by U.S. Geological Survey Thursday, June 14, 2018
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 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.
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.
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.
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 on"y 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.
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