Bureau of Mines / Minerals yearbook: Metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)
Silicon, pp. 1123-1128 PDF (495.5 KB)
1123Silicon By E. Shekarchi' Major domestic producers of ferrosilicon and metallurgical-grade silicon engaged during 1972 in expansion toward specialization, and/or plant modernization to coinply with 1975 antipollution standards set by local governments and the Federal Government. Domestic production of ferrosilicon and silicon metal in 1972 increased sharply to meet the rising demands of a wide variety of products. However, increased production of ferrosilicon and silicon metal throughout the world led to severe price erosion both domestically and internationally. High-purity and ultra-high-purity silicon metal, though small in volume, continued to be an important element in the electronics industry; shipments were up 18%. The new demand for silicones as sealants for encapsulation of electric parts greatly increased during the year. DOMESTIC PRODUCTION On a gross weight basis, net production of ferrosilicon and silicon metal increased 18% in 1972 while shipments were 23% higher than in 1971. Silicon metal for metallurgical uses was produced at 11 plants of seven companies as shown in table 2. Northwest Ahoy, Inc., a newly formed subsidiary of Aluminum Co. of America (Alcoa), planned construction of a magnesium and silicon plant at Addy, Wash. Initial plant capacity will be 24,000 -tons per year, and the final annual capacity will reach 40,000 tons. The plant will be the first of its kind in -the United States to employ the megatherm (electrothermal) process with dolomite as raw material. This process, in operation at Marignac, France, since 1964, involves the reduction of calcined dolomite by ferrosilicon at a temperature in excess of 1,500° C. The magnesium and silicon metal extracted will be used by Alcoa and will make the company nearly self-sufficient in silicon metal. The Adcly plant was scheduled to begin operation in 1975. It is to be -the most modern and efficient environmentally controlled facility of its kind. Total cost has been estimated at $50 million. 1 Physical scientist, Division of Ferrous Metals. Table 1.—Production, shipments, and stocks of silvery pig iron, ferrosilicon, and silicon metal in 1972 1 (Short tons, gross weight) Alloy Sificon content (%) Producers' stocks as of Dee. 31, 1971' Produc- tion Shipments Producers' stocks as of Dec. 31, 1972 Silvery pig iron Ferrosilicon (includes briquets) Do Do Do Silicon metal (excludes semiconductor grades) Miscellaneous silicon alloys (exclusive of silicomanganese) Other silicon alloys and products 5-24 25—55 56-70 71-80 81—95 96—99 - - W 66,134 14,812 27,688 2,144 13,028 10,136 2,622 W 491,967 59,672 109,961 9,089 116,376 58,282 8,788 W 421,200 63,145 109,176 9,889 107,151 52,515 8,526 W 58,200 10,025 24,706 1,312 7,456 10,568 2,832 ' Revised. W Withheld to avoid disclosing individual company confidential data. ' Excludes ferrosilicon used to make other silicon alloys.
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