Fruit Peels Prove Useful for Recycling Lithium-Ion Batteries

Food waste and electronic waste are two aspects of the waste stream that present a multitude of challenges for human society. Now a team of scientists led by the Nanyang Technological University (NTU), Singapore has developed a way to use food waste–specifically orange peels–to recover precious metals from spent lithium-ion batteries for reuse in the creation of new batteries.

As reported in SciTech Daily,

An estimated 1.3 billion tonnes of food waste and 50 million tonnes of e-waste are generated globally each year.

Spent batteries are conventionally treated with extreme heat (over 500°C) to smelt valuable metals, which emits hazardous toxic gases. Alternative approaches that use strong acid solutions or weaker acid solutions with hydrogen peroxide to extract the metals are being explored, but they still produce secondary pollutants that pose health and safety risks, or rely on hydrogen peroxide which is hazardous and unstable.

Professor Madhavi Srinivasan, co-director of the NTU Singapore-CEA Alliance for Research in Circular Economy (NTU SCARCE) lab, said: “Current industrial recycling processes of e-waste are energy-intensive and emit harmful pollutants and liquid waste, pointing to an urgent need for eco-friendly methods as the amount of e-waste grows. Our team has demonstrated that it is possible to do so with biodegradable substances.”‘

Current industrial processes for recycling batteries involve shredding the batteries and crushing them into a powdery substance. That powdery substance is either smelted at temperatures above 500 degrees Celsius to separate metals or subjected to a chemical leaching technique using a mixture of acids and hydrogen peroxide plus heat. The newly developed process substitutes orange peels instead of the acids and hydrogen peroxide typically used. The researchers oven-dried orange peels, ground them to powder, and mixed them with citric acid, a weak acid found in citrus fruits.

‘Asst Prof Tay explained: “The key lies in the cellulose found in orange peel, which is converted into sugars under heat during the extraction process. These sugars enhance the recovery of metals from battery waste. Naturally-occurring antioxidants found in orange peel, such as flavonoids and phenolic acids, could have contributed to this enhancement as well.”

Importantly, solid residues generated from this process were found to be non-toxic, suggesting that this method is environmentally sound, he added.’

The researchers were further able to use metals recovered via this process to assemble new lithium-ion batteries which displayed a charge-capacity similar to commercially available batteries.  The team is hoping to further optimize the batteries they can produce in this fashion and extend their “waste-to-resource” approach to other cellulose-rich fruit and vegetable waste and other lithium-ion battery types.

Learn more:

“Repurposing of Fruit Peel Waste as a Green Reductant for Recycling of Spent Lithium-Ion Batteries” by Zhuoran Wu, Tanto Soh, Jun Jie Chan, Shize Meng, Daniel Meyer, Madhavi Srinivasan and Chor Yong Tay, 9 July 2020, Environmental Science & Technology.
DOI: 10.1021/acs.est.0c02873

Schematic showing the process of using orange peels to extract metals from lithium-ion batteries
Credit: NTU Singapore

New Recycling Process Turns E-waste into Metal Coating

In a paper published this summer in ACS Omega, Rumana Hossain and Veena Sahajwalla describe an innovative process for transforming electronic waste, or e-waste, into a protective coating for metal.

As reported in Science Daily,

‘A typical recycling process converts large quantities of items made of a single material into more of the same. However, this approach isn’t feasible for old electronic devices, or “e-waste,” because they contain small amounts of many different materials that cannot be readily separated. Now, in ACS Omega, researchers report a selective, small-scale microrecycling strategy, which they use to convert old printed circuit boards and monitor components into a new type of strong metal coating…

Based on the properties of copper and silica compounds, Veena Sahajwalla and Rumana Hossain suspected that, after extracting them from e-waste, they could combine them to create a durable new hybrid material ideal for protecting metal surfaces.

To do so, the researchers first heated glass and plastic powder from old computer monitors to 2,732 F, generating silicon carbide nanowires. They then combined the nanowires with ground-up circuit boards, put the mix on a steel substrate then heated it up again. This time the thermal transformation temperature selected was 1,832 F, melting the copper to form a silicon-carbide enriched hybrid layer atop the steel. Microscope images revealed that, when struck with a nanoscale indenter, the hybrid layer remained firmly affixed to the steel, without cracking or chipping. It also increased the steel’s hardness by 125%. The team refers to this targeted, selective microrecycling process as “material microsurgery,” and say that it has the potential to transform e-waste into advanced new surface coatings without the use of expensive raw materials.’

