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Silicon is a low density element having nonmetallic characteristics. The production of silicon from silica is discussed as is silicon refining technology. The primary uses of silicon are in the chemical, aluminum, and electronics industries. Silicon is the chemical precursor of silicones, a versatile, fast‐growing market, and of advanced ceramics such as silicon nitride. Silicon forms an integral part of the aluminum parts industry; aluminum–silicon alloys are readily cast. Silicon is also important to aluminum production. Silicon forms alloys with a large number of metallic elements. Many of these alloys are of utmost importance to the production and refining of irons and steels. The most prevalent are the ferrosilicons, production of which is discussed.

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Silicon, a low density chemical element having nonmetallic characteristics, is the second most abundant element in the lithosphere (after oxygen). Silicon occurs naturally in the form of oxides and silicates and constitutes over 25% of the earth's crust. The production of silicon from silica and silicon refining technology are discussed in this article as well as the primary uses in the chemical, aluminum, solar electronics, and ceramic industries are also discussed. Silicon is the chemical precursor of silicones, a versatile, fast‐growing market, and of advanced ceramics such as silicon nitride. It forms alloys with a large number of metallic elements; many of these alloys are of importance to the production and refining of irons and steels. The most prevalent are the ferrosilicons, production of which is discussed. Silicon is also one of the leading elements used for making photovoltaic cells for conversion of sun light to electricity and for manufacturing semiconductors in the electronics industry.

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Silicon is a low density element having nonmetallic characteristics. The production of silicon from silica is discussed as is silicon refining technology. The primary uses of silicon are in the chemical, aluminum, and electronics industries. Silicon is the chemical precursor of silicones, a versatile, fast‐growing market, and of advanced ceramics such as silicon nitride. Silicon forms an integral part of the aluminum parts industry; aluminum–silicon alloys are readily cast. Silicon is also important to aluminum production. Silicon forms alloys with a large number of metallic elements. Many of these alloys are of utmost importance to the production and refining of irons and steels. The most prevalent are the ferrosilicons, production of which is discussed.

By DISCLAIMER~s repon was pepared as an account of work sponsored b) an agency of the Uruted Sues Govcmmmt Neither the Umted States Government nor an) agency thereof. nor an) of theu employees. makes any warranty. express or imphed or assumes any iegal Labihty orresponshht). for the accuracy, completeness. or usefulness of any m f o m o n . apparatus, product or process d~sclosed. or EXECUTIVE SUMMARYSilicon and Ferrosilicon Industries in North America have been on the decline for more than a decade, primarily as a result of the availability of low cost import silicon and ferrosilicon.Although the world demand for silicon is increasing, the high energy and feedstock costs associated with current production methods continue to place North American producers at a disadvantage.Silicon is conventionally produced by carbothermic reduction of silica in large open submerged arc ac furnaces. The process off-gas, primarily carbon monoxide, is lost by combustion on top of the bed. This loss can be eliminated by enclosing the furnace with a cover and processing the off-gas in a sealed system. Electrode cost, which represents a significant portion of the variable cost for the production of silicon, can be significantly lowered by smelting in a direct current (dc) system; particularly in a closed dc system.The construction and operation of a 6 MW, closed dc furnace for smelting silicon was the primary focus of Phase 111. A 6 MW, dc closed furnace pilot plant was built in East Selkirk, Manitoba, Canada. The furnace is equipped with world's most modern automatic control system used to control and monitor the process variables and operational data. This control system is suitable for commercial applications and could be used with either closed or open dc furnaces for smelting silicon or ferrosilicon. The construction was started in September 1990, and the facility was operational within 18 months. Following successful commissioning of the pilot plant in June 1992, twelve smelting test campaigns were conducted through November 1994.The first three tests designated as "start-up commissioning runs" were made to demonstrate equipment operation, and resolve any operating problems. The furnace-bottom anode, a critical part of the furnace, was successfully developed and a potentially patentable anode design has emerged through three generations of anode modifications. Anode technology is a key element in successful commercialization of dc silicon smelting technology.Test runs 004-01 2 provided the operating experience for managing carbon theory and optimizing feed rate as a function of power input. Managing the flow of raw materials to the smelting zone remains a problem inspite of modifLing the mix-movement system. The issue of mix-movement is considered to be a consequence of a closed furnace operation. In a semi-closed vi or an open dc furnace, the mix-movement should not be a problem and could be handled as with conventional open, alternating current (ac) furnaces.The targets for electrode consumption in...

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