TOKYO -- Magnesium prices are rising due to tight supplies from China, by far the world's largest producer of the rare-earth metal, and brisk demand from the auto industry.
Magnesium is mainly used in alloys to strengthen aluminum. While demand for magnesium is growing as automakers work to make their cars lighter, it is also expected to be used in new types of batteries for electric vehicles. If the development of eco-cars proceeds as forecast, magnesium will likely continue to gain luster.
The global magnesium market is expanding steadily. Turkish magnesium producer Esan estimates global demand will total just under 1.6 million tons by 2024, up 50% from 10 years earlier.
Prices for magnesium produced in China and shipped to Japan are hovering around $2,630 per ton, including shipping costs, up 7% since the beginning of the year. Prices were sluggish in 2017, primarily due to a glut in China. Now they are rising as China, which accounts for about 80% of global magnesium output, strengthens its environmental regulations. Many Chinese magnesium smelters have been shut down after failing on-site inspections, causing supplies in Japan to tighten.
Growing demand from the auto industry is also pushing up prices. Carmakers are competing to make their vehicles lighter, which allows them to travel farther on a liter of fuel. This is a crucial consideration as regulators around the world impose tougher fuel-efficiency requirements. Because magnesium is both strong and light, it is an attractive material for manufacturers, and should keep prices for the metal buoyant.
Tak Trading, a nonferrous metal importer based in Hachioji, Tokyo, also expects demand for magnesium to grow among battery makers over the medium and long term because it is cheaper than lithium and cobalt, two other rare-earth metals used to make batteries.
Magnesium has promise as a raw material for batteries: Supplies are abundant and power cells made from magnesium are less prone to catching fire or exploding than the lithium-ion batteries widely used in electric cars and smartphones. Magnesium batteries also have the potential to store much more electricity than conventional power cells. Research and development aimed at bringing magnesium batteries to market is taking off around the world.
As a rechargeable battery is charged and discharged, ions shuttle between the battery's anode and cathode. In a lithium-ion battery, only one electron moves for each ion. But in a magnesium battery, two electrons move per ion, which translates to greater storage capacity.
At the end of last year, researchers at Tokyo University of Science developed a cathode for a magnesium battery, focusing on the magnesium and cobalt oxide used in the cathodes of lithium-ion batteries and replacing about 20% of the cobalt with manganese.
Conventional cathodes deteriorate as batteries are repeatedly charged and discharged, but the Tokyo University of Science cathode retained 80% of its capacity despite repeating the charge and discharge cycle five times, although the tests were conducted under controlled conditions. While its lightness gives magnesium an advantage as a raw material, many challenges remain. Among them, magnesium alloys combust easily.
But for automakers and others, the task of meeting increasingly tough environmental regulations is unavoidable. Efforts to develop products that help them do that will continue, taking advantage of magnesium's lightness and other properties.
For now the metal continues to play a supporting role, as an additive to aluminum, for example. But a day may come soon when magnesium is seen as key to essential environmental technologies.