The majority of electronic waste is landfilled
When catalytic converters and electronic waste (e-waste) are exported or go to landfill, the significant quantities of metals such as gold, silver and platinum that they contain are lost. To remedy this, companies have been developing technologies to recover precious metals from the waste – which even includes dust.
Last year, British waste firm Veolia opened a street-sweepings recycling facility at Ling Hall in Warwickshire, with the aim of recovering precious metals from the remaining dust. Veolia’s calculations show that 30,000 tonnes of road dust has a value of about £80,000, since it can yield 5kg of precious metals. While people are driving, ultra-fine particles of platinum-group metals are worn off their vehicles’ catalytic converters and end up on the street. In some urban areas, road dust contains platinum at levels equivalent to those found in the ore when it is mined.
Work is still under way to make the process cost-effective. “We are working on an economically viable method for extracting these platinum particles out of road dust,” says Caroline Rams, Veolia’s communication manager. If the company succeeds in its goal, this plant would be a world first.
However, the used catalytic converters themselves are an even richer source. They each contain 2-3g of precious metal, tucked away in a 1kg brick, that is up for grabs when the converter is finished with. To obtain the same amount of platinum from South African mines, at least 2 tonnes of ore have to be blasted out of the ground, crushed and milled – and then there’s the extraction process.
In recent years, mining companies have failed to keep pace with rising industrial demand for precious metals, such as gold, silver, platinum, palladium, rhodium, iridium and ruthenium. To ease these ongoing supply-demand deficits, it is essential to recycle products containing these metals. But the recycling rate for catalytic converters is still only about 55%. The rest are landfilled or exported.
For e-waste, the situation is even worse. In 3 tonnes of mobile phones, for example, there are 1kg of gold, 5kg of silver and 150g of palladium, but only 10% of these materials gets collected and recycled after use. Between now and 2020, the amount of electronic products purchased in the UK will total 10 million tonnes. That includes
20 tonnes of gold, 400 tonnes of silver and 7 tonnes of platinum group metals worth £1.5 billion, according to the Waste & Resources Action Programme.
But most of this value will be slipping through our fingers, as the majority of this e-waste is landfilled or ends up in countries such as India or China, where unregulated methods of recycling are often used.
Although recycling rates for consumer products remain low, various industrial sectors have become aware that losing precious metals means losing money. As a result, a University of London spin-out firm that has developed a range of metal-scavenging agents is gaining momentum since it went independent in 2003.
Phosphonics’ metal-scavenging agents remove precious metals from process and waste streams down to concentration levels of less than one part per million. “More than 100 companies are using or testing our scavengers,” says Dr Linda Bell, the company’s chief executive officer.
Among the company’s clientele are precious metal refiners, the electronics industry – where gold and platinum figure strongly in silicon chip and wafer production – and chemicals and pharmaceutical companies that run catalytic processes based on precious metals.
These precious metals are captured out of the waste stream by a ‘chemical magnet’ – modified silica beads that trap the trace elements to their surface. A successful operation involves a loading of about 10-80g of precious metal per kilo of silica.
Phosphonics has a non-exclusive refining partnership with German precious metals and technology company Heraeus, which will take the loaded scavengers and get back 97% of the metal on them. In return, Heraeus recommends that its customers use these scavengers to optimise their processes.
Various sizes of installation are available, with the costs reflecting the scale, says Bell. “A relatively small installation would cost a few thousand pounds and a big application could cost £1.5 million or more. We are continuously developing the engineering aspects of the scavenger process – for example, by optimising the chemical part of the process.”
The technology offers a lot of potential, she believes. “It is an exciting technology, with applications that we are still developing worldwide. The recovery of precious metals is particularly of interest to China, which has limited natural resources within its own country. It has to import a lot of precious metals, so it is important to recover as much as possible.”
Meanwhile, most globally competing companies are rushing to get hold of any supply stream that contains precious metals. Not surprisingly, the three largest producers of automotive and industrial catalysts – BASF, Johnson Matthey and Umicore, that together control 90% of the market – each has an extensive recycling division.
In 2011, BASF invested £3 million in doubling the capacity of its pre-processing plant for catalysts and e-waste in the UK. The company also owns, or participates in, refining facilities in Italy, the US, Korea and Japan.
