The Latest Thing

I monitor various news, geology, and materials sources for hot topics to include in What Things Are Made Of. My latest discovery is a wonderful compound, copper indium gallium diselenide, with the unfortunate acronym CIGS.

Indium, gallium, and selenium often combine to generate light when electricity flows through them—variations on that list, often including arsenic, power lots of LEDs (light-emitting diodes) in all sorts of products from hand-held calculators to traffic signal lights.

Dow Chemical in Midland, Michigan, announced their brand of CIGS solar panels last October. They aren’t your traditional solar panels—these are thin films encased in plastic that can be embedded in asphalt shingles. Roofing contractors can install them—no need for specialized solar technicians. No offense to solar technicians, but this should make the panels cheaper to install. Dow hasn’t said what they’ll cost, but they should be on the market by mid-2010.

Indium forms few minerals, and most indium is a byproduct of zinc smelting. Indium supply follows the ups and downs of the zinc industry, which in turn depends largely on large-scale steel galvanizing. Industrialization in China and India, calling for more and more galvanized (zinc-coated) steel communication towers and highway barrier systems, isn’t the controlling factor behind zinc consumption, but it is an important aspect of it.

China leads the world in indium production, and also leads in supplying imports to the United States which is 100% dependent on foreign sources for indium. Likewise, virtually all gallium used in the U.S. is imported, in almost equal proportions from China, Ukraine, Germany, and Canada. Processing bauxite to produce aluminum yields most of the world’s gallium. Selenium is also a byproduct, usually of copper refining. One refinery, ASARCO’s 11-acre building near Amarillo, Texas, produces all primary domestic selenium, but the U.S. also imports nearly 600 tons per year, mostly from copper refineries in Belgium.

Some estimates suggest that indium demand could increase ten-fold over the next five years because of increased CIGS solar panel usage. If that happens, look to China for supplies—China produces 58% of the world’s indium, far ahead of #2 Japan (11%). You don’t care about solar cells? How about your flat-panel TV, computer screen, iPod, and other display devices? They all require indium.

Flat-panel image from Wikipedia, under GNU Free Documentation License.