November/December 1997
This enigmatic metal has been making headlines as it gains a small but growing share of the automotive die-casting market. Will this demand keep it in overdrive, or will price and supply concerns stall its potential?
By Eileen Zagone
Eileen Zagone is an associate editor of Scrap.
Quick, what substance makes the Fourth of July a real blast but soothes the figurative fireworks of upset stomachs, while also lending its strength to fortify the thin walls of aluminum beverage cans?
The answer is magnesium.
In metallic form or as a compound, magnesium can be found in such diverse applications as fireworks, medicinal products (à la Milk of Magnesia), in-line skates, power tools, aluminum alloys, furnace refractory bricks and linings, and more. Magnesium enjoys such widespread use thanks, in part, to its impressive physical characteristics, most notably its ultra-lightweight nature and good strength-to-weight ratio.
Despite its characteristics and broad use, world production of primary magnesium is minuscule compared with most other metals, totaling about 341,000 mt in 1996, according to the U.S. Geological Survey (Reston, Va.). (For more statistics on the magnesium market, see the table on page 62.) This relative dearth of primary magnesium production can be attributed to the fact that it’s one of the more energy-intensive metals to produce. Though magnesium is the eighth most abundant element in Earth’s crust, it doesn’t exist naturally in metallic form but must be converted from sea water, brines, or various magnesia-containing minerals. That’s right—unlike, say, copper ore mining, magnesium production requires energy-intensive electrolytic or thermic processes to convert brines or limestone-like mineral deposits into metal.
On the plus side, however, magnesium literally covers the world in the form of sea water and plentiful and geographically widespread deposits of various forms of magnesium carbonates or silicates, which represent a uniquely rich and virtually inexhaustible resource for magnesium production.
By far, the dominant market for primary magnesium is as an alloying agent with aluminum, an application in which magnesium lends its strength to the other lightweight metal. While UBCs are generally thought to be “all-aluminum used beverage cans,” the can bodies contain, on average, 11/2 percent magnesium while the stiffer lids contain as much as 5 percent magnesium. According to the International Magnesium Association (IMA) (McLean, Va.), more than half of primary magnesium production is consumed in aluminum alloys. In 1995, for instance, 52 percent of magnesium supplies went into this application. And this market segment appears to be secure from competition in that there’s no substitute for magnesium as an alloying element in aluminum, says Byron Clow, IMA’s executive vice president.
Die casting is the second-largest market for primary magnesium, accounting for 21 percent of 1995 production, IMA reports. And of all die castings that contain magnesium, the majority—at least 75 percent—are castings for the automotive market. Such is the auto industry’s appetite for magnesium die castings that magnesium demand has grown 8 percent a year for more than the last decade, according to IMA, with similar growth expected in the future.
Driven to Lighten Up
Magnesium has received considerable industry press coverage in recent years, largely due to the automotive industry’s growing use of magnesium die castings as a way to reduce the weight of passenger vehicles without sacrificing strength.
Experts agree that the single force driving automakers to magnesium is the need to meet the corporate average fuel economy limits, more commonly known as the CAFE standards. The standards require North American carmakers to produce vehicles that meet certain fuel mileage standards—27.5 mpg for cars and 20.7 mpg for light trucks.
One of the chief ways to increase gas mileage is to reduce the weight of the car. So manufacturers have naturally looked to magnesium as well as aluminum and plastics to replace some components that were previously made of heavier materials such as steel. Aluminum still far outweighs magnesium use in cars, with the average North American automobile containing 200 to 250 pounds of aluminum and magnesium accounting for about 61/2 pounds, according to industry groups.
Though magnesium’s share is small, experts are quick to point out that 15 years ago there were essentially no magnesium parts in North American automobiles, so even this modest figure represents a significant shift in material use.
Not that magnesium use in cars is a totally new event. All post-1951 models of the lovable Volkswagen Beetle, a marvel of efficiency and light weight, boasted approximately 40 pounds of magnesium, mostly in engine and transmission parts, according to Bob Brown, publisher of Magnesium Monthly Review (Greenville, S.C.).
