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Dialing Back On Cell Phone Waste

Academics and technology firms seek to reduce the growing problem of electronic waste from old cell phones

by Alex Scott
September 1, 2014 | A version of this story appeared in Volume 92, Issue 35

Credit: Loughborough University
CLEVER’S prototype modular design would enable failed components to be replaced, extending the useful life of the phone.
Modular phone design.
Credit: Loughborough University
CLEVER’S prototype modular design would enable failed components to be replaced, extending the useful life of the phone.

More than 1.8 billion new cell phones will be bought in 2014, but within just a few years, 44% of them will end up “hibernating” in drawers. About the same share will be resold and passed on, and 4% will end up in landfills. Only 3% will be recycled.

Those dispiriting statistics come from Hywel Jones, a materials scientist at En­gland’s Sheffield Hallam University who sees major environmental and resource implications in the lack of phone recycling. Each phone contains about 300 mg of silver and 30 mg of gold. Just the gold and silver used to manufacture the phones sold this year are worth more than $2.5 billion.

Of the 40 elements in a phone, only 17 are ever recovered to a maximum rate of 95%, even in the most sophisticated electronics recycling plants such as the huge smelting and electrolysis facility run by Umicore in Antwerp, Belgium. In developing countries, where manual disassembly of electronics often takes place, the recovery rate is far lower and comes with the added risk of exposure to hazardous chemicals, including heavy metals and strong acids.

In a bid to head off this growing problem, private technology firms are developing systems to make phone recycling easier, cheaper, and less hazardous. Academics, meanwhile, are hoping that designs for extending the useful life of phones—such as modular phones featuring replaceable components and “skins” that look better with age—can prevent them from being left in drawers in the first place.

But market watchers are doubtful about the viability of some of the emerging approaches, which can seem rather fanciful. “A lot of crazy ‘revolutionary’ and ‘groundbreaking’ technologies are actually just chasing loose money, which is typical in spaces where large government and corporate initiatives are fueling the fire,” says Mark Bünger, research director at Lux Research, a firm that analyzes emerging technologies.

Picking Up On Phone Waste

Each cell phone contains 40 chemical elements, including 300 mg of silver, 30 mg of gold, and hazardous elements such as lead and mercury.

Only 27 of these elements are economically recoverable.

Gold concentration in a phone is 50 times as great as it is in ore in a mine.

Only 3% of the 1.8 billion phones expected to be purchased around the world this year will be recycled.

Americans have more than 200 million old phones “hibernating” in their homes.

Credit: Shutterstock
Credit: Shutterstock



Smelting coupled with electrolysis is the dominant recycling approach in the West; processes based on strong acids are used in many developing countries.

Electronics in landfills contain more rare-earth metals than are in all known global reserves.

Less than 1% of rare-earth metals are currently recycled.

SOURCE: Environmental Protection Agency

Ensuring that materials from cell phones are recycled is a complex problem that requires solutions from a number of disciplines, according to David Peck, assistant professor of industrial design engineering at Delft University of Technology in the Netherlands. “Real opportunities to solve the problem will lie in cooperation among chemists, engineers, designers, and the business community,” he says.

Closed Loop Emotionally Valuable E-waste Recovery, an England-based project set up to solve the issue of recovering waste from cell phones, features such a cooperation, drawing in experts from several universities. CLEVER proposes a phone that “ages gracefully” and contains a circuit board that can be dissolved easily to recover valuable metals.

CLEVER’s prototype phone is based on a “skeleton” to which components such as battery, screen, motherboard, and memory—the “organs”—can be attached and readily replaced if they fail, explains Janet L. Scott, training director for the Centre for Sustainable Chemical Technologies at England’s University of Bath and principal investigator of the CLEVER project.

The Engineering & Physical Sciences Research Council, a U.K. government agency, has provided $2.1 million in funding for the project, which began in 2013 and is set to end in 2016.

The researchers with CLEVER at Loughborough University are investigating the reasons consumers become emotionally attached to electronic devices, how that attachment can be extended to prolong the life of a phone, and how to provide the impetus for returning the device for recycling. CLEVER investigators at Newcastle University, also in England, are experimenting with materials for the “skin” of the phone that, like leather, look better with age.

Scott, meanwhile, is developing cellulosic materials for the phone’s skeleton and circuit boards. Her team is currently evaluating novel blends of flame retardants, hydrophobizing agents, and low-dielectric-constant fillers to be used with cellulose in phones.

When the time comes to recycle the phone, enzymes developed for cellulosic ethanol production could convert the phone’s cellulose into sugars. “We don’t need to reinvent the wheel,” Scott says.

CLEVER’s approach addresses the phone recycling industry’s need to separate plastics from metals for reuse. “The plastics are probably more of a challenge than the metals in separating and processing to achieve a suitable raw material,” says Rose Read, manager of MobileMuster, a product stewardship program set up by the Australian Mobile Telecommunications Association. Currently, plastics from recycled phones in Australia are mixed and typically end up being “downcycled” to products such as fence posts.

For the recovery of metals, Scott and her coworkers plan to evaluate selective metal recovery strategies including ones involving selective dissolution in ionic liquids and recovery, for example, by electroplating, in which an electrical current is used to reduce dissolved metal cations such that they “plate out” as pure metal on an electrode.

