Underground reconnaissance: Looking for lithium02-08-12
Treasures from the deep: Mayor Thomas Kirsten, Prof. Armin Müller, Kersten Kühn from GEOS, doctoral candidate in geology Jörg Nessler from TU Freiberg, and employees from the drilling company present the first cores containing lithium
Very little of what was actually going on could be seen: a diagonal drill rod, a work platform, and a truck were all that made up SolarWorld AG’s reconnaissance drilling operation in Zinnwald, eastern Saxony. Below ground, the drillers worked down to a depth of 250 meters to explore the 1200-meter-long and 500-meter-deep lithium deposit.
In March 2011, SolarWorld AG was granted exploration rights to search for the strategically important raw material in the region, which has a long mining tradition.
“The deposit was drilled extensively when the region was still part of the German Democratic Republic, but there remain gaps in the data, which the core samples will fill: How large is the deposit? How much lithium is there? How can it be excavated? What logistics are needed above and below ground?” explained Kersten Kühn from the engineering firm GEOS, which is conducting the project in partnership with SolarWorld Solicium GmbH and Bergakademie Freiberg.
The drilling engineers drilled through the rock mass from two sides at a rate of ten to 15 meters a day. The 101-millimeter-wide core drill hit the layer containing lithium at a depth of around 73 meters. Whitish-gray specks in the stone indicate that it contains zinnwaldite, the mineral that contains lithium. The fact that the core drill was run diagonally underground reflected Zinnwald’s centuries-old mining history: “Below us is a 500-year-old gallery and exhibition mine, which we of course had to bypass. Moreover, we would encounter technical problems if the drill suddenly drilled into unknown cavities,” said Kühn.
The core samples, clearly marked and packed into long wooden boxes, are being sent to a certified lab in Canada, where the lithium content will be tested. The chemists will analyze the samples for other valuable elements like wolfram, cesium, scandium, and indium, which can also be extracted.
What happens thereafter will be based on the results of the deposit survey and chemical analyses, explained Prof. Armin Müller, CEO of SolarWorld Solicium GmbH, which is responsible for SolarWorld’s lithium activities. “If our expectations are correct, we will estimate the costs of excavating, preparing, and chemically processing the material to obtain lithium carbonate.” The global market price of lithium carbonate, which is currently US$ 6000 to 7000 per metric ton, will determine whether the project is economically viable. Approximately 40,000 metric tons of lithium are expected on the German side and another some 80,000 metric tons on the Czech side, where SolarWorld has been working together with Czech partners to explore. Experts predict that the real amount could even be twice as high.
If the profitability analysis proves promising, the next step will be to plan the equipment for extracting and processing the lithium. The final step will involve setting up the mine and chemical processing equipment. “We can expect the feasibility study by late 2012 at the earliest. Then we will need roughly two years to construct the building, which means we can expect production to begin in early 2015,” says Müller. That’s good news for Altenberg’s mayor, Thomas Kirsten, since the mine could bring 250 to 300 new jobs to the region.
From lithium …
Lithium is a whitish-silver light metal and is considered the raw material of the future since it is the most important component of lithium-ion batteries in cell phones and laptops. With its high energy density and low weight, it also supplies mobile energy in the electric and hybrid cars of the future. Roughly 80 to 130 grams of pure lithium in metal or lithium compound are needed per kilowatt-hour of storage capacity, depending on the type of battery. There are an estimated 29 million metric tons of lithium on earth.
… to carbonate
First, the material is pulverized, and then the zinnwaldite is separated from the non-magnetic stone. Next, in a process called flotation, the components of the mineral, which have different weights, attach to small gas bubbles in water. The bubbles rise to the surface, and the froth is skimmed off. The lithium is then leached from the mineral. These lithium-containing solutions are then chemically processed, creating lithium carbonate.