Mineral Resource of the Month: Silicon

Lisa A. Corathers, a mineral commodity specialist for the U.S. Geological Survey, compiled the following information about silicon, an extremely versatile mineral with many applications in the manufacture of iron and steel, aluminum alloys, chemicals and semiconductors.

Silicon is probably best known for its use in computer chips, but electronics only accounts for about 5 percent of silicon usage in the U.S. Credit:  Digital Vision Silicon is probably best known for its use in computer chips, but electronics only accounts for about 5 percent of silicon usage in the U.S. Credit: Digital Vision

Silicon is classified as a metalloid element because it has properties of both metals and nonmetals. As the second-most abundant element in Earth’s crust — second only to oxygen — it accounts for more than 25 percent of the crust by weight. By mass, silicon is the eighth-most common element in the universe. Yet it is rarely found free in nature. Rather, it occurs chiefly in silicate minerals, such as feldspars, hornblendes, phyllosilicates, the serpentine group of minerals and micas, and in quartz and microcrystalline forms of quartz, such as agate and flint. These minerals are found in many different rocks, including granites and schists. Sand is commonly composed of small particles of quartz. 

Silicon impacts all facets of our modern life, from electronics to steel to human health. Though perhaps best known by the public as being part of computer chips, and although its importance in electronics is undeniable, in reality, electronics account for only about 5 percent of total silicon metal consumption.Ultra-pure silicon wafers that are used in the electronics industry must be greater than 99.99 percent silicon, and are used in computer chips and some photo­voltaic cells. 

Silicon may be the second-most abundant element on the planet, but it’s rarely found alone in nature; instead it is usually found in silicate minerals or oxide minerals such as quartz, shown here. Credit: ©StoneTrust, Inc./ESW Image Bank Silicon may be the second-most abundant element on the planet, but it’s rarely found alone in nature; instead it is usually found in silicate minerals or oxide minerals such as quartz, shown here. Credit: ©StoneTrust, Inc./ESW Image Bank

Most silicon metal, however, is consumed to produce chemicals  silanes, silicones and others  as well as silica fume (76 percent of total use) and aluminum alloys (23 percent). Silica fume, a byproduct from furnaces that make silicon metal or ferrosilicon, with a silicon content of at least 75 percent, is used as a binder and filler in cement. Some silicon metal is also consumed in the manufacture of steel.

More than half of the silicon consumed yearly in the United States is in the form of ferrosilicon, which is produced from quartz or quartzite primarily for the iron and steel industries. In 2008, 61 percent of ferrosilicon in the U.S. was used to produce steel, mostly in carbon, high-strength low-alloy, and stainless and heat-resisting steels.

The U.S. produces silicon materials, but imports more than half of its annual consumption. U.S. silicon metal production data are not reported by USGS to avoid disclosing company proprietary information.

For more information on silicon and other mineral resources, visit http://minerals.usgs.gov/minerals.


SILICON PRODUCTION AND CONSUMPTION

In 2008, world production of ferrosilicon was 4.91 million metric tons “contained silicon.”

The top four ferrosilicon producers in 2008 were China, Russia, the United States and Norway. China produced 65 percent of the total.

World production of silicon metal was 1.38 million metric tons contained silicon in 2008, excluding silicon metal production in the United States. China was the top producer with 57 percent of the total.

Silica reserves in most major producing countries are ample in relation to demand, but quantitative estimates are not available.


FUN FACTS

Silicon is named after “silex,” the Latin word for flint or hard stone.

Silicon is the primary component of some types of meteorites and tektites, glassy rock remnants of impacts.

Silicon carbide — the only compound of carbon and silicon — is one of the hardest-known substances and is mainly produced artificially.

The term “Silicon Valley” was first used by Don C. Hoefler, publisher of Microelectronics News, in his Jan. 11, 1971, article entitled “Silicon Valley USA.”

Silicon has been shown to be important to bone function in animals, although it has not yet been designated an essential nutrient for humans. Silicon is found naturally in whole grains, some root vegetables and beer.

Energy Notes: June 2009-2010

 Credit: The American Geosciences Institute Credit: The American Geosciences Institute

U.S. Oil & Petroleum Imports (millions of barrels per day)

Oil and petroleum imports data are preliminary numbers taken from the American Petroleum Institute’s Monthly Statistical Report. For more information visit www.api.org.

 

 

The American Geosciences Institute

AGI was founded in 1948, under a directive of the National Academy of Sciences, as a network of associations representing geoscientists with a diverse array of skills and knowledge of our planet.

Wednesday, October 20, 2010 - 06:00

U.S. Geological Survey

The "Mineral Resource of the Month" column is written by various U.S. Geological Survey mineral commodity specialists. For more information about these and other mineral commodities, visit: USGS Commodity Statistics and Information.

Thursday, October 14, 2010 - 06:00