Metalex agromining special – How to farm rare metals

Some developments in the metal supply world are so exciting they deserve their own post. This is one of them. As metal stockists, this one blows our mind! Thank you to New Scientist magazine.

Did you know scientists are working hard to bring about a brilliant new way to extract the metals we need in our modern world? Apparently, it’s a farming thing, involving plants that actually suck metals from the soil for use in contemporary technology.

Farms are growing metal-rich plants

Farms are growing plants rich in metals and rare minerals. Take the humble Phyllanthus rufuschaneyii, a woody shrub whose sap is a vivid blue-green. How come? It’s absolutely packed with nickel. This, and other metal-containing plants, could solve one of humanity’s biggest puzzles – how to fulfil booming demand for metals that are essential to everyday tech like phones and computers, and, going forward, for wind turbines, electric vehicles, and new battery tech?

Mining these metals is usually a challenge, as well as dangerous and environmentally disastrous. So the possibility of actually growing the metals is an attractive one. We’re already seeing new metal farms across China, Europe and Malaysia, and they’re turning out to be very profitable as well as environmentally responsible.

Traditional nickel mining is unsustainable

Nickel is usually mined via strip-mining. The vegetation is removed and explosives used to reveal the ore. Fewer trees mean rainwater flows away, carrying pollution into rivers and on to the sea and killing sea life. The ore is shipped for smelting, which generates even more toxic fumes and vast amounts of waste. Using plants instead is a no-brainer in so many ways.

How come plants contain metal? They suck it up from the soil through their roots, whether it’s iron, zinc, nickel or something else. It is still a puzzle, though, why some plants contain such huge quantities of metal. Some believe it helps the plant become so toxic that pests and animals that would otherwise eat the plant are put off.

In 1997 scientists proved that a nickel-rich ore could be harvested from plants, and the concept of metal farming became real. When the sap from the shrub Phyllanthus rufuschaneyii was found to contain 25% nickel by weight, the best candidate metal crop so far, things started to move ahead even faster.

Impressive prices per hectare for metal-rich vegetation

Alyssum bertolonii, a relative of kale and cabbage, contains 10 milligrams of nickel per gram of dried plant. It isn’t the only one. So far hundreds more ‘hyperaccumulator’ plants have been found, all living on soils rich in metals.

Borneo is home to the world’s first tropical metal farm, growing Phyllanthus rufuschaneyii. In 2019 it yielded an impressive 250 kilograms of nickel per hectare, worth just under $4000 per 250g. Because the plant loves tropical climates, it isn’t particularly suitable for northern climes. But there are viable alternatives in the pipeline and more discoveries to come. Once you begin looking for things, you tend to start finding them!

While the EU’s metal farms can’t yet come close to the yields they get in Borneo, they still extract as much as 200 kilograms of nickel per hectare, worth $3000 at the moment and more profitable for farmers than a hectare’s worth of wheat, currently valued at around $2100. It’s interesting to note that many of the soils that suit agromining are fairly poor as regards growing food crops. Metal mining is a reliable way to use this land profitably without causing an environmental disaster… as long as things are done with care, bearing the needs of the natural world in mind.

More metal-containing plants are being discovered

Plants have been found that collect arsenic, cobalt, manganese, zinc and rare earth elements, also with the potential to be farmed. Take the fern Dicranopteris dichotoma. It loves growing on slag heaps near traditional rare earth mines in China. Surveys hint it could deliver a harvest of 300 kilograms of mixed rare earth elements per hectare, including the super-rare and difficult to mine lanthanum, cerium, praseodymium and neodymium. When a substance like praseodymium oxide can be sold for as much as fifty thousand dollars per tonne, it looks like an attractive commercial enterprise. Field trials are underway.

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All this innovation takes a while to filter through to the real world. In the meantime, we stock all the quality metals supplies you need, with expert advice on tap whenever you need it.

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