Magnesium was also used briefly by Chrysler in some of its cars in the 1950s, albeit not in appreciable amounts, Brown says. It wasn’t until the early 1980s that the Big Three automakers, compelled by the CAFE standards, began turning to magnesium in their lightweighting efforts, he notes.
In addition to its lightness and strength-to-weight ratio, magnesium offers several other “sideline benefits” in automotive applications, Brown says. Most notable is its effectiveness at dampening vibrations, which can come in handy when used in dashboards that hold increasingly sophisticated automotive stereo components.
Some magnesium alloys also have the tendency to bend rather than break on impact, thus stoking interest in magnesium-cast steering wheels and related components, Brown observes.
Some industry experts also report that magnesium castings can be made with greater precision than their aluminum equivalents and therefore tend to require less machining for a perfect fit. Plus, they add, magnesium lends itself readily to large, single castings that reduce assembly time. Incorporating several of these advantages is a new cast magnesium instrument panel developed by a Canadian magnesium die caster for use in General Motors automobiles slated for production next year.
Clearly, interest in and use of magnesium die castings by the automotive industry is “going faster now than ever before,” says Brown. But why wasn’t it used widely prior to about 15 years ago?
One reason is that the older generation of automotive engineers had less incentive to use the metal and a preference for other materials. Today’s young crop of automotive engineers and designers, in contrast, are talking a lot about magnesium and abandoning some of the prejudices of their predecessors, Brown says.
The chief concern about using magnesium, however, pertains to its notorious flammability. Magnesium’s tendency to burn with a brilliant white light under certain conditions, in fact, is the very reason it’s used in pyrotechnics and flash photography. So naturally, justified or not, concerns about fire are closely associated with magnesium in discussions about producing primary metal, making die castings, handling scrap, or speculation that magnesium castings in an automobile could ignite under crash conditions.
While precautions must be taken to assure fire safety when handling magnesium in some instances, it’s only risky in its molten state or as turnings or other finely divided bits of the metal, explains Brown, who adds that a magnesium casting is no more flammable than any other metal casting. Tests conducted by a number of magnesium producers and die casters back up the safety of the metal in automotive and other applications. As Brown points out, “The Volkswagen Super Beetle had more than 55 pounds of magnesium and it experienced no increased flammability risk.”
Mag Economics
When choosing which metal to use, the bottom line for automakers and other manufacturers is the cost of one versus another.
While demand for magnesium—particularly for use in automotive die-casting applications—is expected to continue growing, it’s a common refrain that the relatively high price of primary magnesium may stunt its growth. Generally, magnesium costs about twice as much as aluminum, its closest competitor, with the recent magnesium price running about $1.60 a pound as opposed to aluminum at around 75 cents a pound.
Such wasn’t always the case. The price of magnesium rose dramatically in the mid-to-late 1970s, quadrupling between 1973 and 1986. So, while magnesium has made great strides in automotive applications during the time of this price runup, its price remains a stumbling block to its increased use in die castings. In fact, Terry Horth, a metal buyer for Meridian Magnesium Products, a Strathroy, Ontario-based company that specializes in magnesium die castings for the automotive industry, believes that if magnesium “stays at this price, it’ll be difficult for growth to continue because the price of aluminum is creating a competitive problem for magnesium.” Plus, he adds, the tight supply market in 1995 cooled some carmakers’ interest in ratcheting up their use of magnesium die castings as fears about available supply combined with these price concerns.
Horth isn’t alone in his bearish outlook. Growing demand for magnesium in both automotive and other applications in the past 15 years or so has been bumping at the ceiling of available supply and thus running up prices for the metal, creating a disincentive to use magnesium when cheaper, more plentiful alternatives are available, according to industry experts. Add to this fears that the relatively few North American magnesium die casters may not be able to meet the high volume demands of the automakers, and it’s easy to see why some car manufacturers are reticent to commit to dramatic increases in the use of magnesium in the short term.
On the bright side, several new primary magnesium producing operations have come online worldwide and a few more are slated to be opened in the next year or two. These operations are expected to ease primary magnesium supply concerns and help stabilize the metal’s price at a lower level that will be more palatable to automobile manufacturers.