Learn more:

Rumana Hossain, Veena Sahajwalla. Material Microsurgery: Selective Synthesis of Materials via High-Temperature Chemistry for Microrecycling of Electronic Waste. ACS Omega, 2020; 5 (28): 17062 DOI: 10.1021/acsomega.0c00485

Porphyrin May Provide Efficient, Cost-Effective Way to Reclaim Gold from E-Waste

An international team of researchers, lead by Yeongran Hong of the Korea Advanced Institute of Science and Technology, have demonstrated that a type of organic compound called a porphyrin could be used to retrieve precious metals, such as gold, from electronic waste in an effective, simple, and relatively inexpensive manner. The researchers used porphyrins to create a sorbent–a type of material that can collect molecules of another substance through adsorption, absorption or ion exhance–called COP-180. This compound remains stable in the acidic solutions which are used to remove metals from circuit boards and video screens.

From an article by Bob Yirka on Phys.org: “Testing the polymer showed it to be efficient at sorbing platinum and unexpectedly highly efficient at sorbing gold. A closer look at both showed that platinum dispersed evenly in an acid solution but gold clumped, allowing the sorbent to gather more of it than expected. Testing on real-world e-waste showed it was possible to collect 64 dollars’ worth of gold using only a gram of the sorbent, which costs five dollars to make. The researchers note that the sorbent can also be reused, making it even more economical.

See Yeongran Hong et al. Precious metal recovery from electronic waste by a porous porphyrin polymer, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2000606117

See also New polymer easily captures gold extracted from e-waste.

Diagram showing the process of using COP-180 to remove gold from an acid solution used to remove metals from circuit boards.

Families of Child Miners Sue Tech Companies Over Human Rights Abuses

In the January 9, 2020 edition of Triple Pundit, Roya Sabri reported on a lawsuit filed by International Rights Advocates (IRA) on behalf of child miners and their families, against several major tech companies, including Apple, Alphabet (parent company of Google), Microsoft, Dell and Tesla. The lawsuit argues that tech companies, profiting from the cobalt supplies which are often supported by child miners’ efforts, should be responsible for the wellbeing of those subsistence cobalt miners.

From Sabri’s article:

The DRC supplies the world with more than 60 percent of its cobalt. A good portion is mined by subsistence miners — independent contractors who take it upon themselves to find and unearth the metal. The miners climb down shafts just wide enough for their bodies with no more than a flimsy headlamp, a hammer and a sack. If a worker gets hurt or dies, buyers take no responsibility and do not offer assistance or support. Reports by Amnesty International and The Washington Post in 2016 revealed these inhumane conditions, but little has changed for the better since then.

Young children are entering this work, often to help their families pay for the essentials needed to survive. The lawsuit’s plaintiff, labeled Jane Doe 1, reports that her nephew began working in mines to pay his $6 a month school fee. Last year, the tunnel where he was digging collapsed. The family never found his body.

The narratives documented by the lawsuit show that this boy’s story is not an isolated incident.

Read the full story at Triple Pundit: https://www.triplepundit.com/story/2020/silicon-valley-giants-sued-over-human-rights-abuses-cobalt-supply-chain/86141.

For the IRA press release related to this lawsuit, see http://www.iradvocates.org/press-release/iradvocates-files-forced-child-labor-case-against-tech-giants-apple-alphabet-dell.

For previous SEI posts related to cobalt in the electronics supply chain, see https://sustainable-electronics.istc.illinois.edu/?s=cobalt.

Video Illustrates Materials Used in Smartphones and Amounts

Check out the video below from the Sustainable Earth Institute of the University of Plymouth (in the UK).

Besides allowing one to vicariously experience childish glee at watching the destruction of a smartphone by blender (which we of course should NOT try at home), the video provides a brief glimpse at the process of analyzing materials in a lab. Most importantly, it does an excellent job of helping viewers visualize the relative amounts of materials present in the phone, including coins for comparison to a familiarly-sized object (few of us know what 0.7 g or 10 mg really looks like without a reference object for comparison).

The video goes a step further by providing a visualization of the relative amounts of those component elements which would be present in a year’s worth of smartphone production, with a human figure and soccer pitch provided for reference. It’s a great example of how to effectively translate abstract statistics into accessible, meaningful information for the general public.

This would be excellent for presentation to students of all ages, as part of discussions related to industrial design, materials sourcing and impacts, why reclamation of materials from electronics is so important, etc.

To read the full post on this video and the scientists behind it ( Dr. Arjan Dijkstra and Dr. Colin Wilkins, geologists from the University’s School of Geography, Earth and Environmental Sciences ), see https://www.plymouth.ac.uk/news/scientists-use-a-blender-to-reveal-whats-in-our-smartphones.

