Rice, Indian Institute researchers use cryo-mill to turn circuit boards into separated powders
Researchers at Rice University and the Indian Institute of Science have an idea to simplify electronic waste recycling: Crush it into nanodust.
Specifically, they want to make the particles so small that separating different components is relatively simple compared with processes used to recycle electronic junk now.
Chandra Sekhar Tiwary, a postdoctoral researcher at Rice and a researcher at the Indian Institute of Science in Bangalore, uses a low-temperature cryo-mill to pulverize electronic waste – primarily the chips, other electronic components and polymers that make up printed circuit boards (PCBs) — into particles so small that they do not contaminate each other.
Then they can be sorted and reused, he said.
The process is the subject of a Materials Today paper by Tiwary, Rice materials scientist Pulickel Ajayan and Indian Institute professors Kamanio Chattopadhyay and D.P. Mahapatra.
The researchers intend it to replace current processes that involve dumping outdated electronics into landfills, or burning or treating them with chemicals to recover valuable metals and alloys. None are particularly friendly to the environment, Tiwary said.
“In every case, the cycle is one way, and burning or using chemicals takes a lot of energy while still leaving waste,” he said. “We propose a system that breaks all of the components – metals, oxides and polymers – into homogenous powders and makes them easy to reuse.”
The researchers estimate that so-called e-waste will grow by 33 percent over the next four years, and by 2030 will weigh more than a billion tons. Nearly 80 to 85 percent of often-toxic e-waste ends up in an incinerator or a landfill, Tiwary said, and is the fastest-growing waste stream in the United States, according to the Environmental Protection Agency.
The answer may be scaled-up versions of a cryo-mill designed by the Indian team that, rather than heating them, keeps materials at ultra-low temperatures during crushing.
Cold materials are more brittle and easier to pulverize, Tiwary said. “We take advantage of the physics. When you heat things, they are more likely to combine: You can put metals into polymer, oxides into polymers. That’s what high-temperature processing is for, and it makes mixing really easy.
“But in low temperatures, they don’t like to mix. The materials’ basic properties – their elastic modulus, thermal conductivity and coefficient of thermal expansion – all change. They allow everything to separate really well,” he said.
The test subjects in this case were computer mice – or at least their PCB innards. The cryo-mill contained argon gas and a single tool-grade steel ball. A steady stream of liquid nitrogen kept the container at 154 kelvins (minus 182 degrees Fahrenheit).
When shaken, the ball smashes the polymer first, then the metals and then the oxides just long enough to separate the materials into a powder, with particles between 20 and 100 nanometers wide. That can take up to three hours, after which the particles are bathed in water to separate them.
“Then they can be reused,” he said. “Nothing is wasted.”
Learn more: Pulverizing e-waste is green, clean — and cold
Further information about: Coefficient of Linear Thermal Expansion (CLTE)
The Latest on: Electronic waste recycling
via Google News
The Latest on: Electronic waste recycling
- Slidell will revert to twice-weekly garbage pickup, recycling on July 1on June 26, 2020 at 11:18 am
The decision to reduce the frequency of collection was a point of consternation for some residents, particularly those with large families who generated more household waste. When the coronavirus ...
- Mark Chalmers: Recycling of uranium waste is a good thingon June 26, 2020 at 7:08 am
According to Wikipedia,“Recycling is the process of converting waste materials into new materials and objects …. [i]t is an alternative to ‘conventional’ waste disposal that can save material and help ...
- Kildare lagging behind in electrical waste recyclingon June 25, 2020 at 10:41 pm
Kildare people recycled a total of 1,187,894 kg of electrical waste for free at local authority centres, WEEE Ireland collection days and participating retailers in 2019 – a yearly rise of 0.9%.
- Argonne Scientists Make Lithium-Ion Battery Recycling Breakthroughson June 25, 2020 at 9:11 am
The Department of Energy’s ReCell Center at Argonne National Laboratory reported making several lithium-ion battery recycling breakthroughs since opening earlier last year.
- North America's Battery Recycling Industry, 2020 to 2028 - Strict Government Regulations and Increasing Concerns on Battery Waste Disposalon June 24, 2020 at 4:41 am
The "North America Battery Recycling Market 2020-2028" report has been added to ResearchAndMarkets.com's offering. According to this report o ...
- Recycling in Bluffton moves to bi-weekly pickup. But, you get bigger cartson June 24, 2020 at 1:45 am
Bluffton recycling pickup will move to every two weeks — rather than every week — starting July 6. Waste Management, which renewed its contract with the town last month, will this week deliver new ...
- Battery Recycling Market 2020, Size, Share, Trends and Forecast By 2025on June 24, 2020 at 1:24 am
According to the latest report by IMARC Group titled Battery Recycling Market Global Industry Trends Share Size Growth Opportunity and Forecast 2020 2025 the global battery recycling market ...
- Computer donations and recycling across Canada, Toronto, Montreal, Vancouveron June 23, 2020 at 3:00 am
Reusable computers in demand by needy charities and non profits, Electronic Reusing Association TORONTO (PRWEB) June 23, 2020 The electronic recycling association (ERA) ...
- Free Electronic Recycling In Walnut Creek Saturdayon June 19, 2020 at 5:01 pm
If you're looking at a pile of electronic waste and wondering what ... Center in Walnut Creek is hosting a free electric waste recycling event from 9 a.m. to 3 p.m. Saturday.
via Bing News