E-waste was recently in the news thanks to this year’s Tokyo Olympic and Paralympic Games, as all the medals awarded to winning athletes were made from recycled metals.
It’s not the first time that recycling and sustainability has been highlighted at these events – the silver and bronze medals for Rio 2016 were produced using 30% recycled materials – but the Tokyo Games went a step further.
100% of the metals required to manufacture the gold, silver and bronze medals – approximately 5,000 in total – were extracted from small electronic devices that were contributed by people from all over Japan in a two-year period from April 2017 to March 2019.
Municipal authorities across Japan collected 78,985 tons of electronic devices, while mobile phone operator NTT Docomo’s shops collected 6.21 million used phones.
The organisers said: “We hope that our project of recycling small consumer electronics, and our efforts to contribute to an environmentally-friendly and sustainable society will form part of the legacy of the Tokyo 2020 Games.”
E-waste is a global issue
According to the Global e-waste Statistics Partnership, which collects global e-waste statistics, 53.6Mt of e-waste was generated globally in 2019, which is up 21% in five years. This figure is projected to grow to 74.7Mt/y by 2030.
This is a growing problem, as most e-waste ends up in landfill where it can cause environmental contamination due to metals leaching into the surrounding environment; just 17.4% of the global e-waste generated in 2019 was officially documented as being properly collected and recycled.
The Graham Sustainability Institute at the University of Michigan in the US calls e-waste a global and growing threat to human and ecosystem health, noting that: “Low-income countries bear a disproportionate burden of the impacts of e-waste, as higher-income countries often export waste to be recycled or disposed of in these less expensive settings.”
The Basel Convention is a multilateral treaty, effective from 1992, that was designed to reduce the movements of hazardous waste between nations – specifically to prevent transfer of hazardous waste from developed to less developed countries.
In 2002, it began addressing the issue of e-waste, including producing guidelines for environmentally sound e-waste management, building worldwide capacity to better manage e-waste and the prevention of illegal traffic of e-waste to developing countries.
Despite this, hundreds of thousands of tonnes of e-waste are sent every year from developed regions such as western Europe, North America and Japan to developing countries such as Ghana, Thailand and India.
Ambiguous wording in the Basel Convention has left a loophole that allows countries to export e-waste, rather than responsibly disposing of it, by claiming that it is repairable.
While e-waste presents a growing challenge, it also offers opportunity, and few businesses are better positioned to take advantage of it than mining.
The Global e-waste Statistics Partnership’s Global E-waste Monitor 2020 report noted that the value of raw materials in the global e-waste generated in 2019 is equal to approximately US$57 billion – which is higher than the gross domestic product of many countries – corresponding to a total of 25Mt.
Most of the total weight of raw waste materials found in that e-waste comprises iron, aluminium and copper.
Some mining companies are already recycling e-waste. Glencore has a recycling division with facilities in the US, Canada and Chile that recycle a variety of e-waste such as circuit boards, electronic components and mobile phones from more than 30 countries to extract sustainable copper and precious metals.
Glencore’s recycling operations form part of its target to become a net-zero emissions company by 2050.
In Europe, mining and smelting company Boliden has been recycling waste materials at its Rönnskär smelter in Sweden since the 1960s, and it currently recycles 120,000t/y of electrical material, including circuit boards from computers and mobile phones.
The company’s Harjavalta smelter in Finland processes almost 10,000t/y of secondary materials from electronics along with copper concentrate.
Its precious metals refining plant located in Hoboken, a district of the city of Antwerp in Belgium, recycles and refines precious metal bearing materials such as electronic scrap, spent industrial and automotive catalysts and old mobile phones.
In 2020, the company launched a campaign with Belgian telecommunications provider Proximus to persuade people to recycle their old mobile phones; their goal for 2021 is to collect 150,000 disused phones from households in Belgium to be recycled.
The process of recycling e-waste is not without its problems, however. In 2020, it was reported that children living close to Umicore’s Hoboken plant had elevated levels of lead in their blood.
Umicore noted in a statement that it has been testing the blood levels of local children twice a year since 1978, and that there had been multiple years of steady decreases in lead detected, with historically low levels in 2019.
After performing an in-depth analysis of the root causes, Umicore concluded that combination of external factors, such as exceptional weather conditions and the children’s increased exposure from spending several months at home due to the COVID-19 lockdown measures, contributed to the elevated readings.
The company is now working on establishing a ‘green zone’ around the plant by offering to purchase the houses located closest to the plant on a voluntary basis, which will increase the distance between the plant and residential areas. And is also adapting its logistics activities in line with the weather conditions.
An environmental approach
UK-based Argo Natural Resources, the commercialisation partner of the University of Leicester, is one company that is developing technology to tackle the global e-waste issue. The company will shortly be rebranded as Descycle.
“E-waste is the world’s fastest growing waste stream,” said Fred White, commercial manager at Argo Natural Resources. “Just looking at the market size, it’s quite significant, and the rate of growth is enormous – it’s projected to grow by 40% over the next 10 years. A lot of recycling capacity needs to come online to deal with that growth.
“We see it as a big opportunity. Global demand for electronic goods is soaring – how many phones and laptops do you have today, compared to 10-15 years ago? And how long do you keep those phones?”
Argo is commercialising Deep Eutectic Solvents (DES), a chemistry that has been under research and development at the University of Leicester for nearly 20 years. DES consists of non-toxic, environmentally benign and chemically stable ionic liquids that can be used to extract a wide range of metals.