 

Scottish Researchers Work to Extract Gold from E-Scrap

According to an Oct. 3, 2018 article by Kirstin Linnenkoper in Recycling International, a research team at the University of Edinburgh, lead by Professor Jason Love, are developing a new chemical reagent to more effectively extract gold from electronic scrap.

Around 7% of the world’s gold is inside e-scrap, of which less than one-third is currently salvaged, according to project leader Professor Jason Love. One tonne of gold ore contains around up to 5 grams of pure gold. However, a tonne of discarded mobile phones easily holds 300 grams of the valuable metal, Love says. The chemical reagent pioneered by in Edinburgh effectively recovers ‘a very high purity of gold’ from various types of discarded electronics. First, the researchers place the printed circuit boards in a mild acid to dissolve metallic parts. An oily liquid containing the new reagent is then added, which allows gold to be extracted selectively from the complex mixture of metals found inside electronics. Professor Love explains that, normally, one molecule of reagent binds directly to a metal molecule. The innovative compound uses a different type of chemistry and can bind to clusters of gold molecules instead of just one. ‘This means you can use a lot less of it to recover the same amount of gold,’ he says.

The researchers hope to find ways to recover other metals, including valuable (e.g. palladium, platinum, and neodymium), common (e.g. copper and tin), and toxic (e.g. lead and cadmium) metals. Similarly, they are interested in exploring chemical means to more effectively recover plastics from electronic scrap.

Read the full article at https://recyclinginternational.com/e-scrap/scottish-researchers-find-way-to-target-metals-in-e-scrap/.

Learn more about the research of Professor Love’s group, and find links to their publications at https://jasonlovegroup.wordpress.com/.

The United Nations Environment Programme (UNEP) 2011 publication, “Recycling Rates of Metals: A Status Report” can provide further background context: https://wedocs.unep.org/bitstream/handle/20.500.11822/8702/-Recycling%20rates%20of%20metals%3a%20A%20status%20report-2011Recycling_Rates.pdf?sequence=3&isAllowed=y.

Finally, visit https://ifixit.org/recycling for more information on why electronics recycling is not as effective a practice as one might think.

close up of circuit board, showing gold

RSN Recommends Regulatory Enforcement, Investor Engagement to Urge Corporate Due Diligence on Conflict Minerals

The Responsible Sourcing Network (RSN), is a project of the nonprofit organization As You Sow, dedicated to ending human rights abuses and forced labor associated with the raw materials found in consumer products. On October 18, 2018, RSN released its Mining the Disclosures 2018: An Investor Guide to Conflict Minerals Reporting in Year Five report, which “analyzes 206 companies’ supply chain due diligence efforts regarding conflict minerals, including tin, tantalum, tungsten, and gold, or 3TG. In the fifth consecutive year of analyzing companies’ conflict minerals compliance and reporting, the report shows that a large number of the companies’ scores stayed flat or decreased.”

Read the full press release at https://www.sourcingnetwork.org/press-release-mtd-2018. You can download this year’s report, those from previous years, and watch a webinar about the 2018 report at https://www.sourcingnetwork.org/mining-the-disclosures.

Cover of the Mining the Disclosures report

According to RSN, “The technology sector outperformed all others, while laggard industries included integrated oil & gas, steel, business services, and building materials. Innovative companies showed constant improvements, including increased participation in on-the-ground initiatives, proactive risk assessments, and comprehensive risk mitigation measures. However, compared to 2017, a majority of companies’ scores that reflect alignment with the OECD’S Conflict Minerals Guidance declined. The results show a global lack of desire to improve due diligence practices over the last few years.

“Conflict minerals” include tin, tantalum, tungsten and gold (aka 3TG). They are so called because these minerals are often sourced from the Democratic Republic of Congo (DRC), which is one of the most mineral-rich countries in the world, and in recent years, unfortunately also one of the most war-torn. Militant groups controlling mines have used violence, including murder, torture, rape and other sexual violence, forced labor and use of child soldiers, in their control of the populace to further their profit from sale of these minerals and their war efforts. Conflict minerals are used in a wide variety of electronic devices, and are also found in a variety of other products, including jewelry, dental products, tools, biocides, ammunition, medical devices, and others. For more information, see https://www.globalwitness.org/en/campaigns/conflict-minerals/ and https://en.wikipedia.org/wiki/Conflict_resource#Conflict_minerals.