To secure a piece of the growing magnesium pie, some carmakers have forged close alliances with magnesium producers and die casters. Volkswagen, for one, has claimed a sizable share of the output of business partner Dead Sea Magnesium Ltd., a new magnesium producer in Sodom, Israel.
Under the agreement, Volkswagen is reportedly entitled to 35 percent of the facility’s production, estimated at 27,500 mt a year with the potential to expand to 55,000 mt annually by 2000. If nothing else, these types of deals suggest that the auto industry is committed to including magnesium in its metal mix in the future.
More Use, More Scrap
With prices fairly high for magnesium and the supply of primary metal still somewhat questionable, there has been more interest in magnesium recycling. Another factor boosting magnesium recycling is that, as with most other metals, reclaiming and using secondary magnesium requires only a fraction of the energy required to produce and use primary metal.
Magnesium recycling in the United States, in particular, has shown steady growth in the past several years, with most of the recovered metal being prompt scrap from manufacturers and die casters. Of note, some figures estimate that current magnesium manufacturing processes result in as much as 30 to 50 percent of the metal being scrapped.
When it comes to obsolete magnesium scrap, the most significant source has heretofore been the Volkswagen Beetle. Since most of these vehicles have already been scrapped, however, this source has all but dried up in the domestic market. On the plus side, as magnesium’s use in cars grows, there will certainly be more magnesium in the nonferrous residue of automobile shredders.
One drawback is that this metal won’t enter the scrap stream until current-model cars reach the end of their useful lives. Another concern is that magnesium looks similar to aluminum and is certainly not as familiar to sorters as aluminum.
Secondary magnesium for use in die castings has also faced some perception problems in the past, with inclusions in the metal being particularly problematic and more common with magnesium than other secondary metals. Some experts dismiss such claims, maintaining that there’s more talk about quality problems than there are actual problems and noting that processors have worked through many of the magnesium recycling challenges. In fact, says one industry executive, the car companies are working closely with secondary magnesium producers to establish strict metallurgical specifications to ensure quality die castings. And some secondary magnesium producers have run extensive tests showing that the current refining processes for recycling die-cast scrap yields magnesium that’s metallurgically comparable to primary metal and can be used to make the same products. This is certainly good news for the scrap industry and magnesium die casters.
Another plus for scrap recyclers is that remelting isn’t the only end use for secondary magnesium. Some processors, for instance, have been successful in mechanically reducing magnesium scrap die castings into powder for use in the desulphurization of steel.
An Automotive Future
For magnesium, its future demand prospects lie—not surprisingly—in the automotive industry. According to IMA, magnesium use in automotive applications is growing at a faster rate than any other automotive production material and this market represents, without a doubt, the largest market for magnesium die cast alloys.
Fueling magnesium’s popularity in this sector is the expectation of many automotive industry experts that standards akin to the CAFE requirements will become even stricter in the next decade, with European nations, in particular, ratcheting up expectations of mpg averages for passenger cars. A similar trend toward increased fuel efficiency requirements could develop in the United States, especially if Vice President Al Gore is elected president. The rationale is that he would likely boost standards to meet his green agenda.
If the fuel efficiency standards continue to ramp up, automakers will have to redouble their efforts to lightweight their vehicles, particularly if Americans continue their love affair with sport utility vehicles and other large, sporty—and gas-guzzling—automobiles.
Exactly how many pounds of magnesium will end up in the cars and trucks of the future is anyone’s guess, though one magnesium trader proclaims that “magnesium is the aluminum of the future” with regard to automotive applications. One automotive industry expert goes so far as to assert that magnesium could eventually make up as much as 300 to 400 pounds of a typical passenger vehicle.
Wishful thinking? Maybe.
But then, it wasn’t that long ago that experts scoffed about aluminum’s prospects in the auto industry, now was it? •
This enigmatic metal has been making headlines as it gains a small but growing share of the automotive die-casting market. Will this demand keep it in overdrive, or will price and supply concerns stall its potential?