“DES is a platform chemistry of millions of different combinations of salts and simple organic compounds,” White explained. “They can be combined in certain ways to do a wide variety of things.”
In the mining industry, the primary application of DES is for the dissolution of metals. “There are different combinations that can be used,” said White. “We can tailor the DES to be selective – to leach certain metals out of an ore, e-waste or other feedstock – and the recovery can be selective too.”
He noted that, as e-waste products are generally in whole components, they are hard to process effectively. For example, along with metals, e-waste like a laptop or a mobile phone contains other materials like plastic and glass, and they can’t all be recycled in the same way.
“There’s a whole ecosystem of recyclers who collect these products, and manually or mechanically strip them down into components,” said White. “Then those pieces are sent on to other recyclers for them to process.
“Our process only recycles metals; the whole components will be processed by our recycling partners.”
An alternative source of metals
One of the primary stocks Argo seeks is e-waste, like printed circuit boards (PCBs) and motherboards, as they contain the highest proportion and value of metals.
In a corporate presentation from July 2020, the company noted that a typical ‘basket’ of e-waste has a total contained metal value of US$1,398/t, while PCBs have a gold grade of 400g/t and a total contained metal value of US$30,263/t, which is a 21x value increase.
“If you have iPhones, it can be twice that,” said White. “Tell a gold miner you’ve got 400g/t of ore, and they’re going to be very excited. This is why economically it’s a really interesting prospect. Although it’s a very different industry to mining, it’s still metals processing.”
White said that the real advantage of using DES to recycle e-waste is that it completely changes the process. “Currently, to recycle e-waste at any kind of scale, almost every operation uses a combination of smelting and refining,” he said.
“These are high-CAPEX, high-energy processes, which are often done at very large scales by big companies with big operations. They usually have one or two large e-waste processing centres that they collect their global feedstock from and follow them through these operations.”
He described DES as being a potential replacement for smelting.
“We believe the current solutions and methods of recycling are outdated,” said White. “Refining is essential, but smelting hasn’t changed much over the last 50 years. There have been some innovations, but fundamentally it’s a very energy and capital-intensive process which can have a significant environmental impact. It’s ripe for disruption
“We’ve flipped the process on its’ head and developed a low energy, low CAPEX method with no particulate emissions. One of the economic highlights of this process is that the capital repayment period is under one year.”
DES also has a low carbon footprint when using standard grid electricity.
“It takes 1.1t of CO2 to mine and produce an ounce of gold from primary mining,” explained White. “Conventional recycling requires about 220kg of CO2 per ounce of gold.
“With our process, using standard grid electricity, it’s only 6kg per ounce. Using renewable energy, it’s carbon neutral. That’s quite a significant saving on a per-ounce-basis, which is another stepping stone towards a net zero world.”
This means that not only can DES scale down e-waste processing from larger smelting and refining operations, but it can also reduce the impact of the metals being recycled.
Argo has plans in place to establish an operational DES plant. When we spoke in July, White had just returned from a site visit with Argo’s development partner, the Centre for Process Innovation (CPI) in Teesside, northern England.
CPI is a not-for-profit centre of excellence focusing on process innovation that was established in 2004, out of different parts of the former British chemicals company Imperial Chemical Industries (ICI).
It provides companies with access to facilities, expertise and networks of public and private funders to develop, prove, prototype and scale-up new products and processes.
“CPI has a £150 million facility in Sedgefield [County Durham], and that’s where we’re doing all of our development work,” said White. “We’ve kicked off a programme which will deliver a pilot plant in September 2022, and then 12 months after that, we’ll construct the first commercial plant. Both plants will likely be in the UK.”
From urban mining to traditional mining
Outside of e-waste, another key target for Argo are virgin nickel laterites.
“We’ve proven that our formulations can effectively leach over 95% of nickel from nickel laterite ores without the need for high pressure acid leaching (HPAL),” said White. “We’re currently investigating the removal of HPAL from the processing of nickel laterites.”
HPAL is an expensive, capital-intensive and often difficult process to run.
“There are high OPEX and maintenance costs attached, and funding a project with HPAL can be tricky,” said White.
“If we can reduce that CAPEX drastically, we’ll unlock a lot of nickel laterite resources that could then become economic, or at least bankable, projects.”
Another area of mining that Argo is targeting is refractory gold processing.
“DES works very well on ores that are amenable to leaching with cyanide,” said White. “But it also works very well where cyanide doesn’t. We’ve tested carbonaceous ores and refractory ores where the gold is trapped in a sulphide matrix.
“Usually, these ores require roasting prior to cyanide treatment, or processes like bio-leaching to unlock that gold.”
White said that DES has outperformed cyanide in every test to date.
“Especially on carbonaceous ores, it’s up to 80 times faster than cyanide,” he said. “All the equipment we’re using is standard or very simple – there are no high-pressure tanks or specialist kit. It’s just a leaching process that can be easily integrated into existing processing circuits.”
The process can be used on a leach pad, but vat leaches are more likely, depending on the gold grade.
“It’s also easier for us to recycle the solvents,” said White. “DES is not a water-based chemistry, which is a key differentiator between it and almost any other leaching process. Because it’s not water-based, the metals behave differently, and that’s how we can extract them so successfully.”
Argo will continue work with its mining partners on this over the next two years, including some major mining companies, so watch this space!