Section 1502 of the Dodd-Frank Wall Street Reform and Consumer Protection Action, passed in 2010 and implemented starting in 2012 by the Securities and Exchange Commission, requires that all companies publicly traded in the the US with products containing any of the four conflict minerals report on the source of the minerals in their supply chain. This required transparency has not eliminated human rights issues associated with conflict mineral sourcing, but it has demonstrably improved conditions for Congolese miners. Before passage of the law, the UN reported that nearly every mine in Congo was controlled by armed groups. As of 2016, the independent research institute, International Peace Information Service (IPIS) found that 79% of “3T” miners surveyed in eastern Congo were working in mines where no armed group involvement had been reported. (See https://enoughproject.org/special-topics/progress-and-challenges-conflict-minerals-facts-dodd-frank-1502).

RSN cites the Trump administration’s “contempt for regulations” and threats made last year to “suspend Section 1502 of the Dodd-Frank Act” as part of the reason for the decline in corporate due diligence related to conflict minerals sourcing. “The disregard of corporate responsibility for conflict minerals during the Trump administration is concerning,” said Raphaël Deberdt, author of the Mining the Disclosures 2018 report. “The increasing neglect of the conflict minerals legislation from some companies over the past few years has been a source of human rights abuses in the Democratic Republic of the Congo. And these abuses extend beyond the 3TG sphere.

According the RSN press release: ‘Companies involved in mineral supply chains — from mines to retailers — now face additional challenges that must be integrated into corporate risk mitigation frameworks. The increasing importance of cobalt, lithium, and nickel in the automotive and technology sectors should trigger red flags in compliance departments in a broader risk context, including environmental degradation, organizational health and safety, human rights, and community impacts. Similarly, the upcoming EU regulation will necessitate increased due diligence from importers of 3TG, not only from the Congo region, but from all conflict-affected and high-risks areas. “The results of this year’s report demonstrate the need for an increase in regulatory enforcement and investor engagement that urge companies to undertake proactive due diligence efforts,” said Patricia Jurewicz, vice president of Responsible Sourcing Network. “These programs must continuously improve to address and mitigate the evolving material risks associated with conflict mineral supply chains.”

RSN further asserted that “leading companies” such as Intel, Microsoft, Apple, Qualcomm, Ford, Royal Philips, and HP “prove that taking a due diligence approach to reduce harmful impacts on the communities producing the raw materials in our electronics is an achievable and beneficial business model.

The Mining the Disclosures report was sponsored by As You Sow and the Responsible Minerals Initiative (RMI), which is holding its annual conference on October 31-November 2, 2018 in Santa Clara, CA.

 

Researchers Use Ultrasound to Recover Gold from Electronic Scrap

The last few months have been ripe with reports on new research related to material recovery from electronic scrap (commonly referred to as “e-scrap” or “e-waste”), as highlighted in a previous post. I’ve learned of yet another exciting innovation in this field, thanks to a feature written by Jared Paben in the latest edition (4/19/18) of E-Scrap News.

As Paben reports, researchers from Sandia National Laboratories have developed a method to use ultrasonic waves, coupled with surfactants, to cheaply and efficiently recover gold from scrap electronics. Their experiments involved application of two different surfactants to the surface of a cell phone SIM card, which was then submerged in water. Ultrasonic waves were applied, which imploded micro-bubbles on the SIM card’s surface. Upon collapse of these micro-bubbles, micro-jets ejected gold nanoparticles from the card’s surface, and the nanoparticles were captured and stabilized by the surfactants.

According to the research group’s paper, published in the journal Small on 3/24/18), this mechanical method may not only present an effective way of reclaiming gold and other metals from electronic scrap, but could potentially be used to manufacture gold nanoparticles from native gold metal directly upon recovery from mining, which they say “may represent the greenest possible approach to nanoparticle synthesis.” (Citation: J. Watt, M. J. Austin, C. K. Simocko, D. V. Pete, J. Chavez, L. M. Ammerman, D. L. Huber, Small 2018, 1703615. https://doi.org/10.1002/smll.201703615)

You can read more about this research in a 4/3/18 article from New Scientist.

To learn about cavitation and cavitation bubbles, the phenomena which allow this mechanical process to work, see https://www.nsf.gov/news/special_reports/science_nation/cavitationbubbles.jsp and https://en.wikipedia.org/wiki/Cavitation.

For more information on gold in electronics, see How Much Gold is in Smartphones and Computers? and Uses of Gold in Industry, Medicine, Computers, Electronics, Jewelry.

To learn about the properties and applications of gold nanoparticles, see https://www.sigmaaldrich.com/technical-documents/articles/materials-science/nanomaterials/gold-nanoparticles.html.

