SCHOTT solutions no. 2/2016 > Products and know-how
Lithium extraction in South America: Salt water is allowed to evaporate inside a large pool until only a brine remains. Lithium carbonate is then extracted from it. Photo: Getty Images
Lithium – in greater demand than ever
The key raw material lithium is found not only in lithium-ion batteries; it is also a component of CERAN® cooktop panels and other products made of glass-ceramic that owe to it their special characteristics. The fast growing demand for lithium is causing the commodity price to climb.
Dr. Uta Neubauer
Lithium occupies a special position in the world of chemical elements. It is in third place in the periodic table, behind the gases helium and hydrogen, which makes it the first solid element. At the same time, it is the lightest metal. Lithium is currently also an exception on the commodities market. While many metals are under pressure, the prices for lithium are exploding. The reason is that battery manufacturers are buying out the market to produce lithium-ion batteries for electric vehicles, smartphones and other mobile devices. Lithium also plays a key role in many other products – from aluminum alloys to lubricants and antidepressants and products from the glass and ceramics industry.
SCHOTT uses lithium in the production of glass-ceramics, for example, for CERAN® cooktop panels, ROBAX® fire viewing windows for fireplaces, ZERODUR® glass-ceramic and for various security and fire protection glasses. ”Our glass-ceramics are based on a lithium aluminum silicate system,” explains Dr. Martin Heming, Director of Research and Development at SCHOTT. ”The glass-ceramic is initially manufactured and melted like glass and produced in the appropriate form,” he adds. Then, unlike glass production, a post-treatment takes place at 800 to 900 degrees Celsius, in which the characteristic nanocrystals are formed.
Although crystals in conventional glass are considered a defect, this does not apply to glass-ceramics. Their lithium aluminum silicate crystals have exceptional properties. They are so tiny that they refract light just like the glass phase – the glass-ceramic therefore remains transparent, despite the crystals. Especially interesting from a technical perspective is the fact that the crystals that contain lithium contract when they are heated instead of expanding like the residual glass. With a crystal content of about 70 percent, the crystal shrinkage negates the expansion of the glass phase altogether. Experts call this ”zero thermal expansion.” SCHOTT glass-ceramics are resistant to both high temperatures and heat shock. Even a red-hot glass-ceramic plate can be immersed in ice water without it warping or shattering.
A complex process takes place during the glass melt. Photo: SCHOTT/ C. Costard
Chefs and fireplace owners are not the only ones to benefit from glass-ceramics that contain lithium. The fire-resistant glass PYRAN® Platinum is also made of it so that it can withstand high temperatures and sudden cooling from extinguishing water undamaged in the event of fire. Glass-ceramics are also used in telescopes and other measurement instruments, as well as in semiconductor manufacturing, because glass-ceramics provide extremely high accuracy due to their zero expansion.
Stronger demand, higher prices
Great care should be taken when selecting the raw materials for glass-ceramics. ”Most lithium minerals do not have the quality we need for our products,” says Dr. Heming. The world’s largest mining areas of lithium are in Chile and Western Australia. In Chile, lithium is recovered from the brine of a salt lake in the Atacama Desert. Australia, on the other hand, has large mineral deposits. There are also mining sites in many other countries, from Argentina and China to Portugal and Zimbabwe. Expansion of capacities is planned in many places due to the growing demand. Production cannot be ramped up quickly, however; it still takes one to two years to put new plants into operation. The extraction from brine is also a lengthy process, since the concentration that takes place in large tanks through solar heat alone takes 12 to 18 months.
Because of booming electromobility, commodities experts predict significant supply shortages in the years to come. This means that prices for lithium compounds will increase significantly. The prices of high-purity lithium carbonate, a lithium compound that is commonly used in industry, are already skyrocketing – at times by more than a factor of four. With the expansion of production capacities in the next few years, the sharp price increases are likely to subside a bit. According to analysts at Deutsche Bank, the price of lithium will settle at a high level starting in 2020.
Lithium carbonate is an important raw material for many glass and glass-ceramic products. Photo: SCHOTT/A. Sell
The recovery of lithium from old batteries could contribute to the easing of the market. But recycling is complicated, says Dr. Heming: ”There are a few pilot projects, but no industrially suitable methods yet.” Ultimately, the batteries of the future will hardly function without lithium, just like production of cooktop panels, fire viewing panels and the like. According to Dr. Heming, there is no alternative to lithium: ”We need a small, highly polar ion which fits into the crystal just perfectly for our glass-ceramics.” And the periodic table of chemical elements does not yet have a replacement to offer for the special lithium element. —