The modular phone approach doesn’t have a good track record so far. In 2007, an Israeli start-up called Modu introduced a smartphone that fit into electronic jackets to become devices such as cameras or music players. The company folded shortly after product launch. Critics said the proprietary hardware was too clunky and the number of modules too limited.

But Modu’s intellectual property was later acquired by Google. The search giant plans to introduce a prototype modular phone in 2015. Apple and ZTE, China’s largest cell phone manufacturer, also are understood to be developing modular phones.

Dubbed Project Ara, Google’s planned modular phone features an aluminum frame with eight rear slots for modules and two front slots for features such as a keyboard or data transmission. Unlike Modu’s clunky interface, Google’s prototype features sleek wireless electro-permanent magnets to keep the modules in place.

Google plans to encourage “hundreds of thousands of developers” to make the modules. A Google partner, Newton, Mass.-based NK Labs, is developing an initial range of modules for the phone, including an oximeter for measuring blood oxygen levels and imaging lenses for night photography. Future uses for the Project Ara phone could be in medical diagnostics and environmental sensing.

In addition to the move to design a more sustainable phone, there is a flurry of activity to develop more efficient and less environmentally harmful processes for recovering materials from old phones. Today, recovery of metals from phones typically is based on large-scale smelting and electrolysis. In developing countries, a nitro-hydrochloric acid solution known as aqua regia is often used to recover gold.

The European Union’s Associated European Research & Technology Organisations (AERTOs) project,which features six technology firms and ended earlier this year, has developed a multistep process for recovering materials from old phones that avoids smelting and aqua regia.

In the AERTOs process, old phones are dismantled to obtain the printed circuit boards, which are crushed and sieved. Plastics and metals are then separated in water by a process known as flotation, in which bubbles carry hydrophobic plastic particles to the surface to be mechanically skimmed, leaving metals such as copper to be selectively leached and recovered with hydrometallurgical methods.

Gold is leached from the residual solids using the chloride-hypochlorite process and then filtered in mycelium mushroom mats. This so-called biomining approach recovers up to 80% of the gold.

“The reason why mycelium biomass is very good at capturing gold from solutions is due to charged groups of biomass, which are especially selective for gold,” says Jarno Mäkinen, research scientist at the Finnish technology institute VTT and a member of the AERTOs team. “When the biosorption filter is full, gold can be recovered by re-leaching or incinerating the biomass.”

Although VTT’s approach falls short of the 95% gold recovery rate attained in some smelting plants, the technology works at ambient temperature. Umicore’s Antwerp facility, in contrast, runs at more than 2,000 °F. VTT’s approach also avoids smelting facilities’ gaseous emissions, Mäkinen says. “The approach could especially be applied in developing countries where smelting investments and operating are problematic,” Mäkinen says. VTT is now scaling up its experiments to pilot scale.

Other firms, including California-based BlueOak Resources and Arizona’s Universal Bio Mining, are also developing novel bioprocesses for recovering metals from phones and other electronic waste.

Demonstration plant.
Credit: Entegris
Entegris claims its eVOLV process can reduce phone recycling costs by 30–40% with no emissions or discharge of effluent.

But Billerica, Mass.-based Entegris, a $700 million-per-year provider of materials to the electronics industry, claims to have developed a closed-loop, acid-based process called eVOLV that can recover 98% of precious metals in electronic waste at ambient temperature and at costs 30–40% lower than smelting. Entegris says the metals it can recover make up more than 99% of the metals in electronics by volume.

“To date, we have agreed to license our technology to four customers, including two in Asia, which plan to begin operating the first eVOLV plants in 2015,” says Michael B. Korzenski, the venture’s vice president and general manager.

In the eVOLV process, motherboards from electronic waste are cleaned. Components such as silicon chips are separated, while lead, tin, and silver solder are removed in an acid-based solution.

The reusable solution is 70% water and contains no solvents, surfactants, cyanide, or aqua regia, according to Entegris. “Our process is cradle-to-cradle where 1 lb of waste in translates to 1 lb of sellable product out, with zero waste generation,” Korzenski says.

Metals are recovered either in pure form or as metal oxide powders, and the silicon chips are sold for reuse or recycled. In a separate step, precious metals, including gold, are removed selectively in solution. All wastewater in the process is recycled. Circuit boards are sold for their copper, iron, or aluminum content.

The eVOLV process can start small and then be scaled up by adding more modules. “You can locate it next to where the waste is being created,” Korzenski says.

In contrast, the largest smelting plants are so big that only five are in operation around the world, typically processing electronic waste in multiton batches. In Japan, China, and the U.S., which don’t have such smelters, interest in eVOLV “is going gangbusters,” Korzenski says.

But not all of the new technologies will be viable, Lux’s Bünger cautions. “Certainly technologies are emerging, but a lot—including biomining—may never work out economically,” he predicts.

Indeed, whatever potential the emerging technologies might have, traditional smelting firms, such as Umicore, don’t seem too concerned about them. The Belgian company has applied for permission to expand its Antwerp recycling plant by 40% at a cost of more than $100 million to a processing capacity of 500,000 tons per year.

Traditional and emerging recyclers may not see eye to eye on most matters, but they can agree on one thing: There are enough old phones for all comers to recycle—if they can just get them out of the kitchen drawer.  


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