Further Developments in E-Waste Recycling

In a previous post, we discussed how researchers at the Illinois Sustainable Technology Center (ISTC), on the campus of the University of Illinois at Urbana-Champaign have developed an energy-efficient, non-toxic, nondestructive chemical process to recover polymers from the complex plastic blends found in items like cellphone cases.

But that’s not the only exciting news this Earth Month related to innovations in reclaiming materials from electronic scrap (commonly referred to as “e-waste”). In a GreenBiz article dated 4/18/18, Heather Clancy highlights an electrochemical process developed by Canadian venture EnviroLeach Technologies, which is similar to the conventional method of leaching gold and other metals out of ores, concentrates and tailings. The difference is that “instead of using cyanide, the patent-pending formula uses five non-toxic, FDA-approved ingredients that are combined with water at ambient temperatures.’The process does not require pressure, elevated temperatures, complex process circuits, intensive gas monitoring or costly detoxification systems,’ explained EnviroLeach on its website.” Read the full story on the GreenBiz web site. You can also check out the EnviroLeach web site for further information. This development is particularly encouraging considering a recent article from Environmental Leader reporting that n a study by researchers from Tsinghua University in Beijing and Macquarie University in Australia, which suggests extracting metals from e-waste costs 13 times less than mining ore. Perhaps the new process will make the economic benefit even more striking, while minimizing environmental impacts.

Elsewhere in Canada, researchers at the University of British Columbia “have perfected a process to efficiently separate fibreglass and resin – two of the most commonly discarded parts of a cellphone – bringing them closer to their goal of a zero-waste cellphone.” As UBC News reports, “Most e-waste recycling firms focus on recovering useful metals like gold, silver, copper and palladium, which can be used to manufacture other products. But nonmetal parts like fibreglass and resins, which make up the bulk of cellphones’ printed circuit boards, are generally discarded because they’re less valuable and more difficult to process. They’re either fed to incinerators or become landfill, where they can leach hazardous chemicals into groundwater, soil and air.” But UBC mining engineering professor Maria Holuszko, along with PhD student Amit Kumar, has developed a process using gravity separation “and other simple phycial techniques to process cellphone fibreglass and resins in an environmentally neutral fashion.” The next step in pursuing this innovation is developing a large-scale commercial model of the process with their industrial partner and recycling company Ronin8. Read the full UBC article on the UBC News web site.

Read more at https://ifixit.org/recycling on why electronics recycling, though of course important, should not be considered the answer to the problem of ever-growing amounts of e-waste, due to the difficulty in reclaiming materials (eased slowly by new innovations like the ones described above) and energy use. While these developments in electronic scrap recycling are heartening, it’s important to remember to keep your electronics in service as long as possible through repair and upgrades, and when you no longer want or need a functioning device, sell or donate it so someone else can use it. Recycling should only come at the ultimate end of a device’s useful life.

Amnesty International Reports on Child Labor in Cobalt Battery Supply Chain

On November 15, 2017, Sustainable Brands reported that Amnesty International had released a new report revealing that tech industry giants such as Microsoft, Lenovo, Renault and Vodafone aren’t doing enough to keep child labor out of cobalt battery supply chains in Democratic Republic of Congo (DRC) and China. “The findings come almost two years after Amnesty exposed a link between batteries used in their products and child labor. Time to Recharge ranks industry leaders, including Apple, Samsung SDI, Dell, Microsoft, BMW, Renault, Vodafone and Tesla according to improvements to their cobalt-sourcing practices since January 2016. The 108-page report revealed that only a handful of companies made progress, with many failing to take even basic steps, such as investigating supply links in the DRC. The report’s publication is timely, arriving just months after the UK government announced plans to ban new petrol and diesel cars and vans from 2040, which would ultimately lead to higher demand for cobalt batteries. This last point is particularly problematic as recent reports have revealed that cobalt resources are on the decline, despite demand growth predicted at 500 percent.”

See http://www.sustainablebrands.com/news_and_views/walking_talk/sustainable_brands/amnesty_international_reveals_tech_industry_giants_fa for the complete article on the Sustainable Brands web site.

To download the report itself, Democratic Republic of the Congo: Time to recharge: Corporate action and inaction to tackle abuses in the cobalt supply chain (15 November 2017, Index number: AFR 62/7395/2017), see https://www.amnesty.org/en/documents/afr62/7395/2017/en/.

Amnesty International logo, with the wordmark on a yellow background beside a stylized image of a lit candle entwined with barbed wire