In our latest installment of our Minor Metals series, we look at magnesium, a metal with huge reserves—and maybe even bigger potential in the energy industry.
Just as bismuth is the "Bis" in Pepto-Bismol, magnesium hydroxide is the "magnesia" in milk of magnesia. (Of course, anything further away from milk in taste or looks would be quite difficult to find!)
Apart from acting as a great antacid, laxative and relaxant for those tired muscles, magnesium is vital to our lives. According to the U.S. National Institutes of Health—Office of Dietary Supplements, "magnesium is the fourth most abundant mineral in the body and is essential to good health." Indeed, the various compounds of magnesium are produced by the hundreds of thousands of tonnes, and consumed by the millions. It's even crucial for nonhuman health: In 2008, the USGS reported that some 31 percent of the caustic-calcined magnesia consumed in the U.S. was used in animal feed and fertilizers.
But as vital as magnesium compounds may be, magnesium metal, although produced and consumed in far smaller quantities, is also extremely important.
Whence The Magnesium?
Unlike for many of the strategic/minor metals, reserves of magnesium are pretty much limitless. Why? Because it's so easy to get at: Not only can the metal be extracted from various mined minerals such as carnellite, brucite, dolomite, magnesite and olivine, it can also be extracted from seawater and natural lake brines. Case in point: US Magnesium LLC, the lone company in the U.S. currently producing primary magnesium metal, recovers it from the brines of Utah's Great Salt Lake at its plant in Rowley, Utah.
In addition, there is significant production of secondary magnesium through scrap recycling. The USGS estimated that, in the U.S. last year, this amounted to some 22,000 tonnes (accounting, perhaps, for some 40-50 percent of total supply in the country). The U.S., in particular, is a hub of magnesium recycling; Advanced Magnesium Alloys Corporation (AMACOR), based in Anderson, Ind., is the largest magnesium recycling facility in the world.
Magnesium is produced using two major different methods: either by thermal reduction (using any one of six different processes) or electrolytically (using any one of eight different processes). The former method is most usually used to extract the metal from its ores, while the latter method, in addition to being used with ore feedstock (particularly carnellite and magnesite), is also used to extract the metal from seawater and brines. (Thus, US Magnesium uses an electrolytic process.)
Thermal processes tend to be more cost-efficient than electrolytic methods. In fact, the low-cost Pidgeon process—developed in Canada in the ‘20s—is the most commonly used production method in China, now by far the world's largest producer of magnesium compounds as well as magnesium metal.
China wasn't always the world's biggest producer. Back in 1995, according to USGS figures, the U.S. accounted for nearly 36 percent of global primary production, amounting to 142,000 tonnes of magnesium metal. China's production, at some 93,600 tonnes, totaled only some 27 percent.
Times have changed, however: In 2009, similar figures from the USGS estimated Chinese production at 470,000 tonnes, or 82 percent of global production. And while figures for U.S. magnesium metal production (now from US Magnesium alone) were "withheld to avoid disclosing proprietary data," suffice to say that the company's Rowley plant produces some 52,000 tonnes per annum, or only around 9 percent of total actual global production.
In fact, over the past 15 years or so, a number of producing countries have fallen by the wayside. According to the USGS, Canada, France and Norway no longer produce primary magnesium. And a significant newcomer is Israel (together with Russia each now contributing a little over 5 percent of global production), which only started producing the metal in any quantities in 1998.
Magnesium has a number of advantages over other structural metals. Amongst the most important are its abundance, lightness and recyclability.
In addition to its lightness, magnesium has a density one-fifth that of iron and two-thirds that of aluminum, making the metal not only highly dent- and impact-resistant, but also very rigid, with an excellent strength-to-weight ratio. It also welds easily and is corrosion resistant.
The greatest use of primary magnesium is in aluminum-based alloys, with the two largest consumers being the packaging and transport industries. In 2009 in the U.S., together with various other applications, they accounted for some "41% of primary metal use."
In the packaging industry, the everyday beverage can alone is a major consumer of magnesium. The aluminum alloy (alloy 3004) used to make its body contains around 1.1 percent magnesium, and to make its top (alloy 5182), around 4.5 percent. (And, according to the International Magnesium Association: "Over 60 percent of the aluminum beverage cans sold in the U.S. today are being recycled, thereby conserving the magnesium component.")
In the transport industry, magnesium is used both to alloy aluminum, and itself, as a base for other alloys. These are then used to produce die cast, wrought and sand cast parts for both the automotive and aerospace industries.
In cars, magnesium finds its way into chassis, driveline, powertrain (i.e., the clutch, transmission, drive shaft and differential) and suspension. (Remember "mag" wheels, too—very cool!)
As for the aerospace industry, magnesium (sometimes alloyed with heavy rare earth metals like yttrium) is often used in helicopter air intakes, speed brakes, engine frames, gearboxes and wheels. Magnesium transmission castings are to be found in F16s, Tornados and Eurofighter Typhoons.
