Saving silver: portable micro-factories could turn e-waste trash into treasure

“We are all micro mine owners.”

This is the mantra preached by Veena Sahajwalla, a materials scientist at the University of New South Wales who wants to fundamentally change how we perceive our electronic waste: not as trash, but as treasure.

Electronic waste, or “e-waste”, is full of valuable resources: a tonne of mobile phones, which is roughly equivalent to 6,000 handsets, contains about 130kg of copper, more than 3kg of silver, 340 grams of gold and 140 grams of another precious material known as palladium.

“We have almost 25m mobile phones just in Australia,” says Sahajwalla. “And these are the ones not in use.” Add to that the huge numbers of TVs, computers, tablets and appliances laying around our homes and that’s a lot of opportunity. Unfortunately, we’re not capitalising.

Globally e-waste is an intensifying problem. Between 2009 and 2014, the amount of e-waste generated worldwide doubled, hitting 42m metric tonnes per year. According to a report by the United Nations University, the combined estimated value of the resources embedded in that waste was A$69bn (US$52bn).

Yet less than one-sixth was diverted to proper recycling plants.

E-waste is challenging to recycle because it contains a spectrum of mixed resources, but also toxins such as mercury, arsenic, chromium and lead.

Australia is one of the world’s largest generators of e-waste, producing more than 15.2kg per inhabitant each year. Regionally, Oceania is second only to Europe in that metric.

Safe recycling of e-waste in Australia has traditionally been limited to high-cost, industrial-scale smelting facilities. Despite efforts to improve management, huge amounts of e-waste still end up in landfill, where toxins can leach into the environment, contaminating soil and groundwater, and posing public health risks. The charity Clean Up estimates that just 10% of the seven million TVs and computers purchased each year in Australia are recycled correctly.

Large amounts of e-waste are also exported from industrial economies like Australia to the developing world, where regulations are less stringent. In some places, these hazardous materials are processed by labourers in unsafe working conditions.

Sahajwalla wants to make e-waste processing safer and more profitable. As part of her Australian Research Council laureate fellowship, she’s developing the fundamental science to transform the resources in e-waste into a range of valuable products.

She is currently developing the prototype for a low-cost alternative to industrial-scale smelting, which will be based at UNSW. The concept is simple yet innovative: portable micro-factories, roughly the size of a shipping container, which can be deployed at collection sites in suburbs, remote communities and throughout the developing world. Sahajwalla is collaborating with industry on the project.

These micro-factories will churn out high-value metal alloys, ceramics, composites and nanomaterials, while simultaneously eliminating any hazardous impact. As the materials already have market value, they could benefit niche manufacturers producing everything from jewellery to marine hardware, says Sahajwalla.

The technical challenge is what Sahajwalla calls selective thermal transformations: working out how to create the valuable products efficiently using precisely controlled, high-temperature chemical reactions in a small-scale furnace.

If her team can overcome the hurdles, the benefits are clear: micro-factories decentralise recycling, allowing e-waste to be processed locally where it’s collected. This helps eliminate emissions associated with shipping the waste across huge distances to recycling plants.

Sahajwalla says large-scale smelters have a high energy cost because they need to extract metal from ore bodies, which have been produced from upstream mining activities. “Parts of what we are processing start their life in an e-waste, in a metallic form,” says Sahajwalla. “So you’re saving on energy to begin with. The energy saving is a no-brainer.”

Sahajwalla says micro-factories will also create new business opportunities for small recyclers, who can transition from being collectors of waste to manufacturers of high-value products.

“The idea absolutely has legs,” says Anna Littleboy, the research director of CSIRO’s mineral futures project, which has studied how to improve metal recovery from e-waste.

Just as 3D printing will enable the manufacturing industry to move away from bulk production, distributed micro-factories will enable on-demand recycling. “You process stuff as it comes in,” says Littleboy. “You don’t have to stockpile and store it to get that economy of scale.”

She agrees it will open up new opportunities for niche manufacturers and small recycling outfits but says the current systems in Australia are designed to support “business-as-usual” operations. “In the past in Australia, this has been the big smelters.”

But Littleboy says centralised e-waste recycling facilities, like those developed in Europe, are impractical in Australia because of the geography and population density.

With micro-factories, there is “great potential for Australia to do something a little bit different around e-waste from the rest of the world”, she says.

Littleboy says the key technical hurdle will be adapting well-understood chemical reactions to a smaller scale, to efficiently separate valuable resources and create a pure product.

Before micro-factories make a dent on our e-waste problem, however, Australia will first need to address policy shortcomings.

A recent review published in the Journal of Environmental Management found that Australia’s four key pieces of legislation governing e-waste management were largely ineffective compared with countries with best practice systems, such as Japan and Switzerland.

This was due in part to outdated targets, poor compliance and auditing measures, access issues for regional communities, and a lack of support for local councils tasked with running e-waste collections.

“If you have a policy or a law, but then there are insufficient mechanisms to measure compliance and monitoring, then sometimes you get the shortest pathway, which might be send it to a landfill or ship it illegally to some other country,” says report author Prof Graciela Metternicht, an environmental scientist at UNSW.

Metternicht says one of the biggest problems around e-waste in Australia is a lack of reliable data. “We all rely on estimations … We go in circles, repeating numbers. What we need is some serious research that can tell us how much is collected, how much is recycled,” she says.

Metternicht says portable micro-factories are a “great plan” and should be considered, but they need to be affordable.

With the design process still under way, Sahajwalla says the price tag for micro-factories is not yet clear, but maintains she’s committed to providing a low-cost, accessible option. “If we can develop these affordable and sustainable solutions, that may well be the tipping point for how it becomes possible for a lot of developing regions to be more safely processing their e-waste.”

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