British chemical engineering company Johnson Matthey, with smelting and refining facilities in the UK and the US, is one of the few big players in precious metals recycling that is not expanding. The company has been plagued by problems at its Salt Lake City refinery and by a
£35 million loss in annual sales due to the end of its accord with Anglo American Platinum.
Johnson Matthey’s biggest competitor is Belgian company Umicore, which owns a huge smelting and refining plant near Antwerp. Umicore has announced a 40% expansion of its facility to treat 500,000 tonnes of feedstock per year. “We are going to de-bottleneck the existing facility – to treat with the same installations more tonnes of material,” says Luc Gellens, vice-president of Umicore’s precious metals division.
This streamlining will allow the company to realise the expansion for a mere €100 million, he says. A larger facility will bring the advantage of scale, so that Umicore can keep the fee for its refining services as low as possible.
Umicore’s main feedstock, apart from e-waste and catalysts, is residues from metal mining and refineries. Until recently, most companies in these sectors opted to outsource the treatment of residues. But now, several of them are investing in equipment to refine these streams in-house.
Mining and smelting company Boliden opened a €130 million e-waste recycling plant in 2012 at its copper smelter in Sweden, almost tripling capacity to 120,000 tonnes a year. This year, a 25-tonne silver recovery facility is due to open at the firm’s zinc-smelting operation in Finland.
Copper and precious metals producer Aurubis has ended its contract with Umicore after opening a €50 million facility for the recovery of precious metal from anode sludge in Hamburg last year. The loss of Aurubis’s business could lead to a 10% fall in Umicore’s gold output, according to a report from Berenberg Equity Research.
Another supplier of Umicore’s feedstock, mining and metals business Nyrstar, has announced a €350 million investment to convert its Australian lead smelter into an advanced metals recovery and refining facility, so it can start treating its own precious metal-containing residues.
Companies such as Umicore, Aurubis and Boliden run large, centralised facilities. By contrast, Tetronics International, in Swindon, has developed a precious metal recovery technology that could complement, or even be disruptive to, this business model.
Over five decades, the company has become a big supplier of plasma technology for waste treatment and metal recovery. It has fine-tuned this technology so it can recover – by smelting – the whole range of precious metals and special metals such as rhenium and molybdenum from a high-value waste stream comprising e-waste, scrapped solar panels and catalysts. Further refining of these metals needs to be done out-of-house.
Tetronics has implemented its technology at commercial scale in eight precious metal recovery plants worldwide, with a further three plants due this year. More than half of these plants – six out of 11 – are located in the Far East and owned by BASF Catalyst, Taiwanese company Solar Applied Materials Technology and Japanese industrial product manufacturer Furuya Metal.
The capacity of a plant can be up to 6,000 tonnes a year, but the standard size is 2,000 tonnes a year, says Dr David Deegan, Tetronics’ chief technical officer. “Such a plant would have an annual output of 150,000 to 170,000 troy ounces [4,666-5,288kg] of platinum group metals.”
The company’s technology yields a particularly high level of recovery, he says. “If you go to the market, and look at refining terms, a recovery rate of 96-98% for platinum and palladium is standard, and around 85% for rhodium. But with our technology, it is 98% for all these elements. And our more recent installations are reprocessing the waste stream to maximise recovery beyond 98%.”
One of the Tectronics plant owners, Furuya Metal, said last year that it was expecting income from its new plasma facility, which recycles spent catalysts, to increase by ¥200 million (£1.17 million). “Our technology pays for itself in less than a year,” says Deegan. “Our clients can either buy refining services or invest in our technology.”
One advantage of treating precious metal-containing scrap locally is a reduction in the transport needed, with consequences for both financial and environmental costs. The idea of transport reduction has already taken form as ‘food miles’ but it could be applied to any industrial product. “Plants could be established where local conditions are best for labour rates and power costs,” says Deegan. He estimates that the UK could support five to 10 Tetronics plants, creating 20 jobs per installation, excluding management.
Such a local approach would also help with sustainability and security, he says. “In a European context, it would give member states independence in their ability to sustainably handle their own waste streams on a competitive basis – and provide each territory with security on critical metals.”