If you asked a school student what magnesium is, they might tell you it’s the ingredient in that science experiment; the one that produces a white-hot flame.
If you asked a nutritionist, they’d say small amounts of it found naturally in food are processed by the body for the proper function of bones, muscle and nerves.
But what do the global markets say about this ultra-light metal, and why is it causing such a stir?
In this article:
- What is magnesium and how is it produced?
- What's so good about it?
- What are the current geopolitical risks?
- What is magnesium’s role in a low-carbon economy?
- From brown coal waste to magnesium
What is magnesium and how is it produced?
Magnesium is a mineral extracted from magnesite or dolomite. In its natural state, it is a grey-white powder and the eighth-most abundant element on earth.
In powder form, it's a highly unstable element, as the high school students will tell you, and is used in pyrotechnics. But as an alloy, it becomes incredibly strong and its applications are diverse. It is non-magnetic, non-toxic, 75% lighter than steel and 33% lighter than aluminium and titanium.
There are a variety of ways to refine magnesium metal.
It can be extracted from dolomite and magnesite ore using electrochemical processes during which the dolomite is crushed, heated and mixed with seawater in large tanks, causing the magnesium hydroxide to settle at the bottom of the tank. From there it is mixed with coke and chlorine to produce molten magnesium chloride. This is electrolysed, releasing magnesium.
It can be extracted from seawater, which contains 10% magnesium chloride. This process requires the compound to be dried out before it can be electrolysed to produce the metal – a technique common in Israel, using Dead Sea brine.
It can also be produced using the Pidgeon Process – a highly labour- and energy-intensive process of thermal reduction that has become popular in China, the globally dominant producer.
And one Australian company has patented the technology to extract magnesium from a waste product, with a negligible carbon footprint – but more about that later.
What’s so good about it?
Magnesium is incredibly light, but it has the best strength-to-weight ratio of all common structural metals.
It is often alloyed with aluminium because while it is one-third lighter than that metal, its relative strength and resistance to denting makes it much more useful in certain applications.
If you think it’s harder to crush a soft drink can underfoot than it used to be, you’re right – ring-pull soft drink cans, once made of neat aluminium, were prone to collapsing under their own weight when stacked in pallets. The addition of magnesium made them tougher – and led to the change in the ring-pull mechanism, which used to peel back easily.
When the two metals are combined, they produce a corrosion-resistant alloy used in die-casting in aircraft, machinery, power tools, lightweight consumer devices and car parts.
Magnesium has an exceptional dampening capacity and low inertia, which makes it ideal for moving parts in engines – this, along with its lightweight properties, makes it an excellent candidate for electric vehicles.
But never mind electric vehicles – the global car industry needs magnesium as a component of the aluminium sheeting that forms the chassis of the cars we drive right now.
What are the current geopolitical risks?
China is responsible for the overwhelming majority of global magnesium production – 900,000 tonnes, half of which is for export – upwards of 87% of the world’s supply.
The process used by Chinese plants is carbon-intensive and it was reported in September that, in a bid to reduce pollution ahead of the winter Olympics next year, the country would slow production dramatically.
Work was halted in 18 magnesium plants and cut by 50% at a further 30 plants in the magnesium-producing region of Shaanxi.
The immediate reaction to this news was a steep global price hike, with prices hitting an unprecedented US$10,200. European prices trebled and have since come down to US$6,000 per tonne, still almost double what they were a decade ago, if you can secure supply.
European, North American and Japanese car markets are dependent on China for magnesium at a time when they are looking to increase fuel-efficient vehicle production. Predictions are that Germany, a key importer, could exhaust its stocks by the end of this year.
Magnesium’s role in the low-carbon economy
Magnesium’s reputation for being ‘the green metal’ is bolstered by its 100% recyclability, though how green it really is depends on the method of production, which as we have seen is currently very carbon-intensive indeed.
But carbon emissions are also the reason for the current interest in magnesium. The metal, a critical component of modern cars, is prized for its carbon-reducing properties – a lightweight vehicle requires less energy to run.
It’s the low-hanging fruit on the path to a lower-emissions car industry, before you factor in which fuel will power that vehicle.
When President Obama instituted a push to reduce automotive pollution in 2009, attention turned to magnesium’s role in driving down industry emissions.
“The more steel and aluminium parts we can replace with magnesium parts, the more fuel-efficient the car becomes,” says Latrobe Magnesium CEO David Paterson.
In the continued push towards lightweight, durable cars, the car industry, currently a consumer of 37% of the world’s magnesium output, will only become hungrier for pure magnesium.
With China’s dominant role in production, there are obvious longer-term risks in store at a time when there is a growing need for magnesium. Many markets are looking to diversify their supply chains.
From brown coal waste to magnesium
Into this breach steps an Australian company that uses its own patented technology to produce magnesium. Latrobe Magnesium has commissioned a 10,000-tonne magnesium plant in the Latrobe Valley, adjacent to the brown coal power plants that currently drive the region’s economy.
The novel technology uses the principles of the circular economy, turning fly-ash waste from burnt brown coal into magnesium and other saleable products.
“We mix the fly-ash with hydrochloric acid and leach off magnesium chloride and calcium chloride," says Paterson. “The calcium chloride becomes an agricultural lime to improve soil, the magnesium chloride is turned into magnesium oxide, which goes through a smelter process to make the metal and there is a cement by-product from the residue in the smelter.”
“We have 100% recovery on all products – there’s no waste.”
“It’s great from a production point of view and it’s great from an environmental perspective too. Fly-ash is very fine and if it does get airborne it can cause silicosis in people’s lungs – we're taking that risk out.”
Importantly, production emissions from this Australian technology will be highly competitive.
“We produce it for 10 tonnes of carbon per tonne of magnesium, which makes it competitive with aluminium, at 12 tonnes of carbon and the 21 tonnes it takes in China – under half the industry average,” Paterson says.
“When we go carbon neutral, using a renewable-powered electric furnace, which we’re looking at for the 10,000-tonne plant, we’ll be producing a genuinely green metal with huge potential.”
Paterson believes the company will scale up considerably from its initial 10,000-tonne plant.
“There are other waste streams that we can use in addition to the Latrobe Valley. We have our technology patented in China, as well as the EU, North America, Indonesia and India – everywhere there is a brown coal deposit, we can take this technology.
In the last few months alone, the company has fielded demand from serious customers to the tune of 20,000 tonnes, in advance of first production next year.
“The car industry can’t go back to steel – it needs the aluminium sheeting, of which magnesium is a necessary component," Paterson says. “The demand is great because customers are realising that diversity of supply is critical.”
And there are other promising uses for magnesium on the horizon, such as a liquid metal battery being used in the USA instead of lithium batteries for large grid storage.
“We don’t even think about these other things now because we’re currently preoccupied with cars,” says Paterson.
“There is significant expansion potential – almost too much for us to handle.”