches you'll have to filter.


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## kjavanb123 (Apr 1, 2013)

rusty,

well noted on that. I also added a centrifugal dryer to the list, which will remove the any remaining solution from the solids after each leach. One thing though, any traces of silver and palladium are inside MMC capacitors, do slot pins or CPU socket pins contain any silver? would silver also be dissolved using cyanide leach?
If not then I have to switch to AR leach instead of cyanide leach.

Also from another post I made, SIPI analysis on misc circuit boards mentioned 5.7 toz of gold, I assume the circuit boards mentioned have their cards and CPUs removed prior to this analysis.

This is a flow chart for this system




Thanks and regards,
Kevin


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## kjavanb123 (Apr 1, 2013)

All,

I worked on previous design and modified to the following,
View attachment Concept Flow Chart for recycling facility in Mashhad.docx


Regards,
Kevin


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## gaurav_347 (May 28, 2014)

Kevin,

Are you following this exact same path as of now? if not then what route have you chosen for the best possible way to process the pcbs on a commercial scale?

Thank you.


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## kjavanb123 (May 28, 2014)

Guarav,

Thanks for your interest in my old post, I have followed some of the steps mentioned here; however, some changes I had to make as following, please note price of labor is fairly inexpensive compare to other parts of the world, so you might be put that into consideration;

1- Collect the boards
2- Log in the total weight
3- Manually separate the boards into different categories, such as telecomm boards, graphics, RAMs etcs,
4- Log in the weight for each categories
5- Using a worker to separate all gold plated items such as pins, connectors and fingers and put them in different buckets
6- Removing all the ICs and put them in different buckets labeled as low, medium and high grades
7- Removing all the golden transistors
8- AR all ceramic CPUs, log in the gold and silver produced
9- Cyanide leach the items 5 and 7, drop the gold, purify it and log it.
10- Incinerate items 6, and process them separately based on low medium and high grades
11- Ball mill them item 10 separate to ash, ferrous and non-ferrous.
12- Use blue bowl, sluice or jig to concentrate the ashes then drop the PMs
13- Cyanide leach the ferrous from item 11
14- Melt non-ferrous into copper anode
15- Grind all the remaining boards to fine powder
16- Use gravity separation to plastics and metals
17- Market and sell the plastics
18- Melt the metals to copper anode and assay sell to copper refinery

Hope that helps
Kevin


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## gaurav_347 (May 28, 2014)

Kevin,

Thank you so much for your reply. You have cleared all my confusion . like you i am a commercial scale e-recycler. The labor is quite cheap in India So following this method would be worthwhile. As of today we were shredding the pcbs after categorizing them in different grades -.granulating to size of 0.5-2mm -> separate metals and plastics and then shipping off these mixed metal fractions to a refiner in Japan. The most difficult part was that our assay and the refinery's were way off . So as of now we have stopped doing that. 

A few more questions.

1) how are you depopulating these boards?

2)are you collecting your own pcbs or buying it from the scrap market?

3) what kind of furnace and incinerator are you using?

4) how many tons per month can you process with this method?

Thank you once again i really appreciate it.


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## kjavanb123 (May 28, 2014)

Hi,

I am glad my response was helpful, please find my responds to your questions as following;

1- Depopulation is done manually, by workforce, each worker can depopulate the boards on average 25kg per day, using mostly chiesel, hammer, and nail cutter.

2- Majority of my boards are from scrap yards, the major ones, roughly around 4tons per month, the city provided the rest as in cases like TVs, CRTs and computer desktops etc, but scrap yards provide me with boards.

3- I have a cupola furnace for right now, if you drop in few ICs per load, the amount of smoke is minimal, but I am trying to build a grinder that produce a fine powder from ICs so no smokes.

4- I am planning to do 4 tons per month right now, will increase in near future once I could cost/profit analyze this system, plus learn more.