On a more everyday level, the magnesium-based cases for many cameras, cell phones and portable computers are, more often than not, also die cast.
Aside from packaging and transportation, magnesium metal's third-biggest consumer is the iron and steelmaking industries. Because of magnesium metal's affinity for sulfur, it is used extensively as a de-sulfurizer, particularly in the production of high-strength, low-alloy steels that need to contain very little sulfur.
Other uses of magnesium metal include:
- As a reducing agent in the production of beryllium, hafnium, uranium and zirconium.
- In the production of nodular iron, used to make ductile iron castings.
- As anodes to prevent steel corrosion in storage tanks and buried pipelines.
- In fireworks and marine flares, in which it burns with a white bright shining light. (In World War II, magnesium fuses were used extensively in incendiary bombs.)
Opportunities For Magnesium
As the world recycles more and fuel efficiency becomes an increasingly important goal for all modes of transport, from bicycles to automobiles to airplanes, magnesium is in a position really to come into its own—particularly, too, as the automobile industry starts to recover.
On the one hand, the metal is eminently suitable for recycling. It costs considerably less to recover magnesium from scrap than it does to produce in the first place, as only about 5 percent of the energy required to produce primary magnesium is needed. What's more, it can be recycled on a continuing basis pretty much without degradation.
On the other hand, because both of its lightness and excellent strength-to-weight ratio, magnesium is very suitable in circumstances where a reduction in weight can lead to fuel efficiencies. For example, the use of magnesium in modern automobiles can significantly reduce their weight and, thereby, increase their fuel economy. And the metal's use in electric bicycles can enable them to both run longer and extend their batteries' lives. Finally, in the aircraft industry (increasingly in nonstructural applications), magnesium, often in wrought components, can offer significant weight reduction (sometimes up to 35 percent) over aluminum components. And this can also be in addition to their "higher specific mechanical properties compared to Al [aluminum]."
At the recent Minor Metals Trade Association (MMTA) conference in London, a speaker from Magnesium Elektron, a subsidiary of the U.K.-based Luxfer Group of companies, pointed out in his presentation that a simple reduction of some 100kg in a 1 1/2 ton car (a big BMW) or a 300 ton aircraft (an Airbus 380) could save $1,000 and $275,000, respectively, over their lifetimes.
That having been said, magnesium does have its drawbacks. Any increased use of the metal (particularly in the aerospace industry) will require further research to determine how to deal with issues such as its flammability, resistance to corrosion, creep and poor strength at high temperatures. These are probably not insurmountable problems. The relatively high price of magnesium, however, may not prove to be such a tractable problem.
One other industry that will probably see increased use of magnesium is the nuclear power industry, where the metal is used to make nuclear fuel containers.
Although magnesium die casters worldwide have recently faced appalling market conditions, with various companies either mothballing operations or simply going out of business, one sector to keep an eye on is that of specialized magnesium alloys, the likes of those produced by Magnesium Elektron. As weight reduction in not only transport but any number of applications becomes increasingly important as a way to improve energy efficiency, the use of magnesium looks set to rise.
In the major primary magnesium countries, only the following companies currently producing magnesium are publicly quoted:
|JSC Solikamsk Magnesium Works||MGNZ:RU|
|Kazakhstan||Ust-Kamenogorsk Titanium and Magnesium Plant JSC||UTMKP:KZ|
|China||China Direct Industries Inc.||CDII:US|
And each one of these companies, save for Solikamsk, is also involved in other mining activities.
Unfortunately, there are currently very few, if any, actual pure-play opportunities in primary magnesium—whether in production or even down the line in magnesium products. For the publicly quoted producers, magnesium is just one of their activities, and the die casters and alloy producers are predominantly private. Even in secondary magnesium, AMACOR is a subsidiary of the privately held Phoenix Global Holdings, LLC.
However, some interesting work continues to be done in developing the use of magnesium as a fuel source to generate energy. (When burned, it produces intense heat but no greenhouse gases.) Some of the most important research in this field is happening at the Tokyo Institute of Technology. If the institute's Professor Yabe can figure out how to recycle the burned magnesium (in the form of magnesium dioxide (MgO2)—and he looks as though he's on the way—then he may be on to an energy winner.
Even as die casters have shut up shop and primary magnesium producers have either halted operations or scaled back, some have still made a tidy profit from magnesium metal—albeit illegally.
At the beginning of May, The Buffalo News reported that a couple of local men had been indicted by a grand jury as "...part of a conspiracy to deliver prohibited magnesium from China into flares that protect U.S. military aircraft from heat-seeking missiles." The men are accused not only of circumventing DoD regulations covering the use of non-U.S.-sourced materials in defense products, but also of evading the payment of the anti-dumping tariffs payable on the magnesium imported from China.
It was reported that the U.S. government would seek to recover some $10 million in unpaid duties.
U.S. Geological Survey (USGS)
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