New Technique for Recycling PCBs

MattSparkes writes "PCBs from discarded computers, cellphones and other devices could be recycled less harmfully using a technique developed by researchers in China. Unlike current methods, it can be used to reclaim metals such as copper without releasing toxic fumes into the air. Only a small numbers of PCBs are currently recycled."

Re:Bulding materials?

[dido]

The plastic used for most PCB's is polyvinyl chloride, which in itself isn't particularly toxic under most circumstances. It's in common use these days for plumbing fixtures and the like, as well as for PCB's. However, if you burn PVC plastic, it gets converted into some particularly nasty dioxins and furans which are dangerously carcinogenic.

Re:Bulding materials?

[ajs318]

The plastic used for most PCB's is polyvinyl chloride

No it isn't. PCBs are made either from glass fibre (FR4) or resin-bonded fabric (CEM1). PVC would soften too much at soldering temperatures.

Follow up

[Emetophobe]

I happened to find a good story with a few pictures. http://www.ban.org/Library/ghosts_in.html [ban.org]

Here's a choice quote:

Every year Guiyu takes in more than a million tonnes of computer waste, earning its residents, according to mainland press reports, RMB1 billion. All day, every day, mountains of wire and other equipment are burned in Guiyu's streets to obtain copper and other scrap metals. Printed circuit boards are heated over charcoal burners to liberate them of computer chips that might be reusable. The boards are then soaked in acid to extract gold, and the waste dumped alongside or in the nearby Lianjiang River. Printer cartridges are ripped apart for their toner and recyclable aluminium, steel and plastic parts. Cathode-ray tubes are hammered open for their copper yokes.

The result is that the air, land and water on which local people depend have all been poisoned. Local well water is already undrinkable, even after boiling, and fresh supplies must be trucked in from the town of Chan Dim 15 kilometres away. According to the report: "It is extremely likely that due to the presence of PVC or brominated flame retardants in wire insulation, the emissions and ashes from such burning will contain high levels of both brominated and chlorinated dioxins and furans - two of the most deadly persistent organic pollutants. It is also highly likely that cancer-causing polycyclic aromatic hydrocarbons are present in the emissions and ash."

"Compared to the rest of China, this place has more miscarriages," says Doctor Li Fai-ping, who works in the maternity ward at the local Chao Yang Yiu Fai Hospital. "Babies simply die in the wombs. There are several cases a month." She adds that the Government has done nothing to assess the damage being done by the e-waste industry. "No scientists have come here to test the effects [of the pollution on the community]. We are sent to work here, we are scared too." "The fact that nobody knows of the dangers is the most depressing thing," says BAN researcher Jim Puckett, co-author of the report.

Re:Recycling

[Anonymous Coward]

Actually there are regulation in China that prevents old PCB from being imported into China on fear of China being dumping ground. Getting China set up as repair depot was (is?) a headache because of that.

Also China is following EU into having their own RoHS program effectively banning PCB made with toxic metals which most older PCB contains.

On the other hand, this would still help China in recycling PCB that is already there.

Acronym collision

[Phreakiture]

As usual, no acronym may ever be expanded, nor definition given, nor even enough info to get a clue, in a Slashdot story summary. The summary needs to somehow clarify that we are discussing Printed Circuit Boards, and not PolyChlorinated Biphenyls. Really big difference, and both are environmental/technological issues, but orders of magnitude different in impact.

Re:Recycling

[lxt518052]

I think the Chinese government's concern is not unjustified.

http://www.chinadaily.com.cn/english/doc/2005-05/2 4/content_445129.htm [chinadaily.com.cn]

Hi-tech waste being smuggled into China has caused big pollution because the method used to recycle them. Recycling is a generally good thing, but not so if the process actually causes harm to the local residents.

I think those waste exporters in developed countries are rather selfish in moving the problem to China and India, although it comes at no surprise to me in that the west is always doing so and pointing fingers at the developing countries.

The SJTU's researcher is doing a good job. Congratualtions! Keep it up!

Re:High-Temperature Furnaces

[lxt518052]

Sure, but to generate the heat needed to sustain such high furnace temperature you've got to burn a large amount of fossil fuel. Note the carbon footprint I mentioned.

Also, heavy metals are not consumed by burning. Think about the pollution when it's escaped into the atomosphere.

With all these cost and danger, what have we gain from it? Not much is recycled. We just add tons of greenhouse gas to the planet.

Re:Bulding materials?

[myth_of_sisyphus]

Here is the article:

http://harpers.org/TheMagicMountain.html [harpers.org]

It's a fascinating look at the underworld of the Garbage Dwellers. It's really sad, horrible, horripilating, and awful.

The author says a recent garbagefall killed hundreds of people. And you're right: the people burn insulation off wires. Which still produces dioxins and carcinogens.

An excerpt:

Wandering from pile to pile, calling out, "Piyesa! Piyesa!" (Parts! Parts!), are brokers of electronic and computer components, a new and lucrative category of waste. I ask Bobby what's worth the most, and he replies without hesitating, "Epson." An empty refillable printer cartridge in working condition can go for as much as 350 pesos. Bobby knows the prices for all these, too: Monitor, 50 pesos. Motherboard, 30. Circuit boards for 25 a kilo, to be melted down for trace amounts of gold. Pentium chips, if the pins can be straightened, 50.