Hope that helps
Kevin


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## gaurav_347 (May 28, 2014)

Thank you once again for all your help . Please pm me your email . I would like to send you some videos that i got from a recycling facility showing how they depopulate these boards. i tried it today and it was much faster . Took less than 3 minutes to scrape off the ic board.


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## Pantherlikher (May 29, 2014)

Well, do not hold the rest of us in suspense.
Post the video here so we can all see.

B.S.


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## gaurav_347 (May 29, 2014)

The video is of a few seconds but you will get the point . Hope it helps!


video added! check it out !
http://youtu.be/kAmROt0C5sQ

mods please embed the video. Not able to do it by myself. Thank you


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## g_axelsson (May 29, 2014)

[youtube]http://www.youtube.com/watch?v=kAmROt0C5sQ[/youtube]

If you press "quote" then you could see how I did to embed the video. Most important is to remove the "s" in "https".

Suddenly I feel a lot happier to have my ordinary job.

Göran


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## gaurav_347 (May 30, 2014)

[youtube]http://www.youtube.com/watch?v=p52mF6fkko0[/youtube]

Hope this helps too!


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## Lou (May 30, 2014)

If you're going to do thermal reduction, you should probably just stop after the organics are off, blend, size, split, assay, and leave it to the copper smelter. Negotiate yourself a good advance (they will charge interest on your collateralized "loan" of material til they sell it).

Getting into this yourself is kind of silly unless you have a million or so pounds to do a month.


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## gaurav_347 (May 30, 2014)

Thank you lou. We collect about a few metric tons per month of various pcbs. We don't own such an equipment. We usually trade it off to the refiners in Japan. But we really want to start refining at our facility. Just getting our basics cleared as of now. Thanks to this wonderful community and the pool of knowledge maybe in the near future we shall be able to do so.


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## kjavanb123 (May 31, 2014)

Gaurav

Thanks for your comments, I forgot to mention that workers during disassembly do not touch any SMD or MLCCs, as they get grinded to fine powder with the rest of the unpopulated boards.

Regards,
Kevin


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## gaurav_347 (May 31, 2014)

Kevin,

Thank you for that info. Until now we were grinding the pcb as a whole without depopulating it. After reading your posts it sounded much feasible to depopulate the boards for the main parts and grinding the pcbs to recover copper rich mixture! Thank you once again. I really appreciate it.

Regards,
Gaurav


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## kjavanb123 (Jun 29, 2014)

All,

After some testing and some succesful result, please find the following as a system I am working to recycle and refine PCBs.

1- Collecting and log in the type and weight of each PCB.
2- Removing gold plated items (i.e. fingers, pins, green part of N/S bridges, connectors etc)
3- Removing gold filled items (i.e. ICs, black part of N/S bridges, ceramic CPUs)
4- Removing all the other items, except MLCCs and resistors.
5- Hcl leaching the item 4, to scrape off the MLCCs, Tantalium caps and resistors
6- Cyanide leach items 2
7- Incincerate then ball mill and separate ashe, ferrous and non ferrous item 3
8- Melt the ashes from item 7, use silver cell to get silver and gold as slime.
9- Recovering tin from solution of item 5 using electrolysis 4V 12A on graphite anode and cathode
10- Smelt the item 5 MLCCs, Ta caps and resistors, silver cell the result bar, collect and assay the slimes
11- Grind the boards and all non ferrous parts in a hammer mill to fine powder
12- Separate ferrous from the item 11
13- Separate and collect non-ferrous of item 11 and combine it with non ferrous of item 7 melt to copper ingot
14- Collect and dry the plastics and fiber from item 11 and put them as plastic scrap
15- Combine all ferrous parts, melt in induction to ingot or sell as it is for iron scrap

I will post update on each item as how much cost and any profit.

Regards
Kevin


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## Sophisticatedscrap (Dec 25, 2016)

Any update on how this worked out? I'm new to e waste and refining. Currently sitting on a lot of high grade boards and still trying to figure out the best way possible.


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