
Metals settle at the bottom of a vial after being separated from other components in a crushed circuit board through flash Joule heating. The process developed at Rice University could lead to “urban mining” for valuable metals from electronic waste.
(Credit: Jeff Fitlow/Rice University)
Flash Joule heating by Rice lab recovers precious metals from electronic waste in seconds
In what should be a win-win-win for the environment, a process developed at Rice University to extract valuable metals from electronic waste would also use up to 500 times less energy than current lab methods and produce a byproduct clean enough for agricultural land.

The flash Joule heating method introduced last year to produce graphene from carbon sources like waste food and plastic has been adapted to recover rhodium, palladium, gold and silver for reuse.
A report in Nature Communications by the Rice lab of chemist James Tour also shows highly toxic heavy metals including chromium, arsenic, cadmium, mercury and lead are removed from the flashed materials, leaving a byproduct with minimal metal content.
Instantly heating the waste to 3,400 Kelvin (5,660 degrees Fahrenheit) with a jolt of electricity vaporizes the precious metals, and the gases are vented away for separation, storage or disposal. Tour said that with more than 40 million tons of e-waste produced globally every year, there is plenty of potential for “urban mining.”
“Here, the largest growing source of waste becomes a treasure,” Tour said. “This will curtail the need to go all over the world to mine from ores in remote and dangerous places, stripping the Earth’s surface and using gobs of water resources. The treasure is in our dumpsters.”
He noted an increasingly rapid turnover of personal devices like cell phones has driven the worldwide rise of electronic waste, with only about 20% of landfill waste currently being recycled.
“We found a way to get the precious metals back and turn e-waste into a sustainable resource,” he said. “The toxic metals can be removed to spare the environment.”
The lab found flashing e-waste requires some preparation. Guided by lead author and Rice postdoctoral research associate Bing Deng, the researchers powdered circuit boards they used to test the process and added halides, like Teflon or table salt, and a dash of carbon black to improve the recovery yield.
Once flashed, the process relies on “evaporative separation” of the metal vapors. The vapors are transported from the flash chamber under vacuum to another vessel, a cold trap, where they condense into their constituent metals. “The reclaimed metal mixtures in the trap can be further purified to individual metals by well-established refining methods,” Deng said.
The researchers reported that one flash Joule reaction reduced the concentration of lead in the remaining char to below 0.05 parts per million, the level deemed safe for agricultural soils. Levels of arsenic, mercury and chromium were all further reduced by increasing the number of flashes.
“Since each flash takes less than a second, this is easy to do,” Tour said.
The scalable Rice process consumes about 939 kilowatt-hours per ton of material processed, 80 times less energy than commercial smelting furnaces and 500 times less than laboratory tube furnaces, according to the researchers. It also eliminates the lengthy purification required by smelting and leaching processes.
Original Article: Urban mining for metals flashes electronic trash into treasure
More from: Rice University
The Latest Updates from Bing News & Google News
Go deeper with Bing News on:
Urban mining
- How electric vehicles are sparking a battery recycling revolutionon February 4, 2023 at 4:01 am
A new generation of Canadian recyclers have sprung up to make sure used EV batteries — and the precious minerals inside — don’t go to waste.
- 'Mind-blowing' abandoned £10million mansion found all kitted out in 1960s glamouron February 4, 2023 at 3:32 am
Urban explorer Dave has taken incredible photos of a "mind-blowing" mansion in Northern Ontario, Canada that was beautifully decorated by its owners complete with brightly coloured rooms ...
- Tata Steel sets up an Innovation Centre for Mining and Mineral Research at IIT (ISM) Dhanbadon February 2, 2023 at 8:38 pm
Tata Steel has established a Centre for Innovation in Mining and Mineral Beneficiation at the Indian Institute of Technology (Indian School of Mines), Dhanbad. The Company aims to strengthen its long- ...
- Global Urban Mining Market Outlook Report 2022-2027: Market is Poised to Grow by Almost $20 Billionon January 21, 2023 at 5:44 am
The global urban mining market is expected to grow at a CAGR of 13.12% during 2021-2027. The urban mining market aims to pull waste from landfills and reclaim non-renewable materi ...
- Global Urban Mining Market Outlook Report 2022-2027: Market is Poised to Grow by Almost $20 Billionon January 21, 2023 at 4:28 am
DUBLIN, Jan. 21, 2023 /PRNewswire/ -- The "Urban Mining Market - Global Outlook and Forecast 2022-2027" report has been added to ResearchAndMarkets.com's offering. The global urban mining market ...
Go deeper with Google Headlines on:
Urban mining
[google_news title=”” keyword=”urban mining” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]
Go deeper with Bing News on:
Flash Joule heating
- The 'Death Star' is not the only planet-killing sci-fi superweaponon February 4, 2023 at 2:52 am
You know the "Death Star," ut have you heard of the Lexx or two-stage cyclonic torpedoes? Join us as we explore other planet-killer superweapons.
- Researchers Turn Asphaltene into Graphene for Compositeson January 29, 2023 at 3:59 pm
Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is employing Rice’s unique flash Joule heating process to convert asphaltenes instantly into turbostratic ...
- Highsmith continues to flash NBA skill set for Heat: ‘I just couldn’t take him out of the game’on January 25, 2023 at 12:53 pm
Whether forward Haywood Highsmith has been in or out of the Miami Heat’s rotation this season has usually been based on the team’s injury report. So when the Heat announced just about an hour ...
- Maine Republicans propose legislation to reduce heating costson January 24, 2023 at 3:29 pm
Republicans in Maine said Tuesday they will propose a host of legal changes to try to cap the surging cost of home heating in the state. Maine is heavily dependent on heating oil, and the cost of ...
- Heat pumps: The 'geeks' obsessing over their new heating systemson January 23, 2023 at 4:21 pm
He's got heat meters fixed to the pipework. Room temperature monitors. And gadgets tracking how much electricity his solar panels are generating. The jewel in the crown of this system, though ...
Go deeper with Google Headlines on:
Flash Joule heating
[google_news title=”” keyword=”flash Joule heating” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]