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Bureau of Mines / Minerals yearbook metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)

Shekarchi, E.
Silicon,   pp. 1123-1128 PDF (495.5 KB)


Page 1123

  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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