Where do PCBs go to die? - Page 1
Forum section: electronics / general

author: Unknown
author_rank: Unknown
timestamp: May 01, 2012, 06:34:30 pm
content: We all have seen those piles of e-waste in China and elsewhere but this is on an entirely different level.Thanks toPFILMalso known for his excellent series on particle physics.Quote

author: wkb
author_rank: Super Contributor
timestamp: May 01, 2012, 07:48:11 pm
content: Unbelievable.The difficult to translate German phrase "Ohne Woerter" would even be better.

author: Mint.
author_rank: Frequent Contributor
timestamp: May 01, 2012, 09:13:12 pm
content: Awesome thanks for sharing! I never seen this from another perspective. All I hear is people talking about it on the news sometimes. But they never say how bad it actually is!

author: nanofrog
author_rank: Super Contributor
timestamp: May 01, 2012, 09:26:28 pm
content: Truly sad.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 12:35:29 am
content: Does anybody know of an acceptable way for reclaiming copper from PCBs?I think we need to devise a method of recycling electronic waste in clean and efficient way.If PCBs are shreded/pulverized using mechanical methods would it be possible to separate the copper using some sort of induction heating or electrostatic method?

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: May 02, 2012, 12:44:26 am
content: This seems like recurring topic on here. The whole situation is screwed.Previous threads on this (for those who are interested):https://www.eevblog.com/forum/general-chat/electronics-waste-what-can-we-do/https://www.eevblog.com/forum/general-chat/electronic-waste-and-its-associated-problems/

author: sonicj
author_rank: Frequent Contributor
timestamp: May 02, 2012, 01:27:04 am
content: Quote from: HAL-42b on May 02, 2012, 12:35:29 amthere are much better methods for reclaiming copper and other recyclables from electronics. they don't include working out of buckets with your shirt as a respirator. if you really want to help, buy them a hazmat suit and a science book.-sj

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 01:46:19 am
content: Quote from: sonicj on May 02, 2012, 01:27:04 amLet's hear them, I'm all ears.QuoteThat takes care of the problem eh?

author: Hypernova
author_rank: Unknown
timestamp: May 02, 2012, 02:03:09 am
content: Quote from: HAL-42b on May 02, 2012, 12:35:29 amOne guy here in TW got rich reclaiming all the metals from PCBs (gold and copper by the tonnes every year) but it takes entire factories to do it. Not something you can just ask the peasants to copy.Found a news article on the company, it's in mandarin though there are plenty of pics:http://www.techbang.com/posts/1495-green-alchemy-of-science-and-technology-recycling-resources-in-waste-to-gold-topBasically they grind it to fine dust and then separate the metals out using static electricity, magnets and some chemical formula the founder invented. They claim that from a tonne of waste they get 1 pound of gold, compared to a tonne of gold ore which yields maybe 5 grams, and that's not even counting all the copper/silver/platinum etc. The glass dust is turned into building material.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 02:31:00 am
content: Quote from: Hypernova on May 02, 2012, 02:03:09 amMany of those around. These people in Switzerland have done the same thing: "" Basically a huge mill that grinds the waste to dust and then sifts and separates based on density. Incidentally I have been involved in the design of similar setup for reclaiming old car tires. To be honest I was not impressed by the efficiency of the method at all and I am even less impressed with the same thing applied to electronics. Too much energy consumption, too many moving parts hence too much wear and tear, needs huge investment, it almost certainly over-processes the material, and simply not applicable at the location where the waste is. It may work in Switzerland but not in rural India.Something of much smaller scale is needed.A hand operated shear like device can be made to shave off the components off the PCB. Then the components follow different routes and not everything needs to be ground down to dust. Now if there was a simple way to de-laminate the PCB and extract the traces without dissolving them in acid....

author: Hypernova
author_rank: Unknown
timestamp: May 02, 2012, 04:11:18 am
content: Even if you got a clean solvent that removes solder mask I don't think it's possible to reach the inner layers of a 4+ layer board without grinding.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 04:53:45 am
content: Quote from: Hypernova on May 02, 2012, 04:11:18 amTrue, not sure if even the acid reaches to the inner layers. Never tried it but maybe repeated back and froth flexing would cause de-lamination. Or maybe rolling the PCB between two cylinder would disintegrate the material enough to let the copper be separated. Lets say like rolling a 1.6mm PCB between two steel cylinders with 1.2mm gap between them. The copper would deform, the glass fiber would disintegrate and fall off.

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: May 02, 2012, 05:10:32 am
content: Perhaps mashing the whole thing in a giant crucible would be more economical. That way you don't have to worry about replacing grinding teeth, plus having a big solid block pounding at it would be more effective than using rollers.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 05:56:35 am
content: Quote from: AntiProtonBoy on May 02, 2012, 05:10:32 amI was thinking more on the lines of hand cranked compact machines like this oneIf it works it would be affordable and dust free. Dust might pose a danger of silicosis I'm afraid, much of it is glass.The way you describe it I imagine something like a ball mill. The only ball mills that I've seen are the huge cement mills.

author: free_electron
author_rank: Super Contributor
timestamp: May 02, 2012, 06:43:26 am
content: grinding would be a solution but you better have a damn good way to filter the exhaust air.. you do NOT want to breathe the fiberglass/resin material... you'd be better of inhaling asbestos powder ...and how much power are you going to us to grind and extract all this material ?i think high temperature incineration in a smelter is the best solution. the glass is reusable ,all metals go liquid and can be scraped off. as for the material that is 'burned' ( paint , resin , epoxy ) : send the exhaust gas through a chemical scrubber.you could use . cool the hot gas in a heat exchanger to make steam and drive an electrical turbine, that way you recuperate part of the energy as well.or you could use a solar incinerator...

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: May 02, 2012, 07:00:02 am
content: Quote from: HAL-42b on May 02, 2012, 05:56:35 amAh yes, ball mill, even better! I totally forgot about those.Going with the ball mill, one could mitigate dust problems by actually adding liquids into the mill. Even things like mild acids will not only eliminate dust, but also dissolve the metal compounds in the slurry. Of course, the slurry will need to be flushed with fresh acid to leech as much metal as possible.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 12:28:23 pm
content: Here is a quick idea.A manual PCB component stripper for stripping components without using heat and perhaps avoiding some exposure to lead from the solder.The operator places a PCB into the shown place and pushes the handle away from himself. The heavy C section slides on the table around the pivot and gathers enough momentum to shave off components from the PCB. The components fall through the chute into the part bin. Operator retracts the arm, replaces PCB and repeats. The working part is a hardened tool steel blade bolted underneath the C section arm. The height of cut is adjusted through the crank wheel on the pivot.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 01:36:26 pm
content: Quote from: AntiProtonBoy on May 02, 2012, 07:00:02 amIn a rural setting as above any liquid will eventually find its way into arable land. Even if only water is used, it will still carry Pb and other heavy metals into the soil. Besides, I think that grinding overprocesses the material. We only need the copper to delaminate from the PCB but the major part of the energy is wasted for turning the glass fiber into dust.

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: May 02, 2012, 03:07:51 pm
content: QuoteYeah, it's a problem, no matter how you're looking at it. Even less aggressive stripping techniques will end up having lead in places where it shouldn't be.QuoteI think if we are going to recycle stuff, might as well do the whole lot. Assuming the most metals have been leached away from the slurry, the glass byproducts might be a useful ingredient for basic construction and cement mix materials. You can also fuse fine glass dust particles together into much larger clumps with some heat exposure, turning it into something like grains of sand.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 04:38:27 pm
content: This is what I think would happen if we were to crush PCBs with rollers. Grossly exaggerated of course, but nevertheless I expect some delamination. Only if I could test...

author: G7PSK
author_rank: Super Contributor
timestamp: May 02, 2012, 05:30:18 pm
content: Why not just stick them in an induction smelting furnace the metals would melt and then be refined in the usual manner and the resins would be either burnt or if the furnace was in a vacuum they would vaporize and could then be collected and recycled as well.

author: Unknown
author_rank: Unknown
timestamp: May 02, 2012, 07:03:46 pm
content: Quote from: G7PSK on May 02, 2012, 05:30:18 pmYou are right of course, induction furnaced do work. I guess I wasn't sure about the fumes and the energy cost. Needs to be tested.

author: Hypernova
author_rank: Unknown
timestamp: May 02, 2012, 11:38:10 pm
content: I got a feeling someplace like rural India is not going to have to power to run such a thing.IMO the core problem is that these people are doing this to survive, doesn't matter what tech is "out there", if no one there can afford it it's all moot. These guys are stuck with the job that is slowly killing them just to stay alive.

author: Unknown
author_rank: Unknown
timestamp: May 03, 2012, 04:00:04 am
content: Quote from: Hypernova on May 02, 2012, 11:38:10 pmThe maker of the film said in a message that the main reason for them to do this is because they are earning more doing this compared to farming their own land. Now, I'm not after solving all the problems of the third world, the only problem I'm after is extracting the copper off of old PCBs in the simplest possible way without causing health and environmental damage.It says on the video description that this is illegal. Well...the law has never been relevant to solving problems anyway. Every step until this one has been legal yet this one is not? Hell that 20$ DVD has been in at least three countries already and probably travelled more miles than this guy ever did, and never once it has been illegal in any jurisdiction... Ok